GORA - A SCORING SYSTEM FOR THE QUANTIFICATION OF RISK OF GRAFT OCCLUSION

Auditing the outcome from vascular surgery with regard to graft occlus ion is made difficult by variations in the type of surgery performed a nd the case mix. These difficulties are compounded when attempting to compare units. In the present study we have attempted to develop a sco ring system to predict the risk of graft occlusion, and thus compensat e for these variables. Prospectively collected data from 214 consecuti ve patients undergoing vascular reconstructive surgery (233 arterial g rafts) were analysed. Graft occlusion occurred in 82 patients (35.2%). Using a multivariate linear regression analysis of these data a five- factor, five-grade scoring system has been devised (GORA: Graft Occlus ive Risk Assessment). Logistic regression analysis of the observed ris k of occlusion with this derived score produced the following relation ship between the odds ratio of occlusive risk and GORA score (log(e)R/ 1-R = (0.229 x score)-4.165) The score was then validated in a differe nt group of 186 patients (196 arterial grafts). In both groups the sco re was found to predict accurately the risk of graft occlusion (P<0.00 1). There was no significant difference in the receiver operating char acteristic curves between the estimation and validation groups.