Influence of risk factors on coronary flow reserve in patients with 1-vessel coronary artery disease.

Coronary artery disease (CAD) risk factors influence the hyperemic response in patients without coronary artery stenosis. The aim of this study was to evaluate the influence of risk factors on coronary flow reserve (CFR) estimated by (99m)Tc-sestamibi cardiac imaging in patients with 1-vessel CAD. METHODS: Forty-eight patients with 1-vessel CAD were enrolled in the study. Systemic hypertension, hypercholesterolemia, diabetes mellitus, and cigarette smoking were considered CAD risk factors. Within 48 h, all patients underwent coronary angiography and regional CFR assessment by (99m)Tc-sestamibi imaging with dipyridamole (0.74 mg/kg of body weight). Eight patients had no risk factors, 14 had 1 risk factor, 18 had 2 risk factors, and 8 had 3 risk factors. RESULTS: The mean +/- SD CFR of the narrowed coronary vessel was 1.28 +/- 0.43 in the overall study population (1.52 +/- 0.30 in patients with 50%-70% stenosis and 0.94 +/- 0.75 in patients with >70% stenosis; P < 0.001). Two-factor ANOVA showed that the number of risk factors significantly affected CFR (P < 0.001) in patients with 50%-70% stenosis, whereas significance was only borderline in patients with >70% stenosis. Finally, a significant interaction among the degree of coronary artery stenosis, the number of risk factors, and the estimated CFR was found (F(3) = 14.0; P < 0.001). CONCLUSION: CFR is inversely related to the number of conventional risk factors in patients with 1-vessel CAD and intermediate coronary artery stenosis, whereas this influence is less evident in patients with more severe stenosis.