Assessment of myocardial viability using echocardiographic strain imaging in patients with ST-elevation myocardial infarction: comparison with cardiac PET imaging.

Abstract

A speckle tracking echocardiographic (STE) strain imaging can predict myocardial viability. The study compared the STE strain imaging using low-dose dobutamine stress with 18fluoro-deoxyglucose positron emission tomographic (18FDG-PET) imaging for the detection of myocardium viability. We studied 57 patients with ST-elevation myocardial infarction (STEMI) having angiographic evidence of total arterial cut off and akinetic myocardium. These patients underwent low-dose dobutamine echocardiography and 18FDG-PET imaging. The STE was used to measure the peak systolic longitudinal and circumferential strain and strain rate at rest and after low-dose dobutamine stress. A total of 298 akinetic segments were evaluated. The viable myocardium showed an increased strain and strain rate values following the dobutamine stress in comparison to the nonviable myocardium. The peak longitudinal strain rate [AUC 0.83 (95% confidence interval (CI) 0.67-0.99], p = 0.001; optimal cutoff - 0.64s-1 for sensitivity 0.87 and specificity 0.81), post-dobutamine peak longitudinal strain rate [AUC 0.94 (95% CI 0.87-1.00), p = 0.001; optimal cutoff - 0.85s-1 for sensitivity 0.89 and specificity 0.77), change in peak longitudinal strain rate [AUC 0.93 (95% CI 0.86-1), p = 0.001; optimal cutoff - 0.2s-1 for sensitivity 0.87 and specificity 0.87] predicted viability. The post-dobutamine peak circumferential strain rate [AUC 0.92 (95% CI 0.81-1.0), p = 0.001; optimal cutoff - 1.1s-1 for sensitivity and specificity 0.86], were predictor of viability. Both resting and post-dobutamine longitudinal and circumferential strain rate had better accuracy for the prediction of viability. The resting and post-dobutamine stress STE strain and strain rate parameters can assess the viability in akinetic segments.