Lipoprotein (a) level and mortality in patients with critical lower limb ischaemia

Abstract

Objective: to investigate if serum lipoprotein (a) level is a predictor of survival in patients with lower limb atherosclerotic occlusive disease. Design: prospective follow up study. Methods: demographic, biochemical and disease variables were collected prospectively in 441 patients with lower limb arterial occlusive disease. Survival data were obtained at a mean follow up of 44 months, and significant risk factors identified by the life table method and multivariate Cox regression analysis. Results: the cumulative survival for all patients at three and five years was 79% and 63%. Lipoprotein (a) level was the only significant independent biochemical predictor for all deaths and cardiorespiratory deaths on multivariate analysis, along with age, diabetes mellitus, renal impairment, cardiac diseases and major amputation. An elevated Lipoprotein(a) level of >24 mg/dl incurred a 107% and 45% increase in mortality at three and five years respectively. The higher mortality associated with elevated Lipoprotein (a) was particularly evident in patients with critical ischemia, in whom three and five year survival was reduced from 85% to 63% and 67% to 53% (p = 0.0064). In claudicants a survival discrepancy was manifested only after five years (73% vs 62%), and the overall association did not reach statistic significance (p = 0.52). Conclusions: lipoprotein (a) level is a reliable biochemical marker for survival in patients with critical ischemia where traditional atherosclerosis risk factors were prevalent.