July 4, 2008 An analysis of previous studies indicates that among men and high-risk women with a certain type of heart attack or angina an invasive treatment strategy (such as cardiac catheterization) is associated with reduced risk of rehospitalization, heart attack or death, whereas low-risk women may have an increased risk of heart attack or death with this treatment, according to a new article.
Although an invasive strategy is frequently used in patients with unstable angina and non--ST-segment elevation myocardial infarction (NSTEMI; a type of heart attack with certain findings on an electrocardiogram), data from some trials suggest that this strategy may not benefit women, with a possible higher risk of death or heart attack, according to background information in the article. "Thus, the benefit of an invasive strategy in women remains unclear. However, individual trials have not been large enough to explore outcomes reliably within subgroups," the authors write.
For this study, an invasive strategy was defined as the referral of all patients with heart attacks and unstable angina for cardiac catheterization (a procedure that allows physicians to find and open potential blockages in the coronary arteries to help prevent heart attacks and death) prior to hospital discharge. A conservative treatment strategy was defined as a primary strategy of medical management and subsequent catheterization only for those patients with ongoing chest pain or a positive stress test.
Michelle O'Donoghue, M.D., of Brigham and Women's Hospital and Massachusetts General Hospital, Boston, and colleagues conducted a meta-analysis of randomized trials to examine the benefits and risks of an invasive strategy in women vs. in men with unstable heart disease. Through a review of medical literature, the researchers identified eight randomized trials. Data were combined for these trials, and the incidence of death, myocardial infarction (MI; heart attack), or rehospitalization with ACS (unstable angina or heart attack) were available for 10,150 patients, including 3,075 women and 7,075 men.
Women who received an invasive strategy had a 19 percent lower risk for the composite of death, MI, or ACS, compared to women who received a conservative strategy (21.1 percent vs. 25.0 percent); men had a 27 percent lower risk for the composite of death, MI, or ACS, compared to men who received a conservative strategy (21.2 percent vs. 26.3 percent).
Among high-risk biomarker-positive women, an invasive strategy was associated with a 33 percent lower odds of death, MI, or ACS and a nonsignificant 23 percent lower odds of death or MI. In contrast, an invasive strategy was not associated with a significant reduction in the triple composite end point in biomarker-negative women and was associated with a nonsignificant 35 percent higher odds of death or MI. Among men, the risk for death, MI, or ACS was 44 percent lower if biomarker-positive and 28 percent lower if biomarker-negative.
"Our data provide evidence to support the updated American College of Cardiology/American Heart Association guidelines that now recommend that a conservative strategy be used in low-risk women with non--ST-segment elevation acute coronary syndromes (NSTE ACS)," the authors write.
"Combination of these data enabled us to explore the association of sex with outcomes both overall and within high-risk subgroups, whereas individual studies may be insufficiently powered in this regard. Future investigations should include novel methods for identifying women at high-risk of adverse outcomes after NSTE ACS and whose risk could be modifiable with an invasive approach."
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- Michelle O'Donoghue; William E. Boden; Eugene Braunwald; Christopher P. Cannon; Tim C. Clayton; Robbert J. de Winter; Keith A. A. Fox; Bo Lagerqvist; Peter A. McCullough; Sabina A. Murphy; Rudolf Spacek; Eva Swahn; Lars Wallentin; Fons Windhausen; Marc S. Sabatine. Early Invasive vs Conservative Treatment Strategies in Women and Men With Unstable Angina and Non-ST-Segment Elevation Myocardial Infarction: A Meta-analysis. JAMA, 2008;300(1):71-80 [link]
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