Perspective:

This study sheds further light on sex-related outcomes after thoracic aortic surgery. Interestingly, reasons that might readily explain the worse outcomes in women (e.g., older age, more comorbidities, connective tissue disease/bicuspid aortic valve, more emergent/urgent presentation, more extensive operations, longer cross-clamp/cardiopulmonary bypass/HCA times) were not apparent. In fact, women were on average only 5 years older than men, had better ejection fraction, were less likely to be re-operative, had higher frequency of trileaflet aortic valve, and had similar HCA times with shorter cross-clamp and bypass times. (The cross-clamp and bypass times may have been related to the lower incidence of aortic valve/root surgery.)

However, one important way in which women differed from men was in their lower average BSA, which, given the similar mean maximum aortic diameter, translated into a greater indexed aortic diameter. Currently, the multisociety guidelines for size threshold for thoracic aortic aneurysm surgery consider aortic diameter rather than indexed diameter. The authors infer that women may be presenting later in the disease process, with resulting technical challenges due to their smaller size and tissue fragility. The lower BSA was also likely related to the higher incidence of transfusion, specifically packed red blood cells, in women (74% vs. 62%, p < 0.001), which carries its own morbidity/mortality. Further study is needed to elucidate the underlying biological mechanisms and clinical characteristics, especially regarding indexed aortic diameter, which may explain sex-related differences in outcomes after thoracic aortic surgery.