Is CABG better than percutaneous coronary intervention?

October 20, 2018

Cardiology experts from Canada and around the world have gathered in Toronto this weekend to attend the Canadian Cardiovascular Congress (CCC), the largest gathering of cardiovascular and allied healthcare professionals in the country. The Congress draws hundreds of speakers highlighting innovations in science, prevention, treatment and recovery.

Dr. Louise Sun, a staff anesthesiologist in Division of Cardiac Anesthesiology at the University of Ottawa Heart Institute is one of those speakers. A rising star for her recent research at the Heart Institute, Dr. Sun’s recent presentation at CCC explored the differences in long-term survival after Coronary Artery Bypass Grafting (CABG) compared to Percutaneous Coronary Intervention (PCI) as strategies for treating patients with Ischemic Cardiomyopathy (ICM). 

Louise Sun, MD, is a staff anesthesiologist at the University of Ottawa Heart Institute and an Assistant Professor at the Department of Anesthesiology and School of Epidemiology, Public Health and Preventative Medicine, University of Ottawa.

“There are two major treatment strategies for ICM, and that's bypass surgery (or CABG) and PCI,” explains Dr. Sun. “CABG is a more invasive procedure which requires an open chest surgery. It requires harvesting blood vessels from other parts of the body and using them to bypass the blocked arteries of the heart.”

CABG is still considered the gold standard treatment for severe coronary artery disease. The graft patency and long-term results are quite good but the sacrifice here is that it is a higher risk procedure and is harder on the body, according to Dr. Sun.

PCI, on the other hand, is a less invasive procedure in which a cardiologist typically uses a sheath in either the patient’s arm or groin and, from there, stents can be inserted into the body to keep diseased heart vessels open. “It's an attractive alternative for people who don't want to go through a long recovery.”

According to Dr. Sun, there is currently a lack of head-to-head data in randomized trials comparing CABG against PCI surgeries in patients with ICM.

To be epidemiologically incorrect, ‘better’ is the word. We found CABG definitely led to better outcomes over the long term compared to PCI. This is actually the conclusion of our study.

- Louise Sun, MD

Researchers conducted a population-based, retrospective cohort study of Ontario residents using CorHealth Ontario and Canadian Institute of Health Information data. Included in the study were patients with ICM between the ages of 45 and 80 who had undergone either a CABG or PCI procedure between October 1, 2008 and March 31, 2016. A total of 11,916 patients were included in the study, of whom 4,769 (40.0%) had CABG and 7,147 (60.0%) had PCI.

“It did take us a few months to link up the data set that we wanted and to perform the analysis,” said Dr. Sun. “Because this was a retrospective study, the data is already captured. We had a massive amount of data and details at our command.” 

Dr. Sun’s study concluded that in patients with ICM, CABG was associated with a lower adjusted risk of long-term mortality compared to PCI, despite CABG patients having a higher burden of comorbidities.

Dr. Sun laughed when asked if CABG is indeed a superior strategy to PCI. “To be epidemiologically incorrect, ‘better’ is the word,” she said. "We found CABG definitely led to better outcomes over the long term compared to PCI. This is actually the conclusion of our study.”

Dr. Sun said the study should pave the way for clinical trials to validate these findings. “Further research is needed to evaluate the comparative effectiveness of CABG versus PCI in major adverse cardiac events and the quality of life in patients with ICM.”

The Beat caught up with Dr. Louise Sun following her presentation on Day One at CCC at the Metro Toronto Convention Centre. Watch the video below to learn more!

Dr. Sun would like to acknowledge the contribution of her friend and mentor, Dr. Jack Tu, who passed away during the initial revisions of this manuscript.

You can access Dr. Sun’s presentation slides: Long-Term Survival after Coronary Artery Bypass Grafting versus Percutaneous Coronary Intervention in Patients with Ischemic Cardiomyopathy (pdf).