Role of myocardial perfusion scintigraphy in predicting global cardiovascular risk and differentiating between patients with moderate and high cardiovascular risk.

Abstract

The usefulness of stress myocardial perfusion scintigraphy (MPS) for cardiovascular (CV) risk stratification in patients at moderate and high CV risk remains controversial. We tested the hypothesis that different clinical risk profiles influence the test and the likelihood of obtaining a positive coronary angiography (CA) in the following 12 months. We assessed the prognostic value of MPS in 230 patients classified according to the European Society of Cardiology guidelines. Patients at high and very-high CV risk had a higher prevalence of positive MPS (25.5 vs. 36.7%, P=0.014 and 9.8 vs. 19.5%, P=0.011, respectively), whereas patients at moderate risk had a higher prevalence of negative MPS (45.1 vs. 38.3, P=NS). Multivariate regression analysis showed that positive MPS was an independent predictor of 12-month positive CA only in patients at high CV risk [odds ratio (OR) 8.03, 95% confidence interval (CI) 1.53-42.03, P=0.014] independent of age>60 and coexistence of obesity and previous percutaneous coronary intervention (OR 3.78, 95% CI 1.18-12.78, P=0.032; OR 1.83, 95% CI 1.03-3.26, P=0.039). The C-statistic showed a good discriminatory power of positive MPS in predicting 12-month positive CA (0.68, 95% CI 0.55-0.80, P=0.015). Mantel-Cox analysis showed that after 12 months of follow-up, in patients at high risk, there was a statistically significant difference in the distribution of patients with positive than those without negative CA (log rank P=0.04). CV risk stratification on the basis of MPS is useful only in patients at high and very-high CV risk. In these groups, MPS can aid stratification for the risk of CV events.