EARLY ALLOGRAFT VASCULOPATHY IN ORTHOTOPI C HEART-TRANSPLANT RECIPIENTS - ANGIOGRAPHIC, INTRAVASCULAR ULTRASOUND, AND FUNCTIONAL IN-VIVO FINDINGS

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, intr avascular ultrasound, and intracoronary acetylcholine infusion. Fourte en patients (11 male, 3 female; mean age 49.3 years) were examined ear ly after heart transplantation (mean interval after transplantation: 1 1 weeks) because of coronary artery disease (n = 8), idiopathic dilata tive cardiomyopathy (n = 7), mitral valve replacement (n: 1) or left a trial filiae of a leiomyosarcoma (n = 1). Mean age of the donor hearts (female n = 8) was 29 years; 3 patients received double- and 14 patie nts triple-immunosuppression. All patients underwent biplane ventricul ography and coronary angiography; a total of 120 coronary segments (ma in 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 anterio r descending artery (0.15 mug/min to 150.0 mug/min) to evaluate vasomo tion within this segment. Ventriculography demonstrated regional wall abnormalities in 2 patients, angiography revealed 9 noncritical stenot ic segments in 5 patients. Intravascular ultrasound detected 52 cross- sectional areas with a three-layer appearance indicating intimal thick ening. Mean circumferential expansion of intimal proliferation was 192 degrees and mean intimal thickness was 0.35 mm. Only 5 segments of th e sonographically pathological cross-sectional areas showed angiograph ic evidence of atherosclerotic lesions. After intracoronary infusion a t a lower dose (0.15 and 1.5 mug/min) of acetylcholine, vasoconstricti on was observed in 2 patients, at a dose of 15.0 and 150.0 mug/min in 10 patients. This response to acetylcholine did not depend on the intr avascular or angiographical extent of atherosclerotic vessel abnormali ties. In heart transplant recipients, coronary artery abnormalities ca n already be depicted at an early stage using intravascular ultrasound . The majority of patients show coronary vasoconstriction following in fusion of acetylcholine at a higher dose. Further investigation is nec essary to clarify whether the depicted vessel wall abnormalities can a lready be interpreted as newly developed graft atherosclerosis and whe ther abnormal vasomotion after acetylcholine is indicative of endothel ial dysfunction.