Angiographic quantification of diffuse coronary artery disease: Reliability and prognostic value for bypass operations

Objectives: Diffuse distal coronary disease is thought to worsen the outcome of coronary bypass operations, but it is not easily quantified. The present study seeks to show that distal coronary diffuseness can be assessed by a structured reading of the coronary angiogram and that the resulting measure predicts operative mortality. Methods: Sequential survivors (n = 100) and nonsurvivors (n = 34) of nonemergency bypass operations were studied retrospectively. Angiograms were read as follows: (1) Coronary branches at risk were identified; (2) the amount of myocardium supplied by each branch was estimated in steps of 0.5 such that the entire left ventricle added to 8 segments; (3) distal disease severity in each branch was rated on a 5-point scale; and (4) a distal coronary diffuseness score was determined by summing (severity rating x segments supplied) for all branches. Reliability was assessed by correlating the results of blinded re-readings of the same angiograms by the same and different investigators. The score's association with mortality was determined by means of logistic regression. Results: A distal coronary diffuseness score could be determined from all angiograms. Interobserver and intraobserver reliabilities were high, with r values of 0.81 and 0.83, respectively (P < .001), The score was 1 of 3 significant independent predictors of operative mortality, along with nonelective and repeat operations. Conclusion: Diffuse distal coronary disease can be quantified by a structured reading of the coronary angiogram and is a powerful independent predictor of surgical death. Inclusion of a standardized measure of this risk factor would improve statistical models of operative risk.