Design of a New Risk Score in Critical Limb Ischaemia: The ERICVA Model

It is difficult to establish which patients suffering from critical lower limb ischaemia will benefit from revascularization. Risk scores can provide objectivity in decision making. The aim was to design a new risk score (ERICVA) and compare its predictive power with the PREVENT III and Finnvasc scores.

An observational retrospective study of patients who underwent revascularization (open or endovascular) in Valladolid's University Hospital between 2005 and 2010 was designed. The sample was divided into two subgroups (development and validation subsamples). After univariate analysis followed by a multivariate Cox regression, a number of variables associated with death and/or major amputation were selected, creating a weighed score called ERICVA, and a simplified version of it. The area under the curve (AUC) of receiver operating characteristic (ROC) curve analysis was performed and the AUC of these two scores were additionally compared with the AUC of the PREVENT III and Finnvasc scales.

Six hundred and seventy two cases with an average surveillance of 778 days were included in the study. Amputation free survival (AFS) was 84.8% at 30 days and 63.1% at 1 year. Variables associated with death and/or major amputation in the Cox regression were cerebrovascular disease, prior contralateral major amputation, diabetes mellitus, dialysis, chronic obstructive pulmonary disease, cancer, haematocrit less than 30%, neutrophil/lymphocyte ratio exceeding 5, absence of arterial Doppler signal at the ankle, emergency admission, and Rutherford stage 6; these variables were used for the ERICVA and simplified ERICVA score designs. Scores were applied to both subsamples; in the development sample the AUC of ERICVA and simplified ERICVA was significantly higher than the PREVENT III (p = .008 and p = .045) and Finnvasc (p < .0001 and p = .0013) scores; in the validation sample the AUC of ERICVA and simplified ERICVA were significantly higher than Finnvasc score (p = .0323 and p = .0017).

The ERICVA model has a good predictive capacity for death and/or major amputation in the clinical setting, and is better than the PREVENT III and Finnvasc scores.