Correspondence
Underuse of Coronary Revascularization Procedures
N Engl J Med 2001; 345:294-296July 26, 2001
- Article
To the Editor:
Hemingway et al. (March 1 issue)1 conclude that, according to criteria set by an expert panel, coronary revascularization procedures are underused; patients who should have undergone a surgical intervention were incorrectly treated medically. But what is the basis for the criteria of the expert panel?
Current recommendations regarding surgery are derived largely from data from the 1970s and early 1980s,2 which preceded the development of aggressive medical therapies both for the management of ischemia (e.g., nitrates and beta-blockers) and for the reduction of risk factors (especially cholesterol levels). Even the most recent study comparing surgical treatment with medical management, conducted in the mid-1990s, did not include the goal of aggressive lipid lowering.3 Less than 25 percent of the patients in the medical-treatment group in the study by Hemingway et al. were receiving hypocholesterolemic agents. Yet it is clear from other data that aggressive lipid management leads to clear benefit within six months of initiating therapy.4,5 As compared with coronary angioplasty, aggressive lipid lowering with 80 mg of atorvastatin (bringing the ratio of total cholesterol to high-density lipoprotein cholesterol down to 2.8) decreased the rate of ischemic events by 36 percent over a period of 18 months.4 Since no trial has compared state-of-the-art medical management (especially aggressive lipid lowering) with surgery, it is difficult to conclude that coronary revascularization is underutilized, especially for patients with chronic cardiac symptoms.
5 ReferencesGeoffrey A. Modest, M.D.
Upham's Corner Health Center, Dorchester, MA 02125
gmodest@partners.org 1
Hemingway H ,Crook AM ,Feder G , et al. Underuse of coronary revascularization procedures in patients considered appropriate candidates for revascularization. N Engl J Med 2001;344:645-654
Full Text | Web of Science | Medline2
Eagle KA ,Guyton RA ,Davidoff R , et al. ACC/AHA guidelines for coronary artery bypass graft surgery: executive summary and recommendations: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1991 Guidelines for Coronary Artery Bypass Graft Surgery). Circulation 1999;100:1464-1480
Web of Science | Medline3
Davies RF ,Goldberg AD ,Forman S , et al. Asymptomatic Cardiac Ischemia Pilot (ACIP) study two-year follow-up: outcomes of patients randomized to initial strategies of medical therapy versus revascularization. Circulation 1997;95:2037-2043
Web of Science | Medline4
Pitt B ,Waters D ,Brown WV , et al. Aggressive lipid-lowering therapy compared with angioplasty in stable coronary artery disease. N Engl J Med 1999;341:70-76
Full Text | Web of Science | Medline5
The Pravastatin Multinational Study Group for Cardiac Risk Patients
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To the Editor:
Hemingway et al. conclude that patients who would be considered by an independent panel to be appropriate candidates for coronary-artery bypass grafting (CABG) have a greater risk of adverse outcomes if they are treated medically than if they receive CABG. This conclusion may be valid if the base-line characteristics of the medically and surgically treated patients are uniform. However, important differences existed in this study.
First, there were significantly more patients with heart failure and fewer treated with beta-blockers in the medically treated group. Beta-blockers reduce mortality among patients with heart failure,1 so the differences in mortality that were observed in the study could be associated with their underuse. Second, the medically treated group included a higher percentage of patients with diabetes and patients with previous myocardial infarction. The mortality rate among patients with diabetes with multivessel coronary disease is reduced with the use of CABG.2 Previous CABG also has a cardioprotective effect in patients with diabetes who have a myocardial infarction.3 Thus, the overall results may be skewed by a significant effect on a small group of high-risk patients in whom revascularization has proven benefit.
3 ReferencesKausik K. Ray, M.R.C.P.
Paul J. Sheridan, M.R.C.P.
Koo H. Chan, M.R.C.P.
University of Sheffield, Sheffield S5 7AU, United Kingdom
k.k. ray@sheffield. ac. uk 1
The Cardiac Insufficiency Bisoprolol Study II (CIBIS-II): a randomised trial. Lancet 1999;353:9-13
CrossRef | Web of Science | Medline2
Seven-year outcome in the Bypass Angioplasty Revascularization Investigation (BARI) by treatment and diabetic status. J Am Coll Cardiol 2000;35:1122-1129
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Detre KM ,Lombardero MS ,Brooks MM , et al. The effect of previous coronary-artery bypass surgery on the prognosis of patients with diabetes who have acute myocardial infarction. N Engl J Med 2000;342:989-997
Full Text | Web of Science | Medline
To the Editor:
I am concerned that the article by Hemingway et al. may overstate the benefits of cardiac revascularization because of a possible bias in the data resulting from the failure to consider the social class of patients. The group that received medical treatment may have included a disproportionate number of patients from lower socioeconomic classes. I base this conclusion on the fact that nonwhite patients were overrepresented in the medical-treatment groups as compared with the groups assigned to percutaneous transluminal coronary angioplasty (PTCA) (17 percent vs. 12 percent) and CABG (20 percent vs. 14 percent) and the fact that in the United States nonwhite race is associated with lower social class,1 which I believe is also the case in the United Kingdom.
There is a well-established association between socioeconomic class and death rates from heart disease.2,3 Including a disproportionate number of lower-class patients in a study group can be expected to result in increased death rates, independently of the treatment the patients receive. Until the authors can control for differences in social class between their treatment groups, their conclusions about improved outcomes with revascularization may need to be muted somewhat.
In addition, it appears that in the United Kingdom, as in the United States,4 nonwhite patients with heart disease are referred for revascularization less often than white patients with a similar level of disease. This finding is as important as the difference in treatment outcomes. The adverse health effects of racial bias in the availability of revascularization procedures far outweigh the effects of underuse of these procedures among predominantly white, upper-class patients.
4 ReferencesDonald A. Barr, M.D., Ph.D.
Stanford University, Stanford, CA 94305-2160
barr@stanford.edu 1
Bureau of the Census. Money income in the United States: 1999. Current population reports. Series P-60. No. 209. Washington, D.C.: Government Printing Office, 2000.
2
Black D, Morris JN, Smith C, Townsend P, Whitehead M. Inequalities in health: the Black Report: the health divide. London: Penguin, 1988.
3
Marmot MG ,Kogevinas M ,Elston MA . Social/economic status and disease. Annu Rev Public Health 1987;8:111-135
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Peterson ED ,Shaw LK ,DeLong ER ,Pryor DB ,Califf RM ,Mark DB . Racial variation in the use of coronary-revascularization procedures: are the differences real? Do they matter? N Engl J Med 1997;336:480-486
Full Text | Web of Science | Medline
To the Editor:
Hemingway et al. report data suggesting that the use of explicit measures of appropriateness may result in a more judicious use of revascularization procedures. We wonder whether patients in this study were assigned to the CABG group on an intention-to-treat basis or on the basis of the treatment they received. Specifically, if a patient who was going to receive CABG died before he was able to undergo surgery, in which group was he counted? We note in Figure 1 of the article that large numbers of deaths or nonfatal myocardial infarctions occurred soon after the initial angiography was performed, particularly in the medically treated group. Thus, the failure to categorize the patients according to the intention-to-treat principle would bias the results of this study against medical treatment.
Aarif Y. Khakoo, M.D.
Darius A. Rastegar, M.D.
Johns Hopkins Bayview Medical Center, Baltimore, MD 21224
akhakoo@jhmi.edu Author/Editor Response
The authors reply:
To the Editor: The correspondents raise important issues in interpreting the finding in the Appropriateness of Coronary Revascularization study of the underuse of CABG after angiography. However, these further considerations (the subjects of detailed reports published elsewhere) do not alter the main conclusion of the study. We report here hazard ratios for death among patients in whom CABG was deemed appropriate, comparing patients who received no revascularization with those who underwent CABG. Hazard ratios greater than 1.0 denote an underuse of CABG.
In order to address the suggestion made by both Modest and Ray et al. that optimizing medical management might alter our findings, we carried out subgroup analyses among patients who were taking a statin or a beta-blocker and calculated hazard ratios of 4.47 (P=0.002) and 3.79 (P<0.001), respectively. The similarity between these hazard ratios and the ratio of 4.96 we reported suggests that optimizing medical management may make little difference in the effect of the underuse of CABG on mortality.
Ray and colleagues note an excess of diabetes, myocardial infarction, and heart failure among the medically treated group. Adjustment for these factors (in Table 3, Table 4 and Table 5 of our article) had little effect on our results; analyses that excluded patients with any of these coexisting conditions actually found a stronger effect of the underuse of CABG on mortality (hazard ratio, 5.97; P<0.001).
As Barr suggested, we have now controlled for social class and race; neither of these factors attenuated the effect of the underuse of CABG on mortality, with hazard ratios of 4.49 (P<0.001) and 3.89 (P<0.001), respectively. We found no evidence that South Asian patients were less likely than whites either to be deemed appropriate candidates for revascularization or to be referred for a revascularization procedure.
The primary, prestated intention of our study was to compare the clinical outcomes among patients who received a given treatment for coronary disease with the outcomes among those who did not, according to prespecified levels of appropriateness. Because the timeliness with which patients undergo a revascularization procedure is a crucial consideration for any investigation of the magnitude of underuse, any patient who died before receiving revascularization was included in the analyses as a member of the medical group. To do otherwise would be to create a conservative bias. However, our results are robust enough to support an intention-to-treat analysis of the type suggested by Khakoo and Rastegar. Among those classified as appropriate candidates for CABG, the patients for whom medical treatment was intended had higher mortality rates than those for whom CABG was intended, regardless of the actual therapy they received (hazard ratio, 2.05; P=0.004).
The challenge now is to determine the extent to which clinical outcomes are improved when suitably updated appropriateness criteria for angiography1 and revascularization are used to support clinical decisions in routine practice; the application of these criteria should not be delayed.2
2 ReferencesHarry Hemingway, M.R.C.P.
Angela M. Crook, M.Sc.
Kensington & Chelsea and Westminster Health Authority, London W2 6LX, United Kingdom
harry.hemingway@ha. kcw-ha. nthames. nhs. uk Adam D. Timmis, M.D., F.R.C.P.
Barts and the London NHS Trust, London E2 9JX, United Kingdom1
Hemingway H ,Crook AM ,Banerjee S , et al. Hypothetical ratings of coronary angiography appropriateness: are they associated with actual angiographic findings, mortality, and revascularisation rate? The ACRE study. Heart 2001;85:672-679
CrossRef | Web of Science | Medline2
Shekelle PG . Are appropriateness criteria ready for use in clinical practice? N Engl J Med 2001;344:677-678
Full Text | Web of Science | Medline
