Sixty patients were included in this trial, who were selected randomly (simple random sample) among those referred from the Iranian dialysis center to Shohadae Tajrish hospital for hemodialysis permanent vascular access replacement during a 2 year period (2010-2012). Patients with a negative history of injection or blood sampling during the last couple of weeks and systolic blood pressure greater than 100 mmHg were selected.
Informed consents were applied. Patients were randomly divided into two groups. These groups matched, considering all demographic variables (age, gender, co-morbidities, and previously venous catheter) (, Arteriovenous Fistulae Formation2). Primarily the arteries and venous patency rates were evaluated using history and physical examination which involved arterial and venous duplex ultrasound imaging (pre and post operation), by an experienced vascular surgeon.
Frequency of Patients Based on Age and Type of Treatment
Optimal condition of arteries and veins is crucial for access surgery. An optimal venous condition was defined as a good venous refill after its manual emptying. If superficial veins could not be visualized with a venous pressure tourniquet in place, or if any abnormality was noted on the superficial venous examination, the patient was further evaluated with a superficial venous duplex ultrasound scan. Using venous duplex imaging, superficial veins were examined for their diameter, distensibility, and continuity. The minimal acceptable diameter for use was reported to be 2 to 3 mm, whereas optimal arteries had a three plus positive pulse as an essential criterion. If any abnormality was noted on the clinical arterial examination, the patient was further evaluated with segmental pressures and a duplex ultrasound scan or pulse volume recordings. For optimal outcomes, no pressure gradient should have been noted between the bilateral upper extremities, the arterial diameter should have been greater than or equal to 2 mm throughout the extremity, and a patent palmar arch should have been present.
Dominant versus non-dominant upper extremities were chosen based on their vascultature status. Non dominant upper extremities were selected in identical conditions, while following conditions enforced AVF replacement in dominant upper extremities; unfavorable vessels, previously AVF replacement in non-dominant upper extremity, which is already out of order or same side subclavian temporary vascular access for hemodialysis. Prep and drep was done, followed by a linear incision to explore the arteries and veins of implantation site, while the peri operative systolic blood pressure was preserved at 100 mmHg.
In the STS group after obtaining control over the distal and proximal segments of the artery and vein, longitudinal arteriotomy and venotomy were performed and 10 mm side to side anastomosis was achieved. While in the ETS group, longitudinal arteriotomy was done, proximal end of the vein was anastomosed to the side of the artery using the end to side method. In cases where a good flow and thrill was not obtained, coronary dilatators for dilatation of superficial veins and evaluation of the patency of veins before anastomosis was used. For prevention of venus hypertension, distal venous ligation was performed.
Success in access surgery was defined when a good thrill was obtained whereas in the absence of thrill, hence an unsuccessful access replacement, excluded the patients from the trial. Post-surgery, a light bandage was done and all the precautionaries for early AVF thrombosis and patency preservations were explained.
All patients were required for visits on the first postoperative day, when the patency of AVF was reviewed, i.e. whether it had thrill or not and also the machinery murmur was auscultated. If any access had failed to mature, it was examined with a duplex ultrasound followed by venography if further information was necessary. The next visit was scheduled a month later and the final visit was appointed 6 months after the surgery. After initial maturation, the AV access was monitored routinely while the patient was on dialysis. The preferred method of monitoring was a monthly determination of access flow by the doppler technique. Access flow less than 600 mL/min or access flow less than 1000 mL/min that had decreased by 25% over the past 4 months were evaluated with a duplex ultrasound followed by a fistulogram if further information was necessary.
The data gathered during the 6 months follow up was registered in prepared forms and reviewed later to reach a statistical conclusion. Quantitive and qualitative data measurements were expressed by means and percentages respectively using T-test and chi-square, fisher`s exact tests.