Association between three-year mortality after transcatheter aortic valve implantation and paravalvular regurgitation graded by videodensitometry in comparison with visual grading

BACKGROUND

Estimation of regurgitant fraction by videodensitometry (VD-AR) of aortic root angiograms is a new tool for objective grading of paravalvular regurgitation (PVR) after transcatheter aortic valve implantation (TAVI). Stratification with boundaries at 6% and 17% has been proposed to reflect "none/trace", "mild" and "moderate or higher" PVR.

OBJECTIVE

We sought to investigate the association of strata of VD-AR with 3-year mortality and to compare VD-AR with visual grading of angiograms.

METHODS

We interrogated our database for patients undergoing transfemoral TAVI from 2008 to 2018. Vital status of the patients was obtained from population registers. To test differences in survival and estimate adjusted hazard ratios (HRs) we fitted Cox models.

RESULTS

Our retrospective study included 699 patients with evaluable angiograms at completion of the TAVI procedure. Cumulative 3-year mortality was 35.0% in 261 (37.3%) patients with VD-AR < 6%, 33.9% in 325 (46.5%) patients with VD-AR between 6 and 17% (HR [95% confidence interval] 1.06 [0.80-1.42]; P = 0.684) and 47.2% in 113 (16.2%) patients with VD-AR > 17% (HR 1.57 [1.11-2.22]; P = 0.011). Visually, PVR was graded as "none/trace" in 470 (67.2%) patients, as "mild" in 219 (31.3%) and as "moderate" in 10 (1.4%). Both mild PVR and moderate PVR on visual grading were significantly associated with mortality (HRs 1.31 [1.12-1.54]; P = 0.001 and 1.92 [1.13-3.24]; P = 0.015; respectively).

CONCLUSIONS

VD-AR > 17%, but not VD-AR 6-17%, was independently associated with mortality. Compared with subjective visual evaluation, VD-AR resulted in a smaller proportion of patients with PVR classified as prognostically relevant.

Comparative modeling of the mitral valve in normal and prolapse conditions

Introduction

Computational modeling is one of the best non-invasive approaches to predicting the functional behavior of the mitral valve (MV) in health and disease. Mitral valve prolapse (MVP) due to partial or complete chordae tendineae rapture is the most common valvular disease and results in mitral regurgitation (MR).

Methods

In this study, Image-based fluid-structure interaction (FSI) models of the human MV are developed in the normal physiological and posterior leaflet prolapse conditions. Detailed geometry of the healthy human MV is derived from Computed Tomography imaging data. To provide prolapse condition, some chords attached to the posterior leaflet are removed from the healthy valve. Both normal and prolapsed valves are embedded separately in a straight tubular blood volume and simulated under physiological systolic pressure loads. The Arbitrary Lagrangian-Eulerian finite element method is used to accommodate the deforming intersection boundaries of the blood and MV.

Results

The stress values in the mitral components, and also flow patterns including the regurgitant flow rates are obtained and compared in both conditions through the simulation. These simulations have the potential to improve the treatment of patients with MVP, and also help surgeons to have more realistic insight into the dynamics of the MV in health and prolapse.

Conclusion

In the prolapse model, computational results show incomplete leaflet coaptation, higher MR severity, and also a significant increment of posterior leaflet stress compared to the normal valve. Moreover, it is found more deviation of the regurgitant jet towards the left atrium wall due to the posterior leaflet prolapse.

Left Atrial Volume Correlates with Mitral Annulus Size: An MDCT Study

Aim: Although the association between left ventricular dilation and mitral annulus dilation is well understood, the potential variation in the size of the mitral annulus during dilation of the left atrium is currently unknown. In order to investigate the link between the two variables, we used multidetector computed tomography (MDCT) and looked at patients who had a dilated left atrium, assessing if the mitral valve also dilates. Materials and Methods: The study included 107 patients with paroxysmal and persistent atrial fibrillation, in whom catheter ablation was performed using pulmonary vein isolation ± atrial substrate modification. Eighty patients were male (74.8%), with a mean age of 55.8 years (±9.87 with a minimum age of 26 years and a maximum age of 79 years), of which 57.1% had paroxysmal AF and the rest had persistent fibrillation. All the patients underwent multiple-detector CT (MDCT) with contrast medium before the ablation. CT images were integrated into the three-dimensional mapping system CARTO 3, after which the diameters of the mitral annulus, area, and circumference were measured. Left atrial size was evaluated by measuring the diameters, area, and volume. Results: The left atrial area was 247 ± 65.7 cm2 and the left atrial volume was 139 ± 56.3 mL. The transverse mitral annulus (MA) was 29.9 ± 5.3 mm and the longitudinal diameter was 41.9 ± 7.6 mm. The MA circumference and area were 15.0 ± 3.5 cm and 14.2 ± 4.6 cm2, respectively. The following statistically significant correlation was identified between the dimensions of the mitral annulus and the diameters of the left atrium: the transverse mitral annulus correlates with the antero-posterior (AP) LA diameter (R = 0.594, p < 0.01) and the longitudinal MA diameter correlates with the latero-lateral (LL) LA diameter (R = 0.576, p < 0.01). Furthermore, the MA area correlates with the LA volume (R = 0.639, p < 0.001). Conclusions: The volume of the left atrium correlates with the area of the mitral annulus. In patients with paroxysmal and persistent AF, an increase in left atrial dimensions is further associated with an increase in mitral valve dimensions.

Screening for transcatheter mitral valve replacement: a decision tree algorithm

AIMS

The high frequency of screening failure for anatomical reasons in patients with severe mitral valve regurgitation (MR) is a limiting factor in the screening process for transcatheter mitral valve replacement (TMVR). However, data on optimal patient selection are scarce. The present study aimed to develop a screening algorithm based on TMVR screening data.

METHODS AND RESULTS

A total of 195 screenings for six different TMVR devices were performed in 94 high-risk patients with severe MR. We compared baseline echocardiographic and multislice computed tomography (MSCT) parameters between the subgroups of patients accepted (N=33) and rejected for TMVR (N=61). Reasons for screening failure were assessed, and a decision tree algorithm was statistically derived. Reasons for screening failure were small LV dimensions (30.6%), small (7.5%) or large (22.5%) annular size, potential risk of LVOT obstruction (22.0%) or mitral annulus calcification (15.6%). A four-step decision tree algorithm to assess TMVR eligibility was developed resulting in an AUC of 0.80 (95% CI: 0.71, 0.89, p<0.0001).

CONCLUSIONS

This study presents the first screening algorithm to assess anatomical eligibility for TMVR in patients with severe MR, based on simple MSCT criteria. Given the high rate of TMVR screening failure, this algorithm may facilitate the identification of potential TMVR candidates.

Role of imaging in novel mitral technologies-echocardiography and computed tomography

As minimally invasive cardiovascular procedures gain popularity, novel transcatheter mitral valve repair devices continue to emerge. The success of these technologies is critically dependent on high quality imaging performed at all stages: patient selection, intervention planning, intraprocedural guidance, monitoring complications and follow-up. We present an overview of specific imaging requirements and challenges applicable to mitral valve interventional techniques. Modern valve imaging is multimodal and primarily combines echocardiography and computed tomography (CT). Echocardiography remains the gold standard for detailed anatomic imaging, complete hemodynamic characterization and real-time guidance and evaluation of procedural success. CT is indispensable for mitral annulus (MA) imaging and in predicting left ventricular outflow tract (LVOT) obstruction post transcutaneous mitral valve replacement (TMVR). 3D modeling, fusion imaging and automated image analysis may further contribute to the evolutionary transformation of valvular heart imaging.

Imaging 4D morphology and dynamics of mitral annulus in humans using cardiac cine MR feature tracking

Feature tracking in cine cardiac magnetic resonance (CMR) is a quantitative technique to assess heart structure and function. We investigated 4-dimensional (4D) dynamics and morphology of the mitral annulus (MA) using a novel tracking system based on radially rotational long-axis cine CMR series. A total of 30 normal controls and patients with mitral regurgitation were enrolled. The spatiotemporal changes of the MA were characterized by an in-house developed program. Dynamic and morphological parameters extracted from all 18 radial slices were used as references and were compared with those from subsequently generated sub-datasets with different degrees of sparsity. An excellent agreement was found among all datasets including routine 2-, 3- and 4-chamber views for MA dynamics such as peak systolic velocity (Sm) and mitral annular plane systolic excursion (MAPSE). MA morphology for size and shape was addressed adequately by as few as 6 radial slices, but poorly by only three routine views. Patients with regurgitation showed significantly reduced mitral dynamics and mild annular deformation, which was consistent between three routine views and 18 reference slices. In conclusion, feature tracking cine CMR provided a comprehensive and distinctive profile for 4D MA dynamics and morphology, which may help in studying different cardiac diseases.