Incremental Value of Strain Rate Analysis as an Adjunct to Wall-Motion Scoring for Assessment of Myocardial Viability by Dobutamine Echocardiography: A Follow-Up Study After Revascularization

L. Hanekom
2005 Circulation  
Background-Assessment of myocardial viability based on wall-motion scoring (WMS) during dobutamine echocardiography (DbE) is difficult and subjective. Strain-rate imaging (SRI) is quantitative, but its incremental value over WMS for prediction of functional recovery after revascularization is unclear. Methods and Results-DbE and SRI were performed in 55 stable patients (mean age, 64Ϯ10 years; mean ejection fraction, 36Ϯ8%) with previous myocardial infarction. Viability was predicted by WMS if
more » ... edicted by WMS if function augmented during low-dose DbE. SR, end-systolic strain (ESS), postsystolic strain (PSS), and timing parameters were analyzed at rest and with low-dose DbE in abnormal segments. Regional and global functional recovery was defined by side-by-side comparison of echocardiographic images before and 9 months after revascularization. Of 369 segments with abnormal resting function, 146 showed regional recovery. Compared with segments showing functional recovery, those that failed to recover had lower low-dose DbE SR, SR increment (⌬SR), ESS, and ESS increment (⌬ESS) (each PϽ0.005). After optimal cutoffs for the strain parameters were defined, the sensitivity of low-dose DbE SR (78%, Pϭ0.3), ⌬SR (80%, Pϭ0.1), ESS (75%, Pϭ0.6), and ⌬ESS (74%, Pϭ0.8) was better though not significantly different from WMS (73%). The specificity of WMS (77%) was similar to the SRI parameters. Combination of WMS and SRI parameters augmented the sensitivity for prediction of functional recovery above WMS alone (82% versus 73%, Pϭ0.015; area under the curveϭ0.88 versus 0.73, PϽ0.001), although specificities were comparable (80% versus 77%, Pϭ0.2). Conclusions-The measurement of low-dose DbE SR and ⌬SR is feasible, and their combination with WMS assessment improves the sensitivity of viability assessment with DbE. (Circulation. 2005;112:3892-3900.) Key Words: heart failure Ⅲ echocardiography Ⅲ imaging Ⅲ myocardial infarction Ⅲ stress E vidence of residual viable tissue within the infarct zone has been reported in Ϸ50% of segments after myocardial infarction (MI), 1 implying a potential for recovery 2-5 and prognostic benefit after revascularization. 6 -9 Prediction of functional recovery, based on detection of contractile reserve with dobutamine echocardiography (DbE), is of comparable accuracy to alternative techniques, including myocardial perfusion imaging, metabolic imaging with conventional scintigraphy, and positron emission tomography. 10 However, although DbE is a widely available and low-cost approach for the detection of viable myocardium, its assessment remains subjective and relies on semiquantitative evaluation of endocardial excursion and wall thickening, which requires adequate training of the observer. 11 Editorial p 3820 Strain-rate imaging (SRI) is based on the determination of gradients of myocardial velocity between 2 points in space. 12 SR and its integral, strain, have been validated as methods to quantify regional myocardial function. 13,14 Although a number of animal studies have examined the relation of both resting SRI and its Db response with evidence of viability after MI, 15-17 only one human study has validated the technique as a clinical tool, and that study correlated the Db response with metabolic evidence of viability by positron emission tomography. 18 Therefore, we sought to assess the feasibility and accuracy of SRI and strain during DbE for the prediction of functional recovery in patients undergoing revascularization after MI, its incremental value to conventional wall-motion scoring (WMS), and the optimal SRI parameter for this purpose. Methods Study Design We performed SRI in all patients presenting to the echocardiography laboratory for DbE assessment of myocardial viability in the context
doi:10.1161/circulationaha.104.489310 pmid:16365209 fatcat:klhnfxx6jffdpiz2yzc2erf4om