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Abnormal coronary vasomotion in hypertension: role of coronary artery disease
J Frielingsdorf1, P Kaufmann, C Seiler
1Department of Cardiology, University Hospital, Zurich, Switzerland.
Insights
Dynamic exercise affects coronary vasomotion differently in hypertensive patients with and without coronary artery disease. Hypertensive patients with coronary artery disease exhibit abnormal responses, indicating endothelial dysfunction.
Area of Science:
- Cardiovascular Physiology
- Hypertension Research
- Coronary Artery Disease
Background:
- Arterial hypertension is linked to endothelial dysfunction and impaired coronary vasodilation.
- Abnormal responses to acetylcholine suggest pre-existing endothelial dysfunction in hypertensive individuals.
Purpose of the Study:
- To investigate the impact of dynamic exercise on coronary vasomotion.
- To compare these effects in hypertensive patients with and without coronary artery disease.
Main Methods:
- Quantitative coronary arteriography assessed vessel dimensions at rest and during exercise in 64 patients.
- Patients were categorized into groups based on hypertension and coronary artery disease status.
Main Results:
- Hypertensive patients without coronary artery disease showed normal exercise-induced vasodilation.
- Hypertensive patients with coronary artery disease exhibited reduced vasodilation in normal and stenotic segments.
- Nitroglycerin normalized vasodilation but its effect was diminished in patients with coronary artery disease.
Conclusions:
- Exercise elicits normal coronary vasomotion in hypertensive patients without coronary artery disease.
- Hypertensive patients with coronary artery disease display abnormal vasomotion, suggesting endothelial dysfunction.
- Coronary artery disease presence blunts nitroglycerin's vasodilatory effect, indicating structural defects.
Objectives:
This study sought to evaluate the effect of dynamic exercise on coronary vasomotion in hypertensive patients in the presence and absence of coronary artery disease.
Background:
Endothelial dysfunction with abnormal coronary vasodilation in response to acetylcholine has been reported in patients with arterial hypertension.
Methods:
Coronary artery dimensions of a normal and stenotic vessel segment were determined in 64 patients by biplane quantitative coronary arteriography at rest and during supine bicycle exercise. Patients were classified into two groups: 20 patients without evidence of coronary artery disease (10 normotensive, 10 hypertensive [group 1]) and 44 patients with coronary artery disease (26 normotensive, 18 hypertensive [group 2]). Both groups were comparable with regard to clinical characteristics, serum cholesterol levels, body mass index, exercise capacity and hemodynamic data.
Results:
Mean aortic pressure was significantly higher in hypertensive than normotensive patients. Exercise-induced vasodilation of the normal vessel segment was similar in normotensive and hypertensive patients without coronary artery disease (group 1), namely, +19% versus +20%. However, in hypertensive patients with coronary artery disease, exercise-induced vasodilation was significantly less in both normal and stenotic vessel segments than in normotensive subjects (+1% vs. +20% for normal [p < 0.003] and -20% vs. -5% for stenotic vessels [p < 0.025]). Administration of 1.6 mg of sublingual nitroglycerin at the end of exercise led to a normalization of the vasodilator response in normotensive as well as hypertensive patients. However, this response became progressively abnormal in group 2 when coronary artery disease was present.
Conclusions:
In the absence of coronary artery disease, the vasomotor response to exercise is normal in both normotensive and hypertensive patients. However, in hypertensive patients with coronary artery disease, an abnormal response of the coronary vessels can be observed, with a reduced vasodilator response to exercise in normal arteries but an enhanced vasoconstrictor response in stenotic arteries. This behavior of the epicardial vessels during exercise suggests the occurrence of endothelial dysfunction (i.e., functional defect) that is not evident in the absence of coronary artery disease. Nitroglycerin reverses impaired coronary vasodilation, but this effect is blunted in the presence of coronary artery disease (i.e., structural defect).