(528) - The Clinical Application of Non-Invasive Assessment of Coronary Flow Reserve via Rubidium PET in Heart Transplant Patients

Abstract

Coronary flow reserve (CFR) has been measured through a flow wire and more recently with the use of nuclear imaging. The advantage of nuclear imaging is that the entire heart is being assessed as opposed to a single coronary artery through the use of the flow wire. Reduction of CFR has implied an abnormal microcirculation in the donor heart due to small vessel transplant coronary artery disease. We have been assessing our patients in a cross-sectional study using Rubidium PET scans to assess CFR. It is not known whether an abnormal CFR (<2.0) is correlated to cardiac function and hemodynamics. Between 2010 and 2014 we assessed 93 heart transplant patients who had undergone Rubidium PET scanning to exclude significant transplant coronary artery disease (TCAD). Patients with abnormal CFR (<2.0) and normal CFR (≥2.0) were compared for the presence of coronary ischemia, LVEF at rest and with stress, end diastolic volume index (EDVI) at rest and stress and % left ventricular (LV) enlargement. Subsequent 1-year survival and development of new cardiac allograft vasculopathy (CAV) were also recorded. Those patients with abnormal CFR (<2.0) compared to those with normal CFR (≥2.0) had lower LVEF at rest and with stress, higher average end diastolic volume index (EDVI) at rest and stress and increased % left ventricular (LV) enlargement (see table). There was no difference in 1-year subsequent survival and development of new CAV. (See table) Patients with abnormal CFR (<2.0) have abnormal cardiac function and hemodynamics and may be at risk for poor outcome. Longer follow-up is required to assess for prognostic significance of an abnormal CFR.Tabled 1EndpointsCFRCFR > 2.0 (n=66)P-Value1-Year Subsequent Actual Survival96.2%97.6%0.5321-Year Subsequent Actual Freedom from CAV100.0%96.8%0.517Average LVEF Rest, Mean ± SD56.4 ± 15.8862.9 ± 11.180.028Average LVEF Post Stress, Mean ± SD60.5 ± 17.1067.4 ± 11.830.029Average EDVI Rest, Mean ± SD50.8 ± 30.3741.4 ± 14.060.044Average EDVI Post Stress, Mean ± SD55.3 ± 34.5145.2 ± 13.760.045% LV Enlargement (%)14.8% (4/27)1.5% (1/66)0.024 Open table in a new tab