Critical leg ischaemia: an appraisal of clinical definitions

The reliable prediction of imminent limb death remains a clinical problem. The International Vascular Symposium and European working parties each produced similar definitions of “critical ischaemia”, but this is the first attempt to address the issue with prospectively collected data. Complete 3-year follow-up data were available for 213 patients. In addition to the above two definitions, a simplified modification has been evaluated, after review of the data 1 year into this study. All three definitions were able to identify patients likely to require amputation in the absence of successful reconstruction. The sensitivity, specificity and positive predictive values with which they were able to do so was, however, poor. None of the definitions was able to predict which diabetic patients would require amputation. Diabetics were more likely to undergo amputation than non-diabetics. There was, however, no significant difference in the initial ankle artery pressures between the diabetic and non-diabetic patient subgroups. None of the definitions reliably predicted which grafts would occlude, in which event the 3-year mortality rate was approximately 35 per cent. Critical ischaemia by any of these definitions is associated with a high mortality rate. Arterial reconstruction is associated with a reduction in both mortality and amputation rates These data do not support the hypothesis that critical ischaemia is associated with a greater graft occlusion rate than lesser degrees of severe ischaemia.