[Allograft vasculopathy in the early phase of orthotopic heart transplantation: angiography, intravascular ultrasound and functional in vivo findings]

Abstract

Accelerated graft coronary atherosclerosis disease is the main reason for long-term mortality and morbidity of heart transplant recipients. The aim of this in vivo study was to evaluate coronary atherosclerotic vessel abnormalities and endothelial function using angiography, intravascular ultrasound, and intracoronary acetylcholine infusion. Fourteen patients (11 male, 3 female; mean age 49.3 years) were examined early after heart transplantation (mean interval after transplantation: 11 weeks) because of coronary artery disease (n = 8), idiopathic dilatative cardiomyopathy (n = 7), mitral valve replacement (n: 1) or left atrial filiae of a leiomyosarcoma (n = 1). Mean age of the donor hearts (female n = 8) was 29 years; 3 patients received double- and 14 patients triple-immunosuppression. All patients underwent biplane ventriculography and coronary angiography; a total of 120 coronary segments (main stem 21, left anterior descending artery 85, circumflex artery 14) was examined by intravascular ultrasound (20 MHz, 3.5 F catheters). In 13 patients, acetylcholine was infused into the proximal left anterior descending artery (0.15 microgram/min to 150.0 micrograms/min) to evaluate vasomotion within this segment. Ventriculography demonstrated regional wall abnormalities in 2 patients, angiography revealed 9 noncritical stenotic segments in 5 patients. Intravascular ultrasound detected 52 cross-sectional areas with a three-layer appearance indicating intimal thickening. Mean circumferential expansion of intimal proliferation was 192 degrees and mean intimal thickness was 0.35 mm. Only 5 segments of the sonographically pathological cross-sectional areas showed angiographic evidence of atherosclerotic lesions. After intracoronary infusion at a lower dose (0.15 and 1.5 micrograms/min) of acetylcholine, vasoconstriction was observed in 2 patients, at a dose of 15.0 and 150.0 micrograms/min in 10 patients. This response to acetylcholine did not depend on the intravascular or angiographical extent of atherosclerotic vessel abnormalities. In heart transplant recipients, coronary artery abnormalities can already be depicted at an early stage using intravascular ultrasound. The majority of patients show coronary vasoconstriction following infusion of acetylcholine at a higher dose. Further investigation is necessary to clarify whether the depicted vessel wall abnormalities can already be interpreted as newly developed graft atherosclerosis and whether abnormal vasomotion after acetylcholine is indicative of endothelial dysfunction.