Ever since the first interventional cardiologist threaded a catheter into an occluded artery in the heart and inflated a balloon to widen the narrowed artery, a turf war has ebbed and flowed between interventionalists and surgeons over the best way to treat CAD.
The interventionalists, armed initially with balloons, then with stents — bare metal and later drug-eluting varieties—offer fast revascularization without the often painful recovery experienced by those who have their chests “cracked” to make way for surgeons who restore blood flow via coronary artery bypass grafts (CABG). But the surgeons maintain that arterial grafts offer the most durable fix, without the need for multiple repeat visits to the cath lab and no need for antiplatelet therapy.
For many, findings from the SYNTAX trial reported at the European Society of Cardiology Congress in 2008 and later published in The New England Journal of Medicine offered definite proof supporting CABG for treatment of severe coronary artery disease.
That 1,800-patient trial compared CABG to percutaneous coronary intervention (PCI) using a drug-eluting stent and found that, at 12 months, the rate of severe events — MCI, stroke, urgent revascularization — 17.8% in the PCI group versus 12.4% in the CABG arm (P =0.002), with the difference mainly driven by the need for repeat revascularization in the stent arm. But the stroke rate, which was lower than expected in both arms, was significantly higher in the surgical group (2.2% versus 0.6%, P =0.003).
Now, a group of Canadian researchers jump into the fray with a cohort study that looks at long term outcomes for CABG versus stent among patients who have severely reduced left ventricular function, defined as LVEF <35%
Results of the retrospective cohort study of 12,113 patients, by Louise Y. Sun, MD, of the University of Ottawa Heart Institute, Ottawa, Ontario, Canada, and colleagues was published in JAMA Cardiology.
In this analysis with average follow-up of more than 5 years, the PCI group “had higher rates of long-term mortality (HR, 1.6; 95% CI, 1.4-1.7) than did those who underwent CABG,” they wrote.
The patients were Ontario residents age 40 to 84 who were treated from Oct. 1, 2008 through Dec. 31, 2016. In addition to reduced LVEF, the patients had left anterior descending (LAD), left main, or multivessel CAD. The primary outcome was all cause mortality, and secondary outcomes included cardiovascular death, stroke, revascularization or hospitalization for MI or heart failure.
The mean age of patients in the PCI group (n=7,013) was 64.8 versus 65.6 in the CABG group (n=5,100). In the PCI arm 27.5% were women versus 17.1% in the CABG arm. Sun and colleagues matched 2,397 PCI patients to 2,397 CABG patients for the analysis.
“In the PCI group, a mean (SD) of 1.9 (1.1) stents were implanted per patient. In the CABG group, a mean (SD) of 3.3 (1.0) grafts per patient were placed,” they wrote.
“MACE occurred in a total of 1,221 patients (50.9%) who underwent PCI and 770 (32.1%) who underwent CABG. In patients who underwent PCI, there was a higher risk of MACE compared with those who underwent CABG (HR, 2.0; 95% CI, 1.9-2.2),” they found.
At 30 days the risk of major adverse cardiac events (MACE) was higher in PCI group than in the CABG group, including:
- All-cause mortality 4.8% versus 4.0% P=0.21.
- Cardiovascular death 3.5% versus 2.8% P=0.17.
- Revascularization 10.9% versus 3.2% P=<.001.
- Hospitalization for MI 7.8% versus 1.4% P=<.001.
- Hospitalization for HF 5.6% versus 3.0% P=<.001.
Overall, the median follow-up was 5.2 years and long term the results again favored CABG.
- Overall mortality rate was 30.0% in the PCI group versus 23.3% in the CABG group.
- Cardiovascular mortality rate was 10.8% in the PCI arm versus 8.9% in the CABG group.
The authors noted that the study was limited by its observational design, and other factors such as the inclusion of patients with previous PCI in the analysis.
But in an editorial Eric J. Velazquez, MD, of Yale School of Medicine, in New Haven, wrote that the “limitations do not detract from the substantial strengths of this study, the information gap it begins to address absent randomized clinical trial evidence, and the challenges it poses to the cardiovascular care community to do better and move forward.
Physician and patient preferences underlying decision making for revascularization in patients with HFrEF remain under explored. For example, as cognitive impairment is common among patients with heart failure and known to worsen after cardiovascular procedures, does the choice of revascularization lead to a differential effect? How does the choice of revascularization procedure affect quality of life? These and other issues must factor into the design of future studies of PCI and CABG in HFrEF that leverage available data in a similar fashion to CorHealth Ontario but minimize confounding by means of randomization, are performed pragmatically, and can be generalizable across populations and health systems.”