Arteriovenous Fistula Creation by Nephrologists for Haemodialysis Initiation in End-Stage Kidney Disease: A Single-Centre Experience from India

The survival of patients on Hemodialysis (HD) depends on reliable vascular access to the circulatory system, which is achieved by creating an Arteriovenous Fistula (AVF), placing an arteriovenous graft, or inserting a central venous catheter. Among the three options, AVF, initially developed by nephrologists [1], remains the preferred form of vascular access. However, HD initiation through AVF is low in India. The rate has been reported to be 19% in one study [2], which is very low when compared with those in Japan (65%) and Europe (67%) [3]. The majority of our patients (81%) with End-Stage Kidney Diseases (ESKD) get HD initiation through uncuffed venous catheters [2]. The possible factors for such a low AVF creation in North East India are low affordability of dialysis care, emergency dialysis initiation through venous catheters as the majority of our patients present late when there is an urgent need for dialysis, conservative care until the late stages by primary care physicians without timely creation of AVF, treatment at a peripheral center lacking facilities for vascular surgery, lack of knowledge regarding the timing of AVF creation [4-6], and lack of nephrologist involvement in AVF creation. AVF creation by nephrologists is less common in India and US than in European countries [7]. In our region, AVFs are created exclusively by surgeons and in very few centers by the nephrologist. 

Why should nephrologists be involved in AVF creation in our region? 

The nephrologist is the critical person for ESKD care. Patients with ESKD consult nephrologists before being referred to the surgeon for AVF creation. By the time they reach the surgeon, peripheral veins get thrombosed or inflamed because of repeated venipunctures, which lowers the chances of a successful AVF. AVF creation by the nephrologist can avoid this problem and has a higher chance of success. The patients also get easily convinced and motivated when the primary doctor does the surgery, which is likely to improve the AVF rates at dialysis initiation. Secondly, adequate number of skilled surgeons with a decent knowledge of HD is not available, and accessing them is difficult in our region. Several European investigators have reported nephrologists' successful creation of AVFs, with excellent long-term procedural outcomes. Here, we share our experience of AVF creation by a nephrologist from a single center in North-East India and patient follow-up of 3 months or until maturation.

This prospective observational study was conducted at our hospital over five years, from April 01, 2016, to March 31, 2021. We included all patients undergoing AVF creation by a single nephrologist in our center during the abovementioned period. Each patient was followed up for three months or until maturation. The patients were selected randomly. We took the patients having suitable veins and arteries on examination. Complicated cases referred to surgeons. We obtained informed consent from all patients for inclusion in the study. The hospital's ethical committee approved the study. Preoperative evaluation of the suitability of veins and arteries was done clinically by the operating nephrologist. Short patient history, including age, sex, diabetes, hypertension, chronic kidney disease, and history of procedures via central veins, was obtained. Physical examination included palpating the arterial pulse volume and arterial wall. We assessed the veins by palpation with the aid of a tourniquet and by feeling the thrill on tapping them. We performed the Allen test routinely before proceeding with distal AVFs.We didn't do preoperative Doppler ultrasonography mapping of the vessels as it would exacerbate the financial burden of the patients. 

Baseline characteristics of patients and outcomes of AVFs. 

Surgical technique: All procedures were performed on a day-care basis under local anesthesia in an operation theatre with perioperative prophylactic antibiotic therapy (ceftriaxone 1g, administered intravenously). We made a 5-7 cm curvilinear or linear skin incision at the distal forearm or wrist. The target vein (cephalic) and artery (distal radial) were exposed using a combination of blunt and sharp dissection. Infant feeding tube 6-0 was passed through the vein to the elbow to rule out any thrombus, dilate the vein with saline, and assist during anastomosis. Anastomosis was end-to-side and side-to-side with ligation of the distal vein. Arteriotomy size in all the cases was 8–10 mm. Anastomosis was achieved by a continuous running suture using a double needle prolene 6-0 suture. Accessory veins, if found, were ligated. We didn't use magnifying loupe routinely. The skin was closed using a catgut suture.We did not use heparin or any antiplatelets in the postoperative period and did not perform any intervention in cases where thrill was absent. All the patients received verbal and written instructions about the care of the AVF. They underwent dressing during the dialysis sessions and removed skin sutures, if required, after two weeks. The patients were followed up for 3 months to check for maturation.

Immediate patency was noted based on the presence of thrill in the postoperative period. Primary failure was defined as failed AVF function either immediately after construction or in the first 24 hours. 

Maturation: A mature fistula can consistently provide the prescribed dialysis with two needles for more than two-thirds of the dialysis sessions for four consecutive weeks [8].

The total number of AVFs created over the study period was 60. 53 (88.3%) patients obtained immediate patency, and 46 (76.7%) patients achieved maturation. Detailed results are shown in the table.

Angio-access surgery is not restricted to vascular surgeons. Other specialists (e.g., urologists and general, plastic, and cardiothoracic surgeons) also perform this operation. Surgeons create AVFs in a vast majority of centers in India, and only in a few centers by nephrologists. The significant advantages of AVF creation by nephrologists in our region are freedom from the mercy of surgeons for AVF creation, relatively good venous condition at the time of consultation with the nephrologist before referral to the surgeon, and the shortened waiting time for the procedure. AVF creation by nephrologists has been described globally. Nephrologists construct 85% of the AVFs in Italy and about 25% in Japan [9]. In India, nephrologists began performing AVF surgery at the Tirunelveli Kidney Care Centre in South India. The initial experience of the center with 265 patients was presented at the World Congress of Nephrology in Berlin in 2003. The study reported no difference in the outcomes of AVFs created by nephrologists and surgeons [10,11] also found no difference in the rate of functioning of the AVF, whether created by vascular surgeons or by nephrologists. It also reduced the percentage of patients who initiated dialysis without an AVF from 63% in the general surgery group to 19% in the nephrology group [12] reported a study where nephrologists created 72.9% of all AVFs in their center over 15 years. The results showed that AVFs constructed by vascular surgeons had a 38% greater chance of failure than nephrologists. The better results of the nephrologist in terms of fistula functionality compared with those of the vascular surgeons were not only due to the insufficient motivation of the latter but also due to the more detailed preoperative evaluation of the blood vessels used to create the anastomosis by the former. The nephrologists performed a thorough clinical and radiological assessment to identify the optimal location and quality of the blood vessels for anastomosis. The vascular surgeons' poor results in fistula functionality were attributed to the surgeons being overloaded within their own surgical program and insufficient training. 

Recent studies have documented successful AVF maturation rates between 40% and 80%, with older age, distal fistula location, and small vein diameter associated with greater failure rates. On the other hand, a radial artery diameter of >2 mm and the presence of immediate thrill postoperatively were significantly related to successful cannulation [13]. In a study from India, the maturation of AVF reported by surgeons was 73.2% without postoperative radiological interventions [13]. Similarly, plastic surgeons from India have reported an overall success rate of 72.3% in 271 AVFs; proximal fistulas had a higher success rate than distal fistulas (76% versus 70%) [14], Shrestha S et al [15] from Nepal reported the creation of 166 AVFs by a single nephrologist, of which 139 (83.7%) were functional at three months post-creation. The functional outcomes of radiocephalic, brachiocephalic, and brachiobasilic AVFs were 75.6%, 90.7%, and 100%, respectively, at three months post-creation. The present study has testified the maturation of radiocephalic AVF in 76.7% of the patients, which is consistent with the above study. Chauhan PS et al. [16] from India observed immediate patency in 76.9% of the patients in a cohort of 26 AVFs created by a nephrologist, of which 6 (23%) patients had a primary failure. A study [17] of 159 AVFs created by a nephrologist from Brazil showed immediate and late patency in 124 (78%) and 110 (62.9%) patients, respectively. 

Approximately 18%–65% of the AVFs that facilitate HD in patients fail to mature. Dasari R et al. [18] recorded an overall success rate of 68.3% and a failure rate of 31.7%. The present study has shown immediate patency in 88.3% and primary failure in 11.7% of the patients. These results are encouraging compared to those from other studies [16,17]. This better result is attributable to patient selection, which was performed randomly based on the presence of suitable veins and arteries on clinical examination before AVF creation. We attempted simple and suitable cases. Nephrologists can construct AVF after undergoing surgical training. One can assume that nephrologists focus on various factors critical for maturation and cannulation, e.g., accessory vein ligation, making the vein superficial for future cannulation, and maintaining a long segment for cannulation. The success rate of AVF creation by nephrologists is equal to that of surgeons. However, owing to the lack of specific information in the literature that indicates the primary specificity of physicians creating vascular access, it isn't easy to evaluate the experience of nephrologists concerning that of the surgeons [19]. We encourage young nephrologists in India to come forward for AVF construction in ESKD patients to improve fistula rates at dialysis initiation in our region.

Nephrologists can construct AVFs after undergoing surgical training. The successful maturation of radiocephalic AVFs created by a single nephrologist in our center was 76.7%. The involvement of the nephrologist in vascular access construction may improve the fistula rates at HD initiation, as the nephrologist is the most critical person for ESKD care in our region.

Informed consent was obtained from all individual participants.

Nil.

This report is not submitted elsewhere or under review. The authors have declared that no conflict of interest exists.

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