Time-of-Day and Clinical Outcomes After Surgical or Transcatheter Aortic Valve Replacement: Insights From the PARTNER Trials

Background: Circadian rhythms may influence myocardial tolerance to ischemia-reperfusion phenomena occurring during cardiac procedures. While conflicting results exist on the effect of time-of-day on surgical aortic valve replacement (SAVR), afternoon procedures could be associated with a reduced risk of death, rehospitalization or periprocedural myocardial infarction, compared with morning procedures. We examined the impact of procedure time-of-day on outcomes after transcatheter aortic valve replacement (TAVR) or SAVR. Methods: We analyzed patients at intermediate- or high-surgical risk who underwent elective TAVR (n=4457) or SAVR (n=1129) in the PARTNER (Placement of Aortic Transcatheter Valve) 1 and 2 trials and registries according to time-of-day (morning versus afternoon) using the Kaplan-Meier event rates and multivariable Cox proportional hazards regression models. Sensitivity analysis was conducted using 1:1 propensity-score matching. The primary end point was all-cause death or rehospitalization at 2 years. Results: At 2 years, no difference was observed between patients operated in the morning versus the afternoon within the SAVR (32.3% versus 30.6%, adjusted hazard ratio, 1.08 [95% CI, 0.82–1.41], P =0.58) and TAVR cohorts (35.7% versus 35.4%, adjusted hazard ratio, 1.01 [95% CI, 0.89–1.14], P =0.86) with regards to the primary end point. Rates of periprocedural myocardial infarction were low and similar between morning and afternoon in SAVR (1.6% versus 1.0%, P =0.51) and TAVR (0.4% versus 0.4%, P =0.86), as were all other clinical end points. Similar results were observed in propensity-score matched analysis. Conclusions: Procedure time-of-day was not associated with clinical outcomes after TAVR or SAVR. Registration: URL: https://www.clinicaltrials.gov ; Unique identifiers: NCT00530894, NCT01314313, NCT03222141, and NCT03222128.