Findings from 2 major studies presented at the 2016 Transcatheter Cardiovascular Therapeutics (TCT) meeting reported conflicting results for percutaneous coronary intervention (PCI) vs coronary artery bypass (CABG) in left main coronary artery (LMCA) disease.

The EXCEL (Evaluation of XCIENCE vs Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization ) trial showed that PCI with everolimus-eluting stents was non-inferior to CABG for the primary composite end point of death, stroke, or myocardial infarction (MI) at 3 years in patients with low or intermediate SYNTAX (Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) scores.1

However, researchers with the NOBLE (Nordic–Baltic–British Left Main Revascularization) trial found that the 5-year risk of major adverse events was higher after PCI compared to CABG despite similar mortality.2

EXCEL and NOBLE results were simultaneously published in the New England Journal of Medicine, and  and Lancet, respectively.3

The EXCEL researchers randomly assigned 1905 patients with LMCA disease of low or intermediate anatomical complexity to either PCI with everolimus-eluting stents (n=948) or CABG (n= 957). Anatomic complexity was defined by a SYNTAX score of 32 or lower.

At 3 years, 15.4% of patients in the PCI group experienced the primary end point compared with 14.7% of the CABG group (95% confidence interval [CI], 0.79-1.26). Roughly 5% of the PCI group experienced death, stroke, or MI at 30 days compared with 7.9% of the CABG group. Almost one-quarter of patients in the PCI group (23.1%) experienced the secondary end point event of death, stroke, MI, or ischemia-driven revascularization at 3 years vs 19.1% of the CABG group.

“The main results from EXCEL indicate that PCI is a safe alternative to CABG and results in similar outcomes compared to surgery,” said Ioanna Kosmidou, MD, PhD, an assistant professor of medicine/cardiology at NewYork-Presbyterian/Columbia University Medical Center in New York City and one of the study’s co-authors. “Long-term follow-up of subjects enrolled in EXCEL, up to 5 years, will provide further evidence regarding long-term outcomes with either approach.”

In comparison, results from the NOBLE trial showed superior safety associated with CABG, although mortality was similar.

“Our findings of similar mortality but higher rates of [MI] and repeat revascularization in patients undergoing PCI compared to CABG are consistent with previous studies of coronary revascularization in patients with LMCA disease,”  lead researcher Evald H. Christiansen, MD, PhD, a cardiologist at Aarhus University Hospital in Denmark said in a press release.4

“However, the low mortality following treatment in both groups demonstrates that modern revascularization techniques can lead to excellent survival in stable LMCA patients. Further, the increased rates of non-procedural [MI], repeat revascularization and stroke associated with PCI are important considerations in selecting the optimal treatment for individual patients.”

In the NOBLE trial, 1201 patients were randomly assigned to PCI (n=598) or CABG (n=603); 592 patients in each arm were included in the intent-to-treat population.

At 5 years, Kaplan-Meier estimates for major adverse cardiac or cerebrovascular events (MACCE) were 28.9% for PCI vs 19.1% for CABG (hazard ratio [HR]:1.48; 95% CI, 1.11-1.96). Dr Christiansen stated that those results exceeded the limit for non-inferiority, demonstrating superiority of CABG over PCI.

Dr Kosmidou noted “there are several important methodological differences” between the 2 trials that could explain the discrepancy in results MACCE results including a lower rate of pre- and post-PCI intravascular ultrasound utilization and initial utilization of a first generation stent in 11% of PCI patients in NOBLE.

“Both studies offer significant insight into the management of patients with LM or LM-equivalent disease, but an important key point from both studies is that all-cause mortality as well as cardiac mortality did not differ between PCI and CABG,” she said. “As a result, the main drivers of higher MACCE in the PCI arm in NOBLE were non-procedural MIs and revascularization and both studies demonstrated the safety of PCI in this patient population.”

Dr Kosmidou stressed the importance of a collaborative heart team in making optimal treatment decisions for each patient, and that based on these findings, LM PCI should still be performed at centers with expertise in high risk PCI.

Disclosures: The NOBLE trial was funded by Aarhus University Hospital and an institutional research grant from Biosensors. Drs Mäkikallio and Christiansen reported receiving institutional rants from Biosensors.

The EXCEL trial investigators reported various financial relationships with the pharmaceutical industry. A full disclosure list is available here.

References

  1. Stone GW, Sabik JF, Serruys PW, et al; for the EXCEL trial investigators. Everolimus-eluting stents or bypass surgery for left main coronary artery disease. N Engl J Med. 2016 Oct 31. doi:10.1056/NEJMoa1610227 [Epub ahead of print].
  2. Mäkikallio T, Holm NR, Lindsay M, et al; on behal of the NOBLE study investigators. NOBLE: a prospective, randomized trial comparing biolimus-eluting stents and bypass graft surgery in selected patients with left main coronary artery disease. Presented at: the 2016 Transcatheter Cardiovascular Therapeutics meeting scientific symposium. October 29-November 2 2016; Washington, DC.
  3. Mäkikallio T, Holm NR, Lindsay M, et al; on behalf of the NOBLE study investigators. Percutaneous coronary angioplasty vs coronary artery bypass grafting in treatment of unprotected left main stenosis (NOBLE): a prospective, randomized, open-label, non-inferority trial. Lancet. 2016 Oct 31.  [Epub ahead of print].
  4. Study indicates that open heart surgery may be superior to PCI for treatment of left main coronary artery disease. [press release]. Washington, DC: Transcatheter Cardiovascular Therapeutics http://www.crf.org/crf/news-and-events/news/news/1841-study-indicates-that-open-heart-surgery-may-be-superior-to-pci-for-treatment-of-left-main-coronary-artery-disease. October 31, 2016.