Coronary Angiography in Acute Coronary Ischemic Syndromes: Some Divergent Views
ABSTRACTS & COMMENTARY
Synopsis: Considerable convergence between the expert panel and survey estimates indicate that "evaluations of medical practice based on the judgment of expert panels can closely reflect the beliefs and experiences of practicing physicians for well-studied procedures."
Sources: Boden WE, et al. N Engl J Med 1998;338: 1785-1792; Lange and Hillis. N Engl J Med 1998;338: 1838-1839; Ayanian JZ, et al. N Engl J Med 1998;338: 1896-1904.
Two recent commentaries in The New England Journal of Medicine discussed the use of coronary angiography in the United States with respect to appropriateness, variability of procedure use among physicians, and clinical outcomes. Investigators from Brigham and Women's Hospital and the Harvard School of Public Health assessed the views of practicing physicians from five states (California, New York, Texas, Florida, Pennsylvania) as to the appropriateness of using coronary angiography following acute myocardial infarction. Twenty prespecified clinical scenarios were evaluated by a large cohort of cardiologists, internists, and family practitioners. The responses were compared to those of an expert panel who selected the indications to be assessed and rated each on an appropriateness scale. This approach is similar to a large series of publications of the RAND-UCLA consortium assessing how physicians approach a variety of clinical problems. The goals of the present study were to see whether physicians agreed or disagreed with the expert panel, as well as to explore differences in appropriateness ratings related to a variety of factors, including physician speciality, managed care membership, and a number of other parameters.
From a random sample of more than 4300 physicians, four groups were chosen from each of the four states and were asked to respond to a survey instrument consisting of 20 potential clinical indications for angiographs. Each was rated on an appropriateness scale. The clinical scenarios were comprised of patients with acute infarction who did or did not receive thrombolytic therapy, who did or did not have complications, and whose symptoms were less than six hours or more than 12 hours in duration; separate assessments were made for patients younger than and older than 75 years of age. The results indicated a surprising level of agreement among the physicians and the expert panel with respect to appropriateness scores. Thus, of the 1058 surveys received (an approximate 50% response rate), there was close agreement for patients younger than 75 years, with somewhat more divergent views in the older population. In individuals older than 75 years, practicing physicians were more likely to recommend angiography than the expert panel. Cardiologists were more likely to select an angiographic approach than primary care physicians. Likewise, cardiologists involved in cardiac catheterization were more aggressive with respect to angiography than noninvasive cardiologists, who were more similar to the internists and family practitioners.
All cardiologists were more aggessive with respect to angiography for complicated myocardial infarction (MI) cases, whereas, for uncomplicated infarcts, invasive cardiologists favored angiography more than noninvasive cardiologists or primary care physicians. Whether a patient was in a hospital with a catheterization laboratory and cardiac surgical facilities also influenced choices in uncomplicated subjects; physicians were more likely to recommend angiography if a catheterization laboratory was available. However, for complicated infarcts, there was no difference in angiography recommendations among the three groups of physicians. Geographic location and HMO membership had only a minor influence on decision making. While the authors conclude that considerable convergence between the expert panel and survey estimates indicate that "evaluations of medical practice based on the judgment of expert panels can closely reflect the beliefs and experiences of practicing physicians for well-studied procedures," considerable variation existed among the physicians that appeared to be related to professional characteristics.
Concordance was greater for younger individuals and for complicated infarctions. More uncertainty appeared for patients older than 75 years as well as those who had uncomplicated MI, probably reflecting the lack of randomized trial information in the elderly and possibly a failure to apply available clinical trial data to decisions regarding angiography in uncomplicated patients. The findings that recommendations on angiographic appropriateness differ among physicians with different specialties mirrors a number of other reports in the literature, as does the observation that invasive and noninvasive cardiologists may approach the same clinical scenario differently with respect to angiography. Given that angiography is the strongest predictor of subsequent coronary revascularization, it is reasonable to extrapolate these findings to physician beliefs as to the efficacy of revascularization vs. a medical or "conservative" approach.
In an editorial published in concert with the VANQWISH trial of invasive vs. conservative therapy in individuals with non-Q MI, Lange and Hillis dissect the four large, prospective, randomized trials comparing aggressive and conservative therapy for acute coronary syndromes and conclude that U.S. cardiologists use angiography and revascularization out of proportion to other countries-and not always in conjunction with established clinical guidelines. The authors state that "a substantial number of patients with acute coronary syndromes undergo coronary angiography and revascularization without a clear indication." They call for physician decision making to be guided by well-performed randomized clinical trials, such as VANQWISH. The Harvard survey would indicate that such decision making does take place when physicians are presented with a hypothetical survey document, although this may not necessarily translate into clinical practice. There is considerable concordance overall for sicker or complicated subjects proceeding to angiography (e.g., ischemia, CHF). Both the Harvard survey study and the original GUSTO trial (N Engl J Med, 1993;329:673) suggest that patient and family preference for angiography influences decision making.
In conclusion, it is becoming increasingly clear that the type of physician taking care of a patient with an acute coronary syndrome, the nature of the facility in which the individual is hospitalized, and family and patient wishes are strong influences on decisions for or against routine angiography in uncomplicated MI patients. It has only been in the last year or two that the dialogue has become public with respect to a so-called conservative or medical approach vs. an invasive or aggressive policy in such patients. While the Harvard survey and prior RAND panel experience indicates that physicians can and will make appropriate decisions that are concordant with randomized clinical trial data when presented with an instrument asking for a considered best judgment, it seems obvious that clinical practice does not necessarily mirror these academic and artificial approaches. Lange and Hillis emphasize that in the United States, there is an increased use of angiography and revascularization without conclusive proof that short- and long-term clinical outcomes are always improved by such a strategy.
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