Effects of the intracoronary infusion of cocaine on coronary arterial dimensions and blood flow in humans.

This study was done to assess the influence of large concentrations of cocaine (infused into the left coronary artery) on coronary arterial dimensions and blood flow in humans. In 20 subjects undergoing cardiac catheterization, incrementally increasing doses of (1) saline solution (n = 10, controls) or (2) cocaine hydrochloride (n = 10) were infused into the left coronary artery, and the effects on heart rate, systemic arterial pressure, coronary sinus blood flow, and coronary arterial dimensions were measured. Saline solution induced no change in any variable. With the infusion of cocaine, there was an incremental increase in its concentration in the systemic (femoral arterial) and coronary (coronary sinus) circulations (maximal concentrations, 0.14 +/- 0.06 [mean+/-SD] and 3.50 +/- 0.70 mg/L, respectively). At the maximal cocaine infusion rate, heart rate and diastolic arterial pressure increased slightly, but coronary sinus blood flow and the dimensions of nondiseased and diseased coronary arterial segments did not change. Thus, intracoronary infusion of cocaine in an amount sufficient to achieve a high concentration in the coronary circulation does not induce epicardial coronary arterial vasoconstriction or alter blood flow.