Effects of high-density lipoprotein on acetylcholine-induced coronary vasoreactivity.

Recent evidence suggests that high-density lipoprotein (HDL) cholesterol has important vasoactive properties which may contribute to its beneficial effects on atherosclerotic coronary artery disease. The endothelium-dependent vasodilator acetylcholine has been used in a number of experimental studies to assess endothelial function. The relation between serum lipoproteins and acetylcholine-induced coronary vasoreactivity was investigated in patients (n = 27) undergoing elective coronary arteriography. Mean serum cholesterol, low-density lipoprotein cholesterol, HDL cholesterol and triglyceride levels were 189 +/- 7 (4.84 +/- 0.18 mmol/liter), 134 +/- 6 (3.47 +/- 0.15 mmol/liter), 41 +/- 3 (1.06 +/- 0.08 mmol/liter) and 106 +/- 30 mg/dl (1.20 +/- 0.03 mmol/liter), respectively. After a baseline arteriogram, acetylcholine was infused into the left main coronary artery and percent change from baseline dimension was determined in 27 angiographically smooth coronary artery segments and in 14 arterial segments with evidence of mild atherosclerotic disease. Intact vascular smooth muscle function was then confirmed in all segments by dilation to intracoronary nitroglycerin. Acetylcholine produced significant vasoconstriction of both angiographically smooth (13 +/- 4%, p less than 0.05 vs baseline) and diseased (19 +/- 4%, p less than 0.05 vs baseline) coronary segments. A positive correlation was observed between HDL cholesterol and normal acetylcholine-induced coronary vasoreactivity in both angiographically smooth (r = 0.59, p less than 0.001) and diseased (r = 0.62, p less than 0.02) coronary segments. No significant correlation was observed, however, between total and low-density lipoprotein cholesterol, or between total cholesterol to HDL ratio and the response of coronary artery diameter to acetylcholine infusion.(ABSTRACT TRUNCATED AT 250 WORDS)