INTRODUCTION
Acute lower gastrointestinal bleeding (LGIB) is one of the most common reasons for hospitalization in the United States due to a digestive disorder, accounting for over 100,000 admissions annually (1 2
The purpose of this document was to update the previously published 2016 American College of Gastroenterology (ACG) LGIB guideline (3 colonoscopy and computed tomography angiography (CTA), and the data on urgent vs elective inpatient colonoscopy . We will conclude by reviewing endoscopic hemostatic options and risk and benefits of resumption of antithrombotic medications after cessation of bleeding. We will focus the discussion on updates to management since the previous guideline was published.
METHODS
The panel members formulated clinically pertinent questions related to the management of LGIB framed in the PICO (population, intervention, comparator, and outcome) format. With the assistance of 2 medical librarians, a systematic English-language literature search of bibliographic databases (including EMBASE, Ovid MEDLINE, and ISI Web of Science) was performed from March 2, 2015, through December 1, 2021, for each PICO question. March 2 was chosen as the beginning date because this was when the literature search ended for the previous guideline (3 4
Each recommendation (Table 1 ) includes an assessment of the strength of the recommendation and the quality of evidence based on the GRADE methodology, followed by a summary of the evidence (5
Table 1.: Summary and strength of recommendations
Key concepts are statements that are not amenable to the GRADE process because of the structure of the question and/or limited available evidence. Most key concepts represent expert opinion based on extrapolation of the available evidence. Table 2 summarizes the key concepts in this guideline. Each PICO question, along with the specific literature search strategy and evidence tables, is provided in the Supplementary Material (https://links.lww.com/AJG/C827 https://links.lww.com/AJG/C828
Table 2.: Key concepts
These guidelines are established for clinical practice with the intent of suggesting preferable approaches to particular medical problems as established by interpretation and collation of scientific valid research, derived from extensive review of published literature. When exercising clinical judgment, healthcare providers should incorporate this guideline along with the patient's needs, desires, and their values to fully and appropriately care for patients with LGIB. This guideline is intended to be flexible, not necessarily indicating the only acceptable approach, and should be distinguished from standards of care that are inflexible and rarely violated.
EPIDEMIOLOGY AND RISK FACTORS
LGIB remains one of the most common reasons for hospitalization in the United States due to a digestive disorder. In 2018, there were 271,575 emergency department (ED) visits and 113,020 hospital admissions for LGIB listed as a primary diagnosis (1 6
Epidemiologic studies indicate that the incidence of LGIB may be rising relative to the incidence of UGIB. In a Finnish population-based cohort study, the incidence rate of LGIB was significantly higher than that of UGIB (1.26 per 1,000 person-years; 95% confidence interval [CI] 1.15–1.38 compared with 0.94 per 1,000 person-years; 95% CI 0.85–1.04) (7 8 9–11 12 13
Risk factors of the onset of LGIB include antiplatelet use, including aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and P2Y12 inhibitors such as clopidogrel. In a population-based study of nearly 200,000 new users of low-dose aspirin, the incidence of LGIB was 1.68 per 1,000 person-years and was higher than that of UGIB. Importantly, case-fatality rates were very low for LGIB (<1%), and the majority were managed as outpatients (14 15 16 Helicobacter pylori eradicated (17 18–20 21 22 23,24
There are less data establishing systemic oral anticoagulants as risk factors of LGIB. Vitamin K antagonists (VKAs) are known to increase the risk of all-cause GI bleeding (GIB) by 3-fold compared with placebo (25 26,27 26 28 27
As compared with antiplatelet drugs, DOACs have not been shown to increase the risk of new-onset diverticular hemorrhage (29 30,31 32
For patients with known underlying diverticulosis, data are lacking regarding the risks of subsequently experiencing a diverticular hemorrhage. In a long-term Japanese cohort study of patients with colonoscopy -confirmed asymptomatic diverticulosis, the cumulative risks of new-onset diverticular hemorrhage was 0.21% at 1 year, 2.2% at 5 years, and 9.5% at 10 years, with an overall incidence rate of 0.46 per 1,000 patient-years. Variables that were predictive of new-onset diverticular bleeding included age older than 70 years and presence of right and left-sided diverticulosis (33 34,35
ETIOLOGY OF LGIB
LGIB comprises a heterogeneous group of etiologies, each with a distinct pathophysiology and clinical course. Although diverticular bleeding is the most common cause of LGIB (36 colonoscopy as well as the definition of diverticular bleeding. Defining a source of LGIB as diverticular in the absence of stigmata of hemorrhage (SRH) can be challenging because there is significant variability between institutions in the extent of additional diagnostic workup performed to exclude an upper or small bowel source of bleeding. In the UK audit of patients presenting with LGIB, diverticular bleeding was the most common cause of LGIB, representing 26.4% of cases (13 colonoscopy was performed in 88% of patients, diverticular bleeding was responsible for 64% of all cases; this included patients with definitive diverticular hemorrhage where SRH was seen at a diverticula or presumed diverticular hemorrhage based on a colonoscopy demonstrating diverticulosis and no other source of bleeding being found (37 36–38 colonoscopy , no source of bleeding is often found for patients admitted with LGIB. In fact, 23% of patients with LGIB in the UK audit had no diagnosed etiology of bleeding (13 colonoscopy was used only in 4% of the cohort, limiting the overall generalizability and reflecting wide variation in the approach to investigation and management between countries. In cohorts with high utilization of colonoscopy , the rates of undiagnosed bleeding are as low as 5% (37
INITIAL MANAGEMENT
Initial triage/evaluation
Key concepts
1. A focused history, physical examination, and laboratory evaluation should be obtained at the time of patient presentation to assess the severity of bleeding and its possible location and etiology. Initial patient assessment and hemodynamic resuscitation should be performed simultaneously.
A thorough history and physical examination is needed to determine potential sources of bleeding and help identify patients at risk of severe bleeding and adverse outcomes such as rebleeding and mortality. Pertinent components of the history should include but not be limited to the presence of cardiovascular, oncologic, or renal comorbidities; prior GI surgeries; and associated symptoms such as abdominal pain, alteration in bowel habits, or unintentional weight loss. Physical examination should include careful attention to vital signs and assessment for signs of hypovolemia, which will help dictate resuscitation. Careful rectal examination can help determine whether a bleeding source may be emanating from the anorectal region or indicate the presence of melena, which may increase the likelihood of an UGIB. Medications should be reviewed to determine the presence of NSAIDs, antiplatelets, and anticoagulants. History and examination findings such as a preceding history of decompensated liver disease or prior peptic ulcer disease along with epigastric discomfort on examination or visible stigmata of advanced liver disease may indicate the possibility of an upper GI source of bleeding in a patient with severe hematochezia.
Risk assessment
Recommendations
1. We suggest using risk stratification tools (e.g., Oakland score ≤8) to identify low-risk patients with LGIB who are appropriate for early discharge and outpatient diagnostic evaluation. Risk scores should be used to supplement but not replace clinician judgment. (Conditional recommendation, low-quality evidence)
Initial risk assessment is increasingly important to identify patients who are at either low or high risk of requiring a hospital-based intervention. Patients identified as being low-risk for requiring a hospital-based intervention can be observed and managed conservatively and potentially be discharged from the hospital with early outpatient follow-up, thereby allowing for preservation of scarce resources and significant cost savings.
Low-risk clinical prediction tools are widely used in patients with UGIB. The Glasgow Blatchford Score (GBS) was derived and validated to identify patients with UGIB who would require a hospital-based intervention (39 4 Table 3 ). Investigators then externally validated this score in 288 additional patients with LGIB at 2 UK hospitals and found that age, sex, history of LGIB, rectal examination findings, heart rate, systolic blood pressure, and hemoglobin level strongly discriminated safe discharge in both derivation and validation cohorts. These components made up the Oakland score; a score of 8 or less predicted a 95% probability of safe discharge (40 41 42,43 2 PE score using a retrospective cohort of 581 patients with LGIB; independent predictors of low-risk patients who did not require a hospital-based intervention included systolic blood pressure ≥100 mm Hg, hemoglobin level >12 g/dL, nonuse of antiplatelets and anticoagulants, and pulse <100 (44 2 PE incorrectly classified 14 patients who required a hospital-based intervention as being low-risk (45
Table 3.: Validated clinical prediction tools in LGIB to predict patients at low risk of hospital intervention
Both of these tools are promising and may help identify patients who are low-risk for requiring a hospital-based intervention; patients identified as being low-risk who do not have ongoing bleeding and have had a recent, high-quality colonoscopy excluding etiologies such as colorectal neoplasia may be discharged early from the hospital with outpatient follow-up, thereby avoiding potentially unnecessary inpatient colonoscopy . At present, we lack prospective, multicenter studies demonstrating that using either the Oakland score or the SHA2 PE score in the ED is a safe and effective strategy to manage patients with LGIB in the outpatient setting. Before widespread implementation of this score, further multicenter data on utilization of Oakland score thresholds to guide early discharge are needed to demonstrate that rebleeding rates are low and outpatient follow-up is achievable with minimal loss to follow-up (46
Although several clinical prediction scores have been derived and validated to predict the risk of severe bleeding and adverse outcomes in LGIB, these tools are not widely used by clinicians. The NOBLADS score was derived and validated with the goal of predicting patients at increased risk of severe bleeding; this outcome was defined by continuous bleeding during the first 24 hours (transfusion of ≥2 units of packed red blood cells [PRBCs] and/or a decrease in hematocrit of ≥ 20% from baseline) and/or recurrent bleeding after initial colonoscopy . The NOBLADS score predicted severe bleeding with an AUROC of 0.77, and higher NOBLADS scores were associated with the need for PRBC transfusion, long hospital stay, and requirement of intervention (47 48 colonoscopy .
Several additional scores have been derived and validated to predict adverse outcomes in LGIB. The Birmingham Score, comprising sex and admission hemoglobin level, was found to predict a composite adverse outcomes in LGIB, including need for PRBC transfusion, endoscopic intervention, CTA, surgical intervention, rebleeding, and mortality (49 50 51
At present, no score is widely used to predict adverse outcomes in LGIB. A prospective study of 170 patients with LGIB comparing a variety of pre-endoscopic scoring systems demonstrated that no score had an excellent predictive ability across all important outcomes in LGIB, including severe bleeding, need for PRBC transfusion, in-hospital recurrent bleeding, and need for endoscopic intervention (52 53,54 55
Risk prediction scores should not be used to replace clinical judgment and should likely be used as a supplemental tool in decision making. The likelihood is that clinical prediction scores are unlikely to be widely used unless they are automatically calculated in the electronic health record and then used to alert physicians as to the patient's individual risk (either low risk or high risk), thereby subsequently triggering specific pathways of management (56
Hemodynamic resuscitation
Key concepts
2. Patients with hemodynamic instability and/or suspected ongoing bleeding should receive intravenous fluid resuscitation with the goal of optimization of blood pressure and heart rate before endoscopic evaluation/intervention.
Recommendations
2. We suggest a restrictive strategy of red blood cell transfusion (threshold for transfusion at a hemoglobin level of 7 g/dL) in hemodynamically stable patients with LGIB. (Conditional recommendation, low-quality evidence)
Patients who are hemodynamically unstable should receive intravenous fluid resuscitation with crystalloids with the goal of normalization of blood pressure and heart rate before any diagnostic or therapeutic intervention. In addition, patients with significant hematochezia with reduction in hemoglobin levels may require PRBC transfusion. Data on transfusion targets in LGIB are extrapolated from the UGIB literature. The benefit of a restrictive transfusion strategy was seen in a RCT of patients with UGIB; a restrictive transfusion strategy (hemoglobin threshold for transfusion of 7 g/dL) compared with a liberal transfusion strategy (hemoglobin threshold for transfusion of 9 g/dL) was associated with a significantly improved survival at 6 weeks, with a lower risk of further bleeding (57 58 59 60 4
Exclusion of proximal source of bleeding
Key concepts
3. Hematochezia associated with hemodynamic instability may be indicative of an UGIB source, and an upper endoscopy should be performed if the suspicion is high to exclude a proximal source of bleeding.
For patients presenting with severe hematochezia, the possibility of a brisk, proximal source of bleeding should be considered, based on other clinical factors. In a study of 85 patients presenting with hematochezia and high-risk features who underwent esophagogastroduodenoscopy (EGD) before colonoscopy , 15% had a proximal source of bleeding (61 62 63 64
Nasogastric aspirate has very poor sensitivity to establish an upper GI source of bleeding. In a retrospective cohort of patients with melena undergoing nasogastric aspirate, the sensitivity of nasogastric aspirate to establish an upper GI tract of bleeding was only 28%, and the negative predictive value was <1% (65 66 colonoscopy or radiologic testing such as CTA in patients with severe hematochezia, clinicians ultimately should determine the pretest probability of an UGIB source based on clinical history and laboratory findings and perform an urgent EGD if the risk is considered high.
REVERSAL OF COAGULOPATHY AND MANAGEMENT OF ANTITHROMBOTICS
Management of patients on VKAs
Key concepts
4. Endoscopic hemostasis can be considered safe and effective in patients who have an international normalized ratio (INR) of 2.5 or less.
Recommendations
3. Although most patients with LGIB on VKAs are unlikely to require reversal, we suggest reversal of patients who present with a life-threatening LGIB and have an INR substantially exceeding the therapeutic range. For patients on VKAs to prevent stroke in nonvalvular atrial fibrillation who require reversal, 4-factor prothrombin complex concentrate (PCC) is preferred to fresh frozen plasma (FFP) because of the rapidity of INR reduction (Conditional recommendation, very low-quality evidence).
For patients presenting with LGIB on VKAs, the decision whether to reverse anticoagulation should be dependent on the patient's hemodynamic stability, severity of bleeding, and laboratory parameters including the INR level. In patients with minor bleeding who are unlikely to require a hospital-based intervention (e.g., Oakland score ≤8), oral anticoagulants may be continued if necessary. For patients with more significant bleeding requiring hospitalization, oral anticoagulants should be held at admission. In an analysis of 512 patients with GIB who were on warfarin or dabigatran in 5 phase III clinical trials, 26% were managed with discontinuation of the drug only (67 68
For patients with hemodynamic instability and severe bleeding, reversal of anticoagulation may be warranted; options for reversal include vitamin K, FFP, and 4-factor PCC. European guidelines recommend administering vitamin K along with PCC (strong recommendation, low-quality evidence) or FFP if PCC is unavailable (weak recommendation, very low-quality evidence) for patients with hemodynamic instability (43,69 70
Consideration should also be given to the degree of INR prolongation, severity of bleeding, as well as timing of any diagnostic and therapeutic procedures. Endoscopic therapy is effective even at moderately elevated INR levels (2.5 or less); however, reversal agents should be considered before endoscopy in patients with severe bleeding with hemodynamic instability and significant prolongation in INR substantially exceeding therapeutic levels. Importantly, INR at the onset of GIB or immediately before endoscopy has not been shown to be associated with rebleeding risk, and no significant difference in rebleeding has been seen between patients with an INR of <2.5 compared with >2.5 (71
Data are extremely limited in LGIB specifically on the use of PCC vs other strategies for anticoagulant reversal, despite reversal agents being used relatively commonly. In a multicenter, observational study of patients presenting with major bleeding on warfarin (52% of whom had GIB), 31% of patients received FFP compared with 23% of patients who received PCC (72 73 74 75 76 77 78
Data are clearly needed to help guide reversal strategies in LGIB-specific populations. However, based on its safety profile and the current available data, PCC should be considered as a first-line reversal option in unstable patients with severe, life-threatening LGIB despite resuscitation who have significant prolongation in their INR.
DOAC reversal
Recommendations
4. For patients on DOACs, we suggest reversal for the small subset of patients who present with a life-threatening LGIB that does not respond to initial resuscitation and cessation of the anticoagulant alone. For patients requiring reversal, targeted reversal agents (idarucizumab for dabigatran and andexanet alfa for apixaban and rivaroxaban) should be used when available if the DOAC has been taken within the past 24 hours (Conditional recommendation, very low-quality evidence).
Similar to the management of patients on VKA with LGIB, patients presenting with minor bleeding and who are at low risk of a hospital-based intervention on DOACs can likely have their medications continued. Patients with significant LGIB who are more likely to require an intervention should have their DOACs held at admission. Although data are lacking in the LGIB literature, it is likely that most patients with significant LGIB can likely be managed by holding the drug, adequate resuscitation, and waiting for the anticoagulant effect to dissipate.
Assessment of the anticoagulant effect on GIB using laboratory parameters such as prothrombin time and activated partial thromboplastin time should be considered, although interpretation of the levels and the need to obtain more specialized tests such as anti-factor Xa levels may depend on test availability and the specific clinical situation. Interpretation of prothrombin time and activated partial thromboplastin time may be limited because normal levels do not exclude clinically relevant levels of apixaban or rivaroxaban.
For patients with severe LGIB who have hemodynamic instability, there may be a role for reversal of the DOAC. There is limited benefit of vitamin K, FFP, or cryoprecipitate for the management of DOAC-related LGIB. However, targeted reversal agents are available at present, although data are lacking in patients with LGIB. The specific reversal agents idarucizumab and andexanet alfa have both been assessed in patients with DOAC-associated major bleeding (79,80 81 82 83 84
At present, there is no definitive role for PCC in reversal of factor Xa inhibitors. In a systematic review and meta-analysis, 10 case series of 340 patients were identified who received PCC for reversal of the DOAC effect; the pooled proportion of effective hemostasis achieved was 69%. In addition, there was very little certainty based on single-arm case series, and it was impossible to determine whether PCC administration was superior to cessation of the factor Xa inhibitor alone (85
Management of antiplatelets in an acute setting
Key concepts
5. Platelets should be administered in the setting of severe LGIB to maintain a platelet count of >30 × 109 /L, and a higher threshold of >50 × 109 /L can be considered if endoscopic procedures are required. There is no benefit to routine platelet transfusion for patients on antiplatelets.
6. For patients with LGIB on cardiac aspirin for secondary prevention, aspirin should be continued during hospitalization if possible. Nonaspirin antiplatelets should be held initially for patients with severe hematochezia. However, for patients with recent cardiac stents within 1 year, a multidisciplinary approach should be used to determine the safety of temporarily holding antiplatelets.
There are limited data on the management of antiplatelets in the acute setting of a patient presenting with significant LGIB. Empiric transfusion of platelets is not recommended for patients on antiplatelets. In a case-control study of patients with GIB on antiplatelet agents without thrombocytopenia, patients receiving platelet transfusion had no benefit in rebleeding and had higher mortality compared with controls with GIB who did not receive platelet transfusion (86 9 /L is recommended, and a higher threshold of >50 × 109 /L can be considered if an invasive procedure is required (87 88
Data on the safety and efficacy of endoscopic therapy on antiplatelets are sparse. In a multicenter study of patients with UGIB, patients on antithrombotics at the time of UGIB had similar rates of rebleeding after endoscopic intervention compared with those not on antithrombotics (89 90
Role of antifibrinolytic agents
Recommendations
5. We recommend against the administration of antifibrinolytic agents such as tranexamic acid in LGIB. (Strong recommendation, moderate quality evidence)
To date, antifibrinolytic agents such as tranexamic acid have not been beneficial in the management of patients presenting with LGIB. In a randomized, double-blinded, placebo-controlled trial of 96 patients with LGIB, there was no significant difference between use of tranexamic acid and placebo for the primary outcome of reduction in hemoglobin levels and no difference in transfusion rates, transfusion volumes, intervention rates, or lengths of hospital stay (91 92 93
DIAGNOSTIC TESTING
Role of colonoscopy
Key concepts
7. The colonic mucosa should be carefully inspected during insertion and withdrawal, with aggressive attempts to wash residual stool and blood to identify bleeding sites. The terminal ileum should be intubated to exclude proximal sources of bleeding when feasible if a colonic source of bleeding is not found. The use of a clear cap is recommended to assist in detection and treatment of bleeding.
Recommendations
6a. We recommend the performance of colonoscopy for most patients who are hospitalized with LGIB because of its value in detecting a source of bleeding (Strong recommendation, low-quality evidence).
6b. However, colonoscopy may not be needed in patients where bleeding has subsided, and the patient has had a high-quality colonoscopy within 12 months with an adequate bowel preparation showing diverticulosis with no colorectal neoplasia. (Conditional recommendation, very low-quality evidence)
Colonoscopy is considered the diagnostic test of choice for patients admitted with LGIB, given that it allows for the diagnosis of a specific etiology, mucosal tissue sampling, and possible therapeutic options for control of bleeding. The yield of colonoscopy in detecting the etiology of bleeding varies widely in the literature, depending on the location of the cohort and timing of colonoscopy performed. In a Japanese cohort where colonoscopy was performed in 88% of patients with LGIB, SRH was identified in 31% of cases who underwent endoscopy (37 colonoscopy for LGIB, the overall diagnostic yield (both definitive and presumptive) was 79% (38 colonoscopy within 24 hours were as high as 21%; however, endoscopic hemostasis was not associated with decreased mortality or rebleeding. In addition, there is a difference between diagnostic yield of colonoscopy and detecting SRH and/or active bleeding at the time of colonoscopy . In a cohort of patients undergoing colonoscopy for LGIB, the diagnostic yield was high at 68%; however, SRH was only seen in 15% of the colonoscopies performed and active bleeding only seen in 3.8% of cases (94
Despite having a high diagnostic yield, the performance of endoscopic intervention may be relatively uncommon, particularly in Western cohorts. In a large insurance claims database of 16,640 patients undergoing colonoscopy for diverticular hemorrhage, endoscopic intervention defined using Current Procedural Terminology codes only occurred in 6% of patients. In addition, endoscopic intervention was not protective of 30-day rebleeding (95 colonoscopy for LGIB, endoscopic intervention during colonoscopy was only performed in 3% of patients; variables associated with the need for endoscopic intervention included age, early colonoscopy (<24 hours), and presence of colonic arteriovenous malformations (96 colonoscopy for LGIB, hemostasis was only performed in 144 patients (4.5%) (97
Despite colonoscopy having relatively low rates of intervention, the value in detecting an etiology of bleeding is critical to determine subsequent management and triage of patients. Relatively rarer causes of LGIB include conditions such as ischemic colitis or colorectal cancer, which require close follow-up and specific management. The presence of malignant lesions in a cohort of patients undergoing colonoscopy for LGIB occurred in 2.5% of patients (94 colonoscopy has obvious value in detecting etiologies such as colorectal neoplasia.
Conversely, for patients who have had a recent colonoscopy within 12 months with an adequate bowel preparation and present with stable LGIB, patients can potentially be managed conservatively without performing a colonoscopy if their bleeding subsides while in the hospital. A similar conservative strategy is also reasonable in patients with an established history of recent diverticular bleeding presenting with recurrent stable LGIB. However, even if patients have had a recent colonoscopy within 12 months, a repeat inpatient colonoscopy may be required if there are new symptoms which could be suggestive of a different disease process such as inflammatory bowel disease or ischemic colitis.
In addition to utilization of low-risk identification tools such as the Oakland score, further data on identifying who actually benefits from an inpatient colonoscopy is needed. Chung et al. conducted a retrospective analysis of patients with LGIB and derived a score which predicted patients who had potential bleeding sources requiring hemostasis, active bleeding on colonoscopy , or malignant-appearing lesions (94 colonoscopy in patients with suspected diverticular hemorrhage (98 colonoscopy (99
The use of a transparent clear cap during colonoscopy has several potential benefits. It can help deflect mucosal folds and stabilize the tip of the endoscope, thereby improving mucosal visualization and potentially helping detect subtle sources of bleeding. Moreover, the clear cap can help facilitate endoscopic treatment by placing the target of therapy at an ideal and constant distance for delivering treatment while also aligning the target of therapy with the axis of the accessory channel (100
Role of CTA
Recommendations
7. We suggest performing a CTA as the initial diagnostic test in patients with ongoing hemodynamically significant hematochezia. However, CTA is of low yield in patients with minor LGIB or those in whom bleeding has clinically subsided. (Conditional recommendation, low-quality evidence)
CTA has an increasing role in the diagnosis and management of LGIB because of the ability to rapidly obtain images without the need for a bowel preparation. In a meta-analysis of 14 observational studies, the sensitivity and specificity of CTA in the diagnosis of LGIB were 90% and 92%, respectively. However, the studies included in the meta-analysis were highly heterogeneous and varied as to whether colonoscopy was performed (101 102 103 104
Further data on risk factors to predict which patients with LGIB are likely to have a positive CTA are needed. In a retrospective analysis of 930 patients with LGIB, 10% of the population underwent initial CTA, and these patients were older and more likely to be hypotensive and receive PRBC transfusions. Only 9 of 93 patients had a positive CTA (105 106 107 108 42 109 37
MANAGEMENT OF A POSITIVE CTA
Recommendations
8. We recommend that patients who have a CTA demonstrating extravasation be promptly referred to interventional radiology for transcatheter arteriography and possible embolization. For specialized centers with experience in performing endoscopic hemostasis, a colonoscopy can also be considered after a positive CTA. (Strong recommendation, moderate quality evidence)
Role of transcatheter arteriography.
Patients who have a source identified at the time of CTA benefit from proceeding with a TA and potential mesenteric embolization if extravasation is seen on angiography. In a single-center study, preceding angiography with a diagnostic CTA was shown to improve localization of LGIB compared with TA alone (110 111 112
To provide targeted therapy at the time of angiography, extravasation must be identified. The use of a microcatheter allows for superselective embolization of a single vasa recta at the site of bleeding. Embolization can typically be performed using microcoils, N-butyl cyanoacrylate (NBCA), or an ethylene-vinyl alcohol copolymer (113 114 115
Role of colonoscopy after a positive CTA.
Patients who have a positive CTA are more likely to have a source detected and treated at the time of a subsequent colonoscopy . In retrospective cohorts of patients with LGIB, the bleeding source was detected more frequently on colonoscopy when extravasation had been previously identified on CTA (107,116,117 colonoscopy after urgent CT vs early colonoscopy alone (118 colonoscopy (119 colonoscopy or TA after a positive CTA in reducing rebleeding or mortality. Nonetheless, in a study of 182 patients with LGIB undergoing CTA before colonoscopy , those who underwent colonoscopy after an urgent CT demonstrating extravasation (within 4 hours of presentation) were more likely to have SRH on colonoscopy , in addition to having reduced rebleeding within 30 days, compared with those who had a nonurgent CTA (120 colonoscopy was unavailable. Further data are needed on this approach, particularly in Western settings.
Comparing outcomes of angiography and colonoscopy .
There are limited data comparing outcomes of patients who undergo CTA, have extravasation seen, and are subsequently treated by transarterial embolization with patients who are treated endoscopically by colonoscopy . In a retrospective cohort of patients with LGIB undergoing colonoscopy or angiography within 1 day of presentation, a higher percentage of the angiography group had a previous CTA and required intensive unit care, PRBC transfusion, or vasopressors. After propensity score matching between the 2 groups, there were no differences in mortality between the 2 groups; however, the angiography group was less likely to need emergency surgery within 1 day of admission compared with the colonoscopy group (121 colonoscopy (n = 27) or angiography (n = 44). Angiography had a higher yield of detecting active bleeding compared with colonoscopy (55% vs 26%, P = 0.03), but had similar rates of therapeutic intervention compared with colonoscopy (70% vs 56%, P = 0.21). Shorter time to procedure was the only significant predictor of confirmation of active bleeding and need for therapeutic intervention; rebleeding rates along with adverse events were not different between patients undergoing angiography or colonoscopy after a positive CTA (122
In addition, there are limited available data comparing patients who undergo initial CTA vs initial colonoscopy as their first diagnostic test. In an observational study of 382 patients with LGIB, CTA was noninferior to colonoscopy in bleeding site detection (123 colonoscopy as their first diagnostic test compared with 32 patients undergoing CTA. Time to first diagnostic examination was significantly reduced in the CTA group as compared with colonoscopy (3 vs 22 hours), and active bleeding was found significantly more frequently with CTA compared with colonoscopy (31% vs 15%, P = 0.03) (124 colonoscopy in the setting of undifferentiated LGIB. Of 258 patients, 162 underwent initial elective colonoscopy compared with 96 patients who underwent CTA. When controlling for hypotension, PRBC transfusion, and time to intervention, colonoscopy was associated with a higher probability of source identification and hemostatic intervention; however, in the subgroup of patients with diverticular bleeding, CTA had higher rates of therapeutic intervention compared with colonoscopy (18% vs 3.8%) (125
Although clinical data are limited on this topic, a survey study of radiologists indicated that for patients with hemodynamically significant LGIB, the first-line recommended diagnostic study was CTA, chosen in 62% compared with conventional angiography (19%), surgery (12%), or colonoscopy (4%). Conversely, in those with hemodynamically stable LGIB, the first-line recommended diagnostic study was inpatient colonoscopy (46%), followed by CTA (126 colonoscopy because CTA is unlikely to be positive in the setting of cessation of bleeding. On the other hand, patients with severe ongoing active hematochezia may benefit from initial CTA because they may not be able to tolerate bowel preparation, and colonoscopy may fail to localize the precise source of bleeding because of a large amount of blood in the colon obscuring visualization.
Role of nuclear imaging.
CTA is increasingly used for the diagnosis of LGIB compared with 99m Technetium-labeled RBC scintigraphy; the latter study has significant limitations because of the relatively long duration of the study and the inability to precisely localize the site of bleeding. Owing to these limitations and the advantages of CTA, uptick of use of CTA increased from 3.8% to 57% at an academic medical center, whereas the use of nuclear bleeding scans decreased considerably over time (110 127 128,129
TIMING OF COLONOSCOPY
Recommendations
9. For patients hospitalized with LGIB requiring a colonoscopy , we recommend performing a nonemergent inpatient colonoscopy because performing an urgent colonoscopy within 24 hours has not been shown to improve clinical outcomes such as rebleeding and mortality. (Strong recommendation, moderate-quality evidence)
The optimal timing of inpatient colonoscopy for LGIB has been controversial. Prior guidelines had conditionally recommended performing a colonoscopy within 24 hours for patients with high-risk clinical features and signs or symptoms of ongoing bleeding. This recommendation had been partially based on a prior, nonrandomized, prospective study of 48 patients with severe diverticular bleeding who underwent colonoscopy within 12 hours and 73 historical controls who underwent colonoscopy within 12 hours but did not undergo endoscopic therapy. Endoscopic treatment significantly reduced the risks of rebleeding, need for emergency surgery, and hospital length of stay (130 colonoscopy . In a RCT of early colonoscopy (<24 hours) in LGIB compared with standard colonoscopy (within 24–72 hours), early colonoscopy (n = 79 patients) was associated with not only a reduced hospital length of stay (2 vs 3 days) but also an increased risk of recurrent bleeding (13% vs 3%) and hospital readmission (11% vs 3%) compared with patients undergoing elective colonoscopy (n = 80 patients) (131 colonoscopy (within 24 hours) to elective colonoscopy (24–96 hours), early colonoscopy was not associated with an increased rate of detecting SRH at colonoscopy or reduction in risk of rebleeding; moreover, there were no significant differences in successful endoscopic treatment, transfusion, or mortality (132
Several meta-analyses comparing urgent or early colonoscopy with elective colonoscopy in LGIB have failed to confirm a clear benefit of urgent/early colonoscopy in important clinical outcomes (133–136 colonoscopy was not associated with a difference in therapeutic interventions, mortality, or rebleeding. When including observational studies, the standard colonoscopy group was associated with a higher rate of mortality in the standard group and a reduced length of stay in the urgent group (137 colonoscopy in rebleeding; similarly, a possible benefit of early colonoscopy was seen in mortality, surgery, and PRBC transfusion when including observational studies (138 colonoscopy was not associated with a reduction in further bleeding, mortality, diagnostic yield, or need for endoscopic intervention (139 colonoscopy in the setting of LGIB (Table 4 ).
Table 4.: Meta-analyses comparing urgent (<24 hours) to elective (>24 hours) colonoscopy in LGIB
Similarly, performing urgent colonoscopy as opposed to elective colonoscopy does not seem to have any sustained benefits after hospital discharge. In studies using large administrative data sets, patients undergoing urgent colonoscopy for LGIB had no benefits in post-hospital rebleeding or post-hospital readmissions (140 95 colonoscopy is planned, it should be performed at the next available nonurgent opportunity.
Based on the available data demonstrating a lack of clear benefit in outcomes, urgent colonoscopy should likely only be performed in select, high-risk patients in situations where there is a high pretest probability of detecting SRH and performing endoscopic intervention (e.g., postpolypectomy bleeding). Moreover, this practice should ideally be performed by providers or bleeding teams who have expertise in endoscopic hemostasis in LGIB; however, consideration should be given as to whether there is local availability of CTA and interventional radiology. When urgent colonoscopy is performed, it should be performed with the assistance of a clear cap and water-jet to maximize the yield of finding SRH.
Conservative management of patients with LGIB.
Further real-world data on conservative management of patients hospitalized with LGIB is needed given the high number of colonoscopies performed and the correspondingly low rate of endoscopic intervention. In a single-center, retrospective report of 142 consecutive patients with LGIB, conservative management, based on an elective colonoscopy within 2 weeks after spontaneous hemostasis in patients who had an initial negative CTA and did not present with shock, was an effective management strategy (141 142 143
BOWEL PREPARATION
Key concepts
8. In patients undergoing inpatient colonoscopy , administration of 4–6 L of polyethylene glycol (PEG)-based bowel preparation has historically been recommended; however, split-dose preparation and/or the use of low-volume preparations can also be considered. Unprepared evaluation or routine flexible sigmoidoscopy is not recommended, unless the source is known to be emanating from the anorectal area or distal colon.
Administration of bowel preparation is needed to visualize the colonic mucosa for potential sources of hemorrhage. Risks of bowel preparation in the setting of LGIB are generally low and have not been shown to be more common than bowel preparation for patients without LGIB (144 colonoscopy after tap-water enema was aided by water-jet pumps and mechanical suction devices, the cecum was successfully reached in 9 of 13 cases and endoscopic visualization was believed to be adequate in all cases (145 146
The previous iteration of this guideline had recommended administration of 4–6 L of a PEG-based solution administered over 3–4 hours until the rectal effluent was clear of blood and stool. This recommendation was based on previous studies using large-volume, purge protocols with subsequent urgent colonoscopy (within 24 hours of presentation) demonstrating high rates of definitive diagnosis and hemostasis (3,130 colonoscopy . Compared with a historical inpatient cohort receiving 4 L of PEG the evening beforehand, investigators noted a significant improvement in bowel preparation with the split-dose order set, with bowel preparation adequacy increasing from 43% to 86% after the intervention (147 colonoscopy , patients receiving split-dose preparation experienced fewer procedural delays and decreased use of additional laxatives to ensure complete cleansing. In addition, 91% of patients receiving split-dose preparation favored split-dose administration for future bowel preparations suggesting excellent tolerability (148
Recent data suggest that lower volume preparations may also be a reasonable alternative in patients undergoing inpatient colonoscopy . In a RCT of 44 inpatients, patients were randomized to same-day 1 L PEG vs split-dose 4 L PEG with a colonoscopy being performed within 4 hours of the last dose; patients with same-day 1 L bowel preparation had comparable bowel cleansing compared with the split-dose group (149 colonoscopy (150,151 152 colonoscopy are needed, but split-dose bowel preparation should be the default for patients undergoing elective (or next available) inpatient colonoscopy . For those patients in whom urgent colonoscopy is pursued, a regimen of 4–6 L of PEG administered over 3–4 hours until rectal effluent is clear is considered standard.
There are limited data on additional adjunctive techniques to improve tolerability of bowel preparation for patients undergoing inpatient colonoscopy , such as use of prokinetic or antiemetic drugs. In a RCT evaluating the efficacy of antiemetics before a split-dose 3 L PEG preparation, the use of supplemental domperidone and sulpiride was found to be associated with higher completion of PEG, reduced abdominal discomfort, and higher Boston Bowel Preparation Scale scores compared with the control group (153
Although placement of a nasogastric tube can be considered for patients who are unable to tolerate a bowel preparation before planned colonoscopy , this should be performed cautiously in patients with risk factors of aspiration. Of note, in previous studies of urgent colonoscopy after a rapid, large-volume preparation, a nasogastric tube was needed 33% of the time to facilitate administration of the preparation (130
LGIB PROTOCOLS
Institutional algorithms and protocols on the diagnosis and management of patients presenting with LGIB have been shown to be beneficial in improving certain in-hospital outcomes. Implementation of an institutional LGIB protocol prioritizing CTA for patients with active bleeding led to improvement in certain predefined process outcomes (increased use of the GI consultation service and increasing performance of CTA as opposed to tagged red blood cell scanning) and fewer transfusions (154 155
ENDOSCOPIC TREATMENT
Role of treatment of SRH
Key concepts
9. Endoscopic therapy is recommended when finding active bleeding or SRH, irrespective of the etiology.
When colonoscopy is performed for patients presenting with hematochezia, SRH should be treated endoscopically to reduce the risk of ongoing and recurrent bleeding. In a seminal study of patients with diverticular hemorrhage, endoscopic treatment of those with SRH was associated with a reduction in rebleeding and need for surgery compared with those patients treated medically (130 colonoscopy was associated with a significantly reduced risk of early and late rebleeding compared with those patients who had SRH and were treated conservatively. In this cohort, endoscopic treatment of SRH was also associated with reduced risk of rebleeding compared with patients with presumptive diverticular bleeding who were treated conservatively. Despite endoscopic treatment, however, early and late rebleeding rates remained high even in patients treated for definitive diverticular hemorrhage at 17.4% and 32.0%, highlighting the limitations of colonoscopy and endoscopic intervention for this condition (156
Options for endoscopic treatment include injection of dilute epinephrine, through-the-scope or over-the-scope clips, endoscopic band ligation (EBL), contact thermal therapies including bipolar or multipolar coagulation, noncontact thermal therapy such as argon plasma coagulation (APC), and topical hemostatic therapy. Updates on endoscopic treatment options will be discussed in the context of diverticular hemorrhage, treatment of colonic angioectasias and vascular lesions, and postpolypectomy bleeding. We will not discuss management of bleeding from a hemorrhoidal source in this guideline.
Treatment of diverticular hemorrhage
Recommendations
10. When detected, we recommend treatment of diverticular SRH with through-the-scope clips, EBL, or coagulation. (Strong recommendation, moderate-quality evidence)
Diverticular bleeding typically presents with painless hematochezia, frequently large-volume in nature, because it is an arterial bleed occurring from the neck or dome of a diverticulum. When active bleeding (spurting or oozing) or SRH (nonbleeding visible vessel or adherent clot which cannot be removed with lavage) is seen, endoscopic treatments are effective in achieving initial hemostasis and reducing risks of recurrent bleeding. The most commonly used therapeutic options include through-the-scope clips, EBL, and bipolar coagulation. Endoscopic treatment using clips can be achieved successfully when direct clipping is performed onto a culprit vessel either at the diverticular neck or dome. Other options include indirect placement of clips around the neck or in a zipper fashion to close the diverticula; however, this may be associated with a higher risk of rebleeding compared with direct clipping (157 158 159 157,160
EBL has been demonstrated to be safe and effective in several series (161 162 163 164
In a systematic review and meta-analysis of 16 studies and 384 patients with diverticular bleeding, bipolar coagulation, clipping, and EBL were all highly effective in initial hemostasis (99%–100%); however, EBL was more effective compared with clipping to avoid transarterial embolization or surgery (161 165 P = 0.012), as was late rebleeding (9% vs 29%, P = 0.02) (166 P < 0.001) and late rebleeding (adjusted OR 0.62; P < 0.001), regardless of the timing of colonoscopy or presence of active bleeding at the time of colonoscopy (167 168
Other techniques which have been described in case reports for effective management of refractory or recurrent diverticular bleeding include over-the-scope clips (169,170 171 172 173,174
Colonic angioectasias and vascular etiologies of bleeding
Colonic angioectasias typically present with occult blood loss with iron deficiency anemia, however, may also present with overt LGIB. Endoscopic therapy is indicated if there is evidence of acute or chronic blood loss. Advanced age and anticoagulant use may increase the risk of active bleeding from colonic angiodysplasias (175 176 177 178 179 180 181
Postpolypectomy bleeding
An extensive discussion on risk factors and prevention of post-polypectomy bleeding is beyond the scope of this guideline. However, when patients are hospitalized due to postpolypectomy bleeding, a colonoscopy is typically recommended for patients with ongoing bleeding and any hemodynamic compromise. Endoscopic therapy is indicated when active bleeding or SRH is seen at the polypectomy site. In a multicenter study of patients with postpolypectomy bleeding, 43% of the cohort did not require endoscopic hemostatic therapy; rebleeding and transfusion requirements were very low in those managed without intervention. Variables that were predictive of active bleeding at the time of colonoscopy included use of anticoagulants, left-sided polyps, prior use of electrocautery, and pedunculated polyp morphology (182
Endoscopic management of postpolypectomy bleeding typically consists of through-the-scope clips, which are highly effective in initial treatment of bleeding (183 184 185 186
RECURRENT BLEEDING
Unfortunately, rebleeding is common for patients hospitalized with LGIB. In the UK audit of patients hospitalized with LGIB, rebleeding occurred in 13.6% of cases at a median of 3 days after presentation (13 187,188 38 37 189 190
Role for repeat colonoscopy , angiography, and surgery
Key concepts
10. For patients experiencing rebleeding after initial hemostasis or cessation of bleeding, repeat colonoscopy can be considered depending on the patient's stability and likelihood of successful repeat endoscopic therapy. In patients with suspected recurrent diverticular bleeding with recent colonoscopy who are hemodynamically stable, observation can be considered.
For patients in whom a known source of bleeding is identified and treated endoscopically, but experience an episode of rebleeding, a repeat colonoscopy can be considered. However, there are limited comparative data on the benefit of repeat colonoscopy and attempt at endoscopic intervention vs proceeding to radiologic intervention in the setting of recurrent bleeding. In the setting of a known bleeding site and either recurrent or refractory bleeding despite endoscopic intervention, proceeding to TA with possible embolization is indicated. A previously placed endoclip can help perform a focused TA. A CTA can be considered if more precise localization is needed, followed by transcatheter arteriography (113
Provocative angiography has been used in case series of patients with recurrent LGIB when conventional angiography does not determine active extravasation. In a case series of 12 patients with LGIB, provocative angiography (mainly using urokinase) was successful in identifying contrast extravasation in 50% of cases, subsequently allowing for embolization (191 192
There is a limited initial role for surgical evaluation in the setting of LGIB, and this option should only be considered after endoscopic or radiologic interventions have failed. In the UK audit of patients with LGIB, use of surgery was needed in 0.2% of all cases (13 193 colonoscopy and cannot undergo recurrent embolization due to the presence of or concerns for ischemia. If surgery is deemed necessary, every attempt should be made to precisely localize the site of bleeding in the colon to allow for a limited, targeted resection. A nonlocalized hemicolectomy has a higher risk of recurrent bleeding compared with a localized source and subsequent targeted hemicolectomy. In an analysis of a National Surgical Quality Improvement Database, 85% of all colorectal resections performed in the setting of bleeding underwent partial colectomy and 15% underwent total colectomy; total colectomy was associated with an increased risk of cardiac and renal complications as well as postoperative ileus (194
Resumption of antiplatelet medications and risk of recurrence
Recommendations
11a. We recommend discontinuing nonaspirin NSAIDs after hospitalization for diverticular hemorrhage. (Strong recommendation, low-quality evidence)
11b. We suggest discontinuing aspirin for primary cardiovascular prevention after hospitalization for diverticular hemorrhage given the risks of recurrent diverticular hemorrhage. (Conditional recommendation, low-quality evidence)
11c. We suggest continuing aspirin after hospitalization for diverticular hemorrhage for patients with an established history of cardiovascular disease given the benefits of reducing future ischemic events. (Conditional recommendation, low-quality evidence)
11d. We recommend that providers re-evaluate the risks vs benefits of continuing nonaspirin antiplatelets such as P2Y12 receptor antagonists in a multidisciplinary setting after hospitalization for diverticular hemorrhage given the demonstrated risks of recurrent diverticular hemorrhage. (Strong recommendation, low-quality evidence)
Discontinuation of NSAIDs after hospitalization for diverticular bleeding has been shown to significantly reduce rebleeding risk compared with those patients with ongoing NSAID use (195 188
Resumption and ongoing use of antiplatelet medications have been shown in multiple cohorts to be associated with an increased risk of recurrent diverticular hemorrhage. In a large retrospective analysis of a medical claims database, the use of platelet aggregation inhibitors (including clopidogrel, prasugrel, and ticagrelor) was significantly associated with an increased risk of second diverticular hemorrhage (HR 1.47, 95% CI 1.15–1.88) after an index episode of diverticular hemorrhage. The use of aspirin has also shown to potentially increase the risk of recurrent LGIB. In a retrospective analysis of 295 patients with LGIB on aspirin, continuation of aspirin was associated with a significantly increased risk of recurrent bleeding (HR 2.76, 95% CI 1.26–6.07) while also protective of serious cardiovascular events (HR 0.59, 95% CI 0.37–0.91) and death (HR 0.33, 95% CI 0.17–0.63) (196
Resumption of anticoagulants and risk of recurrence
Recommendations
12. We recommend resuming anticoagulation after cessation of LGIB given that resumption of anticoagulation has been shown to decrease the risks of postbleeding thromboembolism and mortality. (Strong recommendation, moderate-quality evidence)
The net benefit of resumption of anticoagulation after hospitalization for GIB is well-established. Several meta-analyses of observational studies have demonstrated that resumption of anticoagulation after hospitalization for GIB is associated with a reduction in thromboembolic events and mortality while also potentially increasing the risk of recurrent GIB (197–199 200
Data on anticoagulant resumption in LGIB-specific cohorts also indicate a potential benefit of anticoagulant resumption. In a large cohort of patients with an index episode of diverticular hemorrhage using the Optum database, discontinuing anticoagulation was associated with an increased risk of ischemic stroke (HR 1.93, 95% CI 1.17–3.19) at a median time of 115 days. Importantly, resumption of anticoagulation was not associated with an increased risk of recurrent diverticular hemorrhage (HR 0.98, 95% CI 0.79–1.22) (190 90 201
FUTURE RESEARCH PRIORITIES
Compared with other conditions in gastroenterology such as UGIB or inflammatory bowel disease, the lack of high-quality, randomized trial data to guide diagnosis and management in LGIB limits the strength of these recommendations. However, given how frequently clinicians manage patients who are hospitalized with LGIB and the overall high burden of colonoscopy performed for this condition, the panel wanted to provide guidance and evidence-based recommendations whenever possible. Future research in LGIB should be focused on a few key areas, in which further data are urgently needed.
First, additional validation of existing LGIB scores such as the Oakland score is needed to further identify low-risk patients with LGIB who are unlikely to require hospital-based intervention and can potentially be managed as an outpatient. This strategy needs to be proven safe with low risks of rebleeding and missed diagnoses such as colorectal cancer or inflammatory bowel disease before widespread implementation. When used, clinical prediction scores should be embedded into the electronic medical record and automatically trigger pathways and order sets to help guide clinicians. In addition, further clarity on whether a colonoscopy is needed in patients with hemodynamically stable, suspected diverticular bleeding in whom a recent colonoscopy has shown diverticulosis and excluded colorectal neoplasia. Conservative management may be a reasonable option for many of these patients, particularly given the low frequency of endoscopic intervention during colonoscopy for LGIB in Western populations and the high rates of spontaneous hemostasis.
Second, further comparative data are needed between patients who undergo primary initial CTA vs primary colonoscopy for clinically significant LGIB. A validated clinical score predicting which patients have a high likelihood of having extravasation on a CTA would provide clarity in determining who benefits from an urgent CTA. Outcomes that should be captured include rates of diagnostic yield, rates of therapeutic intervention, lengths of stay, rebleeding risks, and complications. For patients who have a positive CTA, further data are needed on outcomes of patients treated by transcatheter arteriography and embolization vs patients undergoing urgent colonoscopy after a positive CTA.
Third, for patients presenting with severe LGIB while on anticoagulant medications, further data on the need and role for reversal agents are needed. Although most patients can likely be managed by withholding the anticoagulant drug, patients who are having severe hematochezia with signs of hemodynamic compromise may benefit from reversal agents before endoscopic intervention. Data on the use of reversal agents (such as PCC and targeted reversal agents) compared with withholding the drug alone are needed to determine the appropriate role for these drugs. Outcomes that should be captured should include time to endoscopy, endoscopic hemostasis, further bleeding, mortality, and thromboembolic complications. For future RCTs, investigators have proposed measuring a global end point of further bleeding leading to blood transfusion, urgent interventions in the case of further bleeding or complications of initial intervention (repeat endoscopy, surgery, or interventional radiology), or death related to GIB (202
Figure 1.: Suggested approach to the management of patients with severe hematochezia.
Figure 2.: Endoscopic treatment based on etiology.
Figure 3.: Anticoagulant reversal strategy based on life-threatening LGIB. 4F-PCC, 4-factor prothrombin complex concentrate; FFP, fresh frozen plasma; INR, international normalized ratio; IV, intravenous; LGIB, lower gastrointestinal bleeding; PRBC, packed red blood cell.
Panel 1 : A 60-year-old man presenting to the emergency department with abrupt onset of painless hematochezia. The patient was found to be tachycardic and borderline hypertensive in the emergency department. The hemoglobin level was 7.6 g/dL. He was transfused 2 units of packed red blood cells and given 1 L of normal saline. After consultation with gastroenterology, a computed tomography angiography (CTA) was obtained. (a ) Noncontrast CT series demonstrating no dense material in the left colon. (b ) Arterial phase of CTA examination showing a linear accumulation of dense contrast within the colon (arrow), which can be seen to directly originate from a colonic diverticulum. This finding in combination with the noncontrast series is diagnostic of active bleeding. (c ) Portal venous phase image of the CTA examination shows that the contrast has increased in volume and decreased in density (arrows). Panel 2 : Coronal maximum intensity projection reformatted images from the same CTA scan demonstrating contrast accumulation within the colon. Panel 3 : (a ) Fluoroscopic inferior mesenteric artery angiogram. (b ) Angiogram image obtained several seconds later shows contrast accumulation within the lumen of the descending colon (arrow). (c ) Fluoroscopic image obtained showing embolization coils (arrows) within the artery supplying the bleeding diverticulum.
CONFLICTS OF INTEREST
Guarantor of the article: Neil Sengupta, MD.
Specific author contributions: N.S. was the primary author and wrote the initial draft of this guideline, as well as coordinated the literature search. J.D.F., V.J., A.K.S., L.L.S., and D.W. were involved in creation of the PICO questions, formulation of clinical questions, and edited the final draft. R.J.W. conducted the GRADE analysis.
Financial support: None to report.
Potential competing interests: N.S. received consulting fees from Alexion Pharmaceuticals. A.K.S. received a research gift from Pentax on ergonomics and received consulting fees from Boston Scientific related to ergonomics. L.L.S. has written chapters for UpToDate. J.D.F., V.J., R.J.W., and D.W.: no relevant COI.
ACKNOWLEDGEMENTS
The authors are grateful to Rebecca Billings, MLIS, and Sudha Ramakrishnan, MSIS, for their assistance in library searches, and the Society of Abdominal Radiology, GI-Bleeding Disease Focused Panel for providing images. The authors acknowledge Berkeley Limketkai, MD, PhD, for his services as a secondary GRADE methodologist.
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