ASCERT Study Compares Survival Rates of CABG and PCI

March 27, 2012—Findings from the ASCERT study, using a collaboration of the American College of Cardiology Foundation–Society of Thoracic Surgeons (ACCF-STS) database on the comparative effectiveness of revascularization strategies, were presented at the American College of Cardiology's annual scientific session in Chicago. ASCERT, which was directed by Lead Investigator William S. Weintraub, MD, indicated that coronary artery bypass graft (CABG) surgery appears to carry a higher long-term survival rate than percutaneous coronary intervention (PCI). 

According to the ACC, ASCERT compared the survival rates after PCI and CABG surgery in older patients with stable multivessel coronary disease. The ASCERT investigators analyzed health outcomes of 190,000 patients across the United States between 2004 and 2008 using data from the ACC's CathPCI Registry, the STS CABG database, and the Medicare claims database. 

Comparing the results of CABG to PCI, the investigators found that patients who underwent PCI had a higher death rate in the first 4 years after treatment than those who had opted for CABG (20.8% and 16.41%, respectively). 

“Our study is the most general one ever done because it uses data from across the whole country. It is also much larger than any other study,” said Dr. Weintraub. “Combining data from several large databases, we found that survival was better with coronary surgery than percutaneous coronary intervention.” 

As noted by the ACC, some previous studies have suggested the two treatments have similar long-term outcomes, and others have shown better outcomes with CABG. Updated American College of Cardiology Foundation/American Heart Association guidelines for both PCI and CABG released last November state that PCI to improve patient survival is a reasonable alternative to CABG in stable patients with left main coronary artery disease who have a low risk of PCI complications and an increased risk of adverse surgical outcomes. The guideline also confirms the superiority of CABG compared to medical therapy and to PCI for most patients with three-vessel disease. 

However, noted the ACC, the guidelines also recommend using a “heart team” approach to determine which procedure should be used. In this approach, the interventional cardiologist and the cardiac surgeon review the patient's condition, determine the pros and cons of each treatment option, and then present this information to the patient, allowing him or her to make a more informed decision.

William Oetgen, MD, the ACC's Senior Vice President for Science and Quality, stated, “Results from studies like ASCERT should be shared with patients as part of the decision-making process.” He further noted that to date, patients and doctors tend to choose the less-invasive PCI when both treatments are an option. 

Dr. Weintraub also cautioned that the results do not mean bypass surgery is best for every patient and pointed out that a major limitation of observational studies, such as this one, is that the groups may not have the same level of risk, and so it is possible that the worse outcomes in the PCI patients were related to these patients being sicker overall. 

 “It does push the needle toward coronary surgery, but not overwhelmingly so,” concluded Dr. Weintraub. “When we're recommending coronary surgery to patients, even though it is a bigger intervention than PCI, we can now have a little more confidence that the decision is a good one.” 

In response to the study's presentation, Christopher J. White, MD, President of the Society of Cardiovascular Angiography and Interventions (SCAI) published a President's Page commentary in SCAI's official journal, Catheterization and Cardiovascular Interventions. In the commentary, Dr. White, along with SCAI Secretary Charles Chambers, MD, and H. Vernon Anderson, MD, a Fellow of SCAI, stated their objections and caveats to the ASCERT's methods and conclusion (2012;79:691–692). 

Dr. White and colleagues stated that SCAI has been closely involved in the ASCERT study and supports efforts like it to compare treatment effectiveness. 

However, the SCAI officials stated that the registry data used in this study were self-reported and not held to the same rigorous standards associated with collection of randomized clinical trial data. They stressed that data consistently show PCI to be a safe and effective option for patients. When considered in the context of other studies, they said, “ASCERT is an outlier, with the most likely reason being the use of registry data.” 

Other limitations of the ASCERT study asserted by Dr. White and colleagues are: (1) important patient characteristics known to influence survival were not measured or studied; (2) some factors that increase procedural risk were likely accounted more often in CABG than in PCI patients, reducing the ability to adjust risk fairly; (3) the effect of patient preference is unknown; (4) all-cause mortality in a generally very sick, elderly population does not lead to distinct conclusions; and (5) ASCERT did not evaluate quality of life.