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![[SYMPOSIUM]](../../../graphics/sym_logo.gif){kind=logo} COMMENTARY: SYMPOSIUM ON ACUTE CORONARY SYNDROMESAvoid the rush to judgment in acute coronary syndromesPrakash Deedwania, MD VOL 118 / NO 3 / SEPTEMBER 2005 / POSTGRADUATE MEDICINE
The author discloses no financial interests in this article.
Deedwania P. Avoid the rush to judgment in acute coronary syndromes. Postgrad Med 2005;118(3):11-4, 22
Click here to see a glossary of terms used in this symposium. Acute coronary syndromes (ACS) are among the most common cardiac emergencies encountered in clinical practice today. Each year in the United States, an estimated 2 million hospitalizations are related to ACS. This number is rising in part because of the increasing use of ultrasensitive markers of cardiac necrosis, such as cardiac troponins. In the past, patients with transmural MI or STEMI accounted for most ACS admissions. Currently, though, most admissions are related to NSTEMI or unstable angina, or both. Management of STEMI is fairly streamlined and has been well summarized in the recent STEMI guidelines (1). However, physicians constantly face the challenge of deciding the most appropriate diagnostic and therapeutic approach (or approaches) in patients with NSTEMI--a population that includes diverse groups ranging from patients with new-onset angina to those with a hemodynamically compromised state in the setting of ACS (2-5). This challenge is complicated by the plethora of choices listed in the available guidelines, some of which are based on opinion rather than hard evidence (2,3). The situation is compounded because of the availability of very sensitive markers, such as troponins, which often produce a positive result in the absence of clinical manifestations of ACS (6-13). Additionally, the increasing emphasis on a routine early invasive approach in most patients with NSTEMI is having a substantial impact on healthcare cost without necessarily improving survival rates or reducing the risk of future MI. Because of the obvious clinical implications of diagnostic and therapeutic strategies in patients with ACS, the symposium articles in this issue (pages 15 and 23) address in detail the logical, evidence-based approach to these aspects of this frequently encountered problem. Both articles emphasize the need for physicians to critically examine available data in the context of the patient's clinical presentation to avoid rushing into any unnecessary interventions. Lessons from a clinical caseTo further highlight the points discussed in these articles, the following clinical scenario emphasizes that ACS is a heterogeneous condition that can occur in diverse clinical settings that demand different diagnostic and therapeutic approaches. Figure 1a shows a 12-lead ECG from an elderly man with known hypertension and CAD who presented to the hospital with diarrhea and dehydration. Because the patient had evidence of orthostatic hypotension, he was not given his usual prescribed beta-blocker and nitrate therapies. The ECG clearly showed evidence of anterior myocardial ischemia, and the patient complained of a vague burning sensation in the epigastrium, which was thought to be related to gastritis. However, the patient had a slight elevation in cardiac troponin level, which would have entailed a diagnosis of NSTEMI. Because of the obvious clinical scenario consistent with coronary hypoperfusion secondary to hypovolemia and associated hypotension, the patient was given fluids intravenously, after which his beta-blocker and nitrate therapies were resumed. Figure 1b shows the second 12-lead ECG, which demonstrated nearly complete resolution of ST-segment depression in the anterior leads, along with relief of epigastric burning. This case clearly illustrates one end of the spectrum of patients with NSTEMI, who obviously need correction of their underlying problem rather than being rushed for coronary intervention. On the other hand, there are patients with NSTEMI who have multiple markers of high risk (table 1), which would necessitate an interventional approach to minimize the risk of a coronary event (3,14).
Therefore, it is not only prudent but essential to evaluate the risk category in each patient to derive the most rational approach, rather than apply a uniform invasive strategy in all patients with NSTEMI. One size does not fit allThe illustrative case just discussed, as well as considerable data that have become available in recent years, indicates that a wide range of therapeutic choices is available for patients with NSTEMI or unstable angina. It is important to note that appropriate aggressive medical treatment, including the proven anti-ischemic and antithrombotic drugs, is the cornerstone of the initial therapeutic strategy for all patients with ACS (2,3,13). The subsequent approach should depend on the response of the patient to initial medical therapy and on risk stratification, in which the predictive variables in table 1 are used to identify high-risk patients. These variables have been derived from a number of different sources. However, most of them have been evaluated only for determining short-term risk, and their utility in prospectively identifying higher-risk patients who will gain long-term benefit from an early invasive approach remains to be established (14). Although there is considerable enthusiasm for taking the early invasive approach in all patients with NSTEMI or unstable angina, this viewpoint is not supported by findings from available randomized trials (4,5,7-13). Dr Carbajal and I highlight specific examples of such trial results in the article beginning on page 23. It is important to emphasize again that many trials used to support the benefits of an early invasive approach have limitations because of potential flaws in trial design and concomitant use of multiple therapies. Furthermore, most of these trials have shown a reduction in composite end points (which often included subjective and soft end points such as hospitalization or need for revascularization, or both) with little evidence to demonstrate substantial benefit in reducing the risk of MI or death (4,5,7-13). These facts have led to ongoing controversy about the utility of a routine early invasive approach in unselected patients with NSTEMI. This issue is compounded by the fact that several recent observational studies have demonstrated the lack of benefit--and even potential for harm--with a routine early invasive approach in all patients with NSTE-ACS (4,5,11-13). These points clearly emphasize that a single predefined approach is neither appropriate nor beneficial for all patients with NSTE-ACS. Physicians must continue to use the totality of available evidence from clinical evaluation, initial response to medical therapy, and results of diagnostic tests to identify the most appropriate therapeutic strategy for a given patient. Because of the increasing prevalence of NSTE-ACS, it is incumbent on physicians to use the most cost-effective, rational approach in patients with these syndromes. Lastly, it is prudent to remind ourselves of the Hippocratic Oath: above all, do no harm.
References
Dr Deedwania, coordinator of this symposium, is professor of medicine, University of California, San Francisco, School of Medicine, and chief, cardiology division, Veterans Affairs Central California Health Care System, Fresno. Correspondence: Prakash Deedwania, MD, Cardiology Division, Veterans Affairs Central California Health Care System, E224, 2615 E Clinton Ave, Fresno, CA 93703. E-mail: deed@fresno.ucsf.edu.
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