Introduction: Neither the prevalence nor the prognostic impact of Prosthesis-Patient Mismatch (PPM) in patients after Transcatheter Aortic Valve Implantation (TAVI) has yet been sufficiently investigated.

Objective: Aim of the analysis was to assess clinical and procedural characteristics in patients with PPM after TAVI as well its prognostic impact.

Methods: All patients who underwent TAVI at our center due to severe symptomatic native aortic valvular stenosis between 2008 and 2016 and provided in-house echocardiographic data on PPM as well as follow-up data were included in the analysis. Patients who underwent valve in valve procedures were excluded. PPM was defined in accordance with VARC2 criteria.

Results: The analysis comprises 1232 patients with a mean follow-up of 2.0 years. Patients were treated with 11 different transcatheter heart valves (THVs) including balloon-expandable (Sapien, Sapien XT, Sapien 3), self-expandable supraannular (Corevalve, Evolut R, Acurate Neo), self-expandable annular (Portico), mechanically-expandable infraannular (Lotus), non-metallic (DFM) or self-expandable cusp fixated THV (JenaValve, Engager). Insignificant PPM was prevalent in 65.7% (N=810), moderate PPM in 22.6% (N=279), and severe PPM in 11.6% (N=143) of the patients. Patients with severe PPM had smaller EOA (All results as follows insignificant vs. moderate vs. severe PPM: 0.8±0.2 vs. 0.8±0.2 vs. 0.7±0.2 cm²; p<0.001) and LVOT diameter (20.8±1.9 vs. 19.6±1.7 vs. 19.1±2.2 mm; p p<0.001) at baseline. Moreover, these patients had smaller annuli (24.3±2.2 vs. 24.0±2.2 vs. 23.6±2.4 mm; p<0.001) and received smaller valve sizes (size ≤23 mm: 22.0% vs. 30.8% vs. 37.8%; p<0.001). Severe PPM was most common after self-expandable cusp fixated THV implantation (21.9%; p=0.006). The prevalence of PPM was lowest in suprannular THV designs (severe PPM order from most to least frequent according to THV type: Engager >Lotus >JenaValve >Sapien XT/3 >Portico >CoreValve/Evolut R >Portico >Acurate Neo). There was no difference in risk for all-cause mortality according to the presence of PPM among the total patient cohort (Figure1A; HR severe vs. insignificant PPM: 1.06 (95%CI 0.57-1.97; p=0.86)). However, in a subgroup of patients with low LVEF low-gradient aortic stenosis (LEF-LG) risk for mortality was higher in patients with severe PPM (Figure1B; HR severe vs. insignificant PPM: 2.14 (95%CI 1.18-3.85), p=0.012). Moreover, in the LEF-LG subgroup severe PPM was found to be an independent predictor for all-cause mortality according to multivariate analysis (HR severe vs. insignificant PPM: 3.28 (95%CI 1.59-6.77; p=0.001)). No association between PPM and mortality was found for patients with high-gradient aortic stenosis (HGAS) and paradoxical low-flow low-gradient aortic stenosis (PLF-LG).

Conclusion: Severe PPM can be found in a substantial amount of patients after TAVI. PPM shows no impact on mid-term mortality among patients with HGAS and PLF-LG. In contrast, in patients with LEF-LG severe PPM after TAVI is a strong independent predictor for adverse outcome.