Vascular surgical society of great britain and ireland: patients with a failed infrainguinal bypass graft have abnormal lipid metabolism

Abstract

BACKGROUND: Dyslipidaemias adversely affect vascular tone, endothelial function and platelet activation. Abnormal lipid metabolism has not been established as a risk factor for infrainguinal bypass graft failure. Lipid metabolism was evaluated prospectively in patients with patent and occluded grafts. METHODS: Twenty-eight patients with failed infrainguinal grafts (group 1) were identified from a prospective computerized database. Twenty matched controls with functioning grafts (group 2) were recruited from a graft surveillance programme. Fasting blood samples were analysed for triglyceride (TG), high-density lipoprotein (HDL) and cholesterol. A newly devised rapid TG tolerance test was conducted with analysis of TG at 1, 2 and 2.5 h. Endothelial lipoprotein lipase (LPL) was measured 30 min after intravenous administration of heparin 50 units kg-1. RESULTS: The cholesterol : HDL ratio was significantly higher in group 1 than group 2 (median 6.0 (range 3. 1-10.0) versus 4.7 (2.3-9.4); P = 0.0008, Mann-Whitney test) as was fasting TG (2.6 (1.0-6.3) versus 1.7 (0.6-4.7) mmol l-1; P = 0.03). The area under the curve of the TG tolerance test was not significantly different (P = 0.08); however, the 2.5-h levels of TG were significantly different between the groups (group 1, 2.0 (0.5-6. 6) mmol l-1; group 2, 1.2 (0.3-6.8) mmol l-1; P = 0.01). LPL was significantly lower in group 1 (52.4 (2.2-235.9) versus 86.8 (28. 6-281.5) mmol/l; P = 0.04). CONCLUSION: These data suggest that abnormal lipid metabolism is a significant risk factor for infrainguinal graft occlusion. This study provides a rationale for randomized trials of lipid-modifying therapies in patients undergoing arterial reconstruction for peripheral vascular disease.