Correspondence
Coronary-Artery Bypass Surgery versus Stenting for Multivessel Disease
N Engl J Med 2001; 345:1641-1643November 29, 2001
- Article
To the Editor:
In a trial comparing coronary-artery bypass surgery with stenting for the treatment of multivessel coronary disease, Serruys et al. (April 12 issue)1 conclude that both treatments offer protection against death, stroke, and myocardial infarction. We disagree. Whether there is “protection” can be determined only through comparison with a group of patients who are assigned to medical therapy alone.
To date, no clinical trial comparing angioplasty with medical therapy for angina has demonstrated a protective effect of angioplasty in multivessel disease.2,3 Indeed, in the second Randomised Intervention Treatment of Angina (RITA-2) trial,3 patients who underwent angioplasty had a significant 91 percent increase (a 3 percent absolute difference) in the rate of death or myocardial infarction during a median of 2.7 years of follow-up. The early randomized, controlled trials comparing coronary surgery with medical treatment also failed to show an improvement in prognosis among patients without stenosis of the left main coronary artery and with good left ventricular function.4 Neither of these treatment options has been shown to offer protection against myocardial infarction or stroke. These results can be explained by the fact that risk of plaque rupture is determined not by the patency of the vessel but by the stability of the atheromatous plaque: most episodes of acute coronary occlusion occur in vessels with stenoses that are not flow-limiting (those resulting in a reduction of less than 70 percent in the luminal diameter).5 These two treatments are palliative, and to portray them as protective is misleading.
5 ReferencesPeter J. Pugh, M.B., B.S.
Lawrence O'Toole, M.D.
Kevin S. Channer, M.D.
Royal Hallamshire Hospital, Sheffield S10 2JF, United Kingdom
kevin.channer@csuh. nhs. uk 1
Serruys PW ,Unger F ,Sousa JE , et al. Comparison of coronary-artery bypass surgery and stenting for the treatment of multivessel disease. N Engl J Med 2001;344:1117-1124
Full Text | Web of Science | Medline2
Folland ED ,Hartigan PM ,Parisi AF . Percutaneous transluminal coronary angioplasty versus medical therapy for stable angina pectoris: outcomes for patients with double-vessel versus single-vessel coronary artery disease in a Veterans Affairs Cooperative randomized trial. J Am Coll Cardiol 1997;29:1505-1511
CrossRef | Web of Science | Medline3
Coronary angioplasty versus medical therapy for angina: the second Randomised Intervention Treatment of Angina (RITA-2) trial. Lancet 1997;350:461-468
CrossRef | Web of Science | Medline4
Yusuf S ,Zucker D ,Peduzzi P , et al. Effect of coronary artery bypass graft surgery on survival: overview of 10-year results from randomised trials by the Coronary Artery Bypass Graft Surgery Trialists Collaboration. Lancet 1994;344:563-570[Erratum, Lancet 1994;344:1446.]
CrossRef | Web of Science | Medline5
Falk E ,Shah PK ,Fuster V . Coronary plaque disruption. Circulation 1995;92:657-671
Web of Science | Medline
To the Editor:
Two important methodologic flaws in the trial by Serruys et al. weaken the conclusion that “coronary stenting for multivessel disease is less expensive than bypass surgery and offers the same degree of protection against death, stroke, and myocardial infarction.”
First, the majority of patients who currently undergo surgery have three-vessel disease and impaired ventricular function. In contrast, two thirds of the patients in the trial had two-vessel disease, and the mean left ventricular function for the entire group was normal (ejection fraction, 61 percent). Yusuf and colleagues1 have emphasized that, unless they have severe disease of the proximal left anterior descending coronary artery, such patients do not receive a survival benefit from surgery as compared with optimal medical therapy. Consequently, although the trial population seems to be highly selected, we are not told what proportion of all patients with multivessel disease, all of whom would be treatable by surgery, were enrolled in the trial (we would hazard a guess of around 10 percent).
Second, transient elevations of creatine kinase MB to more than five times its basal level within 18 hours after surgery is a well-recognized feature of cardiopulmonary bypass, particularly after the harvesting of one or both internal thoracic arteries.2 Such an elevation does not reflect perioperative myocardial infarction unless it continues for 24 to 48 hours.2
Most clinicians understand that, in practice, surgery and angioplasty are used to deal with different spectrums of severity of ischemic heart disease. Suggesting that both techniques are equally efficacious, on the basis of results in a highly selected population of patients with “multivessel” disease (i.e., primarily two-vessel disease and normal ventricular function), serves only to confuse the issue, the general physician, and the patient.
2 ReferencesDavid P. Taggart, M.D., Ph.D.
Adrian Banning, M.D.
Keith Channon, M.D.
John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
david.taggart@orh. nhs. uk 1
Yusuf S ,Zucker D ,Peduzzi P , et al. Effect of coronary artery bypass graft surgery on survival: overview of 10-year results from randomised trials by the Coronary Artery Bypass Graft Surgery Trialists Collaboration. Lancet 1994;344:563-570[Erratum, Lancet 1994;344:1446.]
CrossRef | Web of Science | Medline2
Taggart DP . Biochemical assessment of myocardial injury after cardiac surgery: effects of a platelet activating factor antagonist, bilateral internal thoracic artery grafts, and coronary endarterectomy. J Thorac Cardiovasc Surg 2000;120:651-659
CrossRef | Web of Science | Medline
To the Editor:
There is cause for concern about the generalizability of the conclusions drawn by Serruys and his coauthors.1 Indeed, according to a presentation of the results of the Arterial Revascularization Therapies Study that was given in August 2000,2 only 5 percent of the patients who were screened were actually enrolled in the study. One should carefully examine the criteria for exclusion from this study, which were the presence of disease in the left main coronary artery, previous percutaneous transluminal coronary angioplasty (PTCA) or coronary-artery bypass grafting (CABG), poor left ventricular function, congestive heart failure, previous stroke, recent myocardial infarction, hepatic or renal disease, chronic total occlusions, or any lesion not “potentially amenable to stent” — presumably, any long lesion in a calcified, tortuous, or small vessel. In other words, most patients who are candidates for intervention were excluded from the trial. The danger is that the conclusions of a study involving such a small, select group of patients cannot be generalized to the population at large.
2 ReferencesMichael J. Mack, M.D.
7777 Forest Ln., Suite A323, Dallas, TX 75230
mjmack@earthlink.net 1
Pocock SJ ,Elbourne DR . Randomized trials or observational tribulations? N Engl J Med 2000;342:1907-1909
Full Text | Web of Science | Medline2
Moses J. Results of the ARTS trial. Presented at Coronary Interventions for the New Millennium, Linkoping, Sweden, August 24, 2000. abstract.
To the Editor:
In the study by Serruys et al., one group of patients deserves special consideration. There was a sizable number of patients with diabetes in both groups — 16 percent in the surgery group and 19 percent in the stenting group. It has been shown that patients with diabetes do much better with surgery than with percutaneous coronary intervention for multivessel disease.1,2 Other studies have shown that patients with diabetes have a higher incidence of restenosis and target-vessel revascularization after coronary stenting than do patients without diabetes.3,4
It is important to know the rates of clinical events, including the rates of revascularization, in the patients with diabetes in both groups. The difference in the rates of revascularization among these patients might have affected the overall results of the study, and stenting may be a better procedure for patients without diabetes who have multivessel disease. Similarly, the rates of individual clinical events (i.e., stroke, myocardial infarction, or death) might have been different in the stenting group if the patients with diabetes had not been included in the analysis.
4 ReferencesMohammed Murtaza, M.D.
Manoj Singh, M.D.
Lekshmi Dharmarajan, M.D.
Lincoln Medical and Mental Health Center, Bronx, NY 10451
mohammedmurtaza@hotmail.com 1
Influence of diabetes on 5-year mortality and morbidity in a randomized trial comparing CABG and PTCA in patients with multivessel disease: the Bypass Angioplasty Revascularization Investigation (BARI). Circulation 1997;96:1761-1769
Web of Science | Medline2
Niles NW ,McGrath PD ,Malenka D , et al. Survival of patients with diabetes and multivessel coronary artery disease after surgical or percutaneous coronary revascularization: results of a large regional prospective study. J Am Coll Cardiol 2001;37:1008-1015
CrossRef | Web of Science | Medline3
Elezi S ,Kastrati A ,Pache J , et al. Diabetes mellitus and the clinical and angiographic outcome after coronary stent placement. J Am Coll Cardiol 1998;32:1866-1873
CrossRef | Web of Science | Medline4
Abizaid A ,Kornowski R ,Mintz GS , et al. The influence of diabetes mellitus on acute and late clinical outcomes following coronary stent implantation. J Am Coll Cardiol 1998;32:584-589
CrossRef | Web of Science | Medline
Author/Editor Response
Dr. Serruys replies:
To the Editor: A key criticism of our trial and others that have compared surgery with percutaneous treatment is that they enrolled a highly selected population. The letters question the generalizability of our results, as well as our conclusion that both treatments offer “protection against death, stroke, and myocardial infarction” — a conclusion that Pugh et al. believe can only be drawn on the basis of a comparison with a group of patients assigned to medical therapy alone.
In response to this criticism, I should emphasize that a prospective analysis of the total number of patients with multivessel disease that was diagnosed and treated in the course of one week in each participating center revealed that a leading institution with an annual volume of 1000 bypass operations enrolled up to 33 percent of the patients who were screened during the week of the survey. In addition, in a subgroup of 402 patients with three-vessel disease, 75.0 percent of those who were treated with multivessel stenting remained free of events, whereas 86.5 percent of those with three-vessel disease in the surgery group remained free of events — an absolute difference of 11.5 percent. Moreover, a sizable cohort of 477 patients who had a lesion in the proximal segment of the left anterior descending artery (segment 6 according to the American Heart Association classification) were enrolled in this trial; in this subgroup, the event-free survival in the stenting group was 77.8 percent — 12.3 percentage points lower than that in the corresponding subgroup of the surgery group (90.1 percent).
A subanalysis revealed that in patients with diabetes mellitus and multivessel coronary artery disease, surgical revascularization with routine use of an arterial conduit for bypass in the left anterior descending artery provides a better clinical outcome at one year (84.4 percent of patients event-free) than percutaneous intervention, even when a strategy of angioplasty plus stenting is used. One-year mortality among the patients with diabetes who were assigned to undergo PTCA plus stenting was twice as high as among those assigned to undergo CABG (6.3 percent vs. 3.1 percent, although the difference was not significant). However, surgery carried a substantial risk of cerebrovascular accident in the patients with diabetes (an incidence of 4.2 percent up to the time of discharge, as compared with 0 percent in the stenting group). Furthermore, the difference in favor of CABG in terms of the rate of revascularization at one year was almost twice as great as it was among the patients without diabetes (21.6 percent vs. 12.4 percent), and our multivariable analysis indicates that diabetes was an independent risk factor for major adverse cardiac or cerebrovascular events within one year in the stenting group but not in the surgery group of our study.
Patrick W. Serruys, M.D.
Erasmus University Rotterdam, 3015 GD Rotterdam, the Netherlands
serruys@card.azr. nl - Citing Articles (1)
Citing Articles
1
Ameet Bakhai, Ruaraidh A Hill, Yenal Dundar, Rumona C Dickson, Tom Walley, Ruaraidh A Hill. 2005. Percutaneous transluminal coronary angioplasty with stents versus coronary artery bypass grafting for people with stable angina or acute coronary syndromes. .
CrossRef
