Longitudinal Doppler strain measurement for assessment of damaged and/or hibernating myocardium by dobutamine stress echocardiography in patients with old myocardial infarction
The ratio of systolic lengthening to combined late and postsystolic shortening (L/TS ratio) on longitudinal Doppler strain imaging (Doppler SI) may be an index of myocardial viability. We hypothesized that measuring the postsystolic index (PSI) and the L/TS ratio during dobutamine stress echocardiography (DSE) could quantitatively identify viable myocardium with the potential for regional functional recovery.
Methods
Thirty-eight patients with old myocardial infarction (OMI) underwent DSE with Doppler SI and coronary angiography (Group 1). To clarify the value of measuring the PSI and L/TS ratio by DSE with Doppler SI in patients with OMI, these Doppler parameters and visual analysis of wall motion abnormality (WMA) were compared on a segmental basis. To investigate the prediction of regional functional recovery, 10 patients with OMI (Group 2) and stenosis of the infarct-related coronary artery underwent DSE with Doppler SI before and after percutaneous coronary intervention.
Results
In Group 1, 143 out of 556 segments showed a biphasic WMA pattern during DSE. There were no segments with evidence of necrosis. The PSI at peak stress was ≧0.25 in 114 out of 143 segments and the L/TS ratio at peak stress was >0 in 82 out of 114 segments. Regarding functional recovery, 42 of the 73 segments with WMA at rest showed improvement after reperfusion. The wall motion score (WMS) showed 86% sensitivity and 71% specificity for predicting regional recovery, while PSI and L/TS ratio showed 61% vs. 84% sensitivity and 60% vs. 79% specificity, respectively. The AUC for the ROC curve of the L/TS ratio as a predictor of regional recovery was significantly larger compared with that of WMS (0.894 vs. 0.783, p < 0.05).
Conclusions
The peak stress L/TS ratio could be a specific and quantitative marker for identifying myocardial viability that has the potential for regional functional recovery.
