Procedural hospital volume and outcome after transcatheter edge-to-edge mitral valve repair : Analysis of the German mandatory quality registry.

BACKGROUND

Studies assessing transcatheter edge-to-edge mitral valve repair (M-TEER) suggest lower rates of in-hospital mortality (IHM) at high-volume hospitals, and guidelines recommend minimum caseloads to assure quality standards.

METHODS

Data from all patients undergoing M‑TEER procedures at 154 hospitals in the German mandatory quality assurance registry in 2020 were analyzed. The observed IHM was adjusted against the expected mortality predicted by the German MKL-KATH score (O/E) and EuroScore II (O/E2). Regression analyses and volume quartile analyses were performed on hospital volume (HV), IHM rate, O/E, and intra-hospital complications. Additionally, binomial analysis was performed to verify results.

RESULTS

A total of 5099 patients (age 77.9 ± 2.5 years, mean EuroScore II 17.9 ± 5.9%) underwent M‑TEER procedures during the study period. The mean observed IHM was 1.79 ± 3.4%. Neither unadjusted nor risk-adjusted IHM was related to HV in linear regression (adjusted p = 0.56) or logistic regression (p = 0.515) analyses. The IHM rates for the first and fourth quartiles were nearly identical (p = 0.842). Any selected volume cut-off could not differentiate between hospitals with unacceptable (> 95th percentile O/E of all hospitals), acceptable (O/E ≤ 95th percentile), or better-than-average quality (O/E < 1). A caseload cut-off of 30cases per year would exclude 83 hospitals with acceptable or 72 with better-than-risk-adjusted quality (54% and 47% of all hospitals, respectively).

CONCLUSION

Hospital volume is an imprecise surrogate for assessing the quality of hospitals performing M‑TEER. The association between HV and IHM in patients undergoing elective M‑TEER in Germany was weak and not consistent across various analytical approaches. Other instruments may be more suitable for identifying hospitals with critical performance levels.