Abstract Objectives This study sought to evaluate myocardial perfusion reserve index (MPRI) and diastolic strain rate, both assessed by cardiac magnetic resonance (CMR) as a noninvasive tool for the ...detection of microvasculopathy. Background Long-term survival of cardiac allograft recipients is limited primarily by cancer and cardiac allograft vasculopathy (CAV). Besides epicardial CAV, diagnosed by coronary angiography, stenotic microvasculopathy was found to be an additional independent risk factor for survival after heart transplantation. Methods Sixty-three consecutive heart transplant recipients who underwent CMR, coronary angiography, and myocardial biopsy were enrolled. Stenotic vasculopathy in microvessels was considered in myocardial biopsies by immunohistochemistry and CAV was graded during coronary angiography according to International Society of Heart and Lung Transplantation criteria. In addition, by CMR microvasculopathy was assessed by myocardial perfusion reserve during pharmacologic hyperemia with adenosine and strain-encoded magnetic resonance using a modified spatial modulation of magnetization tagging pulse sequence in all patients. Results Decreasing MPRI and diastolic strain rates were observed in patients with decreasing microvessel luminal radius to wall thickness ratio and decreasing capillary density ( r = 0.45 and r = 0.61 for MPRI and r = 0.50 and r = 0.38 for diastolic strain rate, respectively; p < 0.005 for all). Using multivariable analysis, both MPRI and diastolic strain rate were robust predictors of stenotic microvasculopathy, independent of age, organ age, and CAV by International Society of Heart and Lung Transplantation criteria (hazard ratio: 0.07, p = 0.006 for MPRI; hazard ratio: 0.91, p = 0.002 for diastolic strain rate). Patients without stenotic microvasculopathy in the presence of no or mild CAV (n = 36) exhibited significantly higher median survival free of events, compared with patients with stenotic microvasculopathy in the presence of no or mild CAV (n = 18; p = 0.04 by log rank). Conclusions CMR represents a valuable noninvasive diagnostic tool, which may be used for the early detection of transplant microvasculopathy before the manifestation of CAV during surveillance coronary angiographic procedures.
Milder forms of plaque rupture with subsequent microembolization of atherothrombotic burden into the coronary circulation, however, may occur in patients with stable CAD or even in presumably healthy ...subjects. ...more than a decade ago, healed plaque destruction was observed in postmortem studies (3), whereas angioscopy studies demonstrated that silent plaque rupture is present in ~20% of patients with stable CAD (4).
Patient monitoring following heart transplantation aims to detect complications (eg, acute graft rejection, vasculopathy, infection) early and contributes to risk prognostication. Numerous biomarkers ...of different biologic pathways have been evaluated as ancillary diagnostic and prognostic tools to reduce the need for invasive and expensive technical investigations. With the possible exception of cardiac troponins and N-type natriuretic peptides, no biomarkers have become established firmly in posttransplant patient surveillance. This article aims to show that the identification of a single biomarker that meets all needs (noninvasive diagnosis of rejection, prediction of transplant vasculopathy, survival prognostication) is unlikely. Rather, multiple marker strategies, including gene-based tests, are likely to enhance future monitoring quality and enable individualized risk-adapted patient management.
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