Hospital percutaneous coronary intervention volume and patient mortality, 1998 to 2000: does the evidence support current procedure volume minimums?

Objectives: The aim of this study was to evaluate current American College of Cardiology/American Heart Association (ACC/AHA) hospital percutaneous coronary intervention (PCI) volume minimum recommendations.

Background: In order to reduce procedure-associated mortality, ACC/AHA guidelines recommend that hospitals offering PCIs perform at least 400 PCIs annually. It is unclear whether this volume standard applies to current practice.

Methods: We conducted a retrospective analysis of the Agency for Healthcare Research and Quality's Nationwide In-patient Sample hospital discharge database to evaluate in-hospital mortality among patients (n = 362748) who underwent PCI between 1998 and 2000 at low (5 to 199 cases/year), medium (200 to 399 cases/year), high (400 to 999 cases/year), and very high (1000 cases or more/year) PCI volume hospitals.

Results: Crude in-hospital mortality rates were 2.56% in low-volume hospitals, 1.83% in medium-volume hospitals, 1.64% in high-volume hospitals, and 1.36% in very high-volume hospitals (p < 0.001 for trend). Compared with patients treated in high-volume hospitals (odds ratio [OR] 1.00, referent), patients treated in low-volume hospitals remained at increased risk for mortality after adjustment for patient characteristics (OR 1.21, 95% confidence interval [CI] 1.06 to 1.28). However, patients treated in medium-volume hospitals (OR 1.02, 95% CI 0.92 to 1.14) and patients treated in very high-volume hospitals (OR 0.94, 95% CI 0.85 to 1.03) had a comparable risk of mortality. Findings were similar when high- and very high-volume hospitals were pooled together.

Conclusions: We found no evidence of higher in-hospital mortality in patients undergoing PCI at medium-volume hospitals compared with patients treated at hospitals with annual PCI volumes of 400 cases of more, suggesting current ACC/AHA PCI hospital volume minimums may merit reevaluation.