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Published on: April 28, 2013
Prognostic interplay between cardiac allograft vasculopathy and coronary vascular function by hybrid rubidium-82
Roberta Assante1, Emilia Zampella1, Irene Mattucci2
1Department of Advanced Biomedical Sciences, University of Naples Federico II, Via Pansini 5, Naples, 80131, Italy.
Insights
Cardiac allograft vasculopathy (CAV) and impaired microvascular function (MPR) predict adverse events in heart transplant recipients. Early noninvasive assessment of microvascular dysfunction aids risk stratification and treatment planning.
Area of Science:
- Cardiology
- Transplant Medicine
- Medical Imaging
Background:
- Cardiac allograft vasculopathy (CAV) is a major concern in heart transplant recipients.
- Predicting clinical outcomes in these patients requires robust methods.
Purpose of the Study:
- To evaluate the interrelation of cardiac allograft vasculopathy (CAV), coronary artery calcium (CAC) score, and coronary vascular function using rubidium-82 (82Rb) positron emission tomography (PET)/computed tomography (CT) imaging.
- To assess the predictive value of these parameters for clinical outcomes in heart transplant patients.
Main Methods:
- 100 heart transplant patients were studied, with CAC score measured by the Agatston method.
- Myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) were quantified using 82Rb PET/CT.
- Patients were categorized based on CAC score (<100 vs. ≥100) and MPR (<2 vs. ≥2).
Main Results:
- During a mean follow-up of 27 months, 35 adverse events occurred.
- Patients with events had higher prevalence of CAV, impaired MPR, and CAC score ≥100.
- Multivariable analysis identified CAC score, CAV, and reduced MPR as independent predictors of events.
Conclusions:
- CAV and reduced MPR are associated with poor prognosis and increased adverse events in heart transplant patients.
- In patients without CAV, reduced MPR indicates a worse prognosis.
- Noninvasive evaluation of microcirculatory dysfunction offers improved risk stratification and potential treatment modification for heart transplant recipients.
Purpose:
We evaluated the interrelation of cardiac allograft vasculopathy (CAV) and both coronary artery calcium and coronary vascular function, as assessed rubidium-82 (82Rb) positron emission tomography (PET)/computed tomography (CT) imaging, in heart transplant population with respect to prediction of clinical outcomes.
Methods:
A total of 100 (mean age 60 ± 13 years) consecutive patients were studied. CAC score was measured according to the Agatston method and patients were categorized into 2 groups (< 100, and ≥100). Baseline and hyperemic MBF were automatically quantified. MPR was calculated as the ratio of hyperemic to baseline MBF and it was considered reduced when < 2.
Results:
During the mean time of 27 ± 8 months, 35 events occurred. Patients with events showed a higher prevalence of CAV, MPR impairment and CAC score > 100 as compared to patients without events. At multivariable COX analysis, CAC score, CAV and reduced MPR were independent predictors of events. In patients without previous CAV, the presence of reduced MPR was associated with higher event rate compared to normal MPR.
Conclusions:
In heart transplanted patients, the presence of CAV and reduced MPR were associated with a poor prognosis and higher risk of adverse events. In patients without CAV the presence of reduced MPR was associated with worst prognosis. Thus, the early noninvasive evaluation of microcirculatory dysfunction in HT patients has important clinical implication, providing a better risk stratification and subsequent modification of treatment strategies, with a potential impact on patient management at follow-up.
Clinical Trial Number:
not applicable.
