Eur J Cardiothorac Surg 2008;34:826-832. doi:10.1016/j.ejcts.2008.07.024
Copyright © 2008, European Association for Cardio-thoracic Surgery. Published by Elsevier. All rights reserved.
Influence of sex and age on long-term survival in systematic off-pump coronary artery bypass surgery
Raymond Cartier*,
Olivier Bouchot,
Ismail El-Hamamsy
Department of Surgery, Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada
Received 8 January 2008;
received in revised form 27 June 2008;
accepted 11 July 2008.
* Corresponding author. Tel.: +1 514 376 3330x3715; fax: +1 514 376 4766. (Email: rc2910{at}aol.com).
 |
Abstract
|
|---|
Background: Off-pump coronary artery bypass surgery (OPCAB) is commonly used as an alternative to conventional on-pump coronary artery revascularization. Historically, sex and age have been shown to adversely affect operative mortality risk as well as long-term survival in conventional surgery. Aims of the study: To evaluate the effect of gender and ageing on long-term mortality following OPCAB surgery. Methods: We have prospectively followed up 1000 consecutive and systematic OPCAB patients operated between September 1996 and April 2003. Average follow-up period was 64 ± 28 months and was complete in 98% of the cohort. Results: There were 223 women (21%) and 777 men (79%). Women were older, 68 ± 10 versus 63 ± 10 years (p
< 0.0001) and had higher prevalence of hypertension (p
< 0.0001), peripheral vascular disease (PVD) (p
= 0.03), recent myocardial infarction (p
= 0.04) and a smaller body surface (p
< 0.0001). History of congestive heart failure (CHF) (p
= 0.001) and unstable angina (p
= 0.003) was more frequent in men. Operative mortality was 2.8% in women and 1.4% in men (p
= ns). Eight-year survival was 79 ± 2.5% for men and 68 ± 5% for women, (p
= 0.02). Cox regression analysis model revealed that age (HR: 2.81; 95% CI: 1.89–4.18), CHF (HR: 2.09; 95% CI: 1.33–3.31), PVD (HR: 1.72; 95% CI: 1.10–2.5), incomplete revascularization (HR: 2.35; 1.37–4.02), multiple internal thoracic artery (MITA) graft/patient (ITA/pt) (HR: 0.61; 95% CI: 0.44–0.84), left ventricular ejection fraction (LVEF) (HR: 0.19; 95% CI: 0.05–0.71) and cerebral vascular disease (HR: 1.50; 95% CI: 1.00–2.24) but not female sex (p
= 0.89) were significant predictors of long-term mortality. Above 65 years of age men and women had a comparable overall survival (p
= 0.7) whereas fewer than 65 women had a lower survival than men (p
= 0.001). Cox regression revealed that LVEF (HR: 0.06; 95% CI: 0.006–0.59), lesser use of MITA graft (HR: 0.45; 95% CI: 0.35–0.79), were significant causes of long-term mortality in the younger cohort. Female gender did not reach statistical significance (p
= 0.12). Conclusion: In this series of systematic OPCAB surgery, the lower survival rate observed in younger women was mostly related to a higher prevalence of preoperative comorbidity and a lesser use of MITA grafts than gender itself.
Key Words: Coronary disease • Minimally invasive surgery • Off-pump • Gender
|
1. Introduction
|
|---|
Over the last decade, off-pump coronary artery bypass (OPCAB) surgery has become a widespread alternative to conventional on-pump coronary artery bypass surgery (CABG). Several randomized trials have shown potential benefits in regard to myocardial protection and postoperative morbidity [1–6]. Most of the published studies on the topic have reported limited short-term or mid-term results with the procedure and very few have focused on long-term follow-up and patient characteristics that could influence long-term survival such as patient age and gender. Female sex has long been recognized as risk factors of poor long-term prognosis [7,8]. Women are generally older at the time of surgery and present more comorbidity than males. Younger females (<60 years) have been particularly shown to do poorly after standard coronary artery bypass surgery [9,10]. Lately, OPCAB surgery has been shown to neutralize gender disparity with regards to perioperative mortality and morbidity [11]. Long-term follow-up examining the influence of female gender and age after OPCAB surgery has not been extensively studied. We propose to review the influence of age on gender disparity after OPCAB surgery.
|
2. Materials and methods
|
|---|
Between September 1996 and March 2004, 1000 consecutive and systematic OPCAB procedures were performed at the Montreal Heart Institute by a single surgeon (RC) representing 96% of all revascularization procedures during the same time frame. Short and mid-term results of this series have already been the topic of a general report [12]. Among the patients included in this study, 223 were female and are the focus of the present report. Follow-up was completed at 97% with an average follow-up period of 64 ± 28 months (12–120 months). Patients’ follow-ups were completed at the outpatient clinic, by phone interview, and by family physicians or patients’ cardiologists contact. In cases of postoperative events requiring hospitalization at a different institution, a copy of the hospitalization record was sought for. All data were collected prospectively and entered into a computer database. This review was approved by the Montreal Heart Institutional Board on May 27, 2008. Informed consent was waived by the board for this study.
2.1 Off-pump technique
The off-pump technique used has already been described [13,14]. Briefly, a compression type device (Cor-Vasc retractor-stabilizer, CoroNéo, Montreal, Quebec, Canada) was employed to achieve coronary stabilization. Coronary flow interruption was obtained initially by gentle vessel snaring using silicone vessel loop (‘Swiftloop’, CoroNéo, Montréal, Quebec, Canada). Immobilization of the left anterior descending artery (LAD) and the right coronary [including posterior descending artery (PDA)] were achieved with minimal myocardial manipulation. The posterior wall was exposed by anchoring four deep pericardial retraction sutures. Apical suction cups were used only occasionally (1%) and mainly to assist revascularization of the inferior territory (PDA). Rise of the pulmonary pressure was generally controlled by temporary snaring of the inferior vena cava to decrease venous inflow [15].
Throughout the study the revascularization strategy consisted of revascularizing the culprit lesion first with restoration of antegrade flow before moving to the other targeted vessels. Shunts were used only if ischemia was suspected during a pre-ischemic cross-clamping test of 2 min.
|
3. Definitions
|
|---|
3.1 Demographics and preoperative risk factors
Hypertension was defined by a medical history of chronic usage of blood pressure lowering medications. Diabetes included types 1 and 2 indiscriminately. Chronic pulmonary disease was defined as usage of any type of bronchodilators preoperatively or presence of a FEV1 (forced expiratory volume in 1 s) below 50% of predicted performance. Recent myocardial infarction (MI) was characterized as MI that occurred 4 weeks prior to surgery. Chronic renal insufficiency was identified by a plasmatic creatinine level >177 mmol/l. Peripheral disease was defined as any physical sign of peripheral vascular disease on arterial Doppler evaluation (ankle/brachial index < 0.8), history of peripheral revascularization (surgery or angioplasty), or history of intermittent claudication. Evolving MI was delineated by an elevated myocardial specific creatine phosphate (CKMB) count prior to surgery (>50 IU/l) or immediately after surgery. A preoperative intra-aortic balloon pump (IABP) insertion was defined as inserted prior to the beginning of the procedure. Any IABP insertion occurring during the surgery or after was considered as being installed after surgery.
3.2 Perioperative data
Operative mortality was defined as 30-day mortality following surgery. Perioperative MI was characterized as CKMB >100 IU/l any time after surgery, appearance of an ST-elevation on post-op EKG, or positive transmural necrosis on pyrophosphate nuclear scanning. Revascularization was considered incomplete if a territory was not revascularized because of technical difficulty or absence of reconstructable vascular network.
3.3 Long-term endpoints
Long-term cardiac death was defined by death due to any cardiac causes, sudden death, or any death of undetermined cause.
3.4 Statistics
Data are expressed as mean and standard deviation of the mean. Independent risk factors for operative mortality were studied with univariate regression analysis and multivariate stepwise regression. Cox proportional hazard regression was used for risk factors analysis of time-related events. All patients were considered as intention-to-treat. No more than one variable for 10 events was considered for multivariate analysis purposes. Variables included in the multivariate regression analysis were first selected by univariate regression and a minimum p value of 0.1 was requested before inclusion in the model. For long-term endpoints independent risk factors analysis excluded patients that died within 30 days of the surgery. Actuarial survival was obtained using the Kaplan–Meier method where p
< 0.05 was considered statistically significant. Kaplan–Meier curves were constructed for female and male groups and compared using the log-rank test. Statistical analysis was performed using a computer software packages (SPSS, 11.0, Chicago, IL, USA). Statistical differences were considered significant if the p value was less than 0.05.
|
4. Results
|
|---|
4.1 Demographic and preoperative risk factors
Demographic characteristics and risk factors according to patient's gender are depicted in Table 1
. Female patients were older by 5 years at the time of surgery and had a higher prevalence of hypertension, peripheral vascular disease and recent MI (<4 weeks). Medical history of congestive heart failure, previous MI (>4 weeks), and admission for unstable angina was more common in males. Body surface area was also larger in males.
4.2 Perioperative data
Perioperative characteristics are displayed in Table 2
for men and women. Operative mortality and rate of perioperative MI was higher in females. Although there was no statistical significance, significant difference was almost reached for ‘Q-wave’ MI (p
= 0.06). Use of ITA grafts, including bilateral harvesting and sequential grafts were more frequent in males (p
< 0.001 and p
= 0.02, respectively) whereas radial grafts were used more often in female patients (p
= 0.04). Re-entry for bleeding was more frequent in female patients (p
= 0.03).
4.3 Long-term follow-up
4.3.1 Women versus men
Kaplan–Meier survival curves for both men and women are displayed in Fig. 1
. Non-adjusted overall actuarial survival was lower in women than men at 1 (93 ± 1.7 vs 97 ± 0.5%), 5 (84 ± 2.7% vs 88 ± 1.5%) and 8 years (68 ± 5.1% vs 78 ± 2.4%; p
= 0.02). Similar observations were made for survival free of cardiac deaths during the same time frame: 1 year (96.4 ± 1.3% vs 98 ± 0.5%), 5 years (93 ± 1.8% vs 96 ± 0.7%), and 8 years (91 ± 2% vs 94 ± 1.2%; p
= 0.01).
4.4 Clinical predictors of long-term global and cardiac mortality (Tables 3 and 4)
Clinical predictors of long-term mortality are shown in Table 3
. Operative mortality was excluded from this analysis. Variables included in the Cox regression multivariate model were selected from univariate analysis based on demographic and risk factors depicted in Appendix A
. The model showed that the most significant risk factors were age >65 years, peripheral vascular disease, incomplete revascularization, and the lower use of multiple ITA grafts. After adjusting for these risk factors, female sex was no longer a detrimental factor for long-term survival.
Due to the limited long-term cardiac deaths recorded (35 deaths) we only included the five most significant cardiac variables in the Cox regression model as defined by univariate analysis. These risk factors are depicted in Table 4
. Failure to achieve complete revascularization and lower use of multiple ITA graft were the most significant variables. Here again female sex was not a significant feature (p
= 0.4).
4.5 Sex and age
Under 65 years of age, female patients had a significantly lower overall survival compare to male (Fig. 2A). This was significant at 1 (97 ± 2.0% vs 99 ± 0.5%), 5 (95.6 ± 2.5% vs 97.7 ± 0.8%), and 8 years (93.6 ± 3.5% vs 96.3 ± 1.3%, p
= 0.003) follow-up. This trend was not observed above 65 years of age (Fig. 2B).
View larger version (11K):
[in this window]
[in a new window]
|
Fig. 2. (A) Actuarial overall survival <65 years: male (solid line) versus female (dotted line). (B) Actuarial overall survival >65 years: male (solid line) versus female (dotted line).
|
|
Below 65 years of age (Table 5
), females had a higher prevalence of chronic heart failure, peripheral vascular disease, hypertension, obesity, unstable angina, and a more severe NYHA functional class than men. They also had a lower body surface area and used fewer multiple ITA grafts than men (both with p
< 0.001). As shown in Table 6
, risk factors for long-term mortality differed according to the patient's age cohort. Below 65, Cox regression model showed that left ventricular ejection fraction (LVEF) and a lower use of multiple ITA grafts were significant risk factors for long-term mortality. Even after adjusting for these factors female gender did not reach statistical significance (p
=
0.13) as cause of long-term death. Above 65 years of age, significant variables were incomplete revascularization, history of congestive heart failure, peripheral and cerebral vascular disease, and LVEF.
|
5. Comments
|
|---|
Women are generally recognized to have a less favorable outcome than men after CABG surgery. They are generally older and have more comorbidities. Clinically, this translates to a higher operative mortality and a decreased long-term survival when compared to men [6–9]. In 1993, Weintraub et al. from Emory University Hospitals reviewed their database of 13,368 patients covering 17 years of CABG surgery [7]. They showed that women were on average 5 years older than men and had a higher prevalence of diabetes and emergent operation. Additionally, in-hospital mortality was twice the mortality observed in men (3.6% vs 1.6%). In their regression model, female sex was definitely an independent risk factor for in-hospital mortality. More recently in 2003, the same group reported 51,187 patients (30% women) included in the National Cardiovascular Network database that underwent CABG surgery at 23 different hospitals between October 1993 and December 1999 [6]. Younger women (<60 years) had a higher in-hospital mortality rate than men, a trend that vanished with age [9]. They concluded that further investigations were needed to explain this difference. Similarly, Hassan et al. from Halifax showed in a large series of 3404 patients followed for a minimum of 5 years that women had a worse outcome than men [10]. Gender itself did not affect operative mortality but was identified as a significant risk factor for long-term adverse outcomes even after correction for other risk factors. Other authors have reported similar results but have documented factors other than gender to explain the poorer prognostic observed in women. According to O’Connor et al. factors such as a smaller body surface area and a lesser use of ITA in female patients were connected to less optimal results [8]. The smaller coronary artery diameter generally associated to a small body surface area could explain, more than gender itself, the higher in-hospital cardiac mortality reported in the female population of their series. Following the same path, Kock et al. from the Cleveland Clinic Foundation reported that female gender per se was a marker of higher prevalence of comorbidities than a sex-related risk factor [16]. After adjusting for risk factors, they reported a comparable survival at 6 months and 5 years for both genders following surgery. Congestive heart failure, anemia, and diabetes were among the most significant risks in both women and men in regard to long-term survival but were also more prevalent among the female population. Other authors have also been less pessimistic in regard of women prognosis after CABG surgery.
Tompoulis et al. reported on a large series of over 3000 patients followed for a mean period of 5 years [17]. They observed an identical operative mortality for both men and women. After 5 years, survival was also identical and after normalizing for 62 variables, sex was not identified as a significant risk factor. Guru et al. looked at 15,000 women out of more than 65,000 patients followed through a clinical and administrative database in Ontario, Canada [18]. They specifically targeted non-fatal outcome after coronary artery surgery using Cox modeling and propensity score matching. On average, women were 3 years older than men, had less arterial graft, and were more frequently operated on an emergent basis. Early on and thereafter, they were more frequently readmitted than men for unstable angina and congestive heart failure. However, after correction for risk factors they had a similar death and revascularization rate during the follow-up.
Very few series have compared OPCAB surgery results between men and women. In 2003, Athanasiou from UK retrospectively reviewed their series of 188 women and 232 men revascularized without circulatory support [19]. Groups were matched for age and Parsonnet score. Again, women had more preoperative comorbid factors. Perioperatively they received significantly fewer bypass grafts, and had a lower rate of complete revascularization than men mainly in regard of the circumflex territory. However, after normalization for risk factors female gender was not associated with operative mortality. More recently Bennet et al. published a small series of 255 patients comprising 49 women all operated on by the same surgeon with a similar surgical technique [20]. All deaths were confined in the male group disregarding female gender as preoperative risk factor. Other authors have also confirmed the potential of OPCAB surgery to neutralize the gender disparity normally observed in conventional CABG surgery [11]. Puskas et al. conducting a review of the Society of Thoracic Surgeons database compared gender outcome after both on and off-pump CABG surgery. Forty-two thousand, four hundred and seventy-seven patients were studied. After adjusting for 32 clinical and demographic covariates, adjusted risk of death remained higher for female operated on-pump whereas in patients operated off-pump operative death was comparable for both sex. Overall adjusted risk for death and major complications remained lower in OPCAB patients. The authors concluded that OPCAB surgery had the potential of reducing gender discrepancy in CABG surgery besides reducing surgical risks.
The current series reports a single surgeon experience with its first 1000 consecutive and systematic OPCAB patients followed for an average period of 5 years. They represent 96% of all patients operated on during the same time frame. After 1996, very few patients were denied the OPCAB approach and if it occurred it was mainly due to unstable hemodynamics rather than anatomical features. This cohort is then quite representative of the daily practice of the usual cardiac surgeon.
As previously reported by others, female patients in our series were older at the time of surgery and had more comorbidities. As we previously described (12), female sex was not recognized as significant risk factor for operative mortality although there was a certain trend in favor. However, contrary to current literature, women received an equal number of grafts and a similar rate of complete revascularization when compared to men. At first glance, women had worse outcome than men for both overall and cardiac survival and this seemed more apparent for the younger cohort of patients (<65 years). However, after correction for significant preoperative risk factors, the Cox regression model rejected female gender as a significant determinant of long-term mortality regardless of the patient's age at the time of surgery. Contrary to previous reports, smaller BSA (p
= 0.34) was not detected as a significant factor for both operative and long-term mortalities. However, a strong determinant of prolonged survival was the rate of multiple ITA bypass graft performed. As shown in other series women in our cohort received significantly less multiple ITA graft than men, although 96% of them benefited from at least one arterial graft, which was comparable to men. The benefit of bilateral ITA grafting has been well recognized in regard to freedom of cardiac death and cardiac related events for early and late outcome [21,22]. The higher incidence of diabetes in women, their lower body mass index and their increased prevalence of obesity (BMI >30) are all compelling factors making surgeons reluctant to use bilateral ITA grafting in the female population. The smaller body mass can also reflect in shorter ITA grafts decreasing the opportunity of performing ITA sequential grafting. This was particularly true in our younger population (
65 years) where prevalence of obesity in females was twofold, the prevalence observed in the male and the lower use of multiple ITA graft more accentuated [<65 years: 1.3 + 0.6 vs 1.65 + 0.7 (p
< 0.001) and >65 years: 1.2 + 0.6 vs 1.4 + 0.5 (p
= 0.003) for females and males, respectively]. The decreased survival observed in the young women was then mainly related to their lesser use of multiple ITA graft and higher prevalence of multiple comorbidities.
5.1 Strength and weakness of the study
One major weakness of the series is the relatively small number especially for the female cohort (223 patients). This reduced the number of studied events limiting the amount of variables that could be included in the regression analysis model.
|
6. Conclusion
|
|---|
In this series of OBCAP patients, women were shown to have a decreased long-term overall and cardiac survival compared to men. This was mainly related to higher comorbidity and a lesser use of multiple ITA grafts. Female gender itself was not recognized as a specific risk factor for long-term mortality. The gender disparity in regard to those comorbidities was more accentuated below 65 years of age explaining the more severe outcome observed among women of this particular cohort. Above 65 years of age, men and women had comparable survival due to a more equivalent distribution of preoperative comorbidity.
|
Appendix A
|
|---|
Demographic and risk factors
| Age >65 |
| Sex |
| Body surface area |
| Age (>65) sex |
| Diabetes |
| High blood pressure |
| Tobacco |
| Dyslipidemia |
| COPD |
| CAF |
| PVD |
| Previous CVA/TIA |
| Carotid disease |
| Left main |
| CRF |
| LVEF |
| MI (<4 weeks) |
| MI (>4 weeks) |
| CHF |
| Re-operation |
| Unstable angina |
| Number of vessels |
| Preoperative IABP |
| Emergency |
| Incomplete revascularization |
| Preoperative IABP |
| Number of vessels |
| NYHA class |
| Conversion to CEC |
| Number of grafts |
|
|
References
|
|---|
- Paroli A, Alamanni F, Polyani G, Agrifoglio M, Chen YB, Kassem S, Veglia F, Tremoli E, Biglioli P. Meta-analysis of randomized trials comparing off-pump with coronary artery bypass graft patency. Ann Thorac Surg 2005;80:2121-2125.[Abstract/Free Full Text]
- Wijeysundera DN, Beattie WS, Djaiani G, Rao V, Borger MA, Karkouti K, Cusimano RJ. Off-pump coronary artery for reducing mortality: meta-analysis of randomized and observational studies. J Am Coll Cardiol 2005;46:872-882.[Abstract/Free Full Text]
- Selke FW, DiMaio JM, Caplan LR, Ferguson TB, Gardner TJ, Hirazka LF, Isselbacher EM, Lytle BW, Mack MJ, Murkin JM, Robbins RC, American Heart Association Comparing on-pump and off-pump coronary artery bypass grafting: numerous studies but few conclusions: a scientific statement from the American Heart Association council on cardiovascular surgery and anesthesia in collaboration with the interdisciplinary working group on quality of care and outcomes research. Circulation 2005;111:2858-2864.[Abstract/Free Full Text]
- Bainbridge D, Martin J, Cheng D. Off-pump coronary artery bypass graft surgery versus conventional coronary artery bypass graft surgery: a systematic review of the literature. Semin Cardiothorac Vasc Anesth 2005;9:105-111.[Abstract/Free Full Text]
- Racz MJ, Hannan EL, Isom OW, Subramanian VA, Jones RH, Gold JP, Ryan TJ, Hartman A, Culliford AT, Bennett E, Lancey RA, Rose EA. A comparison of short- and long-term outcomes after off-pump and on-pump coronary artery bypass graft surgery with sternotomy. J Am Coll Cardiol 2004;43:557-564.[Abstract/Free Full Text]
- Hannan EL, Wu C, Smith CR, Higgins RS, Carlston RE, Cukkiford AT, Gold JP, Jones RH. Off-pump versus on-pump coronary artery bypass graft surgery: differences in short-term outcomes and long-term mortality and need for subsequent revascularization. Circulation 2007;116:1145-1152.[Abstract/Free Full Text]
- Weintraub WS, Wenger NK, Jones EL, Craver JM, Guyton RA. Changing clinical characteristics of coronary surgery patient differences between men and women. Circulation 1993;88(Suppl. II):II79-II86.[Medline]
- O’Connor GT, Morton JR, Diehl MJ, Olmstead EM, Coffin LH, Levy DG, Maloney CT, Plume SK, Nugent W, Malenka DJ, The Northern New England Cardiovascular Disease Study Group Differences between men and women in hospital mortality associated with coronary artery bypass graft surgery. Circulation 1993;88:2104-2110.[Abstract/Free Full Text]
- Vaccarino V, Abramson JL, Veledar E, Weintraub WS. Sex differences in hospital mortality after coronary artery bypass surgery: evidence for a higher mortality in women. Circulation 2002;105:1176-1181.[Abstract/Free Full Text]
- Hassan A, Chiasson M, Buth K, Hirsch G. Women have worse long-term outcomes after coronary artery bypass grafting than men. Can J Cardiol 2005;21:757-762.[Medline]
- Puskas JD, Kilgo PD, Kutner M, Pusca SV, Lattouf O, Guyton A. Off-pump techniques disproportionately benefit women and neutralize the effect of gender disparity in outcomes after coronary artery bypass surgery. Circulation 2007;116(Suppl. II):II92-II99.
- El Hamamsy I, Cartier R, Demers P, Bouchard D, Pellerin M. Long-term results after systematic off-pump coronary artery bypass graft surgery in 1000 consecutive patients. Circulation 2006;114(Suppl. I):I486-I491.[Medline]
- Cartier R, Brann S, Dagenais F, Martineau R, Couturier A. Systematic off-pump coronary artery revascularization in multivessel disease: experience of three hundred cases. J Thorac Cardiovasc Surg 2000;119:221-229.[Abstract/Free Full Text]
- Cartier R, Blain R. Off-pump revascularization of the circumflex artery: technical aspect and short-term results. Ann Thorac Surg 1999;68:94-99.[Abstract/Free Full Text]
- Dagenais F, Cartier R. Pulmonary hypertension during beating heart coronary surgery: intermittent inferior vena cava snaring. Ann Thorac Surg 1999;68:1094-1095.[Abstract/Free Full Text]
- Koch CG, Weng YS, Zhou SX, Savino JS, Mathew JP, Hsu PH, Saidman LJ, Mangano DT, Ischemia Research and Education Foundation; Multicenter Study of Perioperative Ischemia Research Group Prevalence of risk factors, and not gender per se, determines short- and long-term survival after coronary artery bypass surgery. J Cardiothorac Vasc Anesth 2003;17:585-593.[CrossRef][Medline]
- Tompoulis IK, Anagnostopoulos CE, Balaram SK, Rokkas CK, Swistel DG, Ashton Jr. RC, DeRos Jr. JJ. Assessment of independent predictors for long-term mortality between women and men after coronary artery bypass grafting: are women different from men?. J Thorac Cardiovasc Surg 2006;131:264-265.[Free Full Text]
- Guru V, Fremes SE, Austin PC, Blackstone EH, Tu JV. Gender differences in outcomes after hospital discharge from coronary artery bypass grafting. Circulation 2006;113:507-516.[Abstract/Free Full Text]
- Athanasiou T, Al-Ruzzeh S, Del Stanbridge R, Casula RP, Glenville BE, Amrani M. Is the female gender an independent predictor of adverse outcome after off-pump coronary artery bypass grafting?. Ann Thorac Surg 2003;75:1153-1160.[Abstract/Free Full Text]
- Bernet F, Baykut D, Reineke D, Matt P, Zerkowski HR. Impact of female gender on the early outcome in off-pump coronary artery bypass surgery. Eur J Med Res 2006;11:114-118.[Medline]
- Christenson JT, Vala D, Faidutti B, Kalangos A. Choice of graft material at primary CABG influences cardiac death and reintervention rates. Med Princ Pract 2002;11:141-146.[CrossRef][Medline]
- Gansera B, Gillrath G, Lieber M, Angelis I, Schmidtler F, Kemkes BM. Are men treated better than women? Outcome of male versus female patients after CABG using bilateral internal thoracic arteries. Thorac Cardiavasc Surgery 2004;52:261-267.[CrossRef]
Top
Abstract
1. Introduction
