Quantitation of mitral regurgitation after percutaneous MitraClip repair: comparison of Doppler echocardiography and cardiac magnetic resonance imaging

Association between echocardiographic velocity time integral ratio of mitral valve and left ventricular outflow tract and clinical outcomes post transcatheter edge-to-edge mitral valve repair

Background

Residual mitral regurgitation (MR) is frequent after transcatheter edge-to-edge repair (TEER). There is controversy regarding the clinical impact of residual MR and its quantitative assessment by transthoracic echocardiography (TTE), which is often challenging with multiple eccentric jets and artifact from the clip. The utility of the velocity time integral (VTI) ratio between the mitral valve (MV) and left ventricular outflow tract (LVOT), (VTIMV/LVOT), a simple Doppler measurement that increases with MR, has not been assessed post TEER.

Methods

Baseline characteristics, clinical outcomes, and TTE data from patients who underwent TEER between 2014 and 2021 across three academic centers were retrospectively analyzed. Post-procedure TTEs were evaluated for VTIMV/LVOT in the first three months after TEER. One-year outcomes including all-cause and cardiac mortality, major adverse cardiac events, and MV reintervention were compared between patients with high VTIMV/LVOT (≥2.5) and low (<2.5).

Results

In total, 372 patients were included (mean age 78.7 ± 8.8 years, 68 % male, mean pre-TEER ejection fraction of 50.5 ± 14.7 %). Follow up TTEs were performed at a median of 37.5 (IQR 30-48) days post-procedure. Patients with high VTIMV/LVOT had significantly higher all-cause mortality (HR 2.10, p = 0.003), cardiac mortality (HR 3.03, p = 0.004) and heart failure admissions (HR 2.28, p < 0.001) at one-year post-procedure. There was no association between raised VTIMV/LVOT and subsequent MV reintervention.

Conclusion

High VTIMV/LVOT has clinically significant prognostic value at one year post TEER. This tool could be used to select patients for consideration of repeat intervention.

Transcatheter mitral valve repair for primary mitral regurgitation

The landscape of transcatheter mitral valve repair devices continues to expand, with many technologies undergoing investigation in patients with primary mitral regurgitation (MR). Transcatheter edge-to-edge repair (TEER) of the mitral valve is currently approved for management of patients with severe primary MR who are deemed to be high risk surgical candidates. The current review will focus on an integrative clinical and echocardiographic approach to guide patient selection, intra-procedural imaging guidance, and post procedural follow up in patients undergoing TEER. This review will also highlight future directions in transcatheter repair techniques of the mitral valve.

Invasive hemodynamics are equivocal for functional outcomes after MitraClip

Objectives

To evaluate invasive hemodynamics in assessing MC therapy success as well as evaluate its effectiveness as a predictor of functional outcomes.

Background

Mitral regurgitation grade is a poor predictor of functional outcomes after a MitraClip. There is a paucity of data on invasive hemodynamics as a predictor of outcomes.

Methods

Sixty-nine patients underwent MC between 2015 and 2018 at the University of Minnesota Medical Center and were retrospectively analyzed. Invasive hemodynamics were performed before and after device deployment with transesophageal echocardiographic guidance. Statistical analysis was performed using STATA version 16. Student's t test was used for continuous variables and Pearson's chi-squared test for categorical variables. Mann-Whitney test was performed for continuous variables where data were not normally distributed. Logistic and linear regression were used to investigate relationships between variables and outcomes.

Results

A total of 69 patients were included in the study. The mean age was 83 (75-87) years and 38 (55%) were male. Eighty-one percentage had >/= NYHA III symptoms. Eighty-seven percentage had severe MR. Pulmonary capillary wedge pressure was 20 (15-24). Overall, there was significant improvement in left atrial pressure including mean left atrial pressure index, MR, and NYHA class after MC (<.001). There was no significant association between invasive hemodynamics (including left atrial mean pressure index or its reduction rate) and functional outcomes (p = NS). MR grade was also not predictive of functional outcomes.

Conclusion

Left atrial pressure may not be a significant predictor of functional outcomes, and, in isolation, may not be an improvement over MR grade.

Direct measurement of atrioventricular valve regurgitant jets using 4D flow cardiovascular magnetic resonance is accurate and reliable for children with congenital heart disease: a retrospective cohort study

BACKGROUND

3D-time resolved flow (4DF) cardiovascular magnetic resonance (CMR) with retrospective analysis of atrioventricular valve regurgitation (AVVR) allows for internal validation by multiple direct and indirect methods. Limited data exist on direct measurement of AVVR by 4DF CMR in pediatric congenital heart disease (CHD). We aimed to validate direct measurement of the AVVR jet as accurate and reliable compared to the volumetric method (clinical standard by 2D CMR) and as a superior method of internal validation than the annular inflow method.

METHODS

We identified 44 consecutive patients with diverse CHD referred for evaluation of AVVR by CMR. 1.5 T or 3 T scanners, intravenous contrast, and a combination of parallel imaging and compressed sensing were used. Four methods of measuring AVVR volume (RVol) were used: volumetric method (VOL; the clinical standard) = stroke volume by 2D balanced steady-state free precession - semilunar valve forward flow (SLFF); annular inflow method (AIM) = atrioventricular valve forward flow [AVFF] - semilunar valve net flow (SLNF); and direct measurement (JET). AVFF was measured using static and retrospective valve tracking planes. SLFF, SLNF, AVFF, and JET were measured by 4DF phase contrast. Regurgitant fraction was calculated as [RVol/(RVol+SLNF)]× 100. Statistical methods included Spearman, Wilcoxon rank sum test/Student paired t-test, Bland Altman analysis, and intra-class coefficient (ICC), where appropriate.

RESULTS

Regurgitant fraction by JET strongly correlated with the indirect methods (VOL and AIM) (ρ = 0.73-0.80, p < 0.001) and was similar to VOL with a median difference (interquartile range) of - 1.5% (- 8.3-7.2%; p = 0.624). VOL had weaker correlations with AIM and JET (ρ = 0.69-0.73, p < 0.001). AIM underestimated RF by 3.6-6.9% compared to VOL and JET, p < 0.03. Intra- and inter- observer reliability were excellent for all methods (ICC 0.94-0.99). The mean (±standard deviation) inter-observer difference for VOL was 2.4% (±5.1%), p < 0.05.

CONCLUSIONS

In a diverse cohort of pediatric CHD, measurement of AVVR using JET is accurate and reliable to VOL and is a superior method of internal validation compared to AIM. This study supports use of 4DF CMR for measurement of AVVR, obviating need for expert prospective prescription during image acquisition by 2D CMR.

3D vena contracta area after MitraClip© procedure: precise quantification of residual mitral regurgitation and identification of prognostic information

BACKGROUND

Percutaneous mitral valve repair (PMVR) is increasingly performed in patients with severe mitral regurgitation (MR). Post-procedural MR grading is challenging and an unsettled issue. We hypothesised that the direct planimetry of vena contracta area (VCA) by 3D-transoesophageal echocardiography allows quantifying post-procedural MR and implies further prognostic relevance missed by the usual ordinal scale (grade I-IV).

METHODS

Based on a single-centre PMVR registry containing 102 patients, the association of VCA reduction and patients' functional capacity measured as six-minute walk distance (6 MW) was evaluated. 3D-colour-Doppler datasets were available before, during and 4 weeks after PMVR.

RESULTS

Twenty nine patients (age 77.0 ± 5.8 years) with advanced heart failure (75.9% NYHA III/IV) and severe degenerative (34%) or functional (66%) MR were eligible. VCA was reduced in all patients by PMVR (0.99 ± 0.46 cm² vs. 0.22 ± 0.15 cm², p < 0.0001). It remained stable after median time of 33 days (p = 0.999). 6 MW improved after the procedure (257.5 ± 82.5 m vs. 295.7 ± 96.3 m, p < 0.01). Patients with a decrease in VCA less than the median VCA reduction showed a more distinct improvement in 6 MW than patients with better technical result (p < 0.05). This paradoxical finding was driven by inferior results in very large functional MR.

CONCLUSIONS

VCA improves the evaluation of small residual MR. Its post-procedural values remain stable during a short-term follow-up and imply prognostic information for the patients' physical improvement. VCA might contribute to a more substantiated estimation of treatment success in the heterogeneous functional MR group.

Echocardiographic evaluation and guidance for MitraClip procedure

Transcatheter mitral valve repair using the MitraClip system (Abbott, Abbott Park, Il, USA) has become a world-wide, well-established therapeutic alternative to treat symptomatic patients with severe mitral regurgitation and prohibitive surgical risk. This article offers a comprehensive review of the important clinical and imaging aspects related to the patient selection, imaging evaluation and intraprocedural guidance for optimal results using this transcatheter device therapy. This article provides an updated framework for the interested practitioners summarizing the current understanding and applications for this device based on the current literature and growing experience of this technique.