Strain rate imaging would predict sub-clinical acute rejection in heart transplant recipients

Non-invasive diagnosis of rejection is a major objective in the management of heart transplant recipients. The ability of strain rate (SR) imaging on echocardiograms to detect rejection in heart transplant recipients was investigated.

A total of 396 endomyocardial biopsies, right-heart catheterisation and echocardiograms were performed in 35 heart transplant recipients. Mean values of systolic strain (epsilon(sys)), peak systolic SR (SR(sys)), and peak early diastolic SR (SR(dia)) obtained from eight left ventricular segments were calculated.

According to the conventional International Society for Heart and Lung Transplantation criteria, 351 biopsies showed a rejection grade (acute rejection, AR) of 0 or 1a (group AR(-)) whereas 45 biopsies showed a grade of 1b or higher (group AR(+)). The epsilon(sys), SR(sys) and SR(dia) were significantly different between group AR(+) and group AR(-) (-20.7+/-8.0 vs -32.6+/-6.3%, p<0.0001, 2.5+/-1.8 vs 3.6+/-1.1/s, p<0.0001, and -1.9+/-1.6 vs -3.5+/-1.3/s, p<0.001, respectively). Multivariate analysis identified epsilon(sys) (p<0.0001) as a strong predictor for group AR(+), and epsilon(sys) cut-off value of -27.4% was associated with a predictive accuracy of 82.3%. The combination of epsilon(sys) and SR(dia) discriminated group AR(+) from group AR(-) with a predictive accuracy of 84.8%. The pulmonary artery wedge pressure was higher in group AR(+) than that in group AR(-) (7.4+/-3.0 vs 9.4+/-4.4 mm Hg, p<0.05).

SR imaging is of potential clinical value for monitoring acute rejection in heart transplant recipients.