Influence of Cocaine, Ethanol, or Their Combination on Epicardial Coronary Arterial Dimensions in Humans

Background: Cocaine and ethanol are often abused concomitantly, and this combination may be more lethal than either substance alone. Although previous studies showed that cocaine causes coronary arterial vasoconstriction, the combined effect of cocaine and ethanol on the coronary vasculature in humans is unknown. Thus, we assessed the effects of intranasal cocaine, intravenous ethanol, or a cocaine-ethanol combination on heart rate, systemic arterial pressure, and coronary arterial dimensions in humans. Methods: Thirty-four subjects with chest pain (27 men and seven women, aged 34 to 67 years) who were referred for catheterization received one of the following pharmacologic interventions: (1) intranasal (2 mL) and intravenous (5 mL/kg) saline (n=8 [group A]); (2) intranasal cocaine (2 mg/kg) and intravenous saline (5 mL/ kg) (n=9 [group B]); (3) intranasal saline (2 mL) and intravenous 10% ethanol (5 mL/kg) (n=9 [group C]); or (4) intranasal cocaine (2 mg/kg) and intravenous 10% ethanol (5 mL/kg) (n=8 [group D]). Heart rate, systemic arterial pressure, left coronary arterial dimensions (by computer-assisted quantitative angiography), as well as blood cocaine, ethanol, and cocaine metabolite concentrations were measured before and 30,60, and 90 minutes after initiation of the intravenous infusions. Results: No hemodynamic or angiographic changes were observed in the group A (saline) subjects. In the group B (cocaine) subjects, the heart rate—systolic arterial pressure product increased by 5% and 10% at 30 and 90 minutes, respectively, and coronary arterial diameter decreased by 14% at these times. In the group C (ethanol) subjects, no hemodynamic changes were noted, but coronary arterial diameters increased by 12%, 11%, and 12% at 30, 60, and 90 minutes, respectively. In the group D (cocaine-ethanol) patients, rate-pressure product increased by 17%, 10%, and 16%, and coronary arterial diameters increased by 7%, 12%, and 13%, at 30, 60, and 90 minutes, respectively. Conclusion: The combination of intranasal cocaine and intravenous ethanol causes an increase in the determinants of myocardial oxygen demand. However, it also causes a concomitant increase in epicardial coronary arterial diameter.