CABG, PCI debate continues with new research, emerging technologies

For patients in need of revascularization, the choice has not changed much in the past decade: percutaneous coronary intervention or CABG.

Yet, this was not the case going back even as late as the mid-1990s, when PCI was used only in a few patients. However, with the introduction of stents, the popularity grew, and by the early 21st century, it was used in about 90% of the cases.

Now, new research is continually shedding light on both PCI and CABG to determine which is preferential in specific conditions and populations.

According to Deepak L. Bhatt, MD, MPH, chief of cardiology, VA Boston Healthcare System and a member of the Cardiology Today Editorial Board, both PCI with stents and CABG are excellent options for revascularization.

Mark Hlatky, MD, notes that young patients tend to do better with PCI, and older patients with CABG. Source: Steve Fisch Photography

“For single-vessel disease, PCI would almost always be preferred. For complex three-vessel disease, with bifurcations involved and chronic total occlusions present, CABG is often the better option,” Bhatt said in an interview. “In between those two extremes, there is a great deal of room for judgment and individualization based on the patient’s level of risk, as well as preferences.”

Research performed in 2009 by Mark Hlatky, MD, professor of health research and policy and of medicine, Stanford University, and colleagues examined the effects of both procedures on mortality modified by patient characteristics. They found that in patients with diabetes, mortality was noticeably lower in the CABG group vs. the PCI group, although it was similar in patients without diabetes and in most patient subgroups with multivessel CAD.

“CABG led to a decreased mortality in the long run that didn’t seem to be explained by anything except diabetes,” Hlatky told Cardiology Today. “That’s a strong message and something that should be considered in making decisions before the patient goes through angiography. Patients should be made aware of this so that they can make an informed decision about whether they want CABG or PCI.”

Similarly, findings from the SYNTAX trial indicated that CABG, when compared with PCI, was associated with a lower rate of major adverse cardiac or cerebrovascular events at 1 year in patients with three-vessel, left main CAD or both, and was suggested by researchers as the standard of care for such patients.

Currently, Hlatky and researchers are investigating the role of age in PCI and CABG procedures. “What we’ve observed is that younger people did better with PCI and older people did better with CABG. This is an important consideration and something we want to drill into a little more,” Hlatky said. “We’re now planning on looking at additional endpoints beyond mortality, as well as confirming this finding in other data.”

Readmission rates and cost differential

When determining which revascularization procedure to choose, two of the most influential variables are readmission rates and cost.

In one study, patients who chose CABG were much more likely to be without repeat revascularization at 1 year (96.2%) and 5 years (90.2%) vs. patients who had PCI via balloon angioplasty trials (1 year, 73.5%; 5 years, 53.9%) and stent trials (5 years, 59.9%).

Bhatt said even in the drug-eluting stent era, there is less of a need for repeat revascularization with CABG. However, the price for this distinction, he added, is a higher risk of stroke in CABG procedures.

Although gathering accurate data on the comparative cost of these two procedures presents inherent difficulties for researchers, including the life-long nature of CAD, Hill and researchers were able to develop an economic model. This model was based on the extrapolation of trends in mortality and revascularization from clinical trials data to a 5-year time horizon, which proved sufficient to indicate long-term trends in cost-effectiveness. The following are some of the data they found comparing the costs and outcomes of stents and CABG in multivessel disease:

• Bare metal stents vs. CABG: CABG was initially more expensive and may have had higher immediate risks, but over time, the cost differential was reduced and long-term outcomes favored CABG.
• Drug-eluting stents vs. CABG: not qualitatively different from bare metal stents. Reduced costs from fewer repeat revascularizations were more than offset by the higher costs of stents. The improved efficacy of the new stents did not eliminate the long-term outcome advantage of CABG.

Advancements in revascularization

Deepak L. Bhatt

PCIs have evolved in the past decade because of the advent of drug-eluting stents in 2001. With this advancement came new stent designs, better polymers and more effective drugs. Drug-eluting stents have helped to decrease revascularization, and there is some evidence that the second generation drug-eluting stents may even reduce ischemic outcomes, although more work is needed to support this hypothesis, Bhatt said.

Technological advances have brought some dramatic changes in the field of CABG, as well. In a study examining the past, present and future of coronary artery revascularization, Bharadwaj and Luthra said the most notable developments include minimally invasive techniques, such as minimally invasive direct coronary artery bypass and totally endoscopic, robot-assisted CABG.

“Robotic surgical systems have permitted the manipulation of surgical instruments through limited thoracic incisions,” Bharadwaj and Luthra wrote. “Minimally invasive and robotic CABG is paving the way for near outpatient coronary surgery.”

However, they said the number of technical issues related to robotic assistance has prevented its widespread acceptance and deployment. “The learning curve is significant, which has translated into long operating room and cardio-pulmonary bypass times,” they said. “In addition, conversion rates to conventional sternotomy remain high and are often related to difficulty with remote-access perfusion or inadequate intra-thoracic working space.”

Bharadwaj and Luthra wrote that the future of revascularization will likely be a multifaceted approach to complete and sustained coronary revascularization with increasing cooperation between the surgeon and the interventional cardiologist.

“Completeness of revascularization is not a competition between these two treatment strategies. Rather, it is an important factor in the decision-making process that requires careful thought before a patient is recommended for either treatment option,” they wrote.

In the area of coronary revascularization, Hlatky said he would like to see a greater emphasis on involving patients in the decision-making process. “In the current environment, we often have no time after an angiography to have an informed discussion with the patient, who is an important individual in choosing the right procedure,” he said. “He or she may care a lot about some of the outcomes and weigh them differently, and that’s something we as physicians need to listen to.” – by Brian Ellis

For more information:

• Bharadwaj C. MJAFI. 2008;64:154-157.
• Bravata D. Ann Intern Med. 2007;147:703-716.
• Hill R. Health Technol Assess. 2004;8:35.
• Hlatky M. Lancet. 2009;373:1190-1197.
• Holmes D. Curr Control Trials Cardiovasc Med. 2001;2:263-265.
• Serruys P. N Engl J Med. 2009;360:961-72.