Correspondence
On-Site Cardiac Catheterization Facilities and the Use of Coronary Angiography after Myocardial Infarction
N Engl J Med 1994; 330:289-290January 27, 1994
- Article
To the Editor:
Every et al. (Aug. 19 issue)1 are to be complimented on their article on the association between the availability of cardiac catheterization facilities and the use of coronary angiography and in-hospital mortality among patients admitted with myocardial infarction. Although they rightly identified several limitations of their study and tried to control for a number of sources of bias, incomplete information may be a more serious problem.
In-hospital mortality is not the only end point that leads most physicians to perform angiography in the post-infarction period2,3. To rely on this end point as the linchpin of evaluation may be misleading. Beyond having insufficient power to detect small differences in short-term outcome, the study did not follow patients long enough. Nor did it address issues related to the quality of life, return to work, or long-term cost savings that might be due to early discharge or reductions in the probability of subsequent unnecessary hospital readmissions for chest pain in patients with minimal disease, particularly if they are younger working adults. No data were provided about the availability and patterns of post-infarction exercise testing (as a measure of functional ability), even though many physicians use such tests to make decisions4.
The authors did not address a logical undercurrent of the article: whether (on a case-by-case basis) the higher rate of use of angiography at sites where it is available is inappropriate according to established guidelines for angiography in such cases5. Simply stating that angiography is more often performed in a group of patients does not clarify whether the problem is overuse in one group or underuse in another.
5 ReferencesNowa Omoigui, M.B., B.S., M.P.H.
Eric Topol, M.D.
Cleveland Clinic, Cleveland, OH 441951
Every NR ,Larson EB ,Litwin PE , et al. The association between on-site cardiac catheterization facilities and the use of coronary angiography after acute myocardial infarction. N Engl J Med 1993;329:546-551
Full Text | Web of Science | Medline2
Topol EJ ,Holmes DR ,Rogers WJ . Coronary angiography after thrombolytic therapy for acute myocardial infarction. Ann Intern Med 1991;114:877-885
Web of Science | Medline3
Topol EJ ,Burek K ,O'Neill WW , et al. A randomized controlled trial of hospital discharge three days after myocardial infarction in the era of reperfusion. N Engl J Med 1988;318:1083-1088
Full Text | Web of Science | Medline4
American College of Physicians
Web of Science | Medline5
ACC/AHA guidelines for the early management of patients with acute myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures (Subcommittee to Develop Guidelines for the Early Management of Patients with Acute Myocardial Infarction)
CrossRef | Medline
To the Editor:
Every et al. highlight the dilemma created by the ready availability of high technology. Not only did cardiac catheterization not change short-term mortality, it also exposed patients to the inherent risks of the procedure. Furthermore, it is well known that the results of coronary angiography may produce more questions than answers about management, especially with regard to angioplasty and surgical revascularization. The mere presence of dangerous-looking lesions, which might otherwise never have caused a problem, could lead to interventional treatment when none was needed. Such treatment may not only expose the patient to the complications of the procedure but may also not notably alter the prognosis. Finally, there is considerable evidence to suggest that the degree of coronary-artery stenosis may not correlate with the most active, vulnerable lesions, which lead to plaque rupture and occlusion.1
1 ReferencesAndrew J. Burger, M.D.
Deaconess Hospital, Boston, MA 022151
Patterson DLH ,Treasure T . The culprit coronary artery lesion. Lancet 1991;338:1379-1380
CrossRef | Web of Science | Medline
Author/Editor Response
The authors reply:
To the Editor: We appreciate the comments of Omoigui and Topol. As they note, our study was not intended to measure possible differences in the quality of life or in costs associated with different strategies of treatment for acute infarction, or to evaluate the appropriateness of cardiac catheterization. Rather, it was designed to determine whether the mere availability of technology, apart from the characteristics of the patients treated, influences its use.
Despite consistent findings of well-designed randomized trials that show that conservative treatment of patients who have had an acute myocardial infarction is as effective as more aggressive strategies,1 the use of invasive cardiac procedures after infarction seems almost routine in this country. Our findings suggest that an important reason for this high rate of use is the ready availability of catheterization facilities. Other factors -- for example, physicians' uncertainty, demand by patients, or perhaps financial incentives -- may play a part in decisions to perform these procedures, but they could not be addressed in our analysis.
We are not aware of any previous trials suggesting that routine revascularization after myocardial infarction improves outcome in patients other than those in high-risk subgroups. Without conclusions about direct therapeutic benefit, the only potential benefit of angiography at present is the identification of patients at highest risk. On the basis of our data, it appears that stratification according to risk can be performed equally well by physicians in hospitals with and without catheterization facilities. Since many patients do not have angina after infarction, watchful waiting for symptoms may be the most reasonable strategy for patients at low or moderate risk.
An alternative strategy promoted by some experts, including Dr. Topol, is the “look but don't touch” approach: most patients who have had an infarction undergo angiography, but only a few high-risk patients undergo revascularization2. Yet, the 40 percent revascularization rate that we observed in hospitals with on-site catheterization suggests that this strategy is not what is practiced. Therefore, we agree with Dr. Burger that the routine use of angiography may indeed result from the availability of technology and may lead to higher health care costs without a clear benefit in terms of outcome.
2 ReferencesNathan R. Every, M.D., M.P.H.
W. Douglas Weaver, M.D.
Stephan D. Fihn, M.D., M.P.H.
University of Washington, Seattle, WA 981021
The TIMI Study Group
Full Text | Web of Science | Medline2
Topol EJ ,Holmes DR ,Rogers WJ . Coronary angiography after thrombolytic therapy for acute myocardial infarction. Ann Intern Med 1991;114:877-885
Web of Science | Medline
