M. Louisa Antoni

Prognostic importance of strain and strain rate after acute myocardial infarction

AIMS Recently, strain and strain rate have been introduced as novel parameters reflecting left ventricular (LV) function. The purpose of the current study was to assess the prognostic importance of strain and strain rate after acute myocardial infarction (AMI). METHODS AND RESULTS A total of 659 patients after AMI were evaluated. Baseline echocardiography was performed to assess LV function with traditional parameters and strain and strain rate. During follow-up, 51 patients (8%) reached the primary endpoint (all-cause mortality) and 142 patients (22%) the secondary endpoint (a composite of revascularization, re-infarction, and hospitalization for heart failure). Strain and strain rate were both significantly related with all endpoints. After adjusting for clinical and echocardiographic parameters, strain was independent related to all endpoints and was found to be superior to LV ejection fraction (LVEF) and wall motion score index (WMSI). Patients with global strain and strain rate higher than -15.1% and -1.06 s(-1) demonstrated HRs of 4.5 (95% CI 2.1-9.7) and 4.4 (95% CI 2.0-9.5) for all-cause mortality, respectively. CONCLUSION Strain and strain rate provide strong prognostic information in patients after AMI. These novel parameters were superior to LVEF and WMSI in the risk stratification for long-term outcome.

Global Longitudinal Strain Predicts Long-Term Survival in Patients with Chronic Ischemic Cardiomyopathy

Background— Left ventricular (LV) global longitudinal strain (GLS) is a measure of the active shortening of the LV in the longitudinal direction, which can be assessed with speckle-tracking echocardiography. The aims of this evaluation were to validate the prognostic value of GLS as a new index of LV systolic function in a large cohort of patients with chronic ischemic cardiomyopathy and to determine the incremental value of GLS to predict long-term outcome over other strong and well-established prognostic factors. Methods and Results— A total of 1060 patients underwent baseline clinical evaluation and transthoracic echocardiography. Median age was 66.9 years (interquartile range, 58.4, 74.2 years); 739 (70%) were men. The median follow-up duration for the entire patient population was 31 months. During the follow-up, 270 patients died and 309 patients reached the combined end point (all-cause mortality and heart failure hospitalization). Compared with survivors, patients who died (270, [25%]) had larger LV volumes (P<0.05), lower LV ejection fraction (P=0.004), higher wall motion score index (P=0.001), and greater impairment of LV GLS (P<0.001). After dichotomizing the population on the basis of the median value of LV GLS (−11.5%), patients with an LV GLS ⩽−11.5% had superior outcome compared with patients with an LV GLS >−11.5% (log-rank &khgr;2, 13.86 and 14.16 for all-cause mortality and combined end point, respectively, P<0.001 for both). On multivariate analysis, GLS was independently related to all-cause mortality (hazard ratio per 5% increase, 1.69; 95% confidence interval, 1.33–2.15; P<0.001) and combined end point (1.64; 95% confidence interval, 1.32–2.04; P<0.001). Conclusions— The assessment of LV GLS with speckle-tracking echocardiography is significantly related to long-term outcome in patients with chronic ischemic cardiomyopathy.

Prognostic Value of Right Ventricular Function in Patients after Acute Myocardial Infarction Treated with Primary Percutaneous Coronary Intervention

Background—Data on the association between right ventricular (RV) function and adverse events after acute myocardial infarction (AMI) are scarce. The purpose of the current study was to evaluate the relation between RV function and adverse events in patients treated with primary percutaneous coronary intervention for AMI. Methods and Results—Consecutive patients admitted with AMI treated with primary percutaneous coronary intervention underwent echocardiography within 48 hours of admission to assess left ventricular and RV function. RV function was quantified with RV fractional area change (RVFAC), tricuspid annular plane systolic excursion, and RV strain. The end point was defined as a composite of all-cause mortality, reinfarction, and hospitalization for heart failure. All patients (n=621) were followed prospectively, and during a mean follow-up of 24 months, 86 patients reached the composite end point. RVFAC, tricuspid annular plane systolic excursion, and RV strain were all univariable predictors of worse outcome. After multivariable analysis, only RVFAC (hazard ratio, 0.96; 95% CI, 0.92 to 0.99) and RV strain (hazard ratio, 1.08; 95% CI, 1.03 to 1.13) independently predicted the composite end point. In addition, RV strain provided incremental value to clinical information, infarct characteristics, left ventricular function, and RVFAC. Conclusions—RV function provides strong prognostic information in patients treated with primary percutaneous coronary intervention for AMI.

Stent Malapposition After Sirolimus-Eluting and Bare-Metal Stent Implantation in Patients with ST-Segment Elevation Myocardial Infarction Acute and 9-Month Intravascular Ultrasound Results of the MISSION! Intervention Study

OBJECTIVES Acute and late stent malapposition (SM) after bare-metal stents (BMS) and sirolimus-eluting stents (SES) in ST-segment elevation myocardial infarction patients were studied. BACKGROUND Stent thrombosis may be caused by SM after primary percutaneous coronary intervention in ST-segment elevation myocardial infarction patients. METHODS Post-procedure and follow-up intravascular ultrasound data were available in 184 out of 310 patients (60%; 104 SES, 80 BMS) included in the MISSION! Intervention Study. To determine the contribution of remodeling and changes in plaque burden to the change in lumen cross-sectional area (CSA) at SM sites, the change in lumen CSA (follow-up minus post-lumen CSA) was related to the change in external elastic membrane CSA (remodeling) and change in plaque and media CSA (plaque burden). RESULTS Acute SM was found in 38.5% SES patients and 33.8% BMS patients (p = 0.51), late SM in 37.5% SES patients and 12.5% BMS patients (p < 0.001). Acquired SM was found in 25.0% SES patients and 5.0% BMS patients (p < 0.001). Predictors of acute SM were reference diameter (SES: odds ratio [OR] 3.49, 95% confidence interval [CI] 1.29 to 9.43; BMS: OR 28.8, 95% CI 4.25 to 94.5) and balloon pressure (BMS: OR 0.74, 95% CI 0.58 to 0.94). Predictors of late SM were diabetes mellitus (SES: OR 0.16, 95% CI 0.02 to 1.35), reference diameter (BMS: OR 19.2, 95% CI 2.64 to 139.7), and maximum balloon pressure (BMS: OR 0.74, 95% CI 0.55 to 1.00). Change in lumen CSA was related to change in external elastic membrane CSA (R = 0.73, 95% CI 0.62 to 0.84) after SES implantation and to change in plaque and media CSA (R = -0.62, 95% CI -0.77 to -0.46) after BMS implantation. After SES implantation, acquired SM was caused by positive remodeling in 84% and plaque reduction in 16% of patients. CONCLUSIONS Acute SM was common after SES and BMS stent implantation in ST-segment elevation myocardial infarction patients. After SES implantation, late acquired SM is common and generally caused by positive remodeling.

Outcomes After Transcatheter Aortic Valve Implantation: Transfemoral Versus Transapical Approach

BACKGROUND Transcatheter aortic valve implantation is commonly implanted through a transfemoral (TFA) or transapical approach (TAA) for patients with severe aortic stenosis. This study aimed to describe the clinical and echocardiographic outcomes of TFA versus TAA. METHODS Clinical and echocardiographic evaluations were performed at baseline, post-TAVI (transcatheter aortic valve implantation), at 6 and 12 months follow-up in 107 consecutive patients who underwent TAVI with balloon-expandable valves. RESULTS The TFA was performed in 44% and the remaining patients underwent TAA. Although procedural complications were not significantly different in both approaches, more vascular complications were observed in the TFA group (18% vs 5%, p = 0.053). Patients with TAA required shorter fluoroscopy time (median 5 vs 12 min, p < 0.001), less contrast volume (median 80 vs 173 mL, p < 0.001), and similar length of hospitalization, as compared with TFA. Importantly, the early 30-day mortality (TFA: 11.1% vs TAA: 8.5%, p = 0.74) were not significantly different between the 2 approaches. Midterm survival at 6 months and 1 year was comparable between TFA and TAA (6 months: 88.9% vs 85.7% and 1 year: 80.2% vs 85.7%). All patients achieved immediate and sustained improvements in transvalvular hemodynamics, together with significant left ventricular mass regression (137 ± 39 vs 113 ± 30 g/m(2), p < 001) and left atrial volume reduction (48 ± 17 vs 34 ± 14 mL/m(2), p < 0.001) at 6 months or less. CONCLUSIONS Early, midterm, clinical, and echocardiographic outcomes were comparable in both approaches. However, TAA has the additional benefit of reducing radiation exposure and contrast use intraoperatively without prolonging the length of hospital stay.

Viability Assessment With Global Left Ventricular Longitudinal Strain Predicts Recovery of Left Ventricular Function After Acute Myocardial Infarction

Background—The extent of viable myocardial tissue is recognized as a major determinant of recovery of left ventricular (LV) function after myocardial infarction. In the current study, the role of global LV strain assessed with novel automated function imaging (AFI) to predict functional recovery after acute infarction was evaluated. Methods and Results—A total of 147 patients (mean age, 61±11 years) admitted for acute myocardial infarction were included. All patients underwent 2D echocardiography within 48 hours of admission. Significant relations were observed between baseline AFI global LV strain and peak level of troponin T (r=0.64), peak level of creatine phosphokinase (r=0.62), wall motion score index (r=0.52), and viability index assessed with single-photon emission computed tomography (r=0.79). At 1-year follow-up, LV ejection fraction was reassessed. Patients with absolute improvement in LV ejection fraction ≥5% at 1-year follow-up (n=70; 48%) had a higher (more negative) baseline AFI global LV strain (P<0.0001). Baseline AFI global LV strain was a predictor for change in LV ejection fraction at 1-year follow-up. A cutoff value for baseline AFI global LV strain of −13.7% yielded a sensitivity of 86% and a specificity of 74% to predict LV functional recovery at 1-year follow-up. Conclusions—AFI global LV strain early after acute myocardial infarction reflects myocardial viability and predicts recovery of LV function at 1-year follow-up.

Validation of ECG Indices of Ventricular Repolarization Heterogeneity: A Computer Simulation Study

Introduction: Repolarization heterogeneity (RH) is functionally linked to dispersion in refractoriness and to arrhythmogenicity. In the current study, we validate several proposed electrocardiogram (ECG) indices for RH: T‐wave amplitude, ‐area, ‐complexity, and ‐symmetry ratio, QT dispersion, and the Tapex‐end interval (the latter being an index of transmural dispersion of the repolarization (TDR)).

Relationship between discharge heart rate and mortality in patients after acute myocardial infarction treated with primary percutaneous coronary intervention

AIMS In patients with coronary artery disease, the prognostic value of heart rate has been mainly evaluated in patients with left ventricular dysfunction. Patients with ST-segment elevation acute myocardial infarction (STEMI) are currently treated with primary percutaneous coronary intervention (PCI) and in this contemporary population of patients, the relationship between heart rate and mortality during a follow-up >1 year has not been investigated. METHODS AND RESULTS The population comprised 1453 STEMI patients treated with primary PCI. Resting heart rate was measured before discharge and all patients were followed prospectively. MAIN OUTCOME MEASURE the endpoints were defined as all-cause mortality and cardiovascular mortality. The median follow-up duration was 40 months. During this period, 83(6%) patients died of which 52(4%) died from cardiovascular disease. After adjusting for parameters reflecting a greater infarct size and the presence of heart failure, heart rate at discharge remained a strong predictor of mortality. Patients with a heart rate of ≥70 b.p.m. had a two times increased risk of cardiovascular mortality at 1- and 4-year follow-up compared with patients with a heart rate <70 b.p.m.. In addition, every increase of 5 b.p.m. in heart rate at discharge was associated with a 29 and 24% increased risk of cardiovascular mortality at 1- and 4-year follow-up, respectively. CONCLUSION In STEMI patients treated with primary PCI and optimal medical therapy, heart rate at discharge was an important predictor of mortality up to 4 years follow-up even after adjustment for parameters reflecting a greater infarct size and the presence of heart failure.

Left atrial strain is related to adverse events in patients after acute myocardial infarction treated with primary percutaneous coronary intervention

Background Left atrial (LA) maximal volume is of prognostic value in patients after acute myocardial infarction (AMI). Recently, LA mechanical function and LA strain have been introduced as alternative methods to assess LA performance more accurately. Objective To evaluate the relation between LA volume, mechanical function and strain, and adverse events in patients after AMI. Methods Patients with AMI underwent two-dimensional echocardiography within 48 h of admission. LA volume and LA performance (mechanical function and systolic strain) were quantified. The endpoint was a composite of all-cause mortality, reinfarction and hospitalisation for heart failure. Results 320 patients (mean age 60±12 years, 78% men) were followed up for 27±14 months. During follow-up, 48 patients (15%) reached the composite endpoint. After adjustment for clinical and echocardiographic parameters, LA maximal volume (HR 1.05, CI 1.00 to 1.10, p=0.04) and LA strain (HR 0.94, CI 0.89 to 0.99, p=0.02) were independently associated with adverse outcome. In addition, LA strain provided incremental value to LA maximal volume (p=0.03) for the prediction of adverse outcome. Conclusions After AMI treated with primary percutaneous coronary intervention, LA strain provides additional prognostic value beyond LA maximal volume.

Left ventricular rotational mechanics in patients with coronary artery disease: differences in subendocardial and subepicardial layers

Objective Subendocardial and subepicardial layers have opposite orientation of the myofibres and they are differently affected by coronary artery disease. This study investigated the differences in subendocardial and subepicardial left ventricular (LV) twist in patients with coronary artery disease. Methods 214 patients were included in the study: 60 with first ST elevation myocardial infarction (STEMI), 111 with chronic ischaemic heart failure (HF) and 43 normal subjects. Real-time three-dimensional echocardiography provided LV volumes and function. Two-dimensional speckle tracking echocardiography differentiating the subendocardial and subepicardial layers was used for the assessment of LV twist. Patients with STEMI were divided into two groups (small and large STEMI). Results Compared with normal subjects, peak subendocardial LV twist was significantly impaired in patients with STEMI (11.2±6.0° vs 15.3±2.7°, p<0.001). In patients with chronic HF, peak subendocardial LV twist was even more impaired (4.6±3.4°, p<0.001 vs normal subjects and patients with STEMI). Conversely, peak subepicardial LV twist was not statistically different between normal subjects and patients with STEMI (8.9±1.9° vs 8.4±4.4°, p=0.98), whereas it was significantly impaired in patients with chronic HF (2.6±2.5°, p<0.001 vs normal subjects and patients with STEMI). Peak subendocardial LV twist was not statistically different between large and small STEMI, whereas peak subepicardial LV twist was significantly lower in large STEMI than in small STEMI (7.1±4.8° vs 9.6±3.6°, p=0.025). Conclusions Subendocardial LV twist is reduced in patients with STEMI and chronic ischaemic HF whereas subepicardial LV twist is reduced only in chronic ischaemic HF. When STEMI are divided into large and small infarctions, it becomes evident that subepicardial LV twist is only reduced in large infarctions.