Coronary revascularization procedures decreased markedly in California after the introduction of drug-eluting stents and the initiation of public reporting in 2003, resulting in a large number of low-volume heart programs. California hospital discharge data were analyzed from 2006 to 2010 to study the impact of this change. In-hospital mortality and hospital readmission for major adverse events at 90 days and 365 days were determined for patients who underwent isolated coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) either with acute coronary syndrome (ACS) or PCI without acute coronary syndrome (PCI-noACS). Three terciles were chosen by case volume as follows: high-volume (747 ± 336 [SD]/yr total PCI, 210 ± 130 isolated CABG), intermediate volume (362 ± 47 PCI, 106 ± 27 CABG), and low-volume (211 ± 6 PCI, 53 ± 17 CABG) terciles were studied. PCI-noACS procedures decreased 33% and CABG 20%, whereas PCI-ACS procedures increased slightly. Risk-adjusted in-hospital mortality was slightly better in high-volume compared with low-volume terciles for CABG (2.0% vs 2.6%) and PCI-noACS (0.64% vs 0.85%). There was no difference in major adverse events at 90 days or 365 days among volume terciles within procedure groups, and no change in event rates was noted over the 5-year period. Wide variation in outcomes, associated with low volume, contributed to poor statistical discrimination among providers. In conclusion, lower volume hospitals had similar overall outcomes with wider variation. Conservative treatment strategies apparently contributed to decreased procedure volume. Collaboration among hospitals of similar structure and case volume may be the most appropriate performance improvement model to reduce variability among providers.
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