Female Gender Does Not Increase Perioperative Risk in Coronary Bypass Surgery[*]

Abstract

Introduction: Female gender has been identified as an independent risk factor for perioperative mortality in several risk scores for cardiac surgery. Since no explanation has been given for this, this study aimed to evaluate potential differences in the distribution of other risk factors between the genders. Patients and Methods: 10 714 consecutive coronary bypass patients were analyzed retrospectively. The distribution of the risk factors as used in the EuroSCORE was evaluated. Diabetes mellitus was added to the analysis as an additional risk factor. Patients aged between 60 and 70 years without any additional risk factors were directly compared in a subgroup analysis. Statistical analysis was done using the t-test or chi-square test where appropriate. Results: Female patients were significantly older compared to male ones (69.1 ± 8.5 vs. 65.4 ± 4 years, p < 0.05). The distribution of the analyzed risk factors did not differ except for diabetes mellitus: female patients were more likely to present with diabetes (42 % vs. 29 %, p < 0.05) and in diabetic patients, the incidence of insulin dependency was higher in female patients (50 % vs. 33 %, p < 0.05). Overall perioperative mortality was higher in female patients (2.7 % vs. 1.8 %, p < 0.05). This difference increased when diabetes was present (3.9 % vs. 1.8 %, p < 0.05) and was even higher in insulin-dependent patients (4.9 % vs. 1.9 %, p < 0.05). However, when adjusting for age and diabetes, the differences were reduced. This was most evident when subgroups of age-adjusted patients without any additional risk factors were analyzed: no gender-specific difference in perioperative mortality was observed. Conclusions: Female gender itself did not present as an independent risk factor. The presence of diabetes mellitus increased the risk in female patients significantly more than in male patients. The higher prevalence of diabetes in female patients in combination with the older age at presentation might result in the higher overall mortality observed in female patients compared to men.

coronary bypass surgery - gender - risk - diabetes mellitus - EuroSCORE - perioperative mortality

References

• 1 Roques F, Nashef S A, Michel P, Gauducheau E, de Vincentiis C, Baudet E, Cortina J, David M, Faichney A, Gabrielle F, Gams E, Harjula A, Jones M T, Pintor P P, Salamon R, Thulin L. Risk factors and outcome in European cardiac surgery: analysis of the EuroSCORE multinational database of 19 030 patients.  Eur J Cardiothorac Surg. 1999;  15 816-822
• 2 Nashef S A, Roques F, Michel P, Gauducheau E, Lemeshow S, Salamon R. European system for cardiac operative risk evaluation (EuroSCORE).  Eur J Cardiothorac Surg. 1999;  16 9-13
• 3 Capdeville M, Chamogeogarkis T, Lee J H. Effect of gender on outcomes of beating heart operations.  Ann Thorac Surg. 2001;  72 S1022-S1025
• 4 Vaccarino V, Lin Z Q, Kasl S V, Mattera J A, Roumanis S A, Abramson J L, Krumholz H M. Gender differences in recovery after coronary artery bypass surgery.  J Am Coll Cardiol. 2003;  41 307-314
• 5 Blankstein R, Ward R P, Arnsdorf M, Jones B, Lou Y B, Pine M. Female gender is an independent predictor of operative mortality after coronary artery bypass graft surgery: contemporary analysis of 31 Midwestern hospitals.  Circulation. 2005;  112 I323-I327
• 6 Guru V, Fremes S E, Austin P C, Blackstone E H, Tu J V. Gender differences in outcome after hospital discharge from coronary artery bypass grafting.  Circulation. 2006;  31 507-516
• 7 Patel S, Smith J M, Engel A M. Gender differences in outcomes after off-pump coronary artery bypass graft surgery.  Am Surg. 2006;  72 310-313
• 8 Bernet F, Baykut D, Reineke D, Matt P, Zerkowski H R. Impact of female gender on the early outcome in off-pump coronary artery bypass surgery.  Eur J Med Res. 2006;  27 114-118
• 9 Humphries K H, Gao M, Pu A, Lichtenstein S, Thompson C R. Significant improvement in short-term mortality in women undergoing coronary artery bypass surgery (1991 to 2004).  J Am Coll Cardio. 2007;  49 1552-1558
• 10 Srinivas V S, Garg S, Negassa A, Bang J Y, Monrad E S. Persistent sex difference in hospital outcome following percutaneous coronary intervention: results from the New York State reporting system.  J Invasive Cardiol. 2007;  19 265-268
• 11 Crilly M, Bundred P, Hu X, Leckey L, Johnstone F. Gender differences in the clinical management of patients with angina pectoris: a cross-sectional survey in primary care.  BMC Health Serv Res. 2007;  7 142
• 12 Ritchison A, Smith J M, Engel A M. Gender differences in diabetic patients following coronary artery bypass graft surgery.  J Card Surg. 2007;  22 401-405
• 13 Kasirajan V, Wolfe L G, Medina A. Adverse influence of female gender on outcomes after coronary bypass surgery: a propensity matched analysis.  Interact Cardiovasc Thorax Surg. 2009;  8 408-411
• 14 Kim C, Redberg R F, Pavlic T, Eagle K A. A systematic review of gender differences in mortality after coronary artery bypass graft surgery and percutaneous coronary interventions.  Clin Cardiol. 2007;  30 491-495
• 15 Puskas J D, Kilgo P D, Kutner M, Pusca S V, Lattouf O, Guyton R A. Off-pump techniques disproportionately benefit women and narrow the gender disparity in outcomes after coronary artery bypass grafting.  Circulation. 2007;  116 I192-I199
• 16 Cartier R, Bouchot O, El-Hamamsy I. Influence of sex and age on long-term survival in systematic off-pump coronary artery bypass surgery.  Eur J Cardiothorac Surg. 2008;  34 826-832
• 17 Puskas J D, Edwards F H, Pappas P A, O'Brien S, Peterson E D, Kilgo P, Ferguson Jr T B. Off-pump techniques benefit men and women and narrow the disparity in mortality after coronary bypass grafting.  Ann Thorac Surg. 2007;  84 1447-1454

1 The paper was presented at the 38^th annual meeting of the DGTHG in Stuttgart, 2009.