Implications of hydrodynamic testing to guide sizing of self-expanding transcatheter heart valves for valve-in-valve procedures

Valve-in-Valve Transcatheter Mitral Valve Replacement: A Large First-in-Human 13-Year Experience

BACKGROUND

Favourable early outcomes have been reported following valve-in-valve transcatheter mitral valve replacement (TMVR). However, reports of long-term outcomes are lacking. We aimed to evaluate early and late outcomes in a large first-in-human valve-in-valve TMVR 13-year experience.

METHODS

All patients undergoing valve-in-valve TMVR in our centre from 2008 to 2021 were included. Clinical and echocardiographic outcomes, defined according to the Mitral Valve Academic Research Consortium, were reported.

RESULTS

A total of 119 patients were analysed: mean age 76.8 ± 10.2 years, mean Society of Thoracic Surgeons score 10.7 ± 6.8%, 55.4% female, 63.9% transapical access. Thirty-day mortality was 2.5% for the total population and 0.0% after transseptal TMVR. Maximum follow-up was 13.1 years. During a median follow-up of 3.4 years (interquartile range 1.8-5.3 years), 55 patients (46.2%) died, mainly from noncardiovascular causes. Valve hemodynamics were acceptable at 5 years, with 2.5% structural dysfunction. Patients treated from 2016 on (n = 68; 57.1%), following the advent of routine use of the Sapien 3 valve, CT screening, and transseptal access, were compared with those treated before 2016 (n = 51; 42.9%). Patients from 2016 on had a higher technical success rate (100.0% vs 94.1%; P = 0.04), shorter hospitalisation (P < 0.001), trending lower 30-day mortality (1.5% vs 3.9%; P = 0.4) and better 5-year survival (74.7% vs 41.1%; P = 0.03).

CONCLUSIONS

Valve-in-valve TMVR can be performed with little morbidity and low mortality. Mid- to long-term survival remains limited owing to advanced age and comorbidities. Structural bioprosthetic valve dysfunction was rare and redo TMVR feasible in selected patients. Outcomes continue to improve, but the role for valve-in-valve TMVR in lower surgical risk patients remains unclear.

A design-based model of the aortic valve for fluid-structure interaction

This paper presents a new method for modeling the mechanics of the aortic valve and simulates its interaction with blood. As much as possible, the model construction is based on first principles, but such that the model is consistent with experimental observations. We require that tension in the leaflets must support a pressure, then derive a system of partial differential equations governing its mechanical equilibrium. The solution to these differential equations is referred to as the predicted loaded configuration; it includes the loaded leaflet geometry, fiber orientations and tensions needed to support the prescribed load. From this configuration, we derive a reference configuration and constitutive law. In fluid-structure interaction simulations with the immersed boundary method, the model seals reliably under physiological pressures and opens freely over multiple cardiac cycles. Further, model closure is robust to extreme hypo- and hypertensive pressures. Then, exploiting the unique features of this model construction, we conduct experiments on reference configurations, constitutive laws and gross morphology. These experiments suggest the following conclusions: (1) The loaded geometry, tensions and tangent moduli primarily determine model function. (2) Alterations to the reference configuration have little effect if the predicted loaded configuration is identical. (3) The leaflets must have sufficiently nonlinear material response to function over a variety of pressures. (4) Valve performance is highly sensitive to free edge length and leaflet height. These conclusions suggest appropriate gross morphology and material properties for the design of prosthetic aortic valves. In future studies, our aortic valve modeling framework can be used with patient-specific models of vascular or cardiac flow.

Transcatheter Aortic Valve Replacement with Self-Expandable ACURATE neo as Compared to Balloon-Expandable SAPIEN 3 in Patients with Severe Aortic Stenosis: Meta-Analysis of Randomized and Propensity-Matched Studies

Frequent occurrence of paravalvular leak (PVL) after transcatheter aortic valve replacement (TAVR) was the main concern with earlier-generation devices. Current meta-analysis compared outcomes of TAVR with next-generation devices: ACURATE neo and SAPIEN 3. In random-effects meta-analysis, the pooled incidence rates of procedural, clinical and functional outcomes according to VARC-2 definitions were assessed. One randomized controlled trial and five observational studies including 2818 patients (ACURATE neo n = 1256 vs. SAPIEN 3 n = 1562) met inclusion criteria. ACURATE neo was associated with a 3.7-fold increase of moderate-to-severe PVL (RR (risk ratio): 3.70 (2.04-6.70); P < 0.0001), which was indirectly related to higher observed 30-day mortality with ACURATE valve (RR: 1.77 (1.03-3.04); P = 0.04). Major vascular complications, acute kidney injury, periprocedural myocardial infarction, stroke and serious bleeding events were similar between devices. ACURATE neo demonstrated lower transvalvular pressure gradients both at discharge (P < 0.00001) and at 30 days (P < 0.00001), along with lower risk of patient-prosthesis mismatch (RR: 0.29 (0.10-0.87); P = 0.03) and pacemaker implantation (RR: 0.64 (0.50-0.81); P = 0.0002), but no differences were observed regarding composite endpoints early safety and device success. In conclusion, ACURATE neo, as compared with SAPIEN 3, was associated with higher rates of moderate-to-severe PVL, which were indirectly linked with increased observed 30-day all-cause mortality.