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Reversal of abnormal coronary vasomotion by calcium antagonists in patients with hypercholesterolemia
P A Kaufmann1, J Frielingsdorf, L Mandinov
1Division of Cardiology, University Hospital, Zurich, Switzerland.
Insights
Calcium channel blockers normalize exercise-induced coronary vasodilation in hypercholesterolemic patients, improving blood flow in normal coronary arteries. This treatment counteracts cholesterol-induced abnormal vasomotion.
Area of Science:
- Cardiology
- Vascular Physiology
- Pharmacology
Background:
- Exercise-induced coronary vasodilation is reduced in hypercholesterolemic patients.
- Abnormal vasomotion in normal coronary arteries is linked to elevated cholesterol levels.
Purpose of the Study:
- To evaluate the effect of calcium channel blockers on coronary vasomotion.
- To assess if calcium channel blockers can normalize exercise-induced vasodilation in hypercholesterolemic patients.
Main Methods:
- 57 patients analyzed: 37 controls (group 1) and 20 on calcium blockers (group 2).
- Groups subdivided by cholesterol levels (normal vs. elevated).
- Coronary luminal area assessed via biplane quantitative coronary angiography during rest and exercise.
Main Results:
- Normal vessels showed reduced vasodilation with elevated cholesterol (13%) compared to normal cholesterol (31%).
- Calcium blocker administration (group 2) resulted in significant vasodilation (22%) regardless of cholesterol levels.
- Stenotic lesions showed vasoconstriction in controls but vasodilation with calcium blockers.
Conclusions:
- Exercise-induced coronary vasomotor response is inversely related to serum cholesterol levels in normal vessels.
- Calcium antagonists normalize exercise-induced vasodilation, counteracting cholesterol-induced abnormal vasomotion.
- The effect is likely a direct action of calcium antagonists on vascular smooth muscle.
Background:
It has been shown that exercise-induced coronary vasodilation of angiographically normal coronary vessels is reduced in hypercholesterolemic patients. The purpose of this study was to evaluate the effect of calcium channel blockers on coronary vasomotion of angiographically smooth coronary arteries in hypercholesterolemic patients.
Methods And Results:
A total of 57 patients were included in the present analysis. Vasomotion of angiographically normal coronary arteries was evaluated in 37 control subjects (group 1) without and 20 patients (group 2) with calcium blocker administration before physical exercise. Both groups were subdivided into subgroup A (normal cholesterol values: < or = 5.5 mmol/L or 212 mg%) and subgroup B (elevated cholesterol values: >5.5 mmol/L or 212 mg%). Coronary luminal area at rest and during exercise was assessed by biplane quantitative coronary angiography. The normal vessels showed a significant increase in coronary luminal area during exercise in subgroup A (n=13) with normal cholesterol values (31%; P<.05) but not in subgroup B (n=24; 13%; P=NS). In contrast, all patients in group 2 showed similar vasodilation during exercise, namely, 22% (P<.05) in subgroups A (n=8) and B (n=12) (P<.05). Independent of the actual cholesterol level, the stenotic lesions showed coronary vasoconstriction during exercise in group 1 but vasodilation in group 2 after pretreatment with calcium antagonists.
Conclusions:
Coronary vasomotor response to exercise is inversely related to actual serum cholesterol level in angiographically normal vessels. Administration of calcium antagonists normalizes exercise-induced vasodilation and thus eliminates cholesterol-induced abnormal vasomotion, probably by a direct effect on the smooth muscles of the vasculature.