Left Ventricular Outflow Tract Obstruction Following Mitral Valve Replacement: Challenges for Transcatheter Mitral Valve Therapy

Mortality and resource utilization in surgical versus transcatheter repeat mitral valve replacement: A national analysis

BACKGROUND

Transcatheter mitral valve replacement (TMVR) has garnered interest as a viable alternative to the traditional surgical mitral valve replacement (SMVR) for high-risk patients requiring redo operations. This study aims to evaluate the association of TMVR with selected clinical and financial outcomes.

METHODS

Adults undergoing isolated redo mitral valve replacement were identified in the 2016-2020 Nationwide Readmissions Database and categorized into TMVR or SMVR cohorts. Various regression models were developed to assess the association between TMVR and in-hospital mortality, as well as additional secondary outcomes. Transseptal and transapical catheter-based approaches were also compared in relation to study endpoints.

RESULTS

Of an estimated 7,725 patients, 2,941 (38.1%) underwent TMVR. During the study period, the proportion of TMVR for redo operations increased from 17.8% to 46.7% (nptrend<0.001). Following adjustment, TMVR was associated with similar odds of in-hospital mortality (AOR 0.82, p = 0.48), but lower odds of stroke (AOR 0.44, p = 0.001), prolonged ventilation (AOR 0.43, p<0.001), acute kidney injury (AOR 0.61, p<0.001), and reoperation (AOR 0.29, p = 0.02). TMVR was additionally correlated with shorter postoperative length of stay (pLOS; β -0.98, p<0.001) and reduced costs (β -$10,100, p = 0.002). Additional analysis demonstrated that the transseptal approach had lower adjusted mortality (AOR 0.44, p = 0.02), shorter adjusted pLOS (β -0.43, p<0.001), but higher overall costs (β $5,200, p = 0.04), compared to transapical.

CONCLUSIONS

In this retrospective cohort study, we noted TMVR to yield similar odds of in-hospital mortality as SMVR, but fewer complications and reduced healthcare expenditures. Moreover, transseptal approaches were associated with lower adjusted mortality, shorter pLOS, but higher cost, relative to the transapical. Our findings suggest that TMVR represent a cost-effective and safe treatment modality for patients requiring redo mitral valve procedures. Nevertheless, future studies examining long-term outcomes associated with SMVR and TMVR in redo mitral valve operations, are needed.

Unmasking Severe Systolic Anterior Motion With Left Ventricular Outflow Tract Obstruction Following Mitral Valve Repair

A 38-year-old male with a history of myxomatous mitral valve disease post-repair presented with recurrent dyspnea during exertion. Initial evaluation showed mild systolic anterior motion and mitral regurgitation, but medical management was unsuccessful. The patient underwent reoperation; intraoperative transesophageal echocardiogram with provocation unmasked severe systolic anterior motion and torrential mitral regurgitation.

Postsurgical Transcatheter Mitral Valve Replacement

Reintervention is commonly required postsurgical mitral valve replacement (SMVR) or repair due to bioprosthetic valve and annuloplasty ring degeneration. However, redo SMVR is associated with a high risk of morbidity and mortality. Postsurgical transcatheter mitral valve replacement (TMVR) is a safe and less-invasive alternative that has repeatedly been shown to be associated with improved survival and lower rates of complications compared with redo SMVR. Comprehensive patient evaluation and thorough procedural planning are key to successful TMVR.

1-Year Outcomes Following Transfemoral Transseptal Transcatheter Mitral Valve Replacement: Intrepid TMVR Early Feasibility Study Results

BACKGROUND

High surgical risk may preclude mitral valve replacement in many patients. Transcatheter mitral valve replacement (TMVR) using transfemoral transseptal access is a novel technology for the treatment of mitral regurgitation (MR) in high-risk surgical patients.

OBJECTIVES

This analysis evaluates 30-day and 1-year outcomes of the Intrepid TMVR Early Feasibility Study in patients with ≥moderate-severe MR.

METHODS

The Intrepid TMVR Early Feasibility Study is a multicenter, prospective, single-arm study. Clinical events were adjudicated by a clinical events committee; endpoints were defined according to Mitral Valve Academic Research Consortium criteria.

RESULTS

A total of 33 patients, enrolled at 9 U.S. sites between February 2020 and August 2022, were included. The median age was 80 years, 63.6% of patients were men, and mean Society of Thoracic Surgeons Predicted Risk of Mortality for mitral valve replacement was 5.3%. Thirty-one (93.9%) patients were successfully implanted. Median postprocedural hospitalization length of stay was 5 days, and 87.9% of patients were discharged to home. At 30 days, there were no deaths or strokes, 8 (24.2%) patients had major vascular complications and none required surgical intervention, there were 4 cases of venous thromboembolism all successfully treated without sequelae, and 1 patient had mitral valve reintervention for severe left ventricular outflow tract obstruction. At 1 year, the Kaplan-Meier all-cause mortality rate was 6.7%, echocardiography showed ≤mild valvular MR, there was no/trace paravalvular leak in all patients, median mitral valve mean gradient was 4.6 mm Hg (Q1-Q3: 3.9-5.3 mm Hg), and 91.7% of survivors were in NYHA functional class I/II with a median 11.4-point improvement in Kansas City Cardiomyopathy Questionnaire overall summary scores.

CONCLUSIONS

The early benefits of the Intrepid transfemoral transseptal TMVR system were maintained up to 1 year with low mortality, low reintervention, and near complete elimination of MR, demonstrating a favorable safety profile and durable valve function.

Innovative use of a self-expanding valve for valve-in-valve transcatheter mitral valve replacement: experience from a four-year single-center study

Background

Valve-in-valve transcatheter mitral valve replacement (ViV-TMVR) is a minimally invasive option for patients with bioprosthetic mitral valve failure. Since January 2019, our center has been using a new innovative option, J-Valve, to treat patients with bioprosthetic mitral valve failure who were at high risk for open heart surgery. The aim of this study is to explore the effectiveness and safety of J-Valve and report the results from the four-year follow-up period of the innovative application of the transcatheter valve.

Methods

Patients who underwent the ViV-TMVR procedure between January 2019 and September 2022 in our center were included in the study. J-Valve™ system (JC Medical Inc., Suzhou, China) with three U-shape grippers was used for ViV-TMVR via transapical approach. Data on survival, complications, transthoracic echocardiographic results, New York Heart Association functional class in heart failure, and patient-reported health-related quality of life according to the Kansas City Cardiomyopathy Questionnaire-12 (KCCQ-12) were collected during the four-year follow up.

Results

Thirty-three patients (mean age 70.1 ± 1.1 years, 13 men) were included and received ViV-TMVR. The surgery success rate was 97%: only one patient was converted to open-heart surgery due to intraoperative valve embolization to the left ventricle. During the first 30 days all-cause mortality was 0%, risk of stroke 2.5% and risk of mild paravalvular leak 15.2%; mitral valve hemodynamics improved (179.7 ± 8.9 at 30 days vs. 269 ± 49 cm/s at baseline, p < 0.0001). Median time from operation to discharge was six days, and there were no readmissions within 30 days from operation. The median and maximum follow-up durations were 28 and 47 months, respectively; during the entire follow-up, all-cause mortality was 6.1%, and the risk of cerebral infarction 6.1%. Cox regression analysis did not identify any variables significantly associated with survival. The New York Heart Association functional class and the KCCQ-12 score improved significantly compared with their preoperative values.

Conclusion

The use of J-Valve for ViV-TMVR is safe and effective with a high success rate, low mortality and very few associated complications, representing an alternative surgical strategy for the elderly, high-risk patients with bioprosthetic mitral valve failure.

Neo-LVOT and Transcatheter Mitral Valve Replacement: Expert Recommendations

With the advent of transcatheter mitral valve replacement (TMVR), the concept of the neo-left ventricular outflow tract (LVOT) was introduced and remains an essential component of treatment planning. This paper describes the LVOT anatomy and provides a step-by-step computed tomography methodology to segment and measure the neo-LVOT while discussing the current evidence and outstanding challenges. It also discusses the technical and hemodynamic factors that play a major role in assessing the neo-LVOT. A summary of expert-based recommendations about the overall risk of LVOT obstruction in different scenarios is presented along with the currently available methods to reduce the risk of LVOT obstruction and other post-procedural complications.

Left Ventricular Outflow Tract Obstruction: A Potential Obstacle for Transcatheter Mitral Valve Therapy

Transcatheter mitral valve replacement is the focus of much enthusiasm as the future of therapy for mitral valve disease. Despite technological advances, left ventricular outflow tract (LVOT) obstruction from the valve prosthesis remains an important issue. In this review the authors discuss the pathophysiology of LVOT obstruction in both the surgical and transcatheter experience, imaging evaluation preprocedure, outcomes to date, and therapeutic options.