Volume-outcome relationship in complication-related mortality after percutaneous coronary interventions: an analysis on the failure-to-rescue rate in the Japanese Nationwide Registry

In-hospital mortality following percutaneous coronary intervention (PCI) varies across institutions with different annual PCI volumes. The failure to rescue (FTR) rate, defined as the mortality rate following PCI-related complications, may account for the volume-outcome relationship. The Japanese Nationwide PCI Registry, a consecutive, nationally mandated registry between 2019 and 2020, was queried. The FTR rate is defined as ‘the number of patients who died following PCI-related complications’ divided by ‘the number of patients who experienced at least one PCI-related complication.’ Multivariate analysis was used to calculate the risk-adjusted odds ratio (aOR) of the FTR rates among hospitals stratified into tertiles as low (≤ 236/year), medium (237–405/year), and high (≥ 406/year). A total of 465,716 PCIs and 1007 institutions were included. A volume-outcome relationship was observed for in-hospital mortality, and the medium-volume (aOR 0.90, 95% confidence interval [CI] 0.85–0.96), as well as high-volume (aOR 0.84, 95% CI 0.79–0.89) hospitals, had significantly lower in-hospital mortality than low-volume hospitals. Complication rates were lower at high-volume centers (1.9%, 2.2%, and 2.6% for high-, medium-, and low-volume centers, respectively; p < 0.001). The overall FTR rate was 19.0%. The FTR rates for the low-, medium-, and high-volume hospitals were 19.3%, 17.7%, and 20.6%, respectively. The medium-volume hospitals had a lower FTR rate (aOR 0.82, 95% [CI] 0.68–0.99), whereas the FTR rate was similar at the high-volume hospitals compared with that of the low-volume hospitals (aOR 1.02, 95% CI 0.83–1.26). In-hospital mortality was low after PCI in high-volume hospitals. However, the FTR rate in high-volume hospitals was not necessarily lower than that in low-volume hospitals. The FTR rate did not account for the volume-outcome relationship in PCI.