Over a 4-year interval, 324 arteriovenous conduits were created in 256 patients with end-stage renal disease as access for chronic hemodialysis. These included 154 Cimino fistulae, 163 polytetrafluoroethylene (PTFE) grafts, and seven miscellaneous grafts. Satisfactory patency rates were demonstrated for as long as 4 years for both Cimino fistulae and PTFE grafts by life-table analysis. Failures of Cimino fistulae usually occurred early in the postoperative period, secondary to attempts to use inadequate veins. Thrombosis caused the majority of PTFE graft failures and was generally the result of venous stenosis. Correction of such venous stenosis is mandatory to restore graft patency and can result in prolonged graft survival.
Doppler sonography and magnetic resonance (MR) angiography were prospectively used in combination as a substitute for conventional angiography in 24 consecutive patients likely to undergo carotid endarterectomy. Of 19 patients (20 lesions) who underwent carotid endarterectomy, 18 had not undergone preoperative angiography. High-grade lesions (> 75%-diameter stenosis) were surgically confirmed in 16; a 60%-70% stenosis, in one; and subtotal occlusion of the internal carotid artery, in another. Angiography was performed in a case of suspected internal carotid artery dissection. In the five nonsurgical cases, no significant stenosis was noted with both techniques in two instances, total occlusion was seen in two cases, and an asymptomatic stenosis was seen in one. Follow-up (average, 4.5 months) showed one case of symptomatic occlusion of the internal carotid artery after endarterectomy. This preliminary study suggests that the combined use of Doppler sonography and MR angiography can, in up to 79% (15 of 19) of cases, replace angiography for the preoperative evaluation of patients likely to need carotid endarterectomy.
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