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We thank Dr Habib and colleagues for their interest in this topic. The issue of whether gender, size, or gender in combination with size can explain the worse early mortality after coronary artery bypass graft (CABG) surgery has been an ongoing debate. There still is no comprehensive evidence of what aspects of gender contribute to this increased early mortality risk; however, a strong association to body size has been previously described.1Christakis G.T. Weisel R.D. Buth K.J. et al.Is body size the cause for poor outcomes of coronary artery bypass operations in women?.J Thorac Cardiovasc Surg. 1995; 110: 1344-1358Abstract Full Text Full Text PDF PubMed Scopus (117) Google Scholar It also has been shown that the gender effect of worse early outcome rates of death and low output syndrome remain despite adjustment for body size, even when more detailed clinical data are available.1Christakis G.T. Weisel R.D. Buth K.J. et al.Is body size the cause for poor outcomes of coronary artery bypass operations in women?.J Thorac Cardiovasc Surg. 1995; 110: 1344-1358Abstract Full Text Full Text PDF PubMed Scopus (117) Google Scholar Size is important, but it is not the only factor that distinguishes men from women, and this certainly deserves more research. A recent article by Koch and coworkers2Koch C.G. Khandwala F. Nussmeier N. Blackstone E.H. Gender and outcomes after coronary artery bypass grafting a propensity-matched comparison.J Thorac Cardiovasc Surg. 2003; 126: 2032-2043Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar used propensity analysis to match women and men using 68 covariates. As seen in this study, only 26% of women from their entire cohort were matched, which certainly limited the generalizability of the study findings for the entire population of women undergoing CABG surgery. Regardless, likely there are factors other than size for women that lead to worse early outcomes after CABG surgery. There is some evidence to show that off-pump coronary artery bypass surgery might reduce adverse outcomes for women.3Petro K.R. Dullum M.K. Garcia J.M. et al.Minimally invasive coronary revascularization in women a safe approach for a high-risk group.Heart Surg Forum. 2000; 3: 41-46PubMed Google Scholar Unfortunately, off-pump coronary artery bypass trials will always have a minority of women and thus not be powered to understand the gender effect fully. Perhaps studies understanding the differential gender response to cardiopulmonary bypass and myocardial ischemia are required to more fully understand why there is a gender difference. Retrospective studies, even with detailed clinical data, will never be sufficient to conclusively identify the cause behind this observation, and size only explains part of the gender story. We can all agree that it is time for the research community to look beyond simple gender differences and work in a concerted manner to try and identify the biologic factors that contribute to gender differences in CABG surgery outcomes. Worse early outcomes in women after coronary artery bypass grafting: Is it simply a matter of size?The Journal of Thoracic and Cardiovascular SurgeryVol. 128Issue 3PreviewGender differences in the outcome of coronary artery bypass grafting (CABG) are currently a topic of much-deserved attention and debate. We read with interest the recent article in the Journal by Guru and colleagues1 in which they compared early and late outcomes in men versus women for the 1991-2000 Ontario, Canada CABG experience (n = 54,425). The authors' conclusions were as follows: (1) early CABG mortality is higher in women, even after adjustment for covariate predictors; (2) the risk of mortality in women becomes equivalent or better than that in men by 1 year after CABG; and (3) future research should focus on ways to reduce early mortality in women. Full-Text PDF Open Archive