INFRAPOPLITEAL BYPASSES TO SEVERELY CALCIFIED, UNCLAMPABLE OUTFLOW ARTERIES - 2-YEAR RESULTS

Purpose: Although severe, circumferential calcification of distal outf low vessels is frequently encountered, its effect on bypass graft pate ncy rates has not been well established. Methods: Using a computerized vascular registry database, we conducted a retrospective review of 19 57 bypass grafts with distal anastomoses to infrapopliteal vessels per formed at a single institution between 1990 and 1995. Of these cases, 101 procedures involved outflow arteries classified by the operating s urgeon as severely calcified and unclampable (requiring intraluminal o ccluders for vascular control), whereas in 105 cases the outflow arter ies had no calcification present at the distal anastomotic site. The r emaining cases had varying intermediate degrees of calcification and w ere not analyzed. Indication for bypass procedure was limb-threatening ischemia in 90% of severe calcification cases and in 84% of cases wit hout calcification. Atherosclerotic risk factors were similar except f or the presence of diabetes (92% vs 74%, p < 0.001), creatinine level > 2.0 mg/dl (21% vs 8%, p < 0.01), and dialysis dependency (17% vs 3%, p < 0.001), all of which were more prevalent in the severe calcificat ion group. Infrapopliteal distal anastomotic location and type of cond uit (>90% autogenous vein) were comparable between groups. Results: Pr imary patency, secondary patency, and foot salvage rates at 24 months were 60%, 65%, and 77% for the severe calcification group and 74%, 82% , and 93% for the no calcification group, respectively. With secondary procedures comprising 26% of cases in each group, data from the 150 p rimary procedures were reanalyzed separately. In this primary procedur e group, 24-month primary patency, secondary patency, and foot salvage rates were 66%, 69%, and 77% for the severe calcification group and 8 4%, 90%, and 96% for the no calcification group, respectively. Althoug h patency and salvage rates were consistently lower for the severe cal cification group in all analyses, these differences did not achieve si gnificance by log-rank life-table analysis at 2-year follow-up. Periop erative 30-day mortality (0.99% severe calcification vs 0.95% no calci fication) and 24-month survival rates (84% severe calcification vs 83% no calcification) were also similar between groups. Conclusion: These data suggest that effective techniques exist to perform infrapoplitea l bypasses to severely calcified, unclampable outflow arteries with re sults comparable with those obtained with clampable, uncalcified vesse ls. The finding of severe, circumferential calcification of outflow ta rget arteries should not dissuade vascular surgeons from distal bypass for limb salvage indications.