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ACE-inhibitors and coronary microcirculation
1Medizinische Klinik und Poliklinik B, Heinrich-Heine-Universität Düsseldorf.
Insights
Arterial hypertension damages coronary microcirculation. ACE-inhibitor enalapril therapy improved coronary flow reserve in hypertensive patients, suggesting it can reverse structural vascular abnormalities.
Area of Science:
- Cardiology
- Vascular Biology
- Pharmacology
Background:
- Arterial hypertension frequently impairs coronary microcirculation, leading to angina and positive exercise tests despite normal epicardial arteries.
- Hypertensive effects on coronary microcirculation involve functional and structural alterations, causing chronic myocardial ischemia.
- Antihypertensive therapy should target blood pressure, myocardial hypertrophy, and coronary microcirculation improvement.
Purpose of the Study:
- To clinically evaluate the impact of long-term angiotensin-converting enzyme (ACE) inhibitor enalapril treatment on coronary flow reserve in hypertensive patients.
- To assess whether enalapril therapy can reverse structural vascular abnormalities in the coronary microcirculation.
- To determine the extent of coronary microcirculation improvement under clinical conditions.
Main Methods:
- A study involving hypertensive patients treated with enalapril (10-20 mg/d) for 9-12 months.
- Coronary microcirculation was assessed by measuring maximal coronary blood flow, minimal coronary resistance, and coronary reserve using dipyridamole.
- Measurements were taken before and after treatment, with a 1-week drug intermission to evaluate chronic effects.
Main Results:
- Enalapril treatment led to an approximate 8% decrease in left ventricular (LV) muscle mass.
- Coronary reserve significantly improved by 48% after enalapril therapy.
- These improvements suggest a reversal of structural vascular abnormalities in the coronary microcirculation.
Conclusions:
- Long-term ACE inhibitor therapy, specifically enalapril, can significantly improve coronary flow reserve in hypertensive patients.
- The observed enhancement in coronary reserve is likely due to the reversal of structural vascular remodeling in the coronary microcirculation.
- ACE inhibitor therapy holds potential for repairing hypertensive damage to the coronary microcirculation and mitigating chronic ischemic consequences.
Abstract:
Arterial hypertension is the most frequent cause of a disturbance of coronary microcirculation. Inspite of having normal epicardial coronary arteries, patients with arterial hypertension often have symptoms of angina pectoris and a positive exercise tolerance test. The angina pectoris-symptoms in patients with arterial hypertension are due to functional and structural alterations of the coronary microcirculation. Consequently, an antihypertensive therapy should not only aim at lowering blood pressure and reversing myocardial hypertrophy, but also improve coronary microcirculation in order to avoid the consequences of chronic ischemia on the myocardium. Until now, only experimental studies have indicated that antihypertensive therapy can improve coronary flow reserve. To determine to what extent under clinical conditions coronary flow reserve can be improved, in hypertensive patients maximal coronary blood flow, minimal coronary resistance, and coronary reserve (Dipyridamol) were studied before and after a long-term antihypertensive treatment (9-12 months) with the ACE-inhibitor enalapril (10-20 mg/d). To assess the chronic effects rather than the acute effects of the antihypertensive pharmacon, the coronary microcirculation was studied after intermission of medical therapy for a period of 1 week. Along with a decrease in LV muscle mass by about 8%, coronary reserve was improved after enalapril by 48%. It is likely that the observed increase in coronary reserve is related to the reversal of structural vascular abnormalities at the level of the coronary microcirculation. Consequently, it seems that reparation of hypertensive remodeling of the coronary microcirculation can be induced by ACE-inhibitor therapy.