Left ventricular global longitudinal strain assessment in patients with takotsubo cardiomyopathy: a call for an echocardiography-based classification.

BACKGROUND: Takotsubo cardiomyopathy (TTC) is classified into 4 types depending on the anatomical area affected identified on gross visual assessment. We have sought to understand if it is feasible and advantageous to use left ventricular global longitudinal strain (LVGLS), LV segmental longitudinal strain and right ventricle free wall strain (RVFWS) to classify TTC. METHODS: We conducted a retrospective observational study on twenty-five patients who meet the Modified Mayo Clinic Criteria for TTC [1]. Two independent reviewers performed strain analysis, they were both blinded to patient's diagnosed classification and outcomes. RESULTS: Based on classification by traditional assessment the 92% (N.=23) were diagnosed with typical TTC, indicating apical involvement. The entire LV was affected, 67% (N.=16) had abnormal strain (STE>-18) in all three LV regions (base, mid-ventricle and apex). Seventy-one percent of patients (N.=17) had abnormal LVGLS (>-18). Abnormal strain across all three LV regions was associated with higher prevalence (70%, N.=8 Vs 30%, N.=4, respectively) of composite cardiovascular events and longer length of hospital stay. There was a statistically significant difference in average length of hospital stay in those patients who had abnormal strain in all three regions compared to those that did not have abnormal strain across all three regions (8 days compared to 3.44 days, P=0.02). CONCLUSIONS: A new classification of TCC based on strain analysis should be developed. The traditional model is arbitrary; it fails to recognize that in most patients the entire LV is affect, it does not have prognostic significance and the most prevalent typical variant indicates apical involvement. Our study suggests that the entire LV is affected, and strain analysis has prognostic significance.

Peak left atrial strain as a single measure for the non-invasive assessment of left ventricular filling pressures.

Echocardiographic assessment of left ventricular (LV) filling pressures is performed using a multi-parametric algorithm. Left atrial (LA) strain was recently found to accurately classify the degree of diastolic dysfunction. We hypothesized that LA strain could be used as a stand-alone marker and sought to identify and test a cutoff, which would accurately detect elevated LV pressures. We studied 76 patients with a spectrum of LV function who underwent same-day echocardiogram and invasive left-heart catheterization. Speckle tracking was used to measure peak LA strain. The protocol involved a retrospective derivation group (N = 26) and an independent prospective validation cohort (N = 50) to derive and then test a peak LA strain cutoff which would identify pre-A-wave LV diastolic pressure > 15 mmHg. The guidelines-based assessment of filling pressures and peak LA strain were compared side-by-side against invasive hemodynamic data. In the derivation cohort, receiver-operating characteristic analysis showed area under curve of 0.76 and a peak LA strain cutoff < 20% was identified as optimal to detect elevated filling pressure. In the validation cohort, peak LA strain demonstrated better agreement with the invasive reference (81%) than the guidelines algorithm (72%). The improvement in classification using LA strain compared to the guidelines was more pronounced in subjects with normal LV function (91% versus 81%). In summary, the use of a peak LA strain to estimate elevated LV filling pressures is more accurate than the current guidelines. Incorporation of LA strain into the non-invasive assessment of LV diastolic function may improve the detection of elevated filling pressures.

Residual native left ventricular function optimization using quantitative 3D echocardiographic assessment of rotational mechanics in patients with left ventricular assist devices.

Preservation of native left ventricular (LV) function in patients supported with LV assist device (LVAD) may be beneficial to attain optimal hemodynamics and enhance potential recovery. Currently, LVAD speed optimization is based on hemodynamic parameters, without considering residual native LV function. We hypothesized that alternatively, LV rotational mechanics can be quantified by 3D echocardiography (3DE), and may help preserve native LV function while optimizing LVAD speed. The goal of this study was to test the feasibility of quantifying the effects of LVAD implantation on LV rotational mechanics and to determine whether conventional speed optimization maximally preserves native LV function. We studied 55 patients with LVADs, who underwent 3DE imaging and quantitative analysis of LV twist. Thirty patients were studied before and after LVAD implantation. The remaining 25 patients were studied during hemodynamic ramp studies. The pump speed at which LV twist was maximal was compared with the hemodynamics-based optimal speed. LV twist decreased following LVAD implantation from 4.2 ± 2.7 to 2.3 ± 1.9° (P < 0.01), reflecting the constricting effects on native function. With lower pump speeds, no significant changes were noted in LV twist, which peaked at a higher speed. In 11/25 (44%) patients, the conventional hemodynamic/2DE methodology and 3DE assessment of maximal residual function did not indicate the same optimal conditions, suggesting that a higher pump speed would have better preserved native function. In conclusion, quantitative 3DE analysis of LV rotational mechanics provides information, which together with hemodynamics may help select optimal pump speed, while maximally preserving native LV function.

Invasive Validation of the Echocardiographic Assessment of Left Ventricular Filling Pressures Using the 2016 Diastolic Guidelines: Head-to-Head Comparison with the 2009 Guidelines.

BACKGROUND: Recent American Society of Echocardiography (ASE)/European Association of Cardiovascular Imaging (EACVI) guidelines for echocardiographic evaluation of left ventricular (LV) diastolic function provide a practical, simplified diagnostic algorithm for estimating LV filling pressure. The aim of this study was to test the accuracy of this algorithm against invasively measured pressures and compare it with the accuracy of the previous 2009 guidelines in the same patient cohort. METHODS: Ninety patients underwent transthoracic echocardiography immediately before left heart catheterization. Mitral inflow E/A ratio, E/e', tricuspid regurgitation velocity, and left atrial volume index were used to estimate LV filling pressure as normal or elevated using the ASE/EACVI algorithm. Invasive LV pre-A pressure was used as a reference, with >12 mm Hg defined as elevated. RESULTS: Invasive LV pre-A pressure was elevated in 40 (44%) and normal in 50 (56%) patients. The 2016 algorithm resulted in classification of 9 of 90 patients (10%) as indeterminate but estimated LV filling pressures in agreement with the invasive reference in 61 of 81 patients (75%), with sensitivity of 0.69 and specificity of 0.81. The 2009 algorithm could not definitively classify 4 of 90 patients (4.4%), but estimated LV filling pressures in agreement with the invasive reference in 64 of 86 patients (74%), with sensitivity of 0.79 and specificity of 0.70. CONCLUSIONS: The 2016 ASE/EACVI guidelines for estimation of filling pressures are more user friendly and efficient than the 2009 guidelines and provide accurate estimates of LV filling pressure in the majority of patients when compared with invasive measurements. The simplicity of the new algorithm did not compromise its accuracy and is likely to encourage its incorporation into clinical decision making.

Non-invasive assessment of the haemodynamic significance of coronary stenosis using fusion of cardiac computed tomography and 3D echocardiography.

AIMS: Abnormal computed tomography coronary angiography (CTCA) often leads to stress testing to determine haemodynamic significance of stenosis. We hypothesized that instead, this could be achieved by fusion imaging of the coronary anatomy with 3D echocardiography (3DE)-derived resting myocardial deformation. METHODS AND RESULTS: We developed fusion software that creates combined 3D displays of the coronary arteries with colour maps of longitudinal strain and tested it in 28 patients with chest pain, referred for CTCA (256 Philips scanner) who underwent 3DE (Philips iE33) and regadenoson stress CT. To obtain a reference for stenosis significance, coronaries were also fused with colour maps of stress myocardial perfusion. 3D displays were used to detect stress perfusion defect (SPD) and/or resting strain abnormality (RSA) in each territory. CTCA showed 56 normal arteries, stenosis <50% in 17, and >50% in 8 arteries. Of the 81 coronary territories, SPDs were noted in 20 and RSAs in 29. Of the 59 arteries with no stenosis >50% and no SPDs, considered as normal, 12 (20%) had RSAs. Conversely, with stenosis >50% and SPDs (haemodynamically significant), RSAs were considerably more frequent (5/6 = 83%). Overall, resting strain and stress perfusion findings were concordant in 64/81 arteries (79% agreement). CONCLUSIONS: Fusion of CTCA and 3DE-derived data allows direct visualization of each coronary artery and strain in its territory. In this feasibility study, resting strain showed good agreement with stress perfusion, indicating that it may be potentially used to assess haemodynamic impact of coronary stenosis, as an alternative to stress testing that entails additional radiation exposure.