This was a retrospective analytical study done at SDM College of Medical Sciences and Hospital, Dharwad in patients who underwent radiocephalic AVFs from March 2017 to February 2020. Ethical concerns were addressed and all the patient data were kept anonymous.

Data collected from the hospital records included patient details like age, sex, date of surgery, aetiology of ESRD, presence of co-morbidities like hypertension and diabetes mellitus, personal habits like smoking and tobacco chewing.

Clinical examination in terms of caliber of cephalic vein and condition of radial artery vessel wall was noted. Patients with inadequate clinical findings underwent Doppler ultrasound scan. Cephalic vein and radial artery diameter were noted in patients who underwent pre-operative doppler ultrasound scan. Hand dominance of the patient was noted and the surgery was preferred on the non-dominant hand. In cases with previous surgery on one limb and extensive venous thrombosis opposite limb was chosen.

All the above-mentioned details were extracted from patient’s case file. The data was then categorised into two groups based on the type of anastomosis - STS anastomosis with distal vein ligation technique and the end cephalic vein to side radial artery anastomotic technique.

During this period, 43 patients underwent radiocephalic arteriovenous fistula. Nineteen patients underwent STS anastomosis technique and 24 ETS anastomosis technique. Follow-up was obtained in collaboration with Nephrology and dialysis unit staff. Loss to follow-up was accounted in two patients from STS group and eight from ETS group. One patient from ETS anastomosis technique group died due to multi-organ failure prior to expected week of fistula maturation which was unrelated to creation of AVF. Seventeen patients from STS anastomosis technique and 15 patients from ETS anastomosis technique were compared with respect to primary failure of AVF, three months fistula patency and maturation of the fistula.

For the study, fistula patency at three months was defined as presence of palpable thrill or audible bruit on auscultation. Maturation of fistula with successful cannulation was defined as ability of vascular access to deliver a flow rate of 350-400 mL per minute with no access recirculation to maintain a treatment time of less than 4 hours [7-9].

As a protocol, all patients are operated under brachial plexus block with tourniquet control. Patient is placed supine with upper limb to be operated at 90 degree abduction. Curvilinear incision measuring 3-3.5 cm made on the radial border of distal 3^rd of forearm 1 cm proximal to the wrist crease. Incision is placed in between the cephalic vein and the radial artery.

Dissection performed under loupe magnification to isolate cephalic vein and radial artery and both the vessels brought in close proximity. In ETS anastomosis technique, the distal side of the cephalic vein ligated, proximal side clamped using atraumatic vascular clamp, vein cut between the vascular clamp and ligature, arteriotomy performed and anatomosis of proximal cut end of the vein and artery using 9-0 nylon in continuous running fashion. In side to side anastomosis technique following clamping of distal and proximal venous sides venotomy performed, arteriotomy done and anastomosis performed employing back wall first technique which is described by Tellis VA et al., [10]. Nylon 9-0 is the suture material used. Tourniquet is deflated and thrill is palpable in most of the cases, in cases where thrill is not palpable or bruit not heard but good venous filling noted, anti-coagulation is started in postoperative period following nephrology consultation. Thorough haemostasis is achieved and the skin incision is closed in two layers. Non-compressive dressings applied. Patient is advised not to apply pressure over the operated site, not to allow blood collection from the operated upper limb. Hand exercises using a soft ball are demonstrated and patient is asked to follow the same in postoperative period. Wound dressing is removed on second postoperative day and patient is discharged.

IBM SPSS (statistical package for social sciences) version 20 was used to analyse the data. Demographic variables were analysed with frequency, mean and standard deviation. Its association with two different operative techniques was analysed using Fisher’s-exact test. Outcome of the two operative procedures was analysed using Independent Student’s t-test.

In the present series (after excluding lost to follow-up patients and death of patient) a total of 32 patients’ data was analysed. Of them, 15 (46.87%) underwent ETS technique and 17 (53.12%) STS technique. The mean age of patients among ETS group was 48.7±17.2 years and STS group was 36±12.5 years. Males constituted the majority of the study population {13 (86.7%) and 13 (76.5%) for ETS and STS groups, respectively}. Non-dominant hand was the preferred site for the AVF creation [Table/Fig-1]. Hypertension contributed majorly as an aetiological factor among both the groups [Table/Fig-2].

Out of 15 patients in ETS anastomosis technique, 3 (20%) had primary failure. Maturation time of AVF ranged from 4 to 8 weeks, with a mean of 4.73 weeks (±2.73). Three months patency was noted in 12 (80%) patients. Out of 17 patients in STS anastomosis technique, 5 (29.41%) had primary failure. Maturation time of AVF ranged from 6 to 10 weeks with a mean of 5.29 weeks (±3.75). Three months patency was noted in 12 (70.58%) patients.

The two operative techniques were compared by performing Independent Student’s t-test for primary failure (p=0.555), maturation time (p=0.115) and three months patency rate (p=0.384) [Table/Fig-3].

Creation and maintenance of an adequate vascular access is an important factor for successful haemodialysis. Multiple vascular accesses may be required for haemodialysis patients in their lifetime as the life expectancy of these patients has improved in recent years.

Radiocephalic fistula was described by Cimino JE [5]. The main drawback of AVF is the significant rate of primary failure which is 20-50% [11-13]. Although there is consensus in terms of location of primary AVF formation at wrist [14,15] there is definitive dearth of evidence supporting the use of STS anastomosis technique and ETS anastomosis technique.

Primary failure rate in the present study in ETS group was 20% and STS group was 29.41% with an overall primary failure rate of 25%. Majority of the large volume centres report primary failure rate of 15-30% for radiocephalic AVF [16,17]. The incidence reported for primary failure in the literature varies from 9% [18] to 40% [19] and results in the present study with 25% primary failures were comparable. Definition of primary failure is absence of well-developed veins accessible for dialysis at 12 weeks after fistula surgery [19]. The primary failure rate of ETS group verses STS group was not statistically significant (p=0.555).

In the present study, fistula survival rate was noted at three months which was 80% in ETS anastomosis group and 70.58% in STS anastomosis technique group. Khan MW et al., reported an overall survival rate of 89.3% in ETS anastomosis group and 85.1% in STS anastomosis group (p=0.253) [20]. Cassioumis D et al., reported that early patency rates did not differ significantly between the ETS group (90%) and the STS group (88%) [21]. In present study, it was noted that there was no statistical significance (p=0.384) in three month patency rates of ETS versus STS groups. Further follow-up of the cases are yet to be done. However, there is evidence which states that the likelihood of overall thrombosis leading to failure of AVF is less than 10% if AVF does not thrombose and fail within first three months of its creation [22]. Hence, if early thrombosis leading to primary failure of AVF is avoided, the primary fistula patency increases and the arterialised vein shall be suitable for early cannulation/early maturation [23].

In patients undergoing haemodialysis, 60% use catheters for haemodialysis access and one of the substantial reasons for prolonged intravascular catheter use is delay in maturation of arterialised vein [24]. Catheter related bacteremia rates range from 2.4-5.5/1000 catheter days, thus increasing the morbidity, increased stay in the hospital and overall cost [25]. When catheter remains in-situ for six months the rate of infection increases up to 48%. Creation of autologous AVF with early maturation allowing nominal use of tunneled catheters will have a large impact on patient morbidity [26]. This signifies the importance of early maturation of AVF. The time for maturation of arterialised cephalic vein in present study ranged from 4 weeks to 10 weeks with a mean of 5.03 weeks (±3.27).

Comparing the results of both the groups with two different methods of AVF creation during a follow-up period of three months, we opine that there is no significant difference between the two techniques with respect to primary failure rate, maturation time and three-month patency rate.

It was conducted retrospectively and the sample size was relatively small. Period of follow-up was short. The possibility of reaching different results with longer duration follow-ups cannot be ruled out and this extra follow-up time will surely help reaching a better insight regarding the AVF patency and access longevity.

This study compared two separate techniques of radiocephalic AVF creation. All the parameters evaluated and their relations revealed no statistical significance between the two. Autologous radiocephalic AVFs at the wrist continues to be the first choice of vascular access and both ETS and STS techniques of anastomosis have proven to be beneficial in creation of AVF with no superiority of one over other.