ENDOTHELIUM-DEPENDENT VASORELAXATION IS IMPAIRED IN COCAINE ARTERIOPATHY

Objectives. This study sought to assess endothelium-dependent vasorela xation in long-term users of cocaine. Background. Cocaine use has been associated with myocardial infarction, stroke and intestinal infarcti on. Previously demonstrated effects of the drug, including increased h eart rate and blood pressure and increased vascular tone, do not expla in the sporadic nature of these vascular events or the occurrence of i schemia remote from acute administration. Abnormal endothelial functio n could contribute to focal vasospasm and thrombosis and predispose to premature atherosclerosis, all of which have been demonstrated in coc aine users with myocardial infarction. Methods. Using plethysmography, we studied the change in forearm blood flow in response to intraarter ial acetylcholine and nitroprusside in 10 long-term cocaine users and 13 control subjects of similar age who had not used cocaine; sample si ze was based on a 70% power to detect a 20% reduction in flow with ace tylcholine between subjects and control subjects. Using graded doses o f intracoronary acetylcholine (from 10(-9) to 10(-6) mol/liter), we st udied a second group of 10 cocaine users with angiographically normal or near-normal arteries. Results. Mean forearm blood flow during acety lcholine infusion was significantly lower in cocaine users than in con trol subjects (p = 0.02). During nitroprusside infusion, there was no difference (p = 0.2) between cocaine users and control subjects. Cigar ette smoking did not explain the differences between cocaine users and control subjects. Acetylcholine elicited coronary vasoconstriction in 8 of 10 subjects. Conclusions. We conclude that endothelium-dependent vasorelaxation is impaired in long-term users of cocaine.