Relation of coronary flow reserve and diastolic function to fractional pulse pressure in hypertensive patients

Fractional pulse pressure (PPf), is thought to more directly reflect arterial stiffness than pulse pressure. Our aim was to evaluate the relationship between coronary flow reserve (CFR), left ventricular diastolic function (LVDf) and PPf in hypertensive patients with normal coronary arteries. Out of 109 hypertensive patients (aged 52.8 ± 9.4 years), with normal coronary angiography, CFR was calculated successfully in 106 patients. CFR was calculated using transthoracic echo Doppler assessment with hyperemia induced by infusion of dipyridamole at a rate of 0.56 mg/kg over 4 minutes, while diastolic function was evaluated by means of transmitral flow and tissue Doppler imaging. PPf was calculated as pulse pressure divided by mean arterial pressure [Systolic blood pressure - Diastolic blood pressure/Mean arterial pressure (SBP - DBP/MAP)], Hypertensive patients with low CFR (n = 54) compared with those with normal CFR (n = 52) exhibited significantly increased PPf (75.2 ± 11.4 vs. 61.5 ± 6.7 P < 0.001). Moreover, patients with higher PPf had significantly decreased transmitral E/A ratio (P < 0.01), as well as increased E/Em ratio (P < 0.01). In hypertensives with low CFR, PPf was negatively correlated with CFR (r = -0.815, P < 0.0001). After applying multivariate linear regression analysis, PPf turned out to be a powerful independent predictor of CFR. Receiver operating characteristic (ROC) analysis revealed that a PPf of ≥0.63 was the best cutoff value for prediction of CFR <2.0 and E/Em ≥ 8 (AUC = 0.916 and 0.929 respectively; P < 0.001). Increased PPf was associated with impaired CFR and diastolic dysfunction in hypertensive patients with normal coronary arteries. PPf could be used as a simple non-invasive index for assessment of coronary microcirculation in hypertensives with normal coronary arteries.