Coronary vasomotility and myocardial blood flow early after heart transplantation.
Serotonin constricts coronary arteries with endothelial dysfunction, a common abnormality in cardiac transplant recipients. To assess whether endothelial dysfunction is associated with myocardial blood flow (MBF) abnormalities, 24 patients were studied 1 to 12 months after transplantation. Serotonin in increasing doses (1, 10, and 20 micrograms/min for 2.5 min each) was infused into the coronary circulation. Diameters were measured by quantitative angiography. Fourteen patients (group A) had a pronounced artery constriction (diameter reduction > 40%), while in 10 other patients (group B), such a constriction was never reached. No patient had evidence of rejection and all had angiographically normal coronary arteries. MBF was measured at rest and after intravenous dipyridamole with dynamic nitrogen-13 ammonia positron emission tomography (PET). The resting MBF was higher in group A than in group B (94 +/- 12 vs 74 +/- 15 ml/min/100 g of tissue; p < 0.05). During dipyridamole, MBF was not significantly different (191 +/- 53 vs 184 +/- 64 ml/min/100 g; p = NS). Coronary flow reserve (the ratio of perfusion after dipyridamole to perfusion at rest) was significantly lower in group A than in group B (2.08 +/- 0.54 vs 2.66 +/- 0.57; p < 0.05). Thus, coronary hypersensitivity to serotonin in cardiac transplant recipients is associated with elevated resting MBF and reduced coronary flow reserve. Immune mechanisms inducing endothelial injuries and inflammation-related hyperemia may account for these abnormalities.
Preumont
N
N
Department of Cardiology, Erasme Hospital, Free University of Brussels, Belgium.
Lenaers
A
A
Goldman
S
S
Vachiery
J L
JL
Wikler
D
D
Damhaut
P
P
Degré
S
S
Berkenboom
G
G
D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging; D016027:Heart Transplantation / Q000502:physiology*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012039:Regional Blood Flow; D014055:Tomography, Emission-Computed; D014666:Vasomotor System / Q000502:physiology*