Prevalence of impaired coronary flow reserve and its association with left ventricular diastolic function in asymptomatic individuals with major cardiovascular risk factors

Aim: The aims of this study were to evaluate: i) the prevalence of impaired coronary flow reserve (CFR), ii) the association of impaired CFR with indices of left ventricular function, and iii) the independent predictors of impaired CFR in a cohort of high-risk asymptomatic individuals.

Methods: Ninety-nine consecutive individuals (age, 52.5 ± 13.2 years; 68% male; left ventricular ejection fraction, 62 ± 6%) with at least one major cardiovascular risk factor (49% hypertension, 23% diabetes mellitus, 42% hypercholesterolemia, 32% smoking) were evaluated. Based on CFR values, patients were divided into normal (CFR ≥2.5), borderline (2.5>CFR ≥2.0), and abnormal (CFR < 2.0). Left ventricular function was assessed with comprehensive transthoracic echocardiography.

Results: Impaired CFR was identified in 39 individuals (borderline, n = 25; abnormal, n = 14). Isovolumic relaxation time was significantly increased for abnormal compared with normal CFR (94 ± 12 vs. 85 ± 11 msec, p < 0.05), as was the left atrial volume index (LAVI) (24 ± 7 cm³/m² vs. 19.1 ± 5.2, p < 0.01). A stepwise linear regression analysis identified the LAVI and the deceleration time of E wave of transmitral flow as the only independent predictors of CFR value. An ordinal regression analysis model revealed two predictors of CFR categorization: diabetes mellitus (proportional odds ratio (POR) for CFR group deterioration, 4.55; 95% confidence interval (CI), 1.13–18.28; p = 0.033) and LAVI (POR, 1.11 per 1 cm³/m² increment; 95% CI, 1.01–1.23; p = 0.034).

Conclusions: CFR is often impaired among asymptomatic individuals with major cardiovascular risk factors and is associated with changes in left ventricular diastolic function and left atrial size. The prognostic importance of these early derangements should be assessed in prospective studies.