Cleveland Clinic, Imaging Institute and Heart & Vascular Institute, Cleveland, USA
In a study recently published in the NEJM (1), funded by the US National Heart, Lung, and Blood Institute, Weintraub et al. describes comparative effectiveness data of long-term survival after percutaneous coronary intervention (PCI) and coronary-artery bypass grafting (CABG). In collaboration between the American College of Cardiology Foundation (ACCF) and the Society of Thoracic Surgeons (STS), the authors linked the ACCF National Cardiovascular Data Registry and the STS Adult Cardiac Surgery Database to claims data from the Centers for Medicare and Medicaid Services for the years 2004 through 2008. Outcomes were compared with the use of propensity scores and inverse-probability-weighting adjustment to reduce treatment-selection bias.
Among patients 65 years of age or older who had two-vessel or three-vessel coronary artery disease without acute myocardial infarction, 86.244 underwent CABG and 103.549 underwent PCI. The median follow-up period was 2.67 years. At 1 year, there was no significant difference in adjusted mortality between the groups (6.24% in the CABG group as compared with 6.55% in the PCI group; risk ratio, 0.95; 95% confidence interval [CI], 0.90 to 1.00). However, at 4 years, there was lower mortality with CABG than with PCI (16.4% vs. 20.8%; risk ratio, 0.79; 95% CI, 0.76 to 0.82). Similar results were noted in multiple subgroups and with the use of several different analytic methods. Residual confounding was assessed by means of a sensitivity analysis.
The authors conclude that among older patients with multivessel coronary disease that did not require emergency treatment, there was a long-term survival advantage among patients who underwent CABG as compared with patients who underwent PCI.
The accompanying editorial (2) cautions that the validity of these data largely depend on adequate control for confounding factors, which is generally challenging in retrospective data analysis from registry data. Obviously, if known or unknown confounding factors were not assessed or adjusted for, these imbalances could explain the difference in mortality. However, the authors provide a careful analysis to quantify the effect of a hypothetical confounding variable on their findings. The editorial also point out that there has been significant changes in the approach to revascularization, both with modern PCI strategies favoring the use of focal treatment for vessels that are associated with myocardial ischemia (3), and with coronary bypass surgery. (4) Furthermore the indication of revascularization versus optimized medical therapy has changed. (5) [see also: http://www.amepc.org/cdt/post/view/research-highlight-on-initial-coronary-stent-implantation-with-medical-therapy-vs-medical-therapy-alone-for-stable-coronary-artery-disease-meta-analysis-of-randomized-controlled-trials]
1. Weintraub WS, Grau-Sepulveda MV, Weiss JM, O'Brien SM, Peterson ED, Kolm P, Zhang Z, Klein LW, Shaw RE, McKay C, Ritzenthaler LL, Popma JJ, Messenger JC, Shahian DM, Grover FL, Mayer JE, Shewan CM, Garratt KN, Moussa ID, Dangas GD, Edwards FH. Comparative Effectiveness of Revascularization Strategies. N Engl J Med. 2012 Mar 27. [Epub ahead of print]
2. Mauri L. Why We Still Need Randomized Trials to Compare Effectiveness. N Engl J Med. 2012 Mar 27. [Epub ahead of print]
3. Tonino PA, De Bruyne B, Pijls NH, Siebert U, Ikeno F, van' t Veer M, Klauss V, Manoharan G, Engstrøm T, Oldroyd KG, Ver Lee PN, MacCarthy PA, Fearon WF; FAME Study Investigators.
Fractional flow reserve versus angiography for guiding percutaneous coronary intervention. N Engl J Med. 2009 Jan 15;360(3):213-24.
4. Lamy A, Devereaux PJ, Prabhakaran D, Taggart DP, Hu S, Paolasso E, Straka Z, Piegas LS, Akar AR, Jain AR, Noiseux N, Padmanabhan C, Bahamondes JC, Novick RJ, Vaijyanath P, Reddy S, Tao L, Olavegogeascoechea PA, Airan B, Sulling TA, Whitlock RP, Ou Y, Ng J, Chrolavicius S, Yusuf S; the CORONARY Investigators.
Off-Pump or On-Pump Coronary-Artery Bypass Grafting at 30 Days.
N Engl J Med. 2012 Mar 26. [Epub ahead of print]
5. Boden WE, O'Rourke RA, Teo KK, et al. COURAGE Trial Research Group. Optimal medical therapy with or without PCI for stable coronary disease. N Engl J Med. 2007;356:1503-16.