Prosthesis–Patient Mismatch After Transcatheter Aortic Valve Replacement

Prosthesis-patient mismatch after transcatheter implantation of contemporary balloon-expandable and self-expandable valves in small aortic annuli

BACKGROUND

Evidence of clinical impact of PPM after TAVI is conflicting and might vary according to the type of valve implanted.

AIMS

To assess the clinical impact of prosthesis-patient mismatch (PPM) after transcatheter aortic valve implantation (TAVI) with balloon-expandable (BEV) and self-expandable valves (SEV) in patients with small annuli.

METHODS

TAVI-SMALL 2 enrolled 628 patients in an international retrospective registry, which included patients with severe aortic stenosis and small annuli (annular perimeter <72 mm or area <400 mm2 ) treated with transfemoral TAVI at 16 high-volume centers between 2011 and 2020. Analyses were performed comparing patients with less than moderate (n = 452), moderate (n = 138), and severe PPM (n = 38). Primary endpoint was incidence of all-cause mortality. Predictors of all-cause mortality and PPM were investigated.

RESULTS

At a median follow-up of 380 days (interquartile range: 210-709 days), patients with severe PPM, but not moderate PPM, had an increased risk of all-cause mortality when compared with less than moderate PPM (log-rank p = 0.046). Severe PPM predicted all-cause mortality in patients with BEV (hazard ratio [HR]: 5.20, 95% confidence interval [CI]: 1.27-21.2) and intra-annular valves (IAVs, HR: 4.23, 95% CI: 1.28-14.02), and it did so with borderline significance in the overall population (HR: 2.89, 95% CI: 0.95-8.79). Supra-annular valve (SAV) implantation was the only predictor of severe PPM (odds ratio: 0.33, 95% CI: 0.13-0.83).

CONCLUSIONS

Patients with small aortic annuli and severe PPM after TAVI have an increased risk of all-cause mortality at early term follow-up, especially after IAV or BEV implantation. TAVI with SAV protected from severe PPM.

Rationale and design of the SMall Annuli Randomized To Evolut or SAPIEN Trial (SMART Trial)

BACKGROUND

The SMall Annuli Randomized To Evolut or SAPIEN (SMART) Trial was designed to compare the performance of the two most widely available commercial transcatheter aortic valve replacement (TAVR) devices in patients with symptomatic severe native aortic stenosis with a small aortic valve annulus undergoing transfemoral TAVR. Patients with small aortic valve annuli are typically female and are often underrepresented in clinical trials.

METHODS

The SMART Trial is an international, prospective, multi-center, randomized controlled, post-market trial. The trial will be conducted in approximately 700 subjects at approximately 90 sites globally. Inclusion criteria include severe aortic stenosis, aortic valve annulus area of ≤430 mm² based on multi-detector computed tomography, and appropriate anatomy for both the Medtronic Evolut PRO/PRO+ self-expanding and Edwards SAPIEN 3/3 Ultra balloon-expandable devices. The primary clinical outcome composite endpoint is defined as mortality, disabling stroke or heart failure rehospitalization at 12 months. The co-primary valve function composite endpoint is defined as bioprosthetic valve dysfunction at 12 months which includes hemodynamic structural valve dysfunction, defined as a mean gradient ≥20 mmHg, non-structural valve dysfunction, defined as severe prothesis-patient mismatch or ≥moderate aortic regurgitation, thrombosis, endocarditis, and aortic valve re-intervention. Powered secondary endpoints will be assessed hierarchically.

CONCLUSIONS

The SMART trial will be the largest head-to-head comparative trial of transfemoral TAVR using the two most widely available contemporary TAVR devices in the setting of small aortic annuli and the largest trial to enroll primarily women.

CLINICAL TRIAL REGISTRATION

URL: www.clinicaltrials.gov, Unique identifier: NCT04722250.

Prosthesis-Patient Mismatch After Aortic Valve Replacement in the PARTNER 2 Trial and Registry

OBJECTIVES

This study aimed to compare incidence and impact of measured prosthesis-patient mismatch (PPM_M) versus predicted PPM (PPM_P) after surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR).

BACKGROUND

TAVR studies have used measured effective orifice area indexed (EOAi) to body surface area (BSA) to define PPM, but most SAVR series have used predicted EOAi. This difference may contribute to discrepancies in incidence and outcomes of PPM between series.

METHODS

The study analyzed SAVR patients from the PARTNER (Placement of Aortic Transcatheter Valves) 2A trial and TAVR patients from the PARTNER 2 SAPIEN 3 Intermediate Risk registry. PPM was classified as moderate if EOAi ≤0.85 cm²/m² (≤0.70 if obese: body mass index ≥30 kg/m²) and severe if EOAi ≤0.65 cm²/m² (≤0.55 if obese). PPM_M was determined by the core lab-measured EOAi on 30-day echocardiogram. PPM_P was determined by 2 methods: 1) using normal EOA reference values previously reported for each valve model and size (PPM_P1; n = 929 SAVR, 1,069 TAVR) indexed to BSA; and 2) using normal reference EOA predicted from aortic annulus size measured by computed tomography (PPM_P2; n = 864 TAVR only) indexed to BSA. Primary endpoint was the composite of 5-year all-cause death and rehospitalization.

RESULTS

The incidence of moderate and severe PPM_P was much lower than PPM_M in both SAVR (PPM_P1: 28.4% and 1.2% vs. PPM_M: 31.0% and 23.6%) and TAVR (PPM_P1: 21.0% and 0.1% and PPM_P2: 17.0% and 0% vs. PPM_M: 27.9% and 5.7%). The incidence of severe PPM_M and severe PPM_P1 was lower in TAVR versus SAVR (P < 0.001). The presence of PPM by any method was associated with higher transprosthetic gradient. Severe PPM_P1 was independently associated with events in SAVR after adjustment for sex and Society of Thoracic Surgeons score (hazard ratio: 3.18;95% CI: 1.69-5.96; P < 0.001), whereas no association was observed between PPM by any method and outcomes in TAVR.

CONCLUSIONS

EOAi measured by echocardiography results in a higher incidence of PPM following SAVR or TAVR than PPM based on predicted EOAi. Severe PPM_P is rare (<1.5%), but is associated with increased all-cause death and rehospitalization after SAVR, whereas it is absent following TAVR.

Predictors and Clinical Impact of Prosthesis-Patient Mismatch After Self-Expandable TAVR in Small Annuli

OBJECTIVES

The aim of this study was to define predictors of prosthesis-patient mismatch (PPM) and its impact on mortality after transcatheter aortic valve replacement (TAVR) with self-expandable valves (SEVs) in patients with small annuli.

BACKGROUND

TAVR seems to reduce the risk for PPM compared with surgical aortic valve replacement, especially in patients with small aortic annuli. Nevertheless, predictors and impact of PPM in this population have not been clarified yet.

METHODS

Predictors of PPM and all-cause mortality were investigated using multivariable logistic regression analysis from the cohort of the TAVI-SMALL (International Multicenter Registry to Evaluate the Performance of Self-Expandable Valves in Small Aortic Annuli) registry, which included patients with severe aortic stenosis and small annuli (annular perimeter <72 mm or area <400 mm² on computed tomography) treated with transcatheter SEVs: 445 patients with (n = 129) and without (n = 316) PPM were enrolled.

RESULTS

Intra-annular valves conferred increased risk for PPM (odds ratio [OR]: 2.36; 95% confidence interval [CI]: 1.16 to 4.81), while post-dilation (OR: 0.46; 95% CI: 0.25-0.84) and valve oversizing (OR: 0.53; 95% CI: 0.28-1.00) seemed to protect against PPM occurrence. At a median follow-up of 354 days, patients with severe PPM, but not those with moderate PPM, had a higher all-cause mortality rate compared with those without PPM (log-rank p = 0.008). Multivariable Cox regression confirmed severe PPM as an independent predictor of all-cause mortality (hazard ratio: 4.27; 95% CI: 1.34 to 13.6).

CONCLUSIONS

Among patients with aortic stenosis and small aortic annuli undergoing transcatheter SEV implantation, use of intra-annular valves yielded higher risk for PPM; conversely, post-dilation and valve oversizing protected against PPM occurrence. Severe PPM was independently associated with all-cause mortality.