Using national registry data and record linkage to inform post-market surveillance of prosthetic aortic valve models over 15-years

Context: Post-market evidence generation for medical devices is important yet limited for prosthetic aortic valve devices in the United Kingdom (UK).
Objective: To identify prosthetic aortic valve models that display unexpected patterns of mortality or re-intervention using routinely collected national registry data and record linkage.
Design: Observational study using the UK National Adult Cardiac Surgery Audit (NACSA) registry for procedures performed between 1998 and 2013. Valves were classified into series of related models. Outcome tracking was performed using multifaceted record linkage. The median follow-up was 4.1 years (maximum 15.3 years). Cox proportional hazards regression with random effects (frailty models) were used to model valve effects on the outcomes, with and without adjustment for (pre-)operative covariates.
Setting: All National Health Service and private hospitals in England and Wales who submit data to the NACSA registry.
Patients and Interventions: All patients undergoing first-time elective and urgent aortic valve replacement surgery (± coronary artery bypass graft) with a mechanical (n=10 series) or biological (n=15 series) prosthetic valve from 5 primary suppliers, and satisfying pre-specified data quality criteria were included (n=43,782 biological, n=11,084 mechanical).
Main Outcome Measures: Time to all-cause mortality or aortic valve re-intervention (surgical or trans-catheter). There were 13,104 deaths and 723 re-interventions during follow-up.
Results: Two series of valves were associated with significantly increased hazard of death or re- intervention were identified: Sorin Biological Series (frailty 1.18 [95%PI: 1.06 to 1.32]) and Sorin Mitroflow series (frailty 1.19 [95%PI: 1.09 to 1.31]). These results were robust to covariate adjustment, and sensitivity analyses. Three biological valve series were associated with significantly decreased hazard.
Conclusions: Meaningful evidence from the analysis of routinely-collected registry data can inform post-market surveillance of medical devices. Although the findings are associated with a number of caveats, two specific biological aortic valve series identified in this study may warrant further investigation.