Effect of Physician Volume on the Relationship Between Hospital Volume and Mortality During Primary Angioplasty

Objectives: We sought to examine the combined effect of hospital and physician volume of primary percutaneous coronary intervention (PCI) on in-hospital mortality. Background: An inverse relationship between volume and outcome has been observed for both hospitals and physicians after primary PCI for acute myocardial infarction. Methods: Using the New York State PCI registry, we examined yearly hospital volume, physician volume, and risk-adjusted mortality in 7,321 patients undergoing primary PCI for acute myocardial infarction. Risk-adjusted mortality rates for high-volume hospitals (>50 cases/year) and high-volume physicians (>10 cases/year) were compared with their respective low-volume counterparts. Results: Primary PCI by high-volume hospitals (odds ratio [OR]: 0.58; 95% confidence interval [CI]: 0.38 to 0.88) and high-volume physicians (OR: 0.66; 95% CI: 0.48 to 0.92) was associated with lower odds of mortality. Furthermore, there was a significant interaction between hospital and physician volume on adjusted mortality (p = 0.02). Although unadjusted mortality was lower when primary PCI was performed by high-volume physicians in high-volume hospitals compared with low-volume physicians in low-volume hospitals (3.2% vs. 6.7%, p = 0.03), the risk-adjusted mortality rate was not statistically significant (3.8% vs. 8.4%, p = 0.09). In low-volume hospitals, the average risk-adjusted mortality rate for low-volume physicians was 8.4% versus 4.8% for high-volume physicians (OR: 1.44; 95% CI: 0.68 to 3.03). However, in high-volume hospitals, the risk-adjusted mortality rate for high-volume physicians was 3.8% versus 6.5% for low-volume physicians (OR: 0.58; 95% CI: 0.39 to 0.86). Conclusions: During primary PCI, physician experience significantly modifies the hospital volume-outcome relationship. Therefore, policymakers need to consider physician experience when developing strategies to improve access to primary PCI. [Copyright &y& Elsevier]