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Prevention of coronary vasoconstriction by diltiazem during dynamic exercise in patients with coronary artery disease
Insights
Calcium antagonists like diltiazem prevent exercise-induced vasoconstriction in coronary artery stenoses. This study shows diltiazem improves coronary blood flow during exercise in angina patients.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Exercise can cause coronary artery vasoconstriction, particularly in stenotic segments.
- Calcium antagonists are used to treat angina, but their effect on exercise-induced coronary artery changes is not fully understood.
Purpose of the Study:
- To investigate if calcium antagonists modify exercise-induced vasoconstriction in coronary artery stenoses.
- To evaluate the effect of intracoronary diltiazem on coronary luminal area during exercise in patients with angina pectoris.
Main Methods:
- 14 patients with classic angina pectoris underwent quantitative coronary arteriography.
- Coronary luminal area was measured at rest, after intracoronary diltiazem, during supine exercise, and after sublingual nitroglycerin.
- Hemodynamic parameters were also monitored.
Main Results:
- Intracoronary diltiazem caused mild dilation in both normal and stenotic coronary segments.
- During exercise, stenotic segments increased in luminal area (23%) unlike in a control group (-29%).
- Nitroglycerin further increased luminal area in both normal and stenotic segments.
Conclusions:
- Diltiazem administration prevents exercise-induced vasoconstriction in coronary artery stenoses.
- Calcium antagonists may improve coronary blood flow during exercise in patients with angina.
Abstract:
Whether exercise-induced vasoconstriction of coronary artery stenoses is modified by the administration of calcium antagonists was examined in 14 patients with classic angina pectoris. In this group the effect of intracoronary diltiazem (2 to 3 mg) on luminal area was evaluated in normal and stenotic segments of epicardial coronary arteries during symptom-limited supine exercise. The luminal area of a normal and a stenotic coronary artery segment was determined by quantitative coronary arteriography with a computer-assisted system. Patients were studied at rest, 6 min after 2 to 3 mg of intracoronary diltiazem, during supine bicycle exercise (96 W) and 5 min after sublingual administration of 1.6 mg nitroglycerin. Heart rate, mean pulmonary and aortic pressure as well as the percent change of both normal and stenotic luminal area were determined. Intracoronary administration of diltiazem was associated with mild dilation of both normal (19%, p less than 0.01) and stenotic coronary luminal area (11%, p less than 0.05). During subsequent exercise, luminal area of the stenotic vessel segment increased by 23% (p less than 0.001) and that of the normal vessel segment by 24% (p less than 0.001), whereas in a previously reported control group, luminal area of the stenotic vessel segment decreased by 29% during exercise. After sublingual administration of nitroglycerin, the luminal area of both the normal and the stenotic vessel segment increased further by 19% (p less than 0.01) and 22% (p less than 0.01), respectively, compared with the values after intracoronary administration of diltiazem.(ABSTRACT TRUNCATED AT 250 WORDS)