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Asymptomatic Deep Vein Thrombosis during Free Flap: Concerns in Free Flap Surgery

Jung, Jae-A M.D., Ph.D.; Park, Bo Young M.D., Ph.D.; Kang, So Ra M.D., Ph.D.; Kim, Min Ji M.D., Ph.D.

Plastic and Reconstructive Surgery: October 2018 - Volume 142 - Issue 4 - p 551e-560e
doi: 10.1097/PRS.0000000000004518
Reconstructive: Lower Extremity: Original Articles
Free
Patient Safety CME
Best Paper

Background: Venous insufficiency is the most frequent cause of failure in free flap reconstruction of the lower extremity. When deep vein thrombosis is detected during preoperative assessment of the lower extremity, decisions regarding treatment plans become difficult, and no relevant guidelines regarding surgery and preoperative treatment of patients with deep vein thrombosis who need a free flap transfer are currently available.

Methods: To find a relevant guideline in decision-making regarding surgery and preoperative treatment of patients with deep vein thrombosis who require free flap reconstruction, a systematic literature review was conducted searching MEDLINE, PubMed Central, Cochrane, and Embase databases for articles published between 1996 and 2015. In addition, the authors introduced six of their cases of deep vein thrombosis diagnosed before free flap surgery in which the flap survived.

Results: The literature review identified two articles that discussed intraoperative deep vein thrombosis diagnosed in three patients, including the reported cases. Analyses included epidemiology, cause, and management strategy. A consensus for the management of asymptomatic deep vein thrombosis before free flap surgery is still lacking. In the authors’ cases, successful flap transfer was possible by proceeding with an appropriate preoperative evaluation, intensive anticoagulation treatment, intraoperative reperfusion procedure, and postoperative care.

Conclusion: Preoperatively detected asymptomatic deep vein thrombosis is not a contraindication for free flap reconstruction, and a flap transfer can be successfully performed with suitable planning and management.

CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

Patient Safety CME.

Seoul, Republic of Korea

From the Department of Plastic Surgery, Korea University College of Medicine; and the Department of Plastic and Reconstructive Surgery, School of Medicine, Ewha Womans University.

Received for publication June 26, 2017; accepted January 4, 2018.

Disclosure:The authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

By reading this article, you are entitled to claim one (1) hour of Category 2 Patient Safety Credit. ASPS members can claim this credit by logging in to PlasticSurgery.org Dashboard, clicking “Submit CME,” and completing the form.

Bo Young Park, M.D., Ph.D., Department of Plastic and Reconstructive Surgery, School of Medicine, Ewha Womans University, Mok 5-dong, Yangcheon-Gu, Seoul 158-710, Republic of Korea, byps@icloud.com

Venous insufficiency is the most frequent cause of reexploration and failure in free flap reconstruction of the lower extremity. Whether the superficial or the deep venous system should be used for microsurgical vessel anastomosis is still the subject of debate. When choosing a recipient vein, the deep vein system is the first consideration, as it provides better perfusion, less vulnerability during injury, and more straightforward inserting of flaps.1–3 Therefore, when lower extremity deep vein thrombosis is detected during preoperative assessment, decisions regarding the treatment plan become challenging. In this situation, surgeons remain unsure about whether a free flap should be performed and which vein should be used.

No guidelines regarding surgery and preoperative treatment of patients with deep vein thrombosis who need a free flap transfer are currently available. There are still few studies about the ideal timing of the operation, preoperative medication (such as anticoagulants), and surgical techniques. Therefore, we performed a comprehensive literature review on the following subjects: Should we proceed with free flap surgery in patients diagnosed preoperatively with deep vein thrombosis? Can deep vein thrombosis influence the survival of flaps or the occurrence of complications? Should any preoperative treatment be used? Which veins should be preferably used? We discuss our experience with asymptomatic deep vein thrombosis in patients who were diagnosed during preoperative evaluation.

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PATIENTS AND METHODS

We performed a retrospective chart review of patients with lower extremity injury requiring soft-tissue reconstruction between January of 2014 and January of 2017. A total of 94 patients with lower extremity injuries underwent free flap coverage, and we investigated six patients (6.4 percent) who developed asymptomatic deep vein thrombosis in the preoperative period. Asymptomatic deep vein thrombosis was detected preoperatively with lower extremity three-dimensional computed tomographic angiography, which was routinely performed in every patient to determine the status of the recipient vessel and the course of perforators in the donor flap. We performed free flap surgery in cases of preoperative asymptomatic deep vein thrombosis, and the Caprini scores were investigated in these patients. Caprini scores were calculated based on the 2005 Caprini Risk Assessment Model.4 We present several cases of preoperative deep vein thrombosis that made microvascular free flap transfer more difficult. A systematic literature review was also conducted.

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Search Strategy, with Inclusion Criteria, Data Extraction, and Study Appraisal

The MEDLINE, PubMed Central, Embase, and Cochrane Library electronic databases were searched for articles published between January 1, 1996, and December 31, 2015. This search was conducted using the following English language keywords combined with Boolean logical operators: (“venous thrombosis” or “deep vein thrombosis” or “DVT” or “chronic venous thrombosis” or “intraoperative venous thrombosis” [title/abstract/Medical Subject Headings terms], and “free flap” [title/abstract/Medical Subject Headings terms]). The references of selected articles were also examined for possible additional relevant articles. Studies identified through electronic and manual searches were listed with key information using Microsoft Excel 2013 (Microsoft Corp., Redmond, Wash.).

We included all original articles about venous thrombosis encountered during free flap reconstructive surgery for the past 20 years. Randomized controlled trials, controlled clinical trials, observational studies (retrospective and prospective), and case reports were included. Articles containing the data from other studies, articles with insufficient data, and duplicate studies were excluded, as were purely technical descriptions, editorials, discussions, commentaries, and letters.

Data were extracted independently by two researchers (J.A.J. and M.J.K.), and disagreements were resolved by consensus. If this was impossible, one of the senior authors (B.Y.P.) was asked to make the final decision. The following data were collected: author, publication date, place of study, type of study, level of evidence, type and number of included flaps, indications, name of the vein affected by thrombosis, success or failure of surgery, number of surgical revisions, and number of venous thromboses.

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RESULTS

Literature Review

Our search strategy identified 527 references. After adding the studies identified from the reference lists and removing duplicates, we examined the titles of 417 studies. After examining the titles, 201 articles were eligible. Of them, 180 articles were excluded by screening the abstract. Of the remaining articles, 14 articles were excluded after we read the entire text, showing that the article included patients with a hypercoagulable status or with thrombophilic gene mutations.5–7 Among seven remaining deep vein thrombosis studies,8–14 we included only those discussing lower extremity reconstruction, and excluded those discussing reconstruction of other regions. Ultimately, two studies were included in the systematic review, for a total of three patients (Fig. 1 and Table 1).8,12

Table 1.

Table 1.

Fig. 1.

Fig. 1.

One publication was North American (Canada), and the other was Asian (Japanese). All studies were published after 2008 (Table 1). Patient age ranged from 30 to 68 years (mean age, 52 years). The defects were all attributable to oncologic resection (100 percent). The most commonly used flap was the latissimus dorsi free flap in 66.7 percent (n = 2), followed by the free fibular osteocutaneous flap in 33.3 percent (n = 1). The flap survived in two cases (66.7 percent) and failed in one case (33.3 percent) (Table 1).

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Technical Aspects and Treatment Algorithm

The literature review failed to identify a suitable option for a method to cover lower extremity wounds in a patient with an asymptomatic deep vein thrombosis (Fig. 2). Therefore, we considered some technical aspects in parallel with medical treatment of asymptomatic calf deep vein thrombosis.

Fig. 2.

Fig. 2.

First, anticoagulation therapy was started in every diagnosed patient at the discretion of the primary physician. If the deep vein thrombosis was located above the knee, or a calf deep vein thrombosis with proximal extension was present, we delayed free flap surgery. Surgery was considered after reevaluation of the deep vein thrombosis and the patient’s medical condition stabilized.

If only calf deep vein thrombosis was present, at least 1 week of anticoagulation was performed before surgery. An inferior vena cava filter was also considered before free flap surgery to prevent an embolic event when deep vein thrombosis was multisegmental or around the knee.

During surgery, we performed an intraoperative reperfusion procedure on the accompanying veins with a 3-mm Fogarty catheter. We used a Fogarty catheter with a small hole at the end to prevent accidental vessel injury during ballooning. Massive heparin irrigation was performed through the hole to ensure flow, with assessment of the targeted area using intraoperative ultrasound. After surgery, we minimized the immobilization period and applied a sequential compression device whenever possible. The duration of anticoagulation treatment was at the discretion of the physician.

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CASE REPORTS

Case 1 (Patient 1)

A 64-year-old man suffered a degloving injury of the right medial foot area combined with bilateral tibiofibular complex fractures following a traffic accident. This patient had a preoperative inferior vena cava filter. After bone fixation, a wide area of skin necrosis in the medial malleolus of the right lower leg was observed. Flap coverage because of bone and tendon exposure was scheduled. Preoperative computed tomographic angiography diagnosed a multilevel deep vein thrombosis in the right lower leg. The Caprini score was 19, and this patient was ranked in the highest-risk category (Table 2). In accordance with standard treatment of deep vein thrombosis, anticoagulation was initiated with administration of low-molecular-weight heparin and a parenteral anticoagulant. After 2 weeks of anticoagulation treatment, free flap coverage was performed because of interval worsening of the open wound, although the deep vein thrombosis has not completely resolved (Fig. 3). A 13 × 10-cm thoracodorsal artery perforator flap was transferred based on one perforator. Vascular anastomoses with the posterior tibial artery in an end-to-side fashion and with two veins (concomitant vein and superficial vein) in an end-to-end fashion were performed. The flap survived well, without any complications. On follow-up computed tomographic angiography after 1 month, the deep vein thrombosis had improved, but the veins above the knee were still affected. Anticoagulation therapy was continued for 3 months.

Table 2.

Table 2.

Fig. 3.

Fig. 3.

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Case 2 (Patient 3)

A 38-year-old woman presented with an open wound in the posterior heel area. She had been injured after a fall and had multiple fractures of the femur, tibia, ribs, and pelvis. After a long period of immobilization, an asymptomatic deep vein thrombosis that segmentally involved the posterior tibial vein from the ankle to the superficial femoral vein was diagnosed on preoperative computed tomographic angiography. The Caprini score was 27, and this patient was ranked in the highest-risk category (Table 2). Flap coverage for the heel defect was delayed for 2 weeks because of standard anticoagulant treatment of the deep vein thrombosis. On follow-up computed tomographic angiography, the deep vein thrombosis has not resolved. An 8 × 5-cm anterolateral thigh free flap was transferred (Fig. 4). Vascular anastomoses were performed with the posterior tibial artery in an end-to-side fashion, and the concomitant vein was transferred in an end-to-end fashion. Intraoperative embolectomy using a 3-mm Fogarty catheter was performed. The flap survived without any complications, and anticoagulation therapy was continued for 6 months.

Fig. 4.

Fig. 4.

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Case 3 (Patient 4)

A 52-year-old man was admitted with diabetic foot ulceration. Preoperative computed tomographic angiography showed an asymptomatic deep vein thrombosis in the posterior and anterior tibial veins from the ankle to the knee. The patient’s Caprini score was 18 (Table 2). After amputation of the fifth toe at the metatarsal level, a 9 × 5-cm anterolateral thigh flap was transferred. Vascular anastomoses were performed to the posterior artery in an end-to-side fashion and to the concomitant vein in an end-to-end fashion. Intraoperative embolectomy with a Fogarty catheter was also performed. The flap healed without any complications, and anticoagulation was maintained for 3 months.

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Case 4 (Patient 6)

A 46-year-old man was referred for an open wound in the posterior heel area for 6 weeks. He had multiple fractures of the pelvis, both femurs, fourth through seventh ribs, and both tibias. In addition, he had been diagnosed with Burger disease 10 years previously. As an external fixator had been applied to his pelvis, he was on bed rest. After a long period of absolute bed rest, an asymptomatic deep vein thrombosis that extended from the calf vein to the superficial femoral vein was diagnosed by preoperative computed tomographic angiography. Because of his peripheral vessel disease, anticoagulant treatment had not been administered. The patient’s Caprini score was 28, and this patient was ranked in the highest-risk category (Table 2). A 12 × 5-cm deep inferior epigastric perforator free flap was elevated based on one dominant perforator (Fig. 5). Vascular anastomoses were performed to the posterior tibial artery in an end-to-side fashion and to the concomitant vein in an end-to-end fashion. Intraoperative embolectomy with a Fogarty catheter at the knee level was also performed. The flap healed without any complications, and anticoagulation was maintained for 6 months. Surgical results of all described cases are shown in Table 3.

Table 3.

Table 3.

Fig. 5.

Fig. 5.

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DISCUSSION

Microsurgical free flap procedures represent an invaluable reconstructive modality of the lower extremities because of the paucity of local tissue availability.15 Nevertheless, ongoing challenges include higher flap failure rates than those in other anatomical sites, originating primarily from vascular-related complications.15,16 Vein-related problems are the most frequent cause of reexploration and failure in lower extremity free flap reconstruction, and selection of appropriate veins is an important issue for microsurgeons.

Approximately 2 million Americans develop a deep vein thrombosis episode annually.10 In hospitalized patients, the incidence of deep vein thrombosis is much higher, ranging from 20 to 70 percent. Following trauma, widespread vascular and perivascular changes occur. These changes, defined as posttraumatic vessel disease, can frequently lead to deep vein thrombosis. Therefore, deep vein thrombosis can often be detected in patients when preparing for the lower extremity free flap reconstruction.

If a deep vein thrombosis is detected during preoperative assessment of the lower extremity, decisions regarding the treatment plan become difficult. Most microsurgeons are aware that deep vein thrombosis can cause free flap failure, but no reports regarding the incidence of free flap failure in the presence of venous thrombosis of the limbs are available in the literature. In this situation, surgeons must decide whether the free flap should be performed and which vein should be used. No known guidelines for decision-making regarding surgery and preoperative treatment of patients with deep vein thrombosis who need a free flap transfer are currently available. Few studies about the ideal timing of surgery, preoperative medication (such as anticoagulants), and surgical techniques are available, indicating the need for such studies.

If a deep vein thrombosis is proximally extended, medical treatment should proceed and surgery will be delayed. However, most cases of deep vein thrombosis we encounter are asymptomatic, especially those in the calf. Although many studies have investigated calf deep vein thrombosis, there is no consensus on treatment of isolated calf deep vein thrombosis (i.e., infrapopliteal or distal deep vein thrombosis without proximal extension or pulmonary embolism). There are few guidelines for treatment of calf deep vein thrombosis, and the available guidelines do not address the current approach to calf deep vein thrombosis management. Treatment of calf deep vein thrombosis may not be of concern for other medical specialties, because it is considered to have low embolic potential.17–20 However, the lower extremity is a major area of focus for the microsurgeon, and vessel status is the most important factor for free flap survival. A revision procedure after partial or total necrosis of the flap is extremely stressful for both patient and surgeon. Therefore, we performed a comprehensive literature review on the following subjects: Should we proceed with free flap surgery in patients with preoperative diagnosed deep vein thrombosis? Can deep vein thrombosis influence the survival of flaps or the occurrence of complications? Should any preoperative treatment be administered? Which veins are preferred? The results of a literature review showed insufficient knowledge about these regimens. There were only rare case reports dealing with free flap transfer in patients with preoperative deep vein thrombosis, and free flap reconstruction failed in one case and succeeded in two cases.8,12 After reviewing the articles, we found that microsurgeons have serious concerns about free flap coverage of patients with deep vein thrombosis. Even subclinical occult venous thrombosis limited to the deep venous system at the calf region has been regarded as a potential cause of venous thrombosis and free flap failure.8,21 Therefore, some precautions should be taken when performing free flap coverage. Based on the article reviews and our experience from the above-mentioned cases, a number of lessons can be learned:

  1. When a deep vein thrombosis is detected in the calf or popliteal area in a patient who has to undergo free tissue reconstruction, clinicians should closely inspect the proximal venous system and the patency of the superficial system. Preoperative identification of a donor vein is essential for planning reconstruction.
  2. In preoperative planning, anticoagulation therapy must be started according to current medical treatment guidelines.22 If the deep vein thrombosis is located above the knee or if a calf deep vein thrombosis with proximal extension is present, free flap surgery might be delayed and anticoagulation is started. Surgery is considered after reevaluation of the deep vein thrombosis and the patient’s medical condition stabilizes. The duration of preoperative anticoagulation remains controversial. If only calf deep vein thrombosis is present, at least 1 week of preoperative anticoagulation is performed. An inferior vena cava filter is also considered before free flap surgery to prevent an embolic event when the deep vein thrombosis is multisegmental or around the knee. When postoperative immobilization is needed or the patient’s condition is poor, anticoagulation therapy must be maintained after surgery according to current treatment guidelines.
  3. The preoperative Caprini scores placed our patients in the high or highest risk groups, but the flaps succeeded when anticoagulation was maintained as recommended by current guidelines for deep vein thrombosis.
  4. Blood flow in the chosen veins should be assessed intraoperatively before anastomosis, if possible. In addition, selection of two veins (an accompanying vein and a superficial vein, or two accompanying veins) might be recommended.
  5. Mainly in multisegmental calf deep vein thrombosis, intraoperative reperfusion of the accompanying deep vein using a 3-mm Fogarty catheter should be performed with heparin irrigation. We used a Fogarty catheter with a small hole in the end to prevent vessel injury. We performed massive heparin irrigation through the hole to ensure flow, with assessment of the targeted area using intraoperative ultrasound.
  6. After surgery, no more than 2 to 3 days of immobilization are recommended. According to deep vein thrombosis guidelines, antithrombotic therapy should be continued for a minimum of 3 to 6 months.23,24

There is still uncertainty regarding the length of time a patient should remain on anticoagulant therapy and the type of anticoagulant that should be used for deep vein thrombosis treatment. In general, the duration of anticoagulation in deep vein thrombosis is dependent on the patient’s risk status.25 However, risk assessment is very difficult with this patient population, because these patients have many risk factors and potential deep vein thrombosis causes. Current recommendations from the American College of Chest Physicians state that long-term low-molecular-weight heparin treatment should be used for acute episodes of deep vein thrombosis, and that it should be continued for a minimum of 3 to 6 months.23,24

Concern for postoperative hematoma may result in underuse of chemoprophylaxis in patients who undergo plastic surgery. Some previous studies have suggested that anticoagulation therapy can increase the rate of complications, such as hematoma, after flap surgery. However, postoperative anticoagulation has no significant effect on the incidence of flap complications, including bleeding, thromboembolism, and flap loss. Several studies have also demonstrated a minimal increase in the rates of postoperative bleeding when prophylactic anticoagulant doses are used.26,27 Ennis reported that the rates of minor bleeding complications in an aspirin group, a less than 12-hour postoperative dosing frequency enoxaparin group, and a 12- to 24-hour postoperative dosing frequency enoxaparin group were 3.1, 5.7, and 2.8 percent, respectively.28 No major bleeding occurred in the aspirin group, whereas the bleeding rate was only 0.9 percent in the enoxaparin group.28

A major limitation of the present study is that it included only a small number of cases. However, many plastic surgeons are still not familiar with calf deep vein thrombosis and lack protocols for management. Therefore, the information in this article and the accompanying literature review of prior studies and cases can help surgeons with preoperative planning and postoperative management of patients with deep vein thrombosis who need free flap coverage. For successful flap coverage, proper preoperative planning using imaging modalities and strict medical treatment (preoperative and postoperative anticoagulation therapy) following the standard protocol should be conducted.

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CONCLUSIONS

Despite its rarity, preoperative venous thrombosis of the deep veins is possible in patients who need flap coverage and is of greatest concern after prolonged bed rest. In this article, we presented a case of preoperative thrombosis of the lower extremity deep veins in a free flap and successful flap transfer with medical treatment using the recanalized lumen. However, although a successful free flap transfer might be possible in patients with asymptomatic deep vein thrombosis, careful preoperative evaluation and adequate treatment are recommended in high-risk patients.

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ACKNOWLEDGMENT

This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI16C0966).

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