INTRODUCTION
The incidence of end-stage renal disease (ESRD) is increasing considerably in the past few years; the incidence in 2008 in the USA was 112,476 compared to 120,435 in 2014. However, more than 87% of the incident patients start their therapy with hemodialysis (HD).[12]
Libya is a sparsely populated medium-developed country, but it has a high prevalence of risk factors for chronic kidney diseases (CKD) such as diabetes, hypertension, and obesity,[345] where the societal, economic, and environmental transformation has contributed to people tending to adopt a sedentary life that further burdens the overall health burdens of the country.[6] Libya was among the first countries in the region to establish free access to maintenance dialysis therapy for patients with ESRD.[7] Although vascular surgery improved in the last few years, it is still lacking and does not meet the needs for access creation and management of the complications.
Vascular access type is one of the most important factors that affect the health outcomes of HD patients. Central venous catheters (CVC), arteriovenous fistula (AVF), and arteriovenous grafts (AVG) are different types of accesses that can be used for HD. However, many factors will influence the location and the type of access that will be used, for example, the patient's arterial, venous and cardiorespiratory systems, other clinical and socioeconomic factors, and duration on HD.[89]
Reports from middle- and low-income countries show a common theme: a high rate of AVF creation but typically only after initiating dialysis with a CVC (90%–95%).[1011] Factors associated with improved outcomes in these countries include early referral and a multidisciplinary approach.[1213]
This study aims to work out the current situation of practice at a Libyan dialysis facility and to look into the complication of each type of vascular accesses in use for HD.
PATIENTS AND METHODS
A cross-sectional study was conducted during the period from November 2020 till January 2021, on 218 patients on chronic hemodialysis; analyzing their file records for types of vascular accesses used at the start of hemodialysis until the creation of chronic access along with records on timing and complications that happened at the study period. Data collected were statistically analyzed using SPSS software. Patients had to meet the following eligibility criteria for inclusion in the study: patient known to have ESRD on regular HD in the included center, age ≥18 years old. Patients who did not meet the inclusion criteria or those who refused to participate were excluded from the study. All patients were on regular HD, twice or thrice weekly. Vascular access type data were collected with specific data relating to the anatomical location of vascular access, and duration of access use, and to avoid the possibility of confusing of dialysis access types, a physical examination of each patient was done to assure the proper vascular access was recorded.
RESULTS
The median age was 49 years (18-92 years) male gender predominates the population of the study group with 64% of patients; diabetic nephropathy was the main cause of CKD (33.9%) followed by hypertension (20.6%). Mean BMI is 26 ranging from 16-54, and the mean duration of hemodialysis was five years (ranging from 6 months to 21-years). Baseline demographic and other characteristics of patients are presented in Table 1; Figure 1.
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Figure 1: Pattern of vascular access at start of hemodialysis and at current time
Table 1: Demographic data
193/218 patients on hemodialysis (88.5%) started hemodialysis via Central venous catheters (CVC), 23/218 patients (10.5%) had an arterio-venous fistula (AVF), and only 2/218 patients (0.9%) used tunneled CVC; none has AV-graft.
Currently, 82.1% of patients have AVF, 7.8% have chronic CVC, 15.9% have acute CVC and only 4.1% have AV-Graft as shown in Table 2.
Table 2: Type of access at start of hemodialysis and at current time
Early AVF creation before the start of hemodialysis was observed only in 10.5% of patients, while later creation after starting of chronic hemodialysis therapy was observed in 45% of patients after one to two months, while 35% of patients have it created after 3-4 months [Table 3].
Table 3: Patients with tunneled central venous catheters as chronic access for hemodialysis
Chronic vascular catheters were grouped into four subgroups as seen in Table 3; no AVF nor AVG group counts 4 patients (23.5%), immature AVF group with 6 patients (35.3%), one previous failed AVF or AVG group with 3 patients (17.6%), and more than one previous attempt of AVF or AVG group with 4 patients (23.5%) as shown in Table 4.
Table 4: Timing of arteriovenous fistulas creation
Many complications were recorded in all types of access with different percentage of occurrence as follows: Thrombosis in 22% of patients, infection in 13.8%, central venous stenosis in 12.4%, aneurysm in 9.2%, hematoma in 6.9%, and steal syndrome in 1.8%, as shown in Figure 2.
Figure 2: Complication
We observed that more vascular access complications occurred in Diabetic patients and female gender.
DISCUSSION
The choice of vascular access should be individualized according to the specific patient characteristics. The primary goal should be a distal autogenous AVF in the non-dominant arm, created three to six months before the expected start of hemodialysis.[141516] This would allow time for maturation and even intervention in the event the fistula fails to mature adequately, which will decrease the need for CVC use. Many previous studies suggested that the benefit of an autogenous fistula is lost when a patient is started on a CVC and then has an AVF created.[17]
There is a wide variation among worldwide countries regarding the types of accesses being used for ESRD patients on HD. In Europe, 66% of new patients start their HD through AVF compared to 15% in the USA, whereas catheters are more widely used in USA among newly diagnosed ESRD patients, with a percentage of 60% versus 31% in Europe.[18]
Our study shown that in Libya the practice pattern is similar, where we recorded that, 82.1% of the patients have AVF, while CVC is the second most common access type practiced in Libya; where (7.8%) of the patients have permanent catheters and (5.9%) have temporary catheters, compared to a previous study done in 2012 on Libyan hemodialysis population (n=1573), showed a higher percentage of using AVF (91.9%).[19]
Arterio-venous fistula is the practiced pattern of vascular access for hemodialysis worldwide especially in the developed countries, with different percentage; Germany (84%), France (77%), Italy (90%), Egypt (67.3%) and In the USA (63.4%) in 2014.[161920] whereas the proportion of CVC is low in developed countries such as France (6%), Germany (4%) Spain (7%), and in the USA (15%).[1421] This change in pattern of practice, is likely due to psycho-social acceptance of the disease itself and financial reasons to have AVF created on own cost, as the number of public facilities for such surgery are not feasible at current time, other reasons include failure of previous AVF or delay in having surgery.
AVG is the least access type used all over, as noticed in our study that only small percentage (4.1%) of patients have AVG as their access for hemodialysis, this is applied also to the USA data, as the use of AVG for hemodialysis has dropped dramatically from 40% to 18% only.[1]
Access complications contribute to ineffective dialysis and interruptions in treatment, which further contribute to the cost of care. Significant problems with AFVs include non-maturation and early thrombosis. Some studies have shown an early failure rate as high as 46%.[8] If no suitable vessels are available, or when all vessels in the arm are exhausted, a prosthetic AVG can be used.[9]
The risk of infection is high for an AVG compared to an autogenous AVF, but primary patency may be higher.[10]
It is well known that the autogenously AVF is superior to the other modalities in terms of patency rates and infection risk. This is reflected in local and international guidelines where it is recommended as the primary option for all patients on hemodialysis.[910] The Fistula First Breakthrough Initiative and the Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines in 2006 set in motion a drive to create more AFVs and limit the use of CVCs.[7]
The most common problem with AVG is stenosis due to an abnormal turbulent flow pattern, which causes focal shear stress in the native blood vessel and neo-intimal hyperplasia, which ultimately leads to narrowing and thrombosis of the graft.[22]
Most of the patients come late to hemodialysis facilities, and start dialysis as an emergency therapy; this leads to use CVC as access for hemodialysis, which is associated with very serious complications, such thrombosis, infection and central venous stenosis.
Vascular access thrombosis and infection are serious complications happen with inappropriate use and care of vascular access. CVCs have a high-risk of infection, which causes permanent damage to the native vessels, further leads to central venous stenosis and occlusion, eventually limiting future access modalities. They also cause less hemodynamic change and no increase in blood flow to the heart, which may be important in patients with congestive cardiac failure.[23] But still they do have some benefits as they could be used as soon as they are placed when urgent dialysis is required.
In this study, the documented complication of vascular access may be underestimated as we relied upon the accuracy of the patient records; that showed, near a quarter of patients have vascular access thrombosis and is considered the most common cause of vascular access dysfunction and failure. Infection of vascular access is the second most common complication recorded in our study, which is associated with increased morbidity and mortality. Central venous stenosis or occlusion was recorded in only (12.4%) patients as evidence of central venous obstruction and stenosis may even be more underestimated since patients are not routinely screened for such complication and only clinically apparent central venous obstruction is recorded. The long-term use of CVCs leads to central venous stenosis, which further compromise future access options.[24]
The late creation of an AVF is another additional problem, as some patients and even dialysis staff do not wait for the fistula to mature causing even more troubling complications; such as hematomas, thrombosis that lead to fistula poor function or even failure. A planned pre-emptive fistula creation should ideally be fashioned three to six months before the first hemodialysis session to allow for maturation and re-intervention if necessary.[25]
A dedicated vascular access coordinator with a pre-operative ultrasound protocol was shown to be the most important factor in improving hemodialysis access outcomes, moreover, joint clinics with surgeon is the ideal practice to be adopted to overcome the difficulties in access availability for hemodialysis.
Another strategy proven to improve outcomes includes pre-operative ultrasound to evaluate the size and quality of the veins to be used. Early referral to the vascular access surgeon, as well as a structured pre-dialysis care program allows the patient to be adequately prepared with counseling and training. Regular multidisciplinary meetings are useful to refer new patients, discuss patients with early concerns about access complications and deal with problematic vascular access.
CONCLUSION
We concluded that although a high percentage of patients have arterio-venous fistula, still pre-emptive arterio-venous fistula counts very low percentage, and starting of chronic hemodialysis by using acute dialysis catheter is the main practice; most likely due to patients' unawareness of benefit and unfeasibility of arterio-venous creation. Very serious complications are still happening adding burden on patients' health due to inefficiency of hemodialysis and burden on country's health economics with additive costs of hospitalization for treatment. We recommend the establishment of joined pre-dialysis clinic with surgeons and psychologists in each dialysis center or at least in referral centers to provide better care and education of patients for early fistula creation and to plan the management.
The use of central venous catheter, even for a short period, should be discouraged. This practice relies on the timeous identification and referral of patients with chronic kidney disease.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
Acknowledgments
The authors gratefully acknowledge the support of the Authority of Azzawiyah Kidney Hospital.
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