Treating menstruating women with thrombolytic therapy: insights from the global utilization of streptokinase and tissue plasminogen activator for occluded coronary arteries (GUSTO-I) trial.

OBJECTIVES

The purpose of this study was to examine the clinical implications of administering thrombolytic therapy to menstruating women with acute myocardial infarction.

BACKGROUND

Although anecdotal case reports have suggested that thrombolytic therapy is safe during menstruation, the risk of increased bleeding in menstruating women receiving such therapy is poorly defined.

METHODS

We identified menstruating women who received thrombolytic therapy by soliciting information on all North American women enrolled in the GUSTO-I trial and then collected additional information about them with use of a one-page data form. We compared the characteristics and outcomes of these women with other GUSTO-I patient populations, including all North American women below the median age of menopause, all women and all patients.

RESULTS

The median age of the 12 menstruating women was 46 years; 75% were cigarette smokers. The median hospital stay was 7 days, 2 fewer than the overall stay in GUSTO-I. None of these women died or had a stroke or severe bleeding. Three patients (25%) had moderate bleeding (vaginal in two patients [66%]) that required transfusion compared with 11% of all GUSTO-I patients and all North American premenopausal women (p = 0.13) and 17% of all female GUSTO-I patients (p = 0.47). Because of the small sample size of 12 women, the power was low (0.37) to detect the observed difference in moderate bleeding. The median nadir hematocrit was 33% in the menstruating women compared with 34% in the premenopausal women and all women. The median time from symptom onset to treatment for the 12 women was 3.7 h, which was 0.9 h longer than the overall median in the trial (p = 0.09).

CONCLUSIONS

Although there was no statistically significant increase in bleeding risk during menstruation, this fact may be a result of low statistical power rather than a lack of effect. Thus, the results suggest that there may be a clinically significant increase in the risk of moderate bleeding. Nevertheless, the GUSTO-I experience is consistent with the concept that the lifesaving benefit of thrombolytic therapy for acute myocardial infarction should generally not be withheld because of active menstruation.