J Lindsay1, E E Pinnow, A D Pichard. 1. Section of Cardiology, The Washington Hospital Center, Washington, DC 20010, USA. JML2@MHG.edu
Abstract
OBJECTIVES: To test one-month outcomes in a single center for their statistical power to corroborate conclusions derived from large multicenter databases. BACKGROUND: Only with large, multicenter databases has it been possible to demonstrate more frequent occurrences of complications in patients treated by "low-volume operators." Critics feel that such analyses mask excellent performance by many "low-volume operators." METHODS: In a high-volume cardiac catheterization laboratory in a large, nonuniversity teaching hospital, baseline clinical and angiographic characteristics were collected for a consecutive series of 1,029 patients treated by 37 percutaneous transluminal coronary intervention (PTCI) operators over a four-month period. One-month follow-up was obtained in 967 (94%) patients who form the basis for this analysis. RESULTS: Only the group of operators performing <50 cases annually had a major adverse cardiac event (MACE) (death, myocardial infarction or symptom-driven revascularization) rate at one month significantly greater than predicted from baseline characteristics. (Observed rate: 15.1%, expected: 9.7%, 95% confidence interval [CI]: 4.7%, 14.6%.) The difference was driven by the significantly more frequent rate at which repeat revascularization was performed in patients treated by that group of operators (observed: 13.8%, expected: 7.1%, 95% CI: 2.8%, 11.4%). CONCLUSIONS: As is true of analyses of large multicenter databases, lower volume operators as a group have less good outcomes than those performing more. The greater statistical power provided by one-month MACE rate offers advantages over the use of in-hospital complications for the analysis of operator performance.
OBJECTIVES: To test one-month outcomes in a single center for their statistical power to corroborate conclusions derived from large multicenter databases. BACKGROUND: Only with large, multicenter databases has it been possible to demonstrate more frequent occurrences of complications in patients treated by "low-volume operators." Critics feel that such analyses mask excellent performance by many "low-volume operators." METHODS: In a high-volume cardiac catheterization laboratory in a large, nonuniversity teaching hospital, baseline clinical and angiographic characteristics were collected for a consecutive series of 1,029 patients treated by 37 percutaneous transluminal coronary intervention (PTCI) operators over a four-month period. One-month follow-up was obtained in 967 (94%) patients who form the basis for this analysis. RESULTS: Only the group of operators performing <50 cases annually had a major adverse cardiac event (MACE) (death, myocardial infarction or symptom-driven revascularization) rate at one month significantly greater than predicted from baseline characteristics. (Observed rate: 15.1%, expected: 9.7%, 95% confidence interval [CI]: 4.7%, 14.6%.) The difference was driven by the significantly more frequent rate at which repeat revascularization was performed in patients treated by that group of operators (observed: 13.8%, expected: 7.1%, 95% CI: 2.8%, 11.4%). CONCLUSIONS: As is true of analyses of large multicenter databases, lower volume operators as a group have less good outcomes than those performing more. The greater statistical power provided by one-month MACE rate offers advantages over the use of in-hospital complications for the analysis of operator performance.