Spatiotemporal Complexity of Vena Contracta and Mitral Regurgitation Grading Using Three-Dimensional Echocardiographic Analysis.

BACKGROUND: Spatiotemporal complexity of the color Doppler vena contracta challenging the assumption of a circular and constant orifice may lead to mitral regurgitation (MR) grading inconsistencies. Using 3D transesophageal echocardiography, we characterized spatiotemporal vena contracta complexity and its impact on MR severity grading. METHODS: In 192 patients with suspected moderate or severe MR (100 primary MR [PMR]; 92 secondary MR [SMR]), we performed three-dimensional vena contracta area (VCA) quantification using single-frame (midsystolic or VCAmid, maximum or VCAmax) and multiframe (VCAmean) methods, as well as measures of orifice shape (shape index) and systolic variation of VCA. Vena contracta complexity and intermethod discrepancies were analyzed and correlated with functional class and pulmonary vein flow (PVF) patterns and with cardiac magnetic resonance (CMR) in a subset of cases (n = 20). RESULTS: The vena contracta was noncircular (shape index > 1.5) in 90% of patients. Severe noncircularity (shape index > 3) was more prevalent in SMR than in PMR (32.4% vs 14.6%). Variations of the VCA were more prominent in SMR than in PMR. VCAmid showed a low grading agreement with VCAmax (62%) and high grading agreement with VCAmean (83.3%). Pulmonary vein flow systolic reversal was associated with MR severity by VCA in SMR but not in PMR. VCAmid and VCAmean showed a stronger association with systolic flow reversal than VCAmax (area under the curve, 0.88, 0.86, and 0.79, respectively). In the subset of patients with CMR quantification, severe MR by VCAmax was graded as nonsevere by CMR more frequently compared with VCAmid and VCAmean. CONCLUSIONS: Highly prevalent spatiotemporal vena contracta complexity features in MR challenge the assumption of a circular and constant orifice. VCAmid seems the best single-frame approximation to multiframe quantification, and VCAmax may lead to severity overestimation.

Classification model based on strain measurements to identify patients with arrhythmogenic cardiomyopathy with left ventricular involvement.

BACKGROUND AND OBJECTIVE: A heterogenous expression characterizes arrhythmogenic cardiomyopathy (AC). The evaluation of regional wall movement included in the current Task Force Criteria is only qualitative and restricted to the right ventricle. However, a strain-based approach could precisely quantify myocardial deformation in both ventricles. We aim to define and modelize the strain behavior of the left ventricle in AC patients with left ventricular (LV) involvement by applying algorithms such as Principal Component Analysis (PCA), clustering and naïve Bayes (NB) classifiers. METHODS: Thirty-six AC patients with LV involvement and twenty-three non-affected family members (controls) were enrolled. Feature-tracking analysis was applied to cine cardiac magnetic resonance imaging to assess strain time series from a 3D approach, to which PCA was applied. A Two-Step clustering algorithm separated the patients' group into clusters according to their level of LV strain impairment. A statistical characterization between controls and the new AC subgroups was done. Finally, a NB classifier was built and new data from a small evolutive dataset was predicted. RESULTS: 60% of AC-LV patients showed mildly affected strain and 40% severely affected strain. Both groups and controls exhibited statistically significant differences, especially when comparing controls and severely affected AC-LV patients. The classification accuracy of the strain NB classifier reached 82.76%. The model performance was as good as to classify the individuals with a 100% sensitivity and specificity for severely impaired strain patients, 85.7% and 81.1% for mildly impaired strain patients, and 69.9% and 91.4% for normal strain, respectively. Even when the severely affected LV-AC group was excluded, LV strain showed a good accuracy to differentiate patients and controls. The prediction of the evolutive dataset revealed a progressive alteration of strain in time. CONCLUSIONS: Our LV strain classification model may help to identify AC patients with LV involvement, at least in a setting of a high pretest probability, such as family screening.

Left ventricular myocardial dysfunction in arrhythmogenic cardiomyopathy with left ventricular involvement: A door to improving diagnosis.

BACKGROUND: Diagnostic Task Force Criteria (TFC) for arrhythmogenic cardiomyopathy (AC) exhibit poor performance for left dominant forms. TFC only include right ventricular (RV) dysfunction (akinesia, dyssynchrony, volumes and ejection fraction). Moreover, cardiac magnetic resonance imaging (CMRI) assessment of left ventricular (LV) dyssynchrony has hitherto not been described. Thus, we aimed to comprehensively characterize LV CMRI behavior in AC patients. METHODS: Thirty-five AC patients with LV involvement and twenty-three non-affected family members (controls) were enrolled. Feature-tracking analysis was applied to cine CMRI to assess LV ejection fraction (LVEF), LV end-systolic and end-diastolic volume indexes, strain values and dyssynchrony. Regions with more frequent strain and dyssynchrony impairment were also studied. RESULTS: Radial dyssynchrony and LVEF were selected (sensitivities 54.3% and 48.6%, respectively at 100% specificity), with a threshold of 70 ms for radial dyssynchrony and 48.5% for LVEF. 71.4% of patients exceeded these thresholds (31.4% both, 22.9% only dyssynchrony and 17.1% only LVEF). Considering these cut-off values as a novel combined criterion, 30% of patients with 'borderline' or 'possible' AC following 2010 TFC would move to a 'definite' AC diagnosis. Strain was globally impaired whereas dyssynchronous regions were more often apical and located at the inferolateral wall. CONCLUSIONS: Mirroring the RV evaluation, we suggest including LVEF and LV dyssynchrony to improve the diagnosis of AC. Two independent mechanisms can be claimed in AC patients with LV involvement: 1) decreased myocardial deformation with global LV affectation and 2) delayed myocardial contraction at localized regions.

Fontan Circulation in Adult Patients: Acoustic Radiation Force Impulse Elastography as a Useful Tool for Liver Assessment.

OBJECTIVE: The development of liver fibrosis and cirrhosis due to long-standing liver congestion is known to occur in adult patients with Fontan circulation. Hepatic elastography has shown to be a useful tool for the noninvasive assessment and staging of liver fibrosis in chronic liver diseases, although the utility of this technique in Fontan patients remains to be adequately studied. METHODS: Twenty-one patients with Fontan circulation underwent an abdominal ultrasound and an acoustic radiation force impulse (ARFI) elastography. In order to compare the results from this group, a cohort of 14 healthy controls and another group containing 17 patients with cirrhosis were included. The association between the velocity values measured with elastography and clinical and analytical parameters were also studied. RESULTS: Mean shear waves propagation velocity in liver tissue in the Fontan group was 1.86 ± 0.5 m/s, with 76% of patients over the cirrhosis threshold (1.55 m/s). The control group had a mean velocity of 1.09 ± 0.06 m/s, while the cirrhotic group obtained 2.71 ± 0.51 m/s. Seven patients with Fontan circulation had increased liver enzymes. Liver ultrasound showed evidence of chronic liver disease in six patients. Velocity values obtained in the presence or absence of analytical or liver ultrasound abnormalities showed significant differences in the univariate analysis (P = .04 and P = .03 respectively). CONCLUSION: In conclusion, ARFI elastography showed increased wave propagation velocity values in the Fontan population suggesting increased liver stiffness which could be related to advanced fibrosis. A statistically significant association between ARFI values and the presence of analytical and ultrasound abnormalities has been demonstrated.