Automated assessment of myocardial viability after acute myocardial infarction by global longitudinal peak strain on low-dose dobutamine stress echocardiography

Evaluation of myocardial viability in patients with acute myocardial infarction: Layer-specific analysis of 2-dimensional speckle tracking echocardiography

BACKGROUND

The value of layer-specific two-dimensional speckle tracking echocardiography (LS2D-STE) for evaluating viable myocardium (VM) in patients with acute myocardial infarction (AMI) was unclear, this study provides new insights into it and to make a comparison with dualisotope simultaneous acquisition single photon emission computed tomography ( DISA-SPECT).

METHODS

Forty hospitalized patients with AMI and left ventricular systolic dysfunction (left ventricular ejection fraction <50%) underwent LS2D-STE and DISA-SPECT before percutaneous coronary intervention (PCI). The longitudinal, circumferential, and radial peak systolic strains and the peak systolic strain rates of 3 myocardiallayers (endocardium, mid-myocardium, and epicardium), as well as the total wall thickness, were determined by LS2D-STE. Routine echocardiography was followedup at 1, 3, 6 months after PCI, with the improvement of the wall motion as the goldenstandard for evaluating VM.

RESULTS

The sensitivity, specificity and accuracy of DISA-SPECT for evaluating VM were 82.1%, 74.3%, and 79.3%, respectively. Among the layer-specific parameters, only endocardial (endo-) longitudinal strain (LS) and endo- longitudinal strain rate (LSr) were used as independent parameters for evaluating VM (P < .05), and the sensitivity, specificity and accuracy of endo-LS and endo-LSr in evaluation of VM were 77.1%, 65.4%, and 72.9% vs 72.9%, 65.4%, and 69.7%. Endo-LS and endo-LSr were superior to total wall thickness LS and LSr (AUC endo-LS 0.767 vs total-LS 0.669; endo-LSr 0.743 vs total-LSr 0.682). The parallel test and the serial test of combination of endo-LS and endo-LSr showed similar sensitivity, specificity and accuracy to DISA-SPECT (P > .05).

CONCLUSION

The endo-LS and endo-LSr analysis of LS2D-STE can evaluate the VM well, and its sensitivity, specificity and accuracy in detection of VM are similar to those of DISA-SPECT, resulting in LS2D-STE being a good option for the assessment of VM.

A Comparison between Quantitative Gated Myocardial Perfusion Scintigraphy and Strain Echocardiography as Indicators of Ventricular Functions in Patients with Anterior Myocardial Infarction

The purpose of this study is to compare the strain echocardiographic and scintigraphic parameters for evaluating of the left ventricular (LV) functions in patients with anterior myocardial infarction (MI). Fifty-four patients (male/female: 36/18; mean age 62 ± 13 years) with anterior MI were prospectively enrolled. All patients were performed gated myocardial perfusion scintigraphy gated single-photon emission computed tomography (GSPECT) and echocardiography (EC). GSPECT data were processed and analyzed using 4D-MSPECT (4DM, Invia Medical Imaging Solutions, Ann Arbor, MI, USA). The echocardiographic strain (S) and strain rate (SR) values were calculated. The results obtained by these techniques were compared each other. A total of 918 segments of LV wall were evaluated. In all patients, 385 segments were automatically scored as normokinetic, 206 as hypokinetic, 122 as akinetic, 205 as dyskinetic and 300 as normal thickening, 348 as decrease thickening and 270 as no thickening. The means of S and SR values in thickening and motion score groups according to GSPECT were statistically different from each other (P < 0.001). There was a negative significant correlation between LV wall thickening sum score and S and SR and between LV wall motion sum score and S and SR (P < 0.001). There was a good correlation between GSPECT and echocardiographic LV-ejection fraction (r = 0.7, P < 0.001). GSPECT and strain EC are similar in quantitative grading of the severity of regional and global myocardial dysfunction in patients with anterior MI and these techniques provide valuable diagnostic information.

Reproducibility of regional and global longitudinal strains derived from two-dimensional speckle-tracking and doppler tissue imaging between expert and novice readers during quantitative dobutamine stress echocardiography

BACKGROUND

Longitudinal strain (LS) is a quantitative parameter that adds incremental value to wall motion analysis. The aim of this study was to compare the reproducibility of LS derived from Doppler tissue imaging and speckle-tracking between an expert and a novice strain reader during dobutamine stress echocardiography (DSE).

METHODS

Forty-one patients (mean age, 65 ± 15 years; mean ejection fraction, 58 ± 11%) underwent DSE per clinical protocol. Global LS derived from speckle-tracking and regional LS derived from both speckle-tracking and Doppler tissue imaging were measured twice by an expert strain reader and also measured twice by a novice strain reader. Intraobserver and interobserver analyses were performed using intraclass correlation coefficients (ICC), Bland-Altman analysis, and absolute difference values (mean ± SD).

RESULTS

Global LS measured by the expert strain reader demonstrated high intraobserver measurement reproducibility (rest: ICC = 0.95, absolute difference = 5.5 ± 4.9%; low dose: ICC = 0.96, absolute difference = 5.7 ± 3.7%; peak dose: ICC = 0.87, absolute difference = 11.4 ± 8.4%). Global LS measured by the novice strain reader also demonstrated high intraobserver reproducibility (rest: ICC = 0.97, absolute difference = 4.1 ± 3.4%; low dose: ICC = 0.94, absolute difference = 5.4 ± 5.9%; peak dose: ICC = 0.94, absolute difference = 6.1 ± 4.8%). Global LS also showed high interobserver agreement between the expert and novice readers at all stages of DSE (rest: ICC = 0.90, absolute difference = 8.5 ± 7.5%; low dose: ICC = 0.90, absolute difference = 8.9 ± 7.1%; peak dose: ICC = 0.87, absolute difference = 10.8 ± 8.4%). Of all parameters studied, LS derived from Doppler tissue imaging had relatively low interobserver and intraobserver agreement.

CONCLUSIONS

Global LS is highly reproducible during all stages of DSE. This variable is a potentially reliable and reproducible measure of myocardial deformation.

Myocardial viability: what we knew and what is new

Some patients with chronic ischemic left ventricular dysfunction have shown significant improvements of contractility with favorable long-term prognosis after revascularization. Several imaging techniques are available for the assessment of viable myocardium, based on the detection of preserved perfusion, preserved glucose metabolism, intact cell membrane and mitochondria, and presence of contractile reserve. Nuclear cardiology techniques, dobutamine echocardiography and positron emission tomography are used to assess myocardial viability. In recent years, new advances have improved methods of detecting myocardial viability. This paper summarizes the pathophysiology, methods, and impact of detection of myocardial viability, concentrating on recent advances in such methods. We reviewed the literature using search engines MIDLINE, SCOUPS, and EMBASE from 1988 to February 2012. We used key words: myocardial viability, hibernation, stunning, and ischemic cardiomyopathy. Recent studies showed that the presence of viable myocardium was associated with a greater likelihood of survival in patients with coronary artery disease and LV dysfunction, but the assessment of myocardial viability did not identify patients with survival benefit from revascularization, as compared with medical therapy alone. This topic is still debatable and needs more evidence.