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Abstract

Since late graft failures are related to intimal hyperplasia within bypass grafts at the anastomoses and at valve sites or are related to progression of proximal or distal atherosclerosis,1Veith FJ Weiser RK Gupta SK et al.Diagnosis and management of failing lower extremity arterial reconstructions prior to graft occlusion.J Cardiovasc Surg. 1984; 25: 381-384PubMed Google Scholar it is essential to monitor carefully all saphenous vein bypasses at follow-up. The goal is to identify those grafts that are failing hemodynamically and that may occlude. Bandyk et al.2Bandyk DF, Schmitt DD, Seabrook GR, Adams MB, Towne JB. Monitoring functional patency of in situ saphenous vein bypasses. The impact of a surveillance protocol and elective revision. J Vasc Surg (submitted for publication).Google Scholar monitored in situ saphenous bypass grafts with continuous-wave Doppler spectral analysis to detect decreases in graft flow velocity that may identify a potentially correctable problem. We observe our patients postoperatively with ankle-brachial indexes (ABI) at 3-month intervals during the first year and at 6-month intervals thereafter. An arteriogram is obtained when a decrease in ABI of more than 0.1 is detected between two consecutive follow-up visits, whether or not the patient has symptoms. In 15 patients with a decrease in ABI at follow-up, 14 had either a bypass stenosis or a large arteriovenous (AV) fistula. We believe that routine surveillance with duplex scanning is unnecessary and time-consuming and there is no evidence to suggest that correction of a lesion detected by duplex scanning, unaccompanied by a decrease in ABI, results in prolonged patency. We agree with Berkowitz and Greenstein3 that balloon dilatation is the primary method of treatment when a stenosis is detected. In contrast to the Southampton group, others have found that the treatment of vein graft stenoses by balloon angioplasty is a useful procedure and can result in long-term success. 4Alpert JR Ring EJ Berkowitz HD et al.Treatment of vein graft stenosis by balloon catheter dilatation.JAMA. 1979; 242: 2769-2771Crossref PubMed Scopus (47) Google Scholar, 5Greenspan B Pillari G Schulman ML Badhey M Percutaneous transluminal angioplasty of stenotic deep vein arterial bypass grafts.Arch Surg. 1985; 120: 492-495Crossref PubMed Scopus (20) Google Scholar In our series two anastomotic stenoses were successfully dilated and remained parent at 12 months each, with confirmation by repeat angiography. In the four midgraft dilatations, one occluded at 21 days; however, three remained patent at 2, 12, and 14 months after dilatation and all of the successes have had a lasting increase in ABI at follow-up. The technique of dilating vein graft stenoses differs from the technique used for arterial lesions in two important respects. First, it is essential to use a balloon with a larger diameter than the bypass. For example, a 5 to 6 mm balloon is used for a 4 mm graft as measured on the x-ray film, which is already somewhat magnified. Second, the inflation time is greater because it is important to stretch the fibrotic lesions that are seen with intimal hyperplasia. Inflation times up to 5 minutes have been suggested by some authors for dilating stenoses in dialysis AV fistulas.6Glanz S Gordon D Butt KM Hong J Adamson R Sclafani SJ Dialysis access fistulas: treatment of stenoses by transluminal angioplasty.Radiology. 1984; 152: 637-642Crossref PubMed Scopus (78) Google Scholar