Clinical and Hemodynamic Outcomes of Balloon-Expandable Mitral Valve-in-Valve Positioning and Asymmetric Deployment: The VIVID Registry

Asymmetrical Expansion of Balloon-Expandable Transcatheter Aortic Valve Prostheses: Implications for Valve Hemodynamic and Clinical Outcomes

BACKGROUND

Asymmetrical expansion of transcatheter heart valves (THVs), manifesting as stent frame deformation, is an occasional fluoroscopic finding in transcatheter aortic valve replacement (TAVR).

OBJECTIVES

The aim of this study was to investigate the impact of asymmetrical expansion of balloon-expandable THVs on hemodynamic valve performance and clinical outcomes.

METHODS

In a prospective registry, TAVR asymmetry index was measured using freeze-frame fluoroscopic images and was defined as the ratio of THV heights: [(longer height/shorter height) - 1] × 100. THV hemodynamic performance was measured using echocardiography before hospital discharge. Impaired hemodynamic valve performance was defined as a mean residual THV gradient ≥20 mm Hg and/or moderate or greater paravalvular regurgitation.

RESULTS

Among 1,216 patients undergoing transfemoral TAVR for native severe aortic valve stenosis with contemporary balloon-expandable THVs between February 2014 and June 2022, asymmetry index was an excellent predictor of impaired hemodynamic valve performance (area under the receiver-operating characteristic curve: 0.88; 95% CI: 0.84-0.92; P < 0.001). The optimal asymmetry index threshold for predicting impaired THV performance was >5.5% (sensitivity 77%, specificity 86%) and occurred in 17% of patients. Higher asymmetry index, as a continuous variable, was associated with impaired hemodynamic valve performance independent of total aortic valve calcium, bicuspid anatomy, balloon-expandable valve prosthesis type or size, and Society of Thoracic Surgeons Predicted Risk of Mortality score (OR: 1.37; 95% CI: 1.29-1.46; P < 0.001). High TAVR asymmetry index was not associated with all-cause mortality during a median of 376 days of follow-up (HR: 1.00; 95% CI: 0.71-1.41; P = 0.989).

CONCLUSIONS

Asymmetrical expansion of balloon-expandable THVs was associated with impaired hemodynamic valve performance but not with clinical outcomes.

Deformation in transcatheter heart valves: Clinical implications and considerations

Transcatheter aortic valve replacement (TAVR) has emerged as a preferred treatment modality for aortic stenosis, marking a significant advancement in cardiac interventions. Transcatheter heart valves (THVs) have also received approval for treating failed bioprosthetic valves and rings across aortic, mitral, tricuspid, and pulmonic positions. Unlike surgically implanted valves, which are sewn into the annulus, THVs are anchored through relative oversizing. Although THVs are designed to function optimally in a fully expanded state, they exhibit a certain degree of tolerance to underexpansion. However, significant deformation beyond this tolerance can adversely affect the valve's hemodynamics and durability, ultimately impacting patient outcomes. Such post-implantation deviations from the valve's intended three-dimensional design are influenced by a variety of physiological and anatomical factors unique to each patient and procedure, leading to underexpansion, eccentric expansion, and vertical deformation. These deformation patterns increase leaflet stress and strain, potentially causing fatigue and damage. This review article delves into the extent of THV deformation, its impact on leaflet function, hypoattenuating leaflet thickening, and structural valve degeneration. It provides an in-depth analysis of deformation specifics in different procedural contexts, including TAVR in native aortic stenosis, aortic and mitral valve-in-valve procedures, and redo-TAVR. Additionally, the review discusses strategies to mitigate THV deformation during the procedure, offering insights into potential solutions to these challenges.

A deep dive into the percutaneous mitral valve data

PURPOSE OF REVIEW

This review offers insights into percutaneous mitral valve management, emphasizing pivotal trials that contributed to its evolution.

RECENT FINDINGS

Mitral regurgitation (MR) is a highly prevalent heart valve disease, with surgical intervention being the gold standard for managing primary MR. However, a notable proportion of patients face ineligibility criteria or are at high surgical risk, particularly in the setting of secondary MR. To fill this gap, transcatheter therapies have emerged as less invasive alternatives. Initially guided by the EVEREST trial criteria, transcatheter leaflet repair techniques have shown impressive technological improvements, addressing nowadays a wide range of anatomical scenarios. Evidence supporting the safety and efficacy of transcatheter leaflet repair is derived from pivotal trials, including EVEREST II, COAPT, MITRA-FR, and CLASP IID, and large multicenter registries including EXPAND, EXPAND G4, and EuroSMR. However, not all patients meet the anatomical and clinical criteria for leaflet repair. For those patients, transcatheter mitral valve replacement may be a minimally invasive option and multiple clinical trials are current underway.

SUMMARY

From MitraClip to newer and more innovative technologies, the landscape of percutaneous mitral valve interventions continues to evolve, offering new hopes to patients who may not be ideal candidates for conventional surgery.