Correspondence
Coronary Angioplasty Compared with Bypass Grafting
N Engl J Med 1995; 332:888-890March 30, 1995
- Article
To the Editor:
It is informative to contrast the results of the two clinical trials comparing bypass surgery and angioplasty (Oct. 20 issue)1,2 with the results of a previous observational study.3 Neither clinical trial found any difference in mortality rates at one year between coronary bypass surgery and angioplasty. However, the observational study found that the patients who underwent coronary bypass surgery had a higher mortality rate, even after adjustment for risk factors. The difference was greatest for low-risk patients.
Differences between the studies may have been due to chance, but there are also potential structural reasons for the differences. Advocates of clinical trials will argue that the adjustment procedure for the observational study is of necessity inadequate. It is possible, however, that the results of the clinical trials are applicable to the general population because the medical care or the patients (or both) were not representative. In particular, the in-hospital mortality rates for the patients who underwent coronary bypass surgery were very low — only 1.0 percent in the Emory Angioplasty versus Surgery Trial, as compared with 3 or 4 percent in most studies of such patients.4,5
Before it is accepted that the outcomes for coronary-artery bypass grafting and percutaneous transluminal coronary angioplasty are similar, much more work is needed. The results of the previous observational study showing a substantially higher in-hospital mortality for low-risk patients who underwent coronary-artery bypass grafting than for low-risk patients who underwent angioplasty makes clinical sense and should not be dismissed without careful examination.
5 ReferencesArthur J. Hartz, M.D., Ph.D.
Evelyn M. Kuhn, Ph.D.
Medical College of Wisconsin, Milwaukee, WI 53226-05091
Hamm CW ,Reimers J ,Ischinger T ,Rupprecht H-J ,Berger J ,Bleifeld W . A randomized study of coronary angioplasty compared with bypass surgery in patients with symptomatic multivessel coronary disease. N Engl J Med 1994;331:1037-1043
Full Text | Web of Science | Medline2
King SB III ,Lembo NJ ,Weintraub WS , et al. A randomized trial comparing coronary angioplasty with coronary bypass surgery. N Engl J Med 1994;331:1044-1050
Full Text | Web of Science | Medline3
Hartz AJ ,Kuhn EM ,Pryor DB , et al. Mortality after coronary angioplasty and coronary artery bypass surgery (the national Medicare experience). Am J Cardiol 1992;70:179-185
CrossRef | Web of Science | Medline4
Hannan EL ,Bernard HR ,O'Donnell JF ,Kilburn H Jr . A methodology for targeting hospital cases for quality of care record reviews. Am J Public Health 1989;79:430-436
CrossRef | Web of Science | Medline5
O'Connor GT ,Plume SK ,Olmstead EM , et al. A regional prospective study of in-hospital mortality associated with coronary artery bypass grafting. JAMA 1991;266:803-809
CrossRef | Web of Science | Medline
To the Editor:
In their editorial on the Emory Angioplasty versus Surgery Trial (EAST),1 Hillis and Rutherford (Oct. 20 issue)2 give a very reasonable and balanced overview with some broad guidelines for management. However, I am concerned that one of their recommendations is not supported by the data. They recommend that patients who have multivessel disease involving the proximal left anterior descending artery undergo surgery because it “improves survival.” It must be remembered that although the article they cite does, in fact, suggest that bypass surgery improves survival in this subgroup of patients,3 the group used for comparison was patients treated with medical therapy alone, not with another revascularization option such as angioplasty. Several studies have shown that angioplasty of the proximal left anterior descending artery is as safe and effective as bypass surgery, even in patients with occlusion of the right coronary artery.4 In fact the EAST study specifically addressed this issue, and over 70 percent of the patients in both the angioplasty and surgery groups had serious lesions of the proximal left anterior descending artery.1 Thus, in this study, one of the largest, most carefully controlled assessments of revascularization options in patients with multivessel disease and stenoses of the proximal left anterior descending artery, survival and overall outcome were similar for angioplasty and coronary bypass surgery. In view of these data, it is surprising that the editorial would recommend that these patients specifically undergo cardiac surgery.
4 ReferencesAndrew J. Doorey, M.D.
Medical Center of Delaware, Newark, DE 197181
King SB III ,Lembo NJ ,Weintraub WS , et al. A randomized trial comparing coronary angioplasty with coronary bypass surgery. N Engl J Med 1994;331:1044-1050
Full Text | Web of Science | Medline2
Hillis LD ,Rutherford JD . Coronary angioplasty compared with bypass grafting. N Engl J Med 1994;331:1086-1087
Full Text | Web of Science | Medline3
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
CrossRef | Web of Science | Medline4
Lafont A ,Dimas AP ,Grigera F ,Pearce G ,Webb M ,Whitlow PL . Percutaneous transluminal coronary angioplasty of one major coronary artery when the contralateral vessel is occluded. J Am Coll Cardiol 1993;22:1298-1303
CrossRef | Web of Science | Medline
To the Editor:
In a day of cost consciousness, the costs relating to the necessity of performing two or more sequential procedures were not mentioned at all in the articles comparing coronary angioplasty with coronary bypass surgery. The initial cost of coronary bypass grafting is probably not a great deal higher than that of angioplasty. However, no one seems to have taken into account the costs of further procedures and hospitalizations in the angioplasty group as well as the greater requirement for medication.
I have scanned both the editorial and the two articles for any comment on this, no matter how obscure. Unless I missed it, it is not present. Does this omission represent a form of bias that is unrecognized?
Josef E. Fischer, M.D.
University of Cincinnati Medical Center, Cincinnati, OH 45267-0558To the Editor:
In their editorial, Drs. Hillis and Rutherford implied that coronary-artery bypass grafting does not prolong survival among patients with three-vessel disease and normal left ventricular function. The European Coronary Surgery Study Group reported1 a significant survival benefit in favor of surgery in a cohort of patients with three-vessel disease and preserved left ventricular function. The five-year survival rate was 80 percent in the medical-therapy group, as compared with 92 percent in the surgery group. Similarly, the eight-year survival rate was 73 percent with medical therapy and 91 percent with surgery. In an overview of randomized trials, Yusuf et al.2 found that reductions in the risk of death at 5 and 10 years with coronary-artery bypass grafting as opposed to medical therapy were similar in patients with left ventricular dysfunction and in patients who had normal left ventricular function. Regression analysis of the interaction between ejection fraction and the treatment effect at five years did not indicate any influence of ventricular function on the benefit of surgery. On the basis of these data, in patients with three-vessel disease, angina, and preserved left ventricular function, aggressive revascularization improves survival more than does medical therapy.
2 ReferencesMassoud A. Leesar, M.D.
S. Abraham Joseph, M.D.
Charles R. Prince, M.D.
University of Louisville, Louisville, KY 402921
Varnauskas E, European Coronary Surgery Study Group
CrossRef2
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
CrossRef | Web of Science | Medline
Author/Editor Response
The authors reply:
To the Editor: We appreciate the comment of Drs. Hartz and Kuhn concerning the mortality rates in patients who have undergone percutaneous transluminal coronary angioplasty and coronary-artery bypass grafting. In our view, any discrepancy between previous observational studies and the recently published randomized trials1-3 do not represent a conflict but rather underscore the necessity for randomized studies. However, the German Angioplasty Bypass Surgery Investigation was not sufficiently large to detect whether there are differences in mortality. A meta-analysis of all randomized trials is under way and will provide a conclusive answer to this crucial question.
We agree with Dr. Fischer that cost is an important issue, and it was considered in our protocol.2 The true costs may vary between countries because of differences in wages and prices. However, a close approximation can be made. Our cost analysis of the German Angioplasty Bypass Surgery Investigation based on the 1994 price index revealed that the initial hospitalization was 49 percent less expensive for patients undergoing percutaneous transluminal coronary angioplasty than for patients undergoing coronary-artery bypass grafting. Because of the higher rate of subsequent interventions in the angioplasty group, the difference was reduced to approximately 25 percent after one and two years of follow-up. The Randomised Intervention Treatment of Angina trial reported similar findings.4
4 ReferencesChristian W. Hamm, M.D.
Jürgen Berger, Ph.D.
Peter Kalmar, M.D.
University Hospital Eppendorf, 20246 Hamburg, Germany1
RITA Trial Participants
CrossRef | Web of Science | Medline2
Hamm CW ,Reimers J ,Ischinger T ,Rupprecht H-J ,Berger J ,Bleifeld W . A randomized study of coronary angioplasty compared with bypass surgery in patients with symptomatic multivessel coronary disease. N Engl J Med 1994;331:1037-1043
Full Text | Web of Science | Medline3
King SB III ,Lembo NJ ,Weintraub WS , et al. A randomized trial comparing coronary angioplasty with coronary bypass surgery. N Engl J Med 1994;331:1044-1050
Full Text | Web of Science | Medline4
Sculpher MJ ,Seed P ,Henderson RA , et al. Health service costs of coronary angioplasty and coronary artery bypass surgery: the Randomised Intervention Treatment of Angina (RITA) trial. Lancet 1994;344:927-930
CrossRef | Web of Science | Medline
Author/Editor Response
Drs. Hartz and Kuhn suggest that the surgical mortality rate in the EAST study is unusually low. It is true that the surgery was performed in a high-volume center (Emory University Hospital) by experienced operators, and the results therefore apply to that type of institution. That the patients in the trial were not at low risk is supported by the fact that the surgical mortality among 270 patients who met the entry criteria and who underwent surgery at Emory during the recruitment phase of the trial was not higher than that in the patients in the EAST study (unpublished data). Observations such as those of Hartz et al.1 continue to provide valuable insights into what is going on in medical practice but do not establish the value of one procedure over another.
Dr. Doorey's observation that the EAST study had a high percentage of patients with disease of the proximal left anterior descending coronary artery and nonetheless did not show a survival benefit for surgery is correct. Further insights from the Bypass Angioplasty Revascularization Investigation (BARI) trial may help expand our understanding of the outcome in this subgroup of patients treated by angioplasty or surgery.
Dr. Fischer was concerned about the lack of an economic analysis in the report of the trial. Such an analysis is difficult but has been performed (unpublished data) and should be of great interest to Dr. Fischer and others. The observation that an excess of repeated procedures in the angioplasty arm significantly diminishes the cost advantage of angioplasty is correct. Within the time frame of the study, however, the medical cost of angioplasty did not quite reach the cost of bypass surgery, despite much greater use of staged procedures in the trial than is the current practice. Future economic comparisons, however, will need to take into account changing economic realities and practice patterns.
1 ReferencesSpencer B. King, III, M.D.
Emory University Hospital, Atlanta, GA 303221
Hartz AJ ,Kuhn EM ,Pryor DB , et al. Mortality after coronary angioplasty and coronary artery bypass surgery (the national Medicare experience). Am J Cardiol 1992;70:179-185
CrossRef | Web of Science | Medline
Author/Editor Response
As Dr. Doorey notes, the European Coronary Surgery Study1 showed that in patients with stable angina pectoris, a normal left ventricular ejection fraction, and multivessel coronary artery disease in whom the proximal portion of the left anterior descending artery was substantially narrowed, survival 10 years after randomization was better with bypass grafting than with medical therapy. In the EAST study,2 in which about 70 percent of the enrollees had narrowing of the proximal left anterior descending artery, survival three years after randomization was similar in those who underwent bypass grafting and in those who underwent balloon angioplasty. At present, it is unknown whether long-term survival will be similar with angioplasty and surgery in patients with multivessel disease in whom the proximal portion of the left anterior descending artery is substantially narrowed. Furthermore, it is important to reiterate that only 8 percent of patients with multivessel coronary artery disease who were screened for the EAST study were, in fact, enrolled, and most of those who were excluded were deemed ineligible because of a contraindication to angioplasty. In short, although either procedure may be appropriate in selected subjects, we believe that most patients with multivessel coronary artery disease who require revascularization are not ideal candidates for balloon angioplasty and are often better suited for bypass grafting.
Although Leesar et al. contend that “in patients with three-vessel disease, angina, and preserved left ventricular function, aggressive revascularization improves survival more than does medical therapy,” there are only limited data to support this contention. The European Coronary Surgery Study Group1 emphasized that the presence of clinically important narrowing of the proximal left anterior descending artery in patients with multivessel coronary artery disease was the strongest predictor of a poor prognosis with medical therapy and an improved prognosis with bypass grafting. In the Veterans Administration Cooperative Study3 and the Coronary Artery Surgery Study,4 both performed in the United States, survival was similar in patients with three-vessel coronary artery disease and a normal left ventricular ejection fraction regardless of whether they were treated surgically or medically. In our opinion, bypass grafting should not be performed in patients with normal left ventricular function and three-vessel coronary artery disease without narrowing of the proximal left anterior descending artery solely in an attempt to improve survival.
4 ReferencesL. David Hillis, M.D.
John D. Rutherford, M.B.
University of Texas Southwestern Medical Center, Dallas, TX 752351
Varnauskas E, European Coronary Surgery Study Group
Full Text | Web of Science | Medline2
King SB III ,Lembo NJ ,Weintraub WS , et al. A randomized trial comparing coronary angioplasty with coronary bypass surgery. N Engl J Med 1994;331:1044-1050
Full Text | Web of Science | Medline3
The Veterans Administration Coronary Artery Bypass Surgery Cooperative Study Group
Full Text | Web of Science | Medline4
Alderman EL ,Bourassa MG ,Cohen LS , et al. Ten-year follow-up of survival and myocardial infarction in the randomized Coronary Artery Surgery Study. Circulation 1990;82:1629-1646
CrossRef | Web of Science | Medline
- Citing Articles (1)
Citing Articles
1
Benson, Kjell, Hartz, Arthur J., . (2000) A Comparison of Observational Studies and Randomized, Controlled Trials. New England Journal of Medicine 342:25, 1878-1886
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