Effect of the Angiotensin Receptor Blocker Valsartan on Coronary Microvascular Flow Reserve in Moderately Hypertensive Patients with Stable Coronary Artery Disease

Abstract

To noninvasively investigate the effects of the angiotensin receptor blocker (ARB) Valsartan. on myocardial microcirculation in moderately hypertensive patients with stable coronary artery disease (CAD). In this prospective open-label study, patients with mild stable CAD and moderate systolic and/or diastolic hypertension were treated with 160 mg Valsartan daily. Myocardial blood flow was quantified noninvasively using positron emission tomography (PET) with N-13 ammonia at baseline, after one week and after 16 weeks. Mean blood pressure at rest improved significantly from baseline to week 16 (105 +/- 10 vs. 98 +/- 9 mm Hg: p = 0.017, n = 12), but no significant change was observed after one week (103 +/- 11 vs. 100 +/- 11, p = 0.43, n = 13). PET analysis revealed that flow increase during endothelial-dependent, sympathetic stimulation by cold pressor testing (CPT) and in response to pharmacologic vasodilation with adenosine improved from baseline after 1 week (CPT: 1.10 +/- 0.3 vs. 1.37 +/- 0.3; p = 0.017, adenosine: 2.34 +/- 0.52 vs. 2.91 +/- 0.81; p = 0.048) and at week 16 (CPT: 1.15 +/- 0.4 vs 1.39 +/- 0.2; p = 0.10, adenosine: 2.34 +/- 0.52 vs 2.81 +/- 0.91; p = 0.039). In patients with stable coronary disease, ARB results in improved PET-determined microvascular flow reserve. Improvements in microcirculation preceded the reduction of blood pressure, suggesting direct beneficial effects on microvascular function.