Noninvasive Detection of Cardiac Allograft Vasculopathy by Stress Exercise Echocardiographic Assessment of Myocardial Deformation

Abstract

Background: The aim of this study was to evaluate the value of noninvasive assessment of cardiac allograft vasculopathy (CAV) in heart-transplanted patients by exercise stress myocardial deformation and coronary flow reserve (CFR) assessment.

Methods: Fifty-eight heart-transplanted patients underwent semisupine exercise echocardiography with assessment of left ventricular (LV) longitudinal myocardial deformation. CAV was assessed by coronary angiography and noninvasive CFR by (15)O-H2O positron emission tomographic imaging and Doppler echocardiography. Patients were divided into three groups on the basis of angiographic CAV: no CAV (n = 21), mild CAV (n = 19), and severe CAV (n = 18).

Results: Patients with severe CAV had significantly lower LV global longitudinal strain (GLS) at rest (no CAV, -16 ± 2%; mild CAV, -15 ± 2%; severe CAV, -12 ± 4%; P < .001), failed to increase LV GLS during exercise (no CAV, -5.7 ± 2.0%; mild CAV, -3.3 ± 2.9%; severe CAV, -0.2 ± 2.8%; P < .0001), and had significantly lower echocardiographic coronary flow velocity reserve (CFVR) (no CAV, 3.2 ± 0.4; mild CAV, 2.7 ± 0.7; severe CAV, 1.8 ± 0.5; P < .0001) and PET CFR (no CAV, 3.4 ± 0.9; mild CAV, 3.1 ± 0.9; severe CAV, 1.9 ± 0.8; P < .0001). Furthermore, patients with mild CAV had significantly lower exercise LV GLS and echocardiographic CFVR than patients with no CAV. Exercise LV GLS, echocardiographic CFVR, and PET CFR were significantly correlated with the presence of severe CAV in a logistic regression model (LV GLS odds ratio, 0.71; 95% CI, 0.60-0.84; P < .0001; echocardiographic CFVR odds ratio: 0.06; 95% CI, 0.01-0.23; PET CFR odds ratio, 0.17; 95% CI, 0.07-0.46). This relation remained significant after adjustment for symptoms and time since transplantation.

Conclusions: Noninvasive assessment of LV longitudinal myocardial deformation during exercise is feasible and strongly associated with the presence and degree of CAV. Exercise stress myocardial deformation analysis, echocardiographic CFVR, or PET CFR may serve as a noninvasive model for the detection of CAV.

Keywords: Cardiac allograft vasculopathy; Coronary flow reserve; Global longitudinal systolic function; Heart transplantation; Positron emission tomography.