Speckle-tracking echocardiography for predicting improvement of myocardial contractile function after revascularization: a meta-analysis of prospective trials.

Some studies have indicated that the use of 2D-Speckle tracking echocardiography (2DSTE) aids in predicting recovery of myocardial contractile function after revascularization in patients with chronic ischemic left ventricular (LV) dysfunction or acute myocardial infarction (MI). The purpose of this meta-analysis was to evaluate the diagnostic accuracy of 2DSTE strain in the detection of myocardial viability at rest and during low-dose dobutamine (LDD) stress. A systematic review for all prospective trials using 2DSTE to assess myocardial viability until January 2019 was done. Using a standard approach of meta-analysis for diagnostic tests. Overall, nine studies including 525 patients with either chronic ischemic heart disease or acute MI fulfilled the inclusion criteria. Seven studies used longitudinal strain (LS) at rest, nine studies used circumferential strain (CS) at rest, four studies used LS during LDD stress, and four studies used CS during LDD stress. LS and CS during LDD stress showed equally high sensitivity (81.5% and 81.5% respectively) and specificity (81.3% and 81.4% respectively) for detecting reversible dysfunction. At rest, LS and CS showed equally lower sensitivity (67.1%, p < 0.0001 vs. LDD stress and 68.7%, p < 0.0001, vs. LDD stress, respectively) and specificity (64%, p < 0.0001 vs. LDD stress and 65.7%, p = 0.0008 vs. LDD stress, respectively) as compared with LDD stress. LS and CS by 2DSTE during LDD stress accurately identify reversible ischemic myocardial dysfunction in patients with chronic ischemic LV dysfunction or after MI. The use of LDD stress can be recommended over resting strain measures in this setting.

Effect of Inhaled Xenon on Cardiac Function in Comatose Survivors of Out-of-Hospital Cardiac Arrest-A Substudy of the Xenon in Combination With Hypothermia After Cardiac Arrest Trial.

This explorative substudy aimed at determining the effect of inhaled xenon on left ventricular function by echocardiography in comatose survivors of out-of-hospital cardiac arrest. DESIGN: A randomized two-group single-blinded phase 2 clinical drug trial. SETTING: A multipurpose ICU in two university hospitals. PATIENTS: Of the 110 randomized comatose survivors after out-of-hospital cardiac arrest with a shockable rhythm in the xenon in combination with hypothermia after cardiac arrest trial, 38 patients (24-76 yr old) with complete echocardiography were included in this study. INTERVENTIONS: Patients were randomized to receive either inhaled xenon combined with hypothermia (33°C) for 24 hours or hypothermia treatment alone. Echocardiography was performed at hospital admission and 24 ± 4 hours after hypothermia. MEASUREMENTS AND MAIN RESULTS: Left ventricular ejection fraction, myocardial longitudinal systolic strain, and diastolic function were analyzed blinded to treatment. There were 17 xenon and 21 control patients in whom echocardiography was completed. Clinical characteristics did not differ significantly between the groups. At admission, ejection fraction was similar in xenon and control patients (39% ± 10% vs 38% ± 11%; p = 0.711) but higher in xenon than control patients after hypothermia (50% ± 10% vs 42% ± 10%; p = 0.014). Global longitudinal systolic strain was similar in xenon and control patients at admission (-9.0% ± 3.8% vs -8.1% ± 3.6%; p = 0.555) but better in xenon than control patients after hypothermia (-14.4.0% ± 4.0% vs -10.5% ± 4.0%; p = 0.006). In patients with coronary artery disease, longitudinal strain improved in the nonischemic myocardial segments in xenon patients. There were no changes in diastolic function between the groups. CONCLUSIONS: Among comatose survivors of a cardiac cause out-of-hospital cardiac arrest, inhaled xenon combined with hypothermia was associated with greater recovery of left ventricular systolic function in comparison with hypothermia alone.

Impact of a decreasing pre-test probability on the performance of diagnostic tests for coronary artery disease.

AIMS: To provide a pooled estimation of contemporary pre-test probabilities (PTPs) of significant coronary artery disease (CAD) across clinical patient categories, re-evaluate the utility of the application of diagnostic techniques according to such estimates, and propose a comprehensive diagnostic technique selection tool for suspected CAD. METHODS AND RESULTS: Estimates of significant CAD prevalence across sex, age, and type of chest pain categories from three large-scale studies were pooled (n = 15 815). The updated PTPs and diagnostic performance profiles of exercise electrocardiogram, invasive coronary angiography, coronary computed tomography angiography (CCTA), positron emission tomography (PET), stress cardiac magnetic resonance (CMR), and SPECT were integrated to define the PTP ranges in which ruling-out CAD is possible with a post-test probability of <10% and <5%. These ranges were then integrated in a new colour-coded tabular diagnostic technique selection tool. The Bayesian relationship between PTP and the rate of diagnostic false positives was explored to complement the characterization of their utility. Pooled CAD prevalence was 14.9% (range = 1-52), clearly lower than that used in current clinical guidelines. Ruling-out capabilities of non-invasive imaging were good overall. The greatest ruling-out capacity (i.e. post-test probability <5%) was documented by CCTA, PET, and stress CMR. With decreasing PTP, the fraction of false positive findings rapidly increased, although a lower CAD prevalence partially cancels out such effect. CONCLUSION: The contemporary PTP of significant CAD across symptomatic patient categories is substantially lower than currently assumed. With a low prevalence of the disease, non-invasive testing can rarely rule-in the disease and focus should shift to ruling-out obstructive CAD. The large proportion of false positive findings must be taken into account when patients with low PTP are investigated.

Determinants of Myocardial Strain in Experimental Chronic Myocardial Infarction.

We evaluated the relationships between regional myocardial strain measured by speckle tracking echocardiography and viability, fibrosis, hypertrophy and oxygen consumption in the infarcted or remote myocardium in a pig model of chronic myocardial infarction (MI). Thirteen farm pigs with surgical occlusion of the left anterior descending coronary artery and five sham-operated pigs were studied 3 mo post-MI. Computed tomography revealed significant left ventricle remodeling. Reduced radial or circumferential strain identified areas of transmural infarction (area under the curve: 0.82 and 0.79, respectively). In the remote non-infarcted area, radial strain correlated inversely with the amount of fibrosis (r = -0.66, p = 0.04) and myocyte hypertrophy (r = -0.68, p = 0.03). Radial strain rate inversely correlated with myocardial resting oxygen consumption assessed with 11C-labeled acetate positron emission tomography (r = -0.71, p = 0.006). In conclusion, myocardial strain and strain rate reflect fibrosis, hypertrophy and oxygen consumption of the remote areas after MI.

The performance of non-invasive tests to rule-in and rule-out significant coronary artery stenosis in patients with stable angina: a meta-analysis focused on post-test disease probability.

Aims: To determine the ranges of pre-test probability (PTP) of coronary artery disease (CAD) in which stress electrocardiogram (ECG), stress echocardiography, coronary computed tomography angiography (CCTA), single-photon emission computed tomography (SPECT), positron emission tomography (PET), and cardiac magnetic resonance (CMR) can reclassify patients into a post-test probability that defines (>85%) or excludes (<15%) anatomically (defined by visual evaluation of invasive coronary angiography [ICA]) and functionally (defined by a fractional flow reserve [FFR] ≤0.8) significant CAD. Methods and results: A broad search in electronic databases until August 2017 was performed. Studies on the aforementioned techniques in >100 patients with stable CAD that utilized either ICA or ICA with FFR measurement as reference, were included. Study-level data was pooled using a hierarchical bivariate random-effects model and likelihood ratios were obtained for each technique. The PTP ranges for each technique to rule-in or rule-out significant CAD were defined. A total of 28 664 patients from 132 studies that used ICA as reference and 4131 from 23 studies using FFR, were analysed. Stress ECG can rule-in and rule-out anatomically significant CAD only when PTP is ≥80% (76-83) and ≤19% (15-25), respectively. Coronary computed tomography angiography is able to rule-in anatomic CAD at a PTP ≥58% (45-70) and rule-out at a PTP ≤80% (65-94). The corresponding PTP values for functionally significant CAD were ≥75% (67-83) and ≤57% (40-72) for CCTA, and ≥71% (59-81) and ≤27 (24-31) for ICA, demonstrating poorer performance of anatomic imaging against FFR. In contrast, functional imaging techniques (PET, stress CMR, and SPECT) are able to rule-in functionally significant CAD when PTP is ≥46-59% and rule-out when PTP is ≤34-57%. Conclusion: The various diagnostic modalities have different optimal performance ranges for the detection of anatomically and functionally significant CAD. Stress ECG appears to have very limited diagnostic power. The selection of a diagnostic technique for any given patient to rule-in or rule-out CAD should be based on the optimal PTP range for each test and on the assumed reference standard.

Accuracy of echocardiographic area-length method in chronic myocardial infarction: comparison with cardiac CT in pigs.

BACKGROUND: We evaluated echocardiographic area-length methods to measure left ventricle (LV) volumes and ejection fraction (EF) in parasternal short axis views in comparison with cardiac computed tomography (CT) in pigs with chronic myocardial infarction (MI). METHODS: Male farm pigs with surgical occlusion of the left anterior descending coronary artery (n = 9) or sham operation (n = 5) had transthoracic echocardiography and cardiac-CT 3 months after surgery. We measured length of the LV in parasternal long axis view, and both systolic and diastolic LV areas in parasternal short axis views at the level of mitral valve, papillary muscles and apex. Volumes and EF of the LV were calculated using Simpson's method of discs (tri-plane area) or Cylinder-hemiellipsoid method (single plane area). RESULTS: The pigs with coronary occlusion had anterior MI scars and reduced EF (average EF 42 ± 10%) by CT. Measurements of LV volumes and EF were reproducible by echocardiography. Compared with CT, end-diastolic volume (EDV) measured by echocardiography showed good correlation and agreement using either Simpson's method (r = 0.90; mean difference -2, 95% CI -47 to 43 mL) or Cylinder-hemiellipsoid method (r = 0.94; mean difference 3, 95% CI -44 to 49 mL). Furthermore, End-systolic volume (ESV) measured by echocardiography showed also good correlation and agreement using either Simpson's method (r = 0.94; mean difference 12 ml, 95% CI: -16 to 40) or Cylinder-hemiellipsoid method (r = 0.97; mean difference:13 ml, 95% CI: -8 to 33). EF was underestimated using either Simpson's method (r = 0.78; mean difference -6, 95% CI -11 to 1%) or Cylinder-hemiellipsoid method (r = 0.74; mean difference -4, 95% CI-10 to 2%). CONCLUSION: Our results indicate that measurement of LV volumes may be accurate, but EF is underestimated using either three or single parasternal short axis planes by echocardiography in a large animal model of chronic MI.