Bypass Surgery vs. Stenting for Multivessel Disease in Stable and Unstable Angina
This is a relatively small randomized trial comparing coronary stenting to bypass surgery in individuals with stable and unstable angina with multivessel coronary disease. A substudy of the Arterial Revascularization Therapy Study (ARTS) trial asked whether type of angina and choice of revascularization strategy had an effect on clinical outcomes. The background comes from earlier reports suggesting that revascularization results in unstable angina are less favorable than in those who have stable angina. In this study, 1205 patients, recruited between 1997 and 1998, were classified as having stable angina or unstable angina. All had 2 coronary lesions in 2 different vessels; at least 1 stent per patient had to be implanted. An internal thoracic artery bypass graft was recommended for left anterior descending (LAD) or diagonal branch revascularization. The primary end point was major cardiac and cerebral vascular events within 12 months of randomization. ARTS will be carried out a full 5 years; early data have been previously reported (Serruys PW, et al. N Engl J Med. 2001;344:1117-1124). In this current report, 12,005 stable and unstable subjects were randomly assigned to stent implantation and PCI or bypass surgery. There were approximately 600 patients in each revascularization strategy, of whom 62% had stable angina. The coronary anatomy and number of lesions were comparable.
Results: The outcomes indicated no difference in major coronary and cerebral vascular events in unstable stented patients compared to those who had stable angina, or those with stable or unstable angina who received bypass surgery. Patients who underwent CABG had fewer events at 1 year, predominately related to the higher frequency of repeat revascularization in stented patients. One-year freedom from angina was greatest in bypass patients with either stable or unstable angina, at 90%, compared to 77% and 83% in stented patients with stable and unstable angina, respectively. A cost analysis favored PCI with a difference from CABG of $2600 at 1 year. They stress the comparability of results between CABG and stenting in this study, aside from the increased need for repeat revascularization procedures for patients who underwent stent implantation. However, they emphasize that the major coronary event difference between bypass surgery and PCI with respect to repeat revascularization had been 30% in early trials; stenting has substantially reduced this to half: (11% of unstable subjects and 16% of stable angina subjects had a repeat procedure at 1 year). They suggest that the new drug- eluting stents may result in a major improvement in event free survival between PCI vs. CABG. The recently published results from the RAVEL study, indicating a virtual abolition of in-stent restenosis with a sirolimus coated stent, would support this contention (de Feyter PJ, et al. Circulation. 2002;105:2367-2372).
Comment by Jonathan Abrams, MD
That subjects with stable and unstable angina do equally well with revascularization is not particularly surprising. Of interest, the bypass-unstable angina subjects actually had a 85.3% 1-year survival rate free from major vascular events vs. 89.2% in stable angina subjects, both substantially greater than 74% in stented subjects with both stable and unstable angina. The burden of repeat revascularization in individuals undergoing PCI, even with a stent, has been documented repeatedly, and is a little emphasized "cost" of PCI; thus, more patients with multivessel disease who undergo bypass grafting will be angina free and will have not needed a repeat procedure at 12 months than those who have had PCI, even with contemporary stent and antiplatelet therapy. The exciting results of the RAVEL trial and other early data with coated stents, indicate that in the future, studies such as this may confirm true equivalency with respect to angina free survival and need for revascularization between coronary surgery and PCI. For the time being, in qualified hands, the choice of bypass or angioplasty should be based on physician and patient preference, and patient-specific characteristics, such as diabetes or LV function, that might favor one strategy over another.
Dr. Abrams is Professor of Medicine, Division of Cardiology, University of New Mexico, Albuquerque.
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