Survival Advantage for Bypass Surgery Compared with Non-surgical Procedure
Project analyzed data from over 189,000 older adults
A new comparative effectiveness study found older adults with stable coronary heart disease (CHD) who underwent bypass surgery had better long-term survival rates than those who underwent a non-surgical procedure to improve blood flow to the heart muscle, also called revascularization.
The National Institutes of Health-supported study compared a type of surgery known as coronary artery bypass graft (CABG) with a non-surgical procedure known as percutaneous coronary intervention (PCI). While there were no survival differences between the two groups after one year, after four years the CABG group had a 21 percent lower mortality.
Principal investigator William Weintraub, M.D., of Christiana Care Health System in Newark, Del., and colleagues will present these findings on Tuesday, March 27, at 9 a.m. EDT, at the American College of Cardiology's annual meeting in Chicago. The findings will appear online today in the New England Journal of Medicine and in the April 19 print issue. Two companion papers that describe the statistical prediction models used to forecast long-term survival rates will also appear in today’s print issue of Circulation.
Comparative effectiveness research results provide information to help patients and health care providers decide which practices are most likely to offer the best approach for a particular patient, what the timing of interventions should be, and the best setting for providing care.
In CABG, or bypass surgery, the most common type of heart surgery in the United States, blood flow to the heart muscle is improved by using ("grafting") a healthy artery or vein from another part of the body to bypass the blocked coronary artery.
PCI is a less invasive, non-surgical procedure in which blocked arteries are opened with a balloon (also called angioplasty). A stent, or small mesh tube, is then usually placed in the opened arteries to allow blood to continue to flow into the heart muscle.
With NHLBI support, the American College of Cardiology Foundation (ACCF) and the Society of Thoracic Surgeons (STS) came together to compare short- and long-term survival outcomes after CABG versus PCI. The investigators linked medical data available in their ACCF and STS databases with follow-up information in the Medicare Provider Analysis and Review database of the Centers for Medicare and Medicaid Services.
Linking these three datasets from 644 U.S. hospitals allowed researchers to analyze information from the STS database on 86,244 older adults (average age 74) with stable CHD who underwent CABG between 2004 and 2007 and 103,549 older adults (average age 74) with stable CHD from the ACCF database who underwent PCI between 2004 and 2007. Follow-up ranged from one to five years, with an average of 2.72 years.
At one year there was no difference in deaths between the groups (6.55 percent for PCI versus 6.24 percent for CABG). However, at four years there was a lower mortality with CABG than with PCI (16.41 percent versus 20.80 percent). This long-term survival advantage after CABG was consistent across multiple subgroups based on gender, age, race, diabetes, body mass index, prior heart attack history, number of blocked coronary vessels, and other characteristics. For example, the insulin-dependent diabetes subgroup that received CABG had a 28 percent increased chance of survival after four years compared with the PCI group.
This project, the ACCF—STS Database Collaboration on the Comparative Effectiveness of Revascularization Strategies (ASCERT) study, was supported through designated comparative effectiveness research funds from the American Recovery and Reinvestment Act. ASCERT involved 16 investigators from among the five collaborating organizations: Christiana Care Center for Outcomes Research; the ACCF in Washington, D.C.; the STS in Chicago; Duke Clinical Research Institute in Durham, N.C.; and PERFUSE Angiographic Core Laboratories & Data Coordinating Center, a non-profit academic research organization in Boston.