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Prosthesis-Patient Mismatch and TAVR Outcomes
Quick Takes
- Using data from a large multicenter registry of patients after TAVR for severe aortic stenosis, the prevalence of prosthesis-patient mismatch (PPM) predicted using core lab hemodynamic data (PPMp) was significantly lower than that of PPM using site-measured data on individual patients (PPMm), with negligible correlation between the two methods.
- In unadjusted analyses, severe PPMm adversely influenced 2-year survival, whereas severe PPMp was not associated with outcomes.
- After adjusting for confounders, neither PPMm nor PPMp had a significant effect on 2-year all-cause mortality.
Study Questions:
Does measured or predicted prosthesis-patient mismatch (PPM) after transcatheter aortic valve replacement (TAVR) affect all-cause mortality at 2 years?
Methods:
The IMPPACT TAVR (Impact of Measured or Predicted Prosthesis-pAtient mismatCh after TAVR) registry included 38,808 patients who underwent TAVR for severe native aortic stenosis at one of 26 centers in Europe and Israel. Valve Academic Research Consortium-3 criteria were used to define PPM severity. Effective orifice area (EOA) and PPM were determined echocardiographically at each site (PPMm) or as predicted (PPMp) based on core lab-derived EOA reference values. The primary endpoint was 2-year all-cause mortality.
Results:
Mean predicted EOA indexed to body surface area (EOAi) values were slightly larger than measured EOAi values but clinically comparable (predicted EOAi 1.02 ± 0.17 cm2/m2, measured EOAi 1.01 ± 0.27 cm2/m2 in the joint cohort; p < 0.001). The prevalence of PPMp (moderate 6.8%, severe 0.6%) was significantly lower than that of PPMm (moderate 20.7%, severe 4.3%; p < 0.001) with negligible correlation between the two methods (Kendall’s tau C correlation coefficient, 0.063; p < 0.001). In unadjusted analyses, severe PPMm adversely influenced 2-year survival (hazard ratio [HR], 1.22; 95% confidence interval [CI], 1.02-1.45; p = 0.027), whereas severe PPMp was not associated with outcomes (HR, 0.81; 95% CI, 0.55-1.19; p = 0.291). After adjusting for confounders, neither PPMm nor PPMp had a significant effect on 2-year all-cause mortality.
Conclusions:
After adjusting for confounders, neither PPMp nor PPMm was significantly associated with 2-year all-cause mortality. The authors conclude that valve selection should not be based solely on hemodynamics but rather on a holistic approach, including patient and procedural specifics.
Perspective:
PPM after surgical aortic valve replacement (SAVR) is associated with increased gradients, less favorable ventricular remodeling, and increased morbidity and mortality. Previously published studies have yielded variable associations between PPM after TAVR and clinical outcomes. As the authors of this study note, measured EOA (and therefore PPMm) involves the potential for site-based measurement errors potentially confounding the accurate recognition of PPM. Although core lab data should reduce measurement error in the calculation of EOA (and therefore PPMp), published core lab data are treated as though they provide point estimates of EOA rather than means with (oftentimes substantial) standard deviations. Most previous comparative studies are concordant in finding a lower prevalence of PPM after TAVR compared to SAVR. However, a mechanism is unclear for an absent clinical impact of severe PPM after TAVR compared to the demonstrable adverse clinical impact of severe PPM after SAVR, raising the possibility that the results of this and other studies might be confounded by the inherent difficulties in obtaining accurate individual measurements of EOAi.
Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Valvular Heart Disease, Aortic Surgery, Cardiac Surgery and VHD, Interventions and Structural Heart Disease
Keywords: Aortic Valve Stenosis, Heart Valve Prosthesis, Transcatheter Aortic Valve Replacement
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