Myocardial blood flow at rest and during pharmacological vasodilation in cardiac transplants during and after successful treatment of rejection

Abstract

Background: The relative intracoronary flow reserve has been found to be reduced during acute transplant rejection, but the effects of rejection on absolute flows at rest and during hyperemia have not been established previously. This has now become possible through noninvasive quantification of myocardial blood flow with positron emission tomography. Methods and Results: Myocardial blood flow (MBF) at rest and during dipyridamole-induced hyperemia was quantified in 10 transplant patients (group A) during an acute, biopsy-proven rejection episode and again after successful immunosuppressive treatment and in 6 transplant patients (group B) without prior rejection episodes. In group A patients, MBF during rejection averaged 1.7±0.3 mL · min-1 · g-1 at rest and 2.5±0.9 mL · min-1 · g-1 during hyperemia; after recovery, MBF at rest had declined to 1.2±0.3 mL · min-1 · g-1 (P