Regional Longitudinal Myocardial Deformation Provides Incremental Prognostic Information in Patients with ST-Segment Elevation Myocardial Infarction

Abstract

Background: Global longitudinal systolic strain (GLS) has recently been demonstrated to be a superior prognosticator to conventional echocardiographic measures in patients after myocardial infarction (MI). The aim of this study was to evaluate the prognostic value of regional longitudinal myocardial deformation in comparison to GLS, conventional echocardiography and clinical information.

Method: In total 391 patients were admitted with ST-Segment elevation myocardial infarction (STEMI), treated with primary percutaneous coronary intervention and subsequently examined by echocardiography. All patients were examined by tissue Doppler imaging (TDI) and two-dimensional strain echocardiography (2DSE).

Results: During a median-follow-up of 5.3 (IQR 2.5-6.1) years the primary endpoint (death, heart failure or a new MI) was reached by 145 (38.9%) patients. After adjustment for significant confounders (including conventional echocardiographic parameters) and culprit lesion, reduced longitudinal performance in the anterior septal and inferior myocardial regions (but not GLS) remained independent predictors of the combined outcome. Furthermore, inferior myocardial longitudinal deformation provided incremental prognostic information to clinical and conventional echocardiographic information (Harrell's c-statistics: 0.63 vs. 0.67, p = 0.032). In addition, impaired longitudinal deformation outside the culprit lesion perfusion region was significantly associated with an adverse outcome (p<0.05 for all deformation parameters).

Conclusion: Regional longitudinal myocardial deformation measures, regardless if determined by TDI or 2DSE, are superior prognosticators to GLS. In addition, impaired longitudinal deformation in the inferior myocardial segment provides prognostic information over and above clinical and conventional echocardiographic risk factors. Furthermore, impaired longitudinal deformation outside the culprit lesion perfusion region seems to be a paramount marker of adverse outcome.

Fig 1. Regional longitudinal deformation and prognosis.

Univariable and multivariable Cox proportional hazards regression models describing the risk of an adverse outcome per 1 decrease in longitudinal performance in each segment described by the TDI parameters and the 2DSE parameters, respectively. Depicting the mean value of the longitudinal deformation parameters in patients without an adverse outcome vs. patients with an adverse outcome, and the hazard ratio (95% confidence intervals) of adverse outcome associated with 1 decrease in longitudinal performance. In the multivariable models, the Regional longitudinal deformation measures are adjusted for age, gender, diabetes, complex lesion, peak TnI and culprit lesion. TDI = Tissue Doppler Imaging, 2DSE = Two-dimensional strain echocardiography, LD = Mitral annular longitudinal displacement determined by color TDI, s’ = Peak systolic longitudinal mitral annular velocity determined by color TDI, SRs = Peak longitudinal systolic strain rate, LVEF = Left Ventricular Ejection Fraction, LVMI = Left Ventricular Mass Index. ANT = Anterior, LAT = Lateral, POST = Posterior, INF = Inferior, SEPT = Septal, ANT SEPT = Anterior septal.

Fig 2. Incremental prognostic information by adding an assessment of the Regional longitudinal deformation.

The Harrell's c-statistic values obtained from the multivariable Cox proportional hazards regression models. Model 1 includes age, gender, peak TnI, systolic dysfunction determined by an LVEF<45 and/or abnormal diastolic function determined by the presence of diastolic dysfunction grade 1 to 3. Model 2 includes model 1 and one of the longitudinal deformation measures described by the TDI parameters or the 2DSE parameters. TDI = Tissue Doppler Imaging, 2DSE = Two-dimensional strain echocardiography, LD = Mitral annular longitudinal displacement determined by color TDI, SRs = Peak longitudinal systolic strain rate.

Fig 3. Regional longitudinal deformation and culprit lesion.

Patients stratified according to the location of their culprit lesion in the left anterior descending (LAD), the right coronary artery (RCA) or the left circumflex coronary artery (LCx). Fig 3A: The mean value of the TDI parameters at all six myocardial walls for patients stratified according to the location of their culprit lesion. Fig 3B: The mean value of the 2DSE parameters at all six myocardial walls for patients stratified according to the location of their culprit lesion. Fig 3C: The typical distribution of coronary artery blood supply to the 6 myocardial walls is displayed[15]. * indicates a p-value < 0.05 (Bonferroni corrected) when comparing LAD lesions with RCA lesions. † indicates a p-value < 0.05 (Bonferroni corrected) when comparing LAD lesions with Cx lesions. ‡ indicates a p-value < 0.05 (Bonferroni corrected) when comparing RCA lesions with Cx lesions. Values represent mean (±SD). LAD = Left Anterior Descending coronary artery, RCA = Right coronary artery, LCx = Left Circumflex coronary artery, s’ = peak systolic longitudinal mitral annular velocity determined by color Tissue Doppler Imaging, LD = Mitral annular longitudinal displacement determined by color TDI, SRs = Peak longitudinal systolic strain rate, ANT = Anterior, LAT = Lateral, POST = Posterior, INF = Inferior, SEPT = Septal, ANT SEPT = Anterior septal.

Fig 4. Regional longitudinal deformation outside the culprit perfusion region and prognosis.

Univariable and multivariable Cox proportional hazards regression models describing the risk of an adverse outcome for patients stratified into high or low regional longitudinal deformation parameters outside the culprit perfusion region. An abnormal conventional echocardiography is defined by systolic dysfunction determined by an LVEF<45 and/or abnormal diastolic function determined by the presence of diastolic dysfunction grade 1 to 3. Depicting the hazard ratio and the 95% confidence intervals. Also depicting the cut-off values, which are obtained from the mean values, for each regional longitudinal deformation parameter in each myocardial wall. s’ = Peak systolic longitudinal mitral annular velocity determined by color Tissue Doppler Imaging, LD = Mitral annular longitudinal displacement determined by color Tissue Doppler Imaging, SRs = Peak longitudinal systolic strain rate.