Objective: To investigate the impacts of blood pressure control on coronary flow reserve (CFR) in hypertensive patients.
Methods: A total of 236 patients without significant coronary stenosis (defined as <50% luminal narrowing which was confirmed by coronary angiography or coronary artery CT scan) between January 2011 to July 2015 were retrospectively enrolled in this study. CFR was measured in the left anterior descending coronary artery (LAD) during adenosine triphosphate-induced hyperemia by transthoracic Doppler echocardiography. Patients were divided into hypertension group (n=173) and non-hypertension group (n=63). The hypertension patients were further divided into ideally controlled (n=31, defined as SBP <120 mmHg (1 mmHg=0.133 kPa) and DBP <80 mmHg), controlled (n=82, defined as SBP 120 to 139 mmHg and DBP <90 mmHg) and uncontrolled groups (n=60, defined as SBP≥140 mmHg and/or diastolic DBP≥90 mmHg) based on their blood pressure after systematic antihypertensive therapy and CFR values were compared among the 4 groups. Multivariate regression analyses were performed to identify the independent determinants of CFR in patients with hypertension.
Results: Compared with non-hypertension group, the CFR was significantly lower in controlled (3.27±0.71 vs. 2.87±0.56, P<0.001) and uncontrolled groups (3.27±0.71 vs. 2.61±0.71, P<0.001), but was similar in ideally controlled group (3.27±0.71 vs. 3.21±0.85, P=0.68). Furthermore, the CFR was significantly lower in uncontrolled group than that of the other two hypertension groups and was significantly lower in controlled group than that of ideally controlled group. Higher blood pressure (β=-0.17, P=0.03) and age(β=-0.02, P=0.03) were independent predictors of lower CFR in patients with hypertension.
Conclusions: Higher blood pressure is an independent predictor of decreased CFR in patients with hypertension. Hypertensive patients with ideally controlled blood pressure have similar CFR level as patients without hypertension.