Narrowing the gap: Early and intermediate outcomes after percutaneous coronary intervention and coronary artery bypass graft procedures in California, 1997 to 2006

Objective

Percutaneous coronary intervention is increasingly used to treat multivessel coronary artery disease. Coronary artery bypass graft procedures have decreased, and as a result, percutaneous coronary intervention has increased. The overall impact of this treatment shift is uncertain. We examined the in-hospital mortality and complication rates for these procedures in California using a combined risk model.

Methods

The confidential dataset of the Office of Statewide Health Planning and Development patient discharge database was queried for 1997 to 2006. A risk model was developed using International Classification of Diseases, Ninth Revision, Clinical Modification procedures and diagnostic codes from the combined pool of isolated coronary artery bypass graft and percutaneous coronary intervention procedures performed during 2005 and 2006. In-hospital mortality was corrected for “same-day” transfers to another health care institution. Early failure rate was defined as in-hospital mortality rate plus reintervention for another percutaneous coronary intervention or cardiac surgery procedure within 90 days.

Results

Coronary artery bypass graft volume decreased from 28,495 (1997) to 15,520 (2006), whereas percutaneous coronary intervention volume increased from 38,098 to 53,703. Risk-adjusted mortality rate decreased from 4.7% to 2.1% for coronary artery bypass graft procedures and from 3.4% to 1.9% for percutaneous coronary intervention. Expected mortality rate increased for both procedures. Early failure rate decreased from 13.1% to 8.0% for percutaneous coronary intervention and from 6.5% to 5.4% for coronary artery bypass graft. For the years 2004 and 2005, the risk of recurrent myocardial infarction or need for coronary artery bypass graft during the first postoperative year was 12% for percutaneous coronary intervention and 6% for coronary artery bypass grafts.

Conclusion

This study shows that as volume shifted from coronary artery bypass grafts to percutaneous coronary intervention, expected mortality increased for both procedures. Risk-adjusted mortality rate decreased for both procedures, more so for coronary artery bypass grafts, so that corrected in-hospital mortality rates essentially equalized at approximately 2.0% in 2006. The post-procedural risk of reintervention, death, or myocardial infarction within the first year was twice as high for percutaneous coronary intervention as for coronary artery bypass grafts.

CTSNet classification: 23

Abbreviations and Acronyms: CABG, coronary artery bypass graft, MI, myocardial infarction, OSHPD-PDD, Office of Statewide Health Planning and Development, PCI, percutaneous coronary intervention, RAMR, risk-adjusted mortality rate