Log in to MyACC
Coronary Flow Reserve in Heart Transplant Recipients
Study Questions:
What is the long-term prognostic value of serial assessment of coronary flow reserve (CFR) by rubidium Rb 82 (82Rb) positron emission tomography (PET) in heart transplantation (HT) patients?
Methods:
The investigators prospectively enrolled a total of 89 patients with a history of HT (71% men, 7.0 ± 5.7 years post-HT, age 57 ± 11 years) scheduled for dynamic rest and stress (dipyridamole) 82Rb PET between March 1, 2008 and July 31, 2009 (PET-1) in a single-center study. PET myocardial perfusion studies were reprocessed using US Food and Drug Administration-approved software (Corridor 4DM, version 2017) for calculation of CFR. Follow-up PET (PET-2) imaging was performed in 69 patients at 1.9 ± 0.3 years following PET-1. Patients were categorized based on CFR values considering CFR ≤1.5 as low and CFR >1.5 as high CFR. To assess the impact of CFR on mortality, the Cox proportional hazards model was used after controlling for the effects of other variables that are known to affect mortality recorded at the time of PET-2.
Results:
Forty deaths occurred during the median follow-up time of 8.6 years. Low CFR at PET-1 was associated with a 2.77-fold increase in all-cause mortality (95% confidence interval [CI], 1.34-5.74; p = 0.004). CFR decreased over time in patients with follow-up imaging (PET-1: 2.11 ± 0.74 vs. PET-2: 1.81 ± 0.61; p = 0.003). Twenty-five patients were reclassified based on PET-1 and PET-2 (high to low CFR: n = 18, low to high CFR: n = 7). Overall survival was similar in patients reclassified from high to low as patients with low to low CFR, whereas patients reclassified from low to high had similar survival as patients with high to high CFR. In multivariate Cox regression of patients with PET-2, higher baseline CFR (hazard ratio [HR] for a 0.73 unit [one standard deviation] increase: 0.36; 95% CI, 0.16-0.82) and reduction in CFR from PET-1 to PET-2 (HR for a 0.79 unit [one standard deviation] decrease: 1.50-7.84) were independent predictors of all-cause mortality.
Conclusions:
The authors concluded that serial assessment of CFR by 82Rb PET independently predicts long-term mortality in HT patients.
Perspective:
This study reports that CFR assessed by dynamic 82Rb PET predicts long-term mortality (>5 years) in HT patients. Furthermore, this study demonstrates the incremental prognostic value offered by serial PET CFR assessment in predicting overall mortality risk in HT recipients. A widespread application of this technique in HT patients for evaluation of cardiac allograft vasculopathy by assessing abnormalities in epicardial flow and microvascular function could potentially decrease the number of invasive coronary angiography procedures that carry infrequent, but risk for major complications. Additional larger prospective studies are indicated to validate the predictive value of PET CFR in the HT population, and to assess whether PET-derived CFR can help tailor HT patient management.
Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Cardiac Surgery and Heart Failure, Statins, Acute Heart Failure, Heart Transplant, Interventions and Imaging, Angiography, Computed Tomography, Nuclear Imaging
Keywords: Allografts, Cardiac Surgical Procedures, Coronary Angiography, Diagnostic Imaging, Dipyridamole, Heart Failure, Heart Transplantation, Positron-Emission Tomography, Rubidium, Rubidium Radioisotopes
< Back to Listings
