Prognostic Role of Diastolic Left Ventricular Mechanical Dyssynchrony by Gated Single Photon Emission Computed Tomography Myocardial Perfusion Imaging in Post-Myocardial Infarction

Objective  This study is aimed to assess the prognostic value of diastolic left ventricular mechanical dyssynchrony (LVMD) measured by gated-single photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI) in post-myocardial infarction (MI). Subjects and Methods  The study was conducted on 106 post-MI from January 2015 to January 2019. First, the indices of diastolic LVMD phase standard deviation (PSD) and histogram bandwidth (HBW) of post-MI were measured using the Cardiac Emory Toolbox. Subsequently, the post-MI patients were followed up, and the primary endpoint was major adverse cardiac events (MACEs). Finally, the prognostic value of dyssynchrony parameters for MACE was analyzed by the receiver-operating characteristics curve and survival analyses. Results  With the cut-off values of 55.5 degrees of PSD, the sensitivity and specificity in prediction of MACE were 75% and 80.8%, with the cut-off values of 174.5 degrees of HBW, the sensitivity and specificity were 75% and 83.3% respectively. There was a significant difference of time to MACE between groups of PSD less than 55.5 degrees and more than 55.5 degrees. PSD, HBW, and left ventricle ejection fraction (LVEF) assessed on GSPECT were significant factors in the prediction of MACE. Conclusion  Diastolic LVMD parameters of PSD and HBW derived from GSPECT are significant prognostic factors in predicting MACE in post-MI patients.

Prognostic value of the normalization of left ventricular mechanical dyssynchrony after revascularization in patients with coronary artery disease

There are no reports indicating a prognostic difference based on normalization of left ventricular (LV) mechanical dyssynchrony after revascularization in patients with coronary artery disease (CAD). We retrospectively investigated 596 patients who underwent rest ²⁰¹Tl and stress ^99mTc-tetrofosmin electrocardiogram-gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging. All patients had significant stenosis with ≥ 75% narrowing of the coronary arterial diameter detected by coronary angiography performed after confirmation of ≥ 5% ischemia by the SPECT. Patients underwent revascularization and thereafter were re-evaluated by the SPECT during a chronic phase, and followed-up to confirm their prognosis for ≥ 1 year. The composite endpoint was the onset of major cardiac events (MCEs) consisting of cardiac death, non-fatal myocardial infarction (MI), unstable angina pectoris (UAP), and severe heart failure requiring hospitalization. The stress phase bandwidth (SPBW) was calculated by phase analysis with the Heart Risk View-F software and its normal upper limit was set to 38°. During the follow-up, 64 patients experienced MCEs: Cardiac death (n = 11), non-fatal MI (n = 5), UAP (n = 26), and severe heart failure (n = 22). The results of the multivariate analysis showed the ∆summed difference score %, ∆stress LV ejection fraction, and stress SPBW after revascularization to be independent predictors of MCEs. Additionally, the results of the multivariate logistic regression analysis showed the summed rest score%, summed difference score%, stress LV ejection fraction, and perfusion defects in the left circumflex artery region before revascularization to be independent predictors for normalized SPBW after revascularization. The prognosis of patients who normalized SPBW after revascularization was similar to that of patients with a normal SPBW before revascularization, while patients who did not normalize after revascularization had the worst prognosis. In conclusion, normalization of LV dyssynchrony after revascularization assessed with nuclear cardiology may help predict future MCEs and thus a useful indicator for predicting improved prognosis in patients with CAD.

Prognostic Significance of Left Ventricular Dyssynchrony Assessed with Nuclear Cardiology for the Prediction of Major Cardiac Events after Revascularization

Objective This retrospective study was aimed at determining whether or not stress phase bandwidth (SPBW), a left ventricular (LV) mechanical dyssynchrony index, predicts major cardiac events (MCEs) and stratifies the risk of those in patients with coronary artery disease (CAD) who undergo revascularization. Methods Patients were followed up to confirm the prognosis for at least one year. The SPBW was calculated by a phase analysis using the Heart Risk View-F software program. The composite endpoint was the onset of MCEs, consisting of cardiac death, non-fatal myocardial infarction, unstable angina pectoris, and severe heart failure requiring hospitalization. Patients The study subjects were 332 patients with CAD who underwent coronary angiography and revascularization after confirming ≥5% ischemia detected by rest ²⁰¹Tl and stress ^99mTc-tetrofosmin electrocardiogram-gated single-photon emission computed tomography myocardial perfusion imaging. Results During the follow-up, 35 patients experienced MCEs of cardiac death (n=5), non-fatal myocardial infarction (n=3), unstable angina pectoris (n=11), and severe heart failure requiring hospitalization (n=16). A receiver operating characteristics analysis indicated that the optimal cut-off value of the SPBW was 52° for predicting MCEs, and the MCE rate was significantly higher in the patients with an SPBW >52° than in those with an SPBW ≤52°. Results of the multivariate analysis showed the SPBW and estimated glomerular filtration rate to be independent predictors for MCEs. In addition, the cut-off value of the SPBW significantly stratified the risk of MCEs according to the results of the Kaplan-Meier analysis. Conclusion Evaluating the SPBW before revascularization may help predict future MCEs in patients with CAD who intended to undergo treatment.

Left ventricular dyssynchrony assessment using tissue synchronization imaging in acute myocardial infarction

Objectives:

To assess left ventricular (LV) dyssynchrony in patients with ST elevation myocardial infarction (STEMI).

Background:

Mechanical synchronization disorder leads to a decrease in LV ejection fraction (LVEF) and stroke volume, an abnormal distribution of wall tension, and increase in workload during cardiac contraction.

Methods:

We enrolled 56 participants, 36 with acute STEMI and 20 healthy controls. The automatically color-coded time to peak myocardial velocity was measured using a 6mm sample volume, manually positioned within the two-dimensional-tissue strain image of the 12 basal and middle LV segments.

Results:

A significant delay was found between the septal-lateral and septal-posterior walls in patients with STEMI compared to patients in the control group (36.36 vs. −6.0ms, P = 0.036; and 42.7 vs. 23.94ms, P = 0.042, respectively). Furthermore, all segment maximum differences and all segment standard deviation (SD; dyssynchrony index) were found to be significantly higher in the STEMI group (131.28 vs. 95.45ms, P = 0.013; and 44.47 vs. 26.45ms, P = 0.001, respectively). A significant delay between the septal-lateral walls and septal-posterior walls, all segment maximum difference, and all segment SD (dyssynchrony index) were found in patients with complicated STEMI (70.89 vs. 15.83ms, P = 0.038; 57.44 vs. 19.06ms, P = 0.040; 138.11 vs. 100.0ms, P = 0.035; and 45.44 vs. 32.50ms, P = 0.021, respectively). There was a significant negative correlation between tissue synchronization imaging parameters and LVEF, and a positive correlation with LV end systolic dimension.

Conclusion:

Patients with acute STEMI showed significant LV dyssynchrony, which was an independent predictor of inhospital complications.

The Effect of Clinical Characteristics and Stent Parameters on Left Ventricular Mechanical Dyssynchrony

Aim. To study short term effect of stent size and number on left ventricular mechanical dyssynchrony after elective percutaneous coronary intervention (PCI) to left anterior descending (LAD) artery.

Materials and methods. the study included 150 adult patients with LAD lesion treated with PCI using drug-eluting stent. Patients were evaluated pre PCI then 1 month and 3 months post PCI for evaluation of mechanical dyssynchrony using tissue synchronization image (TSI).

Results. Before revascularization mean left ventricular ejection fraction was 51.2±5.7 %, mean time to peak TSI was 213.6±10.9 ms; 1 month after PCI TSI improved significantly to 163.7±17.6 ms (p<0.001), 3 months after PCI showed more improvement to 120.7±26.9 ms (p<0.001). After 3m; 61 patients (40.7%) showed recovery to normal TSI value. The predictors of non-improvement of time to peak TSI after 3 months were diabetes mellitus (p=0.007), dyslipidemia (p=0.001) and stent length (p=0.001), number of stents (p=0.004). There were strong negative correlation between stent length and improvement of the time to peak TSI at 1 month (r=-0.352, p<0.001) and at 3 months (r=-0.509, p<0.001),and also with number of stent at 1 month (r= -0.173, p=0.034) and at 3 months (r=-0.499, p<0.001), but the correlation between stent diameter and improvement of the TSI wasn’t significant neither at 1 month nor at 3 months (r=0.055, p=0.504 and r= -0.018, p=0.827) respectively.

Conclusion. Increased number and length of the implanted stents were predictors to non-improvement of mechanical dyssynchrony, while stent diameter didn’t affects the recovery.

Cardiac Magnetic Resonance Left Ventricular Mechanical Uniformity Alterations for Risk Assessment After Acute Myocardial Infarction

Background Despite limitations as a stand-alone parameter, left ventricular (LV) ejection fraction is the preferred measure of myocardial function and marker for postinfarction risk stratification. LV myocardial uniformity alterations may provide superior prognostic information after acute myocardial infarction, which was the subject of this study. Methods and Results Consecutive patients with acute myocardial infarction (n=1082; median age: 63 years; 75% male) undergoing cardiac magnetic resonance at a median of 3 days after infarction were included in this multicenter observational study. Circumferential and radial uniformity ratio estimates were derived from cardiac magnetic resonance feature tracking as markers of mechanical uniformity alterations (values between 0 and 1 with 1 reflecting perfect uniformity). The clinical end point was the 12-month rate of major adverse cardiac events, consisting of all-cause death, reinfarction, and new congestive heart failure. Patients with major adverse cardiac events (n=73) had significantly impaired circumferential uniformity ratio estimates (0.76 [interquartile range: 0.67-0.86] versus 0.84 [interquartile range: 0.76-0.89]; P<0.001) and radial uniformity ratio estimates (0.69 [interquartile range: 0.60-0.79] versus 0.76 [interquartile range: 0.67-0.83]; P<0.001) compared with patients without events. Although uniformity estimates did not provide independent prognostic information in the overall cohort, a circumferential uniformity ratio estimate below the median of 0.84 emerged as an independent predictor of outcome in postinfarction patients with LV ejection fraction >35% (n=959), even after adjustment for established risk factors (hazard ratio: 1.99; 95% CI, 1.06-3.74; P=0.033 in multivariable Cox regression analysis). In contrast, LV ejection fraction was not associated with adverse events in this subgroup of patients with acute myocardial infarction. Conclusions Cardiac magnetic resonance-derived estimates of mechanical uniformity alterations are novel markers for risk assessment after acute myocardial infarction, and the circumferential uniformity ratio estimate provides independent prognostic information for patients with preserved or only moderately reduced LV ejection fraction.

Prognostic significance of NT-proBNP, 3D LA volume and LV dyssynchrony in patients with acute STEMI undergoing primary percutaneous intervention

OBJECTIVES

The aim of the present study was to assess the short term prognostic significance of N-terminal pro BNP (NT-proBNP), 3D left atrial volume (LAV) and left ventricular (LV) dyssynchrony in patients of acute ST-elevation myocardial infarction (STEMI) who underwent primary Percutaneous intervention (PCI).

BACKGROUND

NT-proBNP, LV dyssynchrony and LAV in patients with acute coronary syndrome have been associated with PCI outcomes and predict the short and long-term prognosis.

METHODS

This study consisted of 142 patients with a first STEMI who underwent primary PCI. Baseline echocardiographic data was collected at admission and at 6 months follow up. Left ventricular dyssynchrony was measured by tissue Doppler imaging and LAV by real time 3D-echocardiography, plasma NT-proBNP levels were estimated between 72 and 96 h of admission.

RESULTS

During study period 3 patients expired and 4 developed congestive heart failure (CHF). Baseline NT-proBNP and LV dyssynchrony correlated with LV size and LV ejection fraction (LVEF) at baseline and during follow up. Patients with higher NT-proBNP levels and higher LV dyssynchrony showed significant increase in LV size with decrease in LVEF during follow-up. Baseline Left atrial volume index (LAVI) showed significant correlation with LV size but no association with LVEF at baseline and during follow-up.

CONCLUSIONS

Higher levels of NT-proBNP and higher LV dyssynchrony can predict patients with increase in LV size, worsening of LV systolic and diastolic function during follow-up. Patients with higher NT-proBNP levels at baseline developed CHF during follow-up.

Left Ventricular Dyssynchrony Predicts Left Main Coronary Artery Disease in Patients with Non-ST-Segment Elevation Myocardial Infarction

BACKGROUND

The purpose of our study was to examine whether left ventricular dyssynchrony predicts left main coronary artery stenosis in patients with non-ST-segment elevation myocardial infarction.

METHODS

A total of 100 consecutive patients with non-ST-segment elevation myocardial infarction underwent echocardiography and coronary artery angiography. The 3-dimensional echocardiography-derived left ventricular dyssynchrony parameter was determined by using the standard deviation of the time to the minimal systolic volume for the 16 segments. A stenosis ≥ 50% of the diameter of the left main coronary artery or a stenosis ≥ 70% in 1 or more of the major epicardial vessels or their main branches was considered significant.

RESULTS

The logistic regression analysis revealed that this parameter (odds ratio 1.2; 95% confidence interval, 1.01-1.42; p = 0.04) was the independent predictor of left main coronary artery stenosis. The receiver operating characteristic curve analysis revealed 8.86 as the optimal cutoff value to predict left main coronary artery stenosis (sensitivity, 71.4%; specificity, 89.2%).

CONCLUSIONS

The assessment of left ventricular dyssynchrony by 3-dimensional echocardiography is useful for a noninvasive diagnosis of the left main coronary artery stenosis in patients with non-ST-segment elevation myocardial infarction.

KEY WORDS

Dyssynchrony; Left main coronary artery stenosis; Non-ST-segment elevation myocardial infarction.

The prognostic value of mechanical left ventricular dyssynchrony in patients with acute coronary syndrome

Background

Echocardiography is a well-established tool for risk stratification in patients with acute coronary syndrome (ACS). ACS has significant impact on LV dyssynchrony, and detrimental effects on systolic function and long term outcome. The aims of this study were to determine whether LV dyssynchrony carries any predictive information in an unselected ACS population and to evaluate if it has any incremental value to the information given from conventional echocardiographic measurements.

Methods

The study included 227 consecutive ACS patients. Primary endpoint was the composite of death, new MI, or rehospitalisation due to heart failure. Dyssynchrony was measured as intersegmental variation of time to peak strain, the post systolic index (PSI) and myocardial performance index (MPI) with the standard deviation and difference between lowest and highest value (delta) expressing the amount of dyssynchrony. Septal-lateral delay was also tested. All dyssynchrony parameters were compared with Ejection fraction (EF).

Results

The median follow up time was 53 months. 85 patients reached the combined endpoint. Patients with and without a subsequent combined endpoint differed significantly regarding calculated SD: s and delta-value for PSI, time to peak 2D-strain and MPI but not regarding septal-lateral delay. In ROC-analysis none of the dyssynchrony parameters had larger AUC than EF. When adjusting for traditional risk factors none of the dyssynchrony parameters remained associated with outcome, whereas EF still did.

Conclusion

LV dyssynchrony seem to have significant prognostic information in patient with acute coronary syndrome but in comparison to conventional parameters such as EF there is no incremental value of this information.

Predictive value of left ventricular remodeling by area strain based on three-dimensional wall-motion tracking after PCI in patients with recent NSTEMI

We aimed to explore whether a novel left ventricular performance index, area strain (AS), based on three-dimensional wall-motion tracking (3-D-WMT) done before and after percutaneous coronary intervention (PCI) could predict left ventricular (LV) remodeling in patients with recent non-ST elevation myocardial infarction (NSTEMI). Sixty-one patients (53.6 ± 8.8 years) with recent NSTEMI were enrolled. Coronary angiography and PCI were undertaken for reperfusion. Parameters of myocardial deformation (including LV end-diastolic volume, LV end-systolic volume, LV ejection fraction, LV global and regional peak area strain) were measured by 3-D-WMT before and 1 week after reperfusion therapy. Six months after reperfusion, LV negative remodeling was defined as lack of improvement in LV function, with increase in LV end-diastolic volume ≥15%. Patients were subdivided into remodeled group (n = 25) and non-remodeled group (n = 36) at follow-up. Patients with negative LV remodeling had significantly higher cardiac troponin I (cTnI) levels at baseline (21.21 ± 12.22 vs. 15.56 ± 8.91 ng/mL; p = 0.0357), higher B-type natriuretic peptide (BNP) level (247.56 ± 177.39 vs. 170.53 ± 97.89 pg/mL; p = 0.0336) and reduced global AS (-27.9 ± 4.6% vs. -31.9 ± 4.3%; p = 0.001) than those without remodeling. Global AS at baseline had a significantly close correlation with cTnI level 36 h after MI (r = 0.71, p < 0.001). Moreover, a weak relationship was found between LV global AS at baseline and BNP level 24 h after myocardial infarction (r = 0.423, p < 0.001). By multivariate logistic regression analysis, lack of improvement of global AS 1 week after PCI was found to be a powerful independent predictor of negative LV remodeling at follow-up (OR = 1.41, 95% CI 1.28-3.27, p = 0.003). In particular, a global AS ≤32% (absolute value) showed a sensitivity and a specificity of 86.1% and 68.0% in predicting negative LV remodeling. These data suggest that AS could be used to assess myocardial global and regional LV function with good feasibility and repeatability. Global AS 1 week after PCI is a good independent predictor of negative LV remodeling after 6-month follow-up.