Relation between operator and hospital volume and outcomes following percutaneous coronary interventions in the era of the coronary stent

Context Studies have found an association between physician and institution procedure volume for percutaneous coronary interventions (PCIs) and patien t outcomes, but whether implementation of coronary stents has allowed low-v olume physicians and centers to achieve outcomes similar to their high-volu me counterparts is unknown. Objective To assess the relationship between physician and hospital PCI vol umes and patient outcomes following PCIs, given the availability of coronar y stents. Design, Setting, and Participants Analysis of data from Medicare National C laims History files for 167208 patients aged 65 to 99 years who had PCIs pe rformed by 6534 physicians at 1003 hospitals during 1997, Of these procedur es, 57.7% involved coronary stents. Main Outcome Measures Rates of coronary artery bypass graft (CABG) surgery and 30-day mortality occurring during the index episode of care, stratified by physician and hospital PCI volume. Results Overall unadjusted rates of CABG during the index hospitalization a nd 30-day mortality were 1.87% and 3.30%, respectively. After adjustment fo r case mix, patients treated by low-volume (<30 Medicare procedures) physic ians had an increased risk of CABG vs patients treated by high-volume (>60 Medicare procedures) physicians (2.25% vs 1.55%; P<.001), but there was no difference in 30-day mortality rates (3.25% vs 3.39%; P=.27), Patients trea ted at low-volume (<80 Medicare procedures) centers had an increased risk o f 30-day mortality vs patients treated at high-volume (>160 Medicare proced ures) centers (4.29% vs 3.15%; P<.001), but there was no difference in the risk of CABG (1.83% vs 1.83 %; P=.96). In patients who received coronary st ents, the CABG rate was 1.20% vs 2.78% for patients not receiving stents, a nd the 30-day mortality rate was 2.83 % vs 3.94%, Among patients who receiv ed stents, those treated at low-volume centers had an increased risk of 30- day mortality vs those treated at high-volume centers, whereas those treate d by low-volume physicians had an increased risk of CABG vs those treated b y high-volume physicians. Conclusion In the era of coronary stents, Medicare patients treated by high -volume physicians and at high-volume centers experience better outcomes fo llowing PCIs.