The Prognostic Value of Rb-82 Positron Emission Tomography in Patients Following Heart Transplant
Background—Cardiac Allograft Vasculopathy (CAV) is a key prognostic determinant following heart transplant (HT). Detection and risk stratification of patients with CAV is problematic. Positron emission tomography (PET) using Rubidium-82 (Rb-82) allows quantification of absolute myocardial blood flow and may have utility for risk stratification in this population.
Methods and Results—Patients with a history of HT undergoing dipyridamole Rb-82 PET were prospectively enrolled. Myocardial perfusion and left ventricular ejection fraction (LVEF) were recorded. Absolute flow quantification at rest and following dipyridamole stress as well as the ratio of mean global flow at stress and at rest, termed Myocardial Flow Reserve (MFR), were calculated. Patients were followed for all-cause death, acute coronary syndrome (ACS) and heart failure hospitalization. A total of 140 patients (males 81%, median age 62 years, median follow-up 18.2 months) were included. There were 14 events during follow-up (9 deaths, 1 ACS, 4 heart failure admissions). In addition to baseline clinical variables (estimated glomerular filtration rate (eGFR), previously documented CAV), relative perfusion defects, mean MFR and mean stress myocardial blood flow were significant predictors of adverse outcome.
Conclusions—Abnormalities on Rb-82 PET were predictors of adverse events in HT patients. Larger prospective studies are required to confirm these findings.
- Received May 12, 2014.
- Accepted August 17, 2014.