Risk factors for early lower limb loss after embolectomy for acute arterial occlusion : a populationbased case-control study
To identijy risk factors f o r lower limb loss after arterial embolectomy a cohort of I189 patients was studied. Detailed data were obtained for 16. 5 patients who underwent a major amputation within 30 days of embolectomy and jbr 16. 5 matched controls. The amputation risk was increased in patients with two or more myocardial infarctions (odds ratio ( O R ) 3.1, 95per cent confidence interval ( C I ) 0+11.2), chronic ischaemia ( O R 2,1, CI 0.9-4.91, long duration of symptoms ( O R 4.3, CI I-9-9.6,for 3 2.5 h versus d 6 h ) or postoperative heart failure ( O R 3.4, C I 1.8-6.5). Reduced risks were found in association with acute myocardial infarction ( O R 0.3, CI 0.1-0.9) and postoperative anticoagulation treatment with warfarin ( O R 0.3, C I 0.1 -0.9). The independent prognostic value of chronic ischaemia and symptom duration, and the beneficial efect of postoperative anticoagulation gained additional support in multivariate analysis. We conclude that the risk of early amputation after arterial embolectorny or thromhectomy can he predicted by several clinical characteristics.
During the past two decades considerable interest has been focused on the treatment of acute arterial occlusion. T h e poor outlook after conventional embolectomy, with an a m p u t a t i o n risk of 20-40 per cent'.2 a n d a postoperative mortality rate of 15-48 per ~e n t ' . ~. ~, remains a m a j o r challenge in vascular surgery. In recent years, a number of studies have analysed amputation frequency and mortality' *. T h e risk of a m p u t a t i o n after acute embolectomy may be related t o the duration of symptoms. t h e degree of preoperative ischaemia (i.e. the completeness of circulatory arrest in t h e extremity), the pre-existence of peripheral arteriosclerosis, t h e anatomical letel of occlusion, the recurrence of embolism or thrombosis, a n d the degree of haemoconcentration and heart f a i l ~r e ~. ' . ~. ' ~.
Despite this preoccupation with assumed determinants of limb loss, there have been few attempts t o assess in quantitative terms the impact of potential risk factors for amputation' I . T h e identification of valid risk factors might form a basis for differentiation of treatment with the aim of improving the outcome after acute arterial occlusion.
This case-control study w a s undertaken t o identify risk factors for limb loss after embolectomy and to evaluate the preventive effect of postoperative anticoagulation therapy on the risk of amputation within 30 days.