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OASIS-5-Worse outcome in women with invasive strategy

Acute Coronary Syndromes (ACS)

Presenter report:

In patients with non ST-elevation acute coronary syndromes (NSTE ACS), subgroup analyses from several trials have shown a reduction in the composite of death and myocardial infarction with an early invasive strategy among men but a trend for harm amongst women. The aim of this study was to evaluate whether a routine early invasive strategy was superior to a selective invasive strategy in women.


The OASIS 5 Women sub-study randomized 184 women with NSTE ACS to either an early invasive strategy with routine coronary angiography (and, if appropriate, coronary revascularization within 7 days) or to a selective invasive strategy with ischemia guided coronary angiography. The outcomes death, myocardial infarction, refractory ischemia, major bleeding and stroke were evaluated after 2 years.


At one year follow-up 8 patients in the routine invasive group had died compared to 1 patient in the selective invasive group (8.8% vs 1.1%, p=0.013). There was no significant difference in either of the endpoints myocardial infarction (7.8% vs 9.9%, p= 0.634), refractory ischemia (4.4% vs 8.7%, p= 0.230) or stroke (2.3% vs 3.3%, p=0.872). Major bleedings were significantly more frequent in the routine invasive group (10.0% vs 1.1%, p= 0.002). The observed differences between the two groups, persisted at 2 years follow-up.


A routine invasive strategy was associated with an increased rate of major bleeding and mortality in women with NSTE ACS. As the majority of previous trials have predominantly enrolled men, a large randomized trial needs to be performed to determine the safety and efficacy of an early invasive approach in women.

Discussant : Rosengren, Annika (Sweden)


One of the most conspicuous differences in ACS between men and women is that women are older at the onset than men, probably owing to the protective effect of estrogen which seems to delay atherosclerosis in the coronary vessels. Coronary angiography usually shows less extensive atherosclerosis in women. The differences in clinical presentation between men and women are more marked in younger, compared to older, patients. Women have less ST-elevation ACS but instead more NSTE-). However, it should be noted that young women with ACS are a minority, and that the great majority of women who present with ACS are elderly. As a result of their older age many women with ACS have other diseases. The issue whether women with ACS should be treated the same as men has been much debated. There is still little consensus whether modern treatment in ACS is a help in women to the same extent as in men.

The OASIS-5 trial

The OASIS-5 trial was a randomized, double-blind trial of fondaparinux versus enoxaparin in patients with unstable angina or non-ST-segment elevation myocardial infarction. In a substudy, eligible female patients were randomized to receive either routine early coronary angiography and, if appropriate, intervention within 7 days of randomization or selective invasive strategy (coronary angiography only in case of symptoms, or severe ischemia during index hospital admission or on a stress test). 184 patients were randomized, mean age 68 years. Over a 2 year follow-up death, new myocardial infarction, and refractory ischemia occurred in 21% in both groups. Two women died in the selective invasive, compared to 8 in the routine invasive group (NS). There were significant differences in the occurrence of major bleeding, 2 versus 9 women; HR 6.90(1.48-32.13).


In this trial women with NSTE ACS did not benefit from a routine invasive strategy, which confirms results from the FRISC II trial. Differences in anatomy, pathophysiology, age and comorbidity may tip the balance from a benefit to either no effect or an adverse effect in women. This is a valuable addition to our knowledge concerning treatment in women with ACS, but it should be noted that a much larger sample size was planned, based on power calculations. Accordingly, results should be interpreted with caution, particularly with respect to the greater mortality in the routine invasive group. It should be noted that 40% were in need of coronary angiography short-term and altogether 2/3 during follow-up. Large scale randomised trials in women are needed to determine the optimal strategy in NSTE ACS but so far, available evidence suggests that a wait-and-see policy in women with ACS may be justified.




Hotline II

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.