Israel Medical Association Journal

Background: Reliable vascular access is a fundamental tool for providing effective hemodialysis. Vascular access dysfunction is associated with increased morbidity and mortality among hemodialysis patients. Current vascular access guidelines strongly recommend creating an arteriovenous fistula (AVF) as the first option; however, a substantial proportion of new AVFs may not be usable.

Objectives: To assess possible predictors of primary and secondary failure of vascular access.

Methods: This retrospective cohort study included all vascular access sites created at Meir Medical Center from 2006 through 2012. Vascular access site, primary and secondary failure rates, and relevant demographic and clinical data were recorded during 60 months of follow-up.

Results: A total of 612 vascular accesses were created and followed for a median of 32 ± 29.4 months. Of these, 490 (80%) were suitable for initiating hemodialysis. Vascular access site was the most important predictor of primary failure but did not predict secondary failure. Co-morbidities such as diabetes mellitus and congestive heart failure, as well as the use of antiplatelet agents did not predict primary or secondary failure. Preoperative vascular mapping using Doppler ultrasonography was performed in 36.4% of cases and was not associated with lower rates of primary or secondary failure.

Conclusions: Vascular access site is an important predictor of primary failure. We did not find a benefit of pre-operative vessel mapping or chronic antiplatelet therapy in terms of decreasing primary and secondary failure rates. Physicians should carefully consider the characteristics of the patient and blood vessels before creating vascular access in patients requiring chronic hemodialysis.

Background: In recent years there has been an increase in endovascular repair of thoracic aortic aneurysms. In cases of insufficient neck length, occlusion of left subclavian artery achieves proper sealing and is usually well tolerated. Selected cases require revascularization of the left subclavian artery, including patients after coronary bypass surgery (left internal mammary to left anterior descending) and those with arm claudication or subclavian steal syndrome.

Objectives: To evaluate the tolerability of left subclavian artery occlusion by stent graft without revascularization.

Methods: Thirty patients with thoracic aortic aneurysms underwent endovascular repair between July 2000 and November 2004. Eleven of them had occlusion of the left subclavian artery that required revascularization in two. Follow-up (average 3 years) included a) blood pressure measurements of both arms at rest, after effort and pulse palpation, and b) vertebral blood flow by duplex scan.

Results: Of nine patients with no revascularization, 8 (89%) tolerated left subclavian artery occlusion with no claudication or steal syndrome; one (11%) suffered mild claudication only after effort and required no intervention. No left radial pulses were palpated in the nine patients. Blood pressure measurements in the left arm showed an average decrease of 40%, which remained constant after induced effort in all patients and was clinically insignificant. Duplex scan demonstrated reverse flow in the left vertebral artery in 8 of 9 patients (89%) and occlusion in 1 (originating in the arch and covered by the stent graft) with no clinical symptoms.

Conclusions: Left subclavian artery occlusion by stent graft is a tolerable procedure in the long term. In most cases, the constant decrease in blood pressure remained unchanged during follow-up and had no significant adverse affects. Most patients do not require revascularization prior to the endovascular procedure.