Low-risk Women with Unstable Angina and NSTEMI Might be Better off with Medical Therapy than Invasive Treatment

July 2, 2008 By Vijayalakshmi Kunadian MBBS MD MRCP [mailto:vkunadian@perfuse.org]

JAMA- Boston, MA: A meta-analysis suggests that an invasive strategy offered comparable benefits among men and high-risk women following NSTEMI in reducing death, myocardial infarction and re-hospitalization with acute coronary syndrome and recommends conservative strategy for low-risk women.

A recent study published in JAMA investigated the benefits of invasive strategy and conservative strategy among men and women following a non ST elevation acute coronary syndrome (NSTE ACS). This meta-analysis consisted of 8 clinical trials selected from 18 trials that were identified through literature search. The eight studies were TIMI IIIB, MATE, VANQUISH, FRISC II, TACTICS-TIMI 18, VINO, RITA 3 and ICTUS. Patients who had coronary angiography before enrollment, stable angina were excluded from the study.

The study consisted of a total of 10,412 patients who underwent invasive (women vs. men: 1571 vs. 3641 patients) and conservative treatment (women vs. men: 1581 vs. 3619 patients) following NSTE ACS. The mean age of women was 64.1 years and for men it was 61.3 years. Diabetes, hypertension and hyperlipidemia were more prevalent among women. Men were more likely to have elevated cardiac biomarkers and three vessel disease (35% vs. 23%, p<0.001) than women. Women frequently had T-wave inversion than men (53% vs. 43%).

Overall death, myocardial infarction (MI) or re-hospitalization with ACS occurred in 21.1% of patients in the invasive group and 25.9% of patients in the conservative group (Odds ratio 0.78; 95% CI 0.61 to 0.98). Among women, death, MI or re-hospitalization with ACS occurred in 21.1% of patients in the invasive group compared with 25% in the conservative group (OR 0.81; 95% CI 0.65 to 1.01) and among men it was 21.2% in the invasive group and 26.3% in the conservative group (OR 0.73; 95% CI 0.55 to 0.98, p for interaction =0.26).

Among all patients the odds of death or nonfatal MI during index hospitalization following invasive treatment vs. conservative treatment was 1.37 (95% CI 0.93 to 2.02), among women it was 1.49 (95% CI 0.72 to 3.09) and among men it was 1.33 (95% CI 0.93 to 1.89, p for interaction for gender =0.45). Among all patients the odds of death or nonfatal MI from hospital discharge to end of 12 month follow-up following invasive treatment vs. conservative treatment was 0.72 (95% CI 0.52 to 0.99), among women it was 0.71 (95% CI 0.48 to 1.07) and among men it was 0.70 (95% CI 0.50 to 0.98, p for interaction for gender =0.52).

Among all patients with elevated biomarkers, the odds of death, MI re-hospitalization following invasive vs. conservative strategy was 0.59 (95% CI 0.51 to 0.69) compared with 0.79 (95% CI 0.58 to 1.06) in the biomarker negative group. The difference between invasive vs. conservative strategy in the odds of death, MI and re-hospitalization from ACS was more marked among women with elevated cardiac biomarkers (OR 0.67; 95% CI 0.50 to 0.88) compared with those with negative biomarkers (OR 0.94; 95% CI 0.61 to 1.44, p interaction =0.36). An invasive strategy did not offer greater benefit among patients with ST segment changes.

During 12 month follow-up, the risk of death, MI and re-hospitalization with ACS among women was 23% and among men it was 24%. There was no difference in the odds of death, MI and re-hospitalization with ACS among women vs. men who underwent percutaneous coronary intervention (PCI) (OR 1.14; 95% CI 0.96 to 1.35). However, there were higher odds among women vs. men who underwent CABG (OR 1.44; 95% CI 1.15 to 1.81).

The investigators concluded that their findings are consistent with the current ACC/AHA guidelines which recommend a conservative strategy for low-risk women with non ST elevation MI. Furthermore, an invasive strategy has a comparable benefit among men and high risk women in reducing death, MI or re-hospitalization for ACS. The authors report that the main limitation of this study is the heterogeneity between the different clinical trials included in this meta-analysis.

Source

 * 1) http://jama.ama-assn.org/cgi/content/short/300/1/71