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Improvement of coronary flow reserve after long-term therapy with enalapril
1Department of Medicine, Ernst-Moritz-Arndt-University of Greifswald, FRG.
Insights
Long-term enalapril treatment improved coronary flow reserve in hypertensive patients with microvascular angina. This angiotensin-converting enzyme inhibitor demonstrated cardioreparative effects on the coronary microcirculation.
Area of Science:
- Cardiology
- Hypertension Research
- Pharmacology
Background:
- Long-term antihypertensive therapy has not previously shown improved coronary flow reserve.
- The renin-angiotensin system plays a role in hypertensive cardiac remodeling and coronary circulation.
- Angiotensin-converting enzyme (ACE) inhibitors may possess cardioreparative properties in arterial hypertension.
Purpose of the Study:
- To investigate the clinical effects of long-term antihypertensive treatment with an ACE inhibitor on diminished coronary flow reserve in hypertensive patients with microvascular angina pectoris.
- To compare these effects with a normotensive control group.
Main Methods:
- Fifteen hypertensive patients received enalapril (10-20 mg/d) for 11-13 months.
- Measurements included blood pressure, left ventricular muscle mass index, and coronary flow reserve (assessed via dipyridamole-induced maximal coronary blood flow and minimal coronary vascular resistance).
- Functional class of angina pectoris, maximal working capacity, and maximal ST-segment depression were also evaluated.
Main Results:
- Enalapril significantly reduced systolic and diastolic blood pressure.
- Left ventricular muscle mass index decreased by 8% (P < .05).
- Maximal coronary blood flow increased by 43% (P < .001), minimal coronary vascular resistance decreased by 29% (P < .001), and coronary reserve increased significantly (P < .001).
- Angina pectoris functional class improved (P < .01), maximal working capacity increased (P < .05), and maximal ST-segment depression reduced (P < .01).
Conclusions:
- Long-term enalapril therapy is a cardioreparative treatment for the coronary microcirculation in hypertensive heart disease.
- ACE inhibitors like enalapril can improve coronary microvascular function in patients with hypertension and microvascular angina.
- The study provides clinical evidence for the beneficial effects of ACE inhibitors beyond blood pressure reduction in hypertensive cardiovascular disease.
Abstract:
To date, no clinical study shows an improvement in coronary flow reserve due to long-term antihypertensive therapy. in view of the contribution of the renin-angiotensin system to the process of hypertensive remodeling of the heart and coronary circulation, angiotensin-converting enzyme (ACE) inhibitors might act as cardioreparative drugs in arterial hypertension. Accordingly, our objective in this investigation was to examine under clinical conditions to what extent long-term antihypertensive treatment with an angiotensin-converting enzyme inhibitor improved the diminished coronary flow reserve in hypertensive patients with microvascular angina pectoris. For the purpose of comparison, we also treated a normotensive control group of 6 patients with hypertrophic nonobstructive cardiomyopathy. Fifteen hypertensive individuals (10 men, 5 women; age, 58 +/- 6 years) were treated with enalapril (10 to 20 mg/d; mean, 16.7 +/- 4.9 mg/d) for 11 to 13 months. At the end of the treatment period, systolic pressure decreased from 178 +/- 14 to 137 +/- 12 mm Hg and diastolic pressure from 102 +/- 11 to 86 +/- 4 mm Hg under ambulatory conditions. Left ventricular muscle mass index decreased by 8%, from 149 +/- 32 to 137 +/- 28 g/m2 (P < .05). Maximal coronary blood flow after dipyridamole was increased by 43%, from 181 +/- 69 to 258 +/- 116 mL/min per 100 g (P < .001), and minimal coronary vascular resistance was diminished by 29%, from 0.66 +/- 0.23 to 0.47 +/- 0.24 mm Hg x min x 100g x mL-1 (P < .001) after enalapril treatment. Consequently, the calculated coronary reserve increased from 2.2 +/- 0.6 to 3.3 +/- 1.2 (P < .001). After enalapril therapy, the functional class of angina pectoris according to the Canadian classification system had changed from 2.5 +/- 0.6 to 1.5 +/- 0.6 (P < .01). The maximal working capacity had increased from 23.775 +/- 3.970 to 26.255 +/- 4.598 J (mean +/- SE, P < .05). The maximal ST-segment depression at maximal work-load was reduced from 0.18 +/- 0.02 to 0.06 +/- 0.02 (mean +/- SE, (P < .01). In summary, long-term therapy with the angiotensin-converting enzyme inhibitor enalapril must be considered a cardioreparative treatment with respect to the coronary microcirculation in hypertensive heart disease.