1.Circulation. 2013 Aug 6;128(6):598-604. doi: 10.1161/CIRCULATIONAHA.113.002937. Epub 2013 Jun 28.

Cocaine-induced vasoconstriction in the human coronary microcirculation: new evidence from myocardial contrast echocardiography.

Gurudevan SV, Nelson MD, Rader F, Tang X, Lewis J, Johannes J, Belcik JT, Elashoff RM, Lindner JR, Victor RG.

Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.

Abstract

BACKGROUND:

Cocaine is a major cause of acute coronary syndrome, especially in young adults; however, the mechanistic underpinning of cocaine-induced acute coronary syndrome remains limited. Previous studies in animals and in patients undergoing cardiac catheterization suggest that cocaine constricts coronary microvessels, yet direct evidence is lacking.

METHODS AND RESULTS:

We used myocardial contrast echocardiography to test the hypothesis that cocaine causes vasoconstriction in the human coronary microcirculation. Measurements were performed at baseline and after a low, nonintoxicating dose of intranasal cocaine (2 mg/kg) in 10 healthy cocaine-naïve young men (median age, 32 years). Postdestruction time-intensity myocardial contrast echocardiography kinetic data were fit to the equation y=A(1-e(-βt)) to quantify functional capillary blood volume (A), microvascular flow velocity (β), and myocardial perfusion (A×β). Heart rate, mean arterial pressure, and left ventricular work (2-dimensional echocardiography) were measured before and 45 minutes after cocaine. Cocaine increased mean arterial pressure (by 14±2 mm Hg [mean±SE]), heart rate (by 8±3 bpm), and left ventricular work (by 50±18 mm Hg·mL(-1)·bpm(-1)). Despite the increases in these determinants of myocardial oxygen demand, myocardial perfusion decreased by 30% (103.7±9.8 to 75.9±10.8 arbitrary units [AU]/s; P<0 .01="" 0.7="" 111.7="" a="" as="" au="" blood="" capillary="" change="" decreased="" flow="" in="" mainly="" microvascular="" no="" of="" p="" result="" significant="" to="" velocity="" volume="" with="">

CONCLUSIONS:

In healthy cocaine-naïve young adults, a low-dose cocaine challenge evokes a sizeable decrease in myocardial perfusion. Moreover, the predominant effect is to decrease myocardial capillary blood volume rather than microvascular flow velocity, suggesting a specific action of cocaine to constrict terminal feed arteries.

PMID: 23812179 [PubMed - indexed for MEDLINE]