Gender differences in mortality after mitral valve operation: Evidence for higher mortality in perimenopausal women

Background. Hormonal status is a potentially important cause for gender differences in outcomes after cardiovascular operations. Estrogen withdrawal states may potentiate ischemia-reperfusion injury by impairing endothelial cell function and increasing inflammatory cytokine levels. We hypothesized that gender influences mortality after mitral valve operations and that it varies with age, especially during periods of declining ovarian function. Methods. We studied 24,977 patients ( 49% women) in The Society of Thoracic Surgeons National Database who underwent isolated mitral valve repair or replacement from 2002 to 2005. Age-related gender differences in mortality after mitral valve operation were compared by risk-adjusted analysis. Results. Gender and age had a pronounced impact on hospital mortality. Women aged 40 to 49 and 50 to 59 had significantly greater hospital mortality than risk-matched men. The adjusted female/male odds ratio for hospital mortality in the group aged 40 to 49 was 2.56 ( 95% confidence interval, 1.31 to 5.01) but progressively decreased in the four subsequent age groups. This pattern was statistically significant (p=0.028 and p=0.018 for 40 to 49 vs 70 to 79 and 80 to 89, respectively) and represents a declining relative mortality risk for women of advanced age. Conclusions. In patients aged 40 to 59 years, the mortality of mitral valve operation is approximately 2.5 times higher in women compared with men with similar risk factors. This survival disadvantage diminishes with further aging. Changes in ovarian function may be an important cause for this gender-age interaction and are a potential target for novel hormone-based therapies.