The search for long-term outcome predictors

The most suitable technique for revascularisation in patients with left main or multivessel coronary artery disease is still widely debated (1-3). A growing number of randomised controlled trials as well as data from meta analyses have compared both coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) with drug-eluting stents (DES) (4-9). Although there is a growing body of evidence behind the use of CABG over PCI in patients with multivessel and left main coronary artery disease (7-9), in clinical practice the decision is often not clear cut. The identification of specific predictors of post-intervention outcomes may help guide patient-specific, clinical decision making regarding appropriate revascularisation strategies.

Chang and colleagues (10) have recently published the results of their retrospective study of pooled data from the BEST (4), PRECOMBAT (5) and SYNTAX (6) trials: “Predictors of long-term outcomes after bypass grafting versus drug-eluting stent implantation for left main or multivessel coronary artery disease.” They are to be congratulated for their attempts to ascertain potential pre-operative factors which may help us predict outcomes following CABG or PCI with DES in order to help guide the choice of suitable revascularisation strategy.

Chang et al. analysed data from a total 3,230 patients pooled from the above studies (98.5% of the total cohort) with 1,538 having undergone CABG and 1,692 having undergone PCI with DES. They used the Cox proportional hazards model to determine predictors of long-term outcomes. Diabetes mellitus, SYNTAX score and previous MI were found to independently relate to death from any cause in the PCI group. Chronic kidney disease (CKD) was an independent predictor of a composite outcome of death, MI or stroke in the CABG group and complete revascularisation and previous MI in the PCI group. In those without CKD, CABG was more favourable than PCI with regard to the composite outcome. They also demonstrated a higher incidence of stroke after CABG in patients without previous stroke but the inverse in patients with previous stroke. Furthermore, Chang and colleagues found that death from any cause in the CABG group was significantly related to the EuroSCORE, but not to SYNTAX score. All-cause mortality was also found to be significantly lower with CABG than PCI in patients with a high SYNTAX score.

Their results are in keeping with previously established predictors of mortality following CABG or PCI which are already included in the EuroSCORE (11). Based on their findings Chang et al. have proposed that CABG may be a more appropriate revascularisation strategy in patients with a high SYNTAX score, diabetes mellitus or previous MI as well as those with a previous stroke and intermediate SYNTAX score. Caution must be taken however, when interpreting these conclusions given the studies limitations, as outlined by the authors themselves.

Despite a growing number of randomised controlled trials comparing CABG and PCI with DES, the appropriate revascularisation strategy in patients with multivessel or left main coronary artery disease remains unclear, as the trials were underpowered to detect a difference in all-cause mortality. That said, data from meta-analyses would suggest that CABG is superior to PCI with DES in patients with unprotected left main (8) and multivessel (9) coronary artery disease. Further, appropriately powered studies are needed for more definitive conclusions. Until that time, predictors of long-term outcomes may help guide clinical decision making in offering patients the most appropriate revascularisation strategy.

Acknowledgements

None.

Footnote

Conflicts of Interest: The authors have no conflicts of interest to declare.

References

1. Deb S, Wijeysundera HC, Ko DT, et al. Coronary artery bypass graft surgery vs percutaneous interventions in coronary revascularization: a systematic review. JAMA 2013;310:2086-95. [Crossref] [PubMed]
2. Weintraub WS, Grau-Sepulveda MV, Weiss JM, et al. Comparative effectiveness of revascularization strategies. N Engl J Med 2012;366:1467-76. [Crossref] [PubMed]
3. Hannan EL, Wu C, Walford G, et al. Drug-eluting stents vs. coronary-artery bypass grafting in multivessel coronary disease. N Engl J Med 2008;358:331-41. [Crossref] [PubMed]
4. Park SJ, Ahn JM, Kim YH, et al. Trial of everolimus-eluting stents or bypass surgery for coronary disease. N Engl J Med 2015;372:1204-12. [Crossref] [PubMed]
5. Park SJ, Kim YH, Park DW, et al. Randomized trial of stents versus bypass surgery for left main coronary artery disease. N Engl J Med 2011;364:1718-27. [Crossref] [PubMed]
6. Serruys PW, Morice MC, Kappetein AP, et al. Percutaneous coronary intervention versus coronary-artery bypass grafting for severe coronary artery disease. N Engl J Med 2009;360:961-72. [Crossref] [PubMed]
7. Serruys PW, Ong AT, van Herwerden LA, et al. Five-year outcomes after coronary stenting versus bypass surgery for the treatment of multivessel disease: the final analysis of the Arterial Revascularization Therapies Study (ARTS) randomized trial. J Am Coll Cardiol 2005;46:575-81. [Crossref] [PubMed]
8. Benedetto U, Ng C, Smith R, et al. Coronary artery bypass grafting is superior to first-generation drug-eluting stents for unprotected left main coronary artery disease: an updated meta-analysis of 4 randomized, controlled trials. J Thorac Cardiovasc Surg 2014;148:2430-2. [Crossref] [PubMed]
9. Sipahi I, Akay MH, Dagdelen S, et al. Coronary artery bypass grafting vs percutaneous coronary intervention and long-term mortality and morbidity in multivessel disease: meta-analysis of randomized clinical trials of the arterial grafting and stenting era. JAMA Intern Med 2014;174:223-30. [Crossref] [PubMed]
10. Chang M, Lee CW, Ahn JM, et al. Predictors of long-term outcomes after bypass grafting versus drug-eluting stent implantation for left main or multivessel coronary artery disease. Catheter Cardiovasc Interv 2017;90:177-85. [Crossref] [PubMed]
11. Roques F, Nashef SA, Michel P, et al. Risk factors and outcome in European cardiac surgery: analysis of the EuroSCORE multinational database of 19030 patients. Eur J Cardiothorac Surg 1999;15:816-22; discussion 822-3. [Crossref] [PubMed]