Gender-related differences in morbidity and mortality during combined valve and coronary surgery

BACKGROUND: Gender-related differences in morbidity and mortality are well described for coronary artery bypass grafting but are not well understood for combined valve and bypass surgery. METHODS: We reviewed retrospectively the morbidity and mortality of 1570 consecutive patients who underwent combined valve and bypass procedures at the Toronto General Hospital between January 1990 and October 2000. RESULTS: There were 1073 men (68%) and 497 women (32%). The mean ages (+/- 1 SD) of women and men were 69 +/- 9 and 68 +/- 9 years, respectively (P =.02). Of the 1570 total patients, 973 patients (62%) underwent aortic valve and coronary bypass surgery, 481 patients (31%) had mitral valve and coronary bypass operations, and 116 (7%) patients had double or triple valve and coronary bypass operations. Preoperative hypertension (P =.002), diabetes (P =.001), and atrial fibrillation (P =.001) were seen more frequently in women. Body surface area was significantly lower in women (P =.0001). At presentation, more women were in congestive heart failure (69% vs 58%, P =.001) and in New York Heart Association functional class III or IV (25% vs 19%, P =.001). Although there was no difference in the number of women with three or more diseased vessels (32% vs 38%), only 35% of women received three or more grafts compared with 44% of men (P =.001). The use of left internal thoracic grafts, although uncommon in the whole study population (36%), was less common in women than in men (26% vs 41%, P =.001). Multivariable logistic analyses for morbidity and mortality showed female gender to be an independent risk factor. Mitral valve replacement, age, left ventricular dysfunction, New York Heart Association classes III and IV, and association of tricuspid valve disease, diabetes, peripheral vascular disease, and preoperative renal failure were found to be independent risk factors for mortality. CONCLUSION: Female gender is an independent risk factor for combined morbidity and mortality during and after combined valve and coronary bypass surgery. As with isolated coronary artery bypass grafting, women undergoing combined procedures have more premorbid conditions, are more often in heart failure, had an equal incidence of triple vessel disease but received fewer grafts than men, and, therefore, were more frequently incompletely revascularized.     

Early mortality in coronary bypass surgery: the EuroSCORE versus The Society of Thoracic Surgeons risk algorithm

BACKGROUND: We compare two widely used risk algorithms for coronary bypass surgery: The European System for Cardiac Operative Risk Evaluation (EuroSCORE) and The Society of Thoracic Surgeons (STS) risk stratification algorithm. METHODS: Risk factors for all adult patients undergoing heart surgery at the University Hospital of Lund between 1996 and 2001 were collected prospectively at preoperative admission. Predictive accuracy for 30-day mortality was assessed by comparing the observed and the expected mortality for equal-sized quintiles of risk by using the Hosmer-Lemeshow goodness-of-fit test. The discriminatory power was evaluated by calculating the areas under receiver operating characteristics (ROC) curves. RESULTS: The study included 4497 coronary artery bypass-only operations. The average age was 66.4 +/- 9.3 years (range 31 to 90 years). Most patients were men (77.0% versus 23.0%). The actual 30-day mortality was 1.89%. The Hosmer-Lemeshow goodness-of-fit test gave a p value of 0.81 (EuroSCORE) and 0.83 (STS), which indicates a good accuracy of both models. The area under the ROC curve was 0.84 (95% confidence interval [CI] 0.80 to 0.88) for EuroSCORE and 0.71 (95% CI 0.66 to 0.77) for STS. The discriminatory power (area under the ROC curve) was significantly larger for EuroSCORE compared with STS (p < 0.00005). CONCLUSIONS: In this large, single institution study the additive EuroSCORE algorithm had a significantly better discriminatory power to predict 30-day mortality than the STS risk algorithm for patients undergoing coronary artery bypass.     

The logistic EuroSCORE predicts the hospital mortality of the thoracic aortic surgery in consecutive 327 Japanese patients better than the additive EuroSCORE.

OBJECTIVE: Risk stratification in thoracic aortic surgery is a topic of major interest. Recent studies have shown the European System for Cardiac Operative Risk Evaluation (EuroSCORE) to be an extremely useful and reliable risk stratification score and also a good indicator of quality of care in cardiac surgery. The purpose of this study was to evaluate the significance of the additive and logistic EuroSCOREs in patients undergoing surgery on the thoracic aorta in Japan. METHODS: We calculated the predicted mortality according to the additive and logistic EuroSCORE algorithms in 327 consecutive patients who underwent surgery of the thoracic aorta during a 30-year period (between 1976 and 2005). We compared the score validity between the two algorithms and also evaluated the score validity for the patients who underwent thoracic aortic surgery. The score validity was assessed by calculating the area under the receiver operating characteristic (ROC) curve. RESULTS: The overall in-hospital mortality was 13%. The area under the ROC curve was satisfactorily high for the additive (0.68, 0.73, 0.73) as well as the logistic EuroSCORE (0.69, 0.74, 0.75) in the patients who underwent thoracic aortic surgery during 30-, 20-, and 10-year periods, respectively. The actual mortality was 7% (Group 1; an additive EuroSCORE of 3-6), 16% (Group 2; 7-11), and 37% (Group 3; >12). The mortality expected by the additive and logistic EuroSCORE in the three different risk groups were (5%, 9%, 19%) and (5%, 14%, 43%), respectively. Namely, the mortality expected by the logistic EuroSCORE perfectly matched with the actual mortality in any of the three risk groups. In contrast, the mortality expected by the additive EuroSCORE tended to dissociate when the number of risks increased. Significant difference was observed between the observed mortality and the mortality expected by the additive EuroSCORE algorithm in the high-risk group (p=0.0473). CONCLUSIONS: Although both the additive and the logistic EuroSCORE reliably predicted the overall operative mortality for thoracic aortic surgery in 327 Japanese patients, the logistic EuroSCORE better matched with the actual mortality in the operative risk especially in the high-risk group.     

Repeat heart valve surgery: risk factors for operative mortality.

BACKGROUND: Patients undergoing repeat heart valve operations are a diverse population. We assessed risk factors for operative mortality in patients undergoing a first heart valve reoperation. METHODS: A retrospective review of hospital records was performed for 671 patients who underwent first repeat heart valve operations between 1969 and 1998. Univariable and multivariable analyses were performed. RESULTS: Operative mortality was 8.6%. Mortality fell each decade to 4.8% in the most recent period (adjusted chi(2) for linear trend P <.0005). Mortality increased from 3.0% for reoperation for a failed repair or reoperation at a new valve site to 10.6% for prosthetic valve dysfunction or periprosthetic leak and to 29.4% for endocarditis or valve thrombosis. Concomitant coronary artery bypass grafting was associated with a mortality of 15.4% compared with 8.2% when it was not required. Mortality for aortic valve replacement was 6.4%, mitral valve replacement 7.4%, aortic and mitral valve replacement 11.5%, tricuspid valve replacement 25.6%, periprosthetic leak repair 9.1%, and isolated valve repair 2.2%. Among 336 patients requiring replacement of prosthetic valves, mortality was 26.1% for replacement of a mechanical valve compared with 8.6% for replacement of a tissue valve (P <.0005). Multivariable analyses identified year of reoperation, age, coronary artery bypass grafting, indication, and replacement of a mechanical valve rather than a tissue valve as significant explanatory variables for operative mortality. CONCLUSIONS: Heart valve reoperations can be performed with an acceptable operative mortality. However, we have identified several categories of patients in whom reoperation carries an increased risk.     

A multi-centre additive and logistic risk model for in-hospital mortality following aortic valve replacement.

OBJECTIVE: To develop a multivariate prediction model for in-hospital mortality following aortic valve replacement. METHODS: Retrospective analysis of prospectively collected data on 4550 consecutive patients undergoing aortic valve replacement between 1 April 1997 and 31 March 2004 at four hospitals. A multivariate logistic regression analysis was undertaken, using the forward stepwise technique, to identify independent risk factors for in-hospital mortality. The area under the receiver operating characteristic (ROC) curve was calculated to assess the performance of the model. The statistical model was internally validated using the technique of bootstrap resampling, which involved creating 100 random samples, with replacement, of 70% of the entire dataset. The model was also validated on 816 consecutive patients undergoing aortic valve replacement between 1 April 2004 and 31 March 2005 from the same four hospitals. RESULTS: Two hundred and seven (4.6%) in-hospital deaths occurred. Independent variables identified with in-hospital mortality are shown with relevant co-efficient values and p-values as follows: (1) age 70-75 years: 0.7046, p<0.001; (2) age 75-85 years: 1.1714, p<0.001; (3) age>85 years: 2.0339, p<0.001; (4) renal dysfunction: 1.2307, p<0.001; (5) New York Heart Association class IV: 0.5782, p=0.003; (6) hypertension: 0.4203, p=0.006; (7) atrial fibrillation: 0.604, p=0.002; (8) ejection fraction<30%: 0.571, p=0.012; (9) previous cardiac surgery: 0.9193, p<0.001; (10) non-elective surgery: 0.5735, p<0.001; (11) cardiogenic shock: 1.1291, p=0.009; (12) concomitant CABG: 0.6436, p<0.001. Intercept: -4.8092. A simplified additive scoring system was also developed. The ROC curve was 0.78, indicating a good discrimination power. Bootstrapping demonstrated that estimates were stable with an average ROC curve of 0.76, with a standard deviation of 0.025. Validation on 2004-2005 data revealed a ROC curve of 0.78 and an expected mortality of 4.7% compared to the observed rate of 4.1%. CONCLUSIONS: We developed a contemporaneous multivariate prediction model for in-hospital mortality following aortic valve replacement. This tool can be used in day-to-day practice to calculate patient-specific risk by the logistic equation or a simple scoring system with an equivalent predicted risk.     

Risk stratification analysis of operative mortality in heart and thoracic aorta surgery: comparison between Parsonnet and EuroSCORE additive model.

OBJECTIVE: Our purpose was to compare the performance of risk stratification model between Parsonnet and European System for Cardiac Operative Risk Evaluation (EuroSCORE) in our patient database. METHODS: From August 1994 to December 2000, 803 consecutive patients have undergone heart and thoracic aorta surgery using cardiopulmonary bypass and scored according to Parsonnet and EuroSCORE algorithm. The population was divided into five clinically relevant risk categories. We compared correlation of predicted mortality and observed mortality between these two models. Score validity was assessed by calculating the area under the receiver operating characteristic (ROC) curve. RESULTS: Overall hospital mortality was 4.5%. In Parsonnet model, predicted mortality was 2.4% for 0-4% risk, 6.7% for 5-9% risk, 12% for 10-14% risk, 17% for 15-19% risk, 25% for 20% plus risk, and 10.4% for overall patients. Observed mortality was 2.4, 0.4, 5.9, 8.7, 11, and 4.5%, respectively. The thoracic aorta and valve cohort indicated poor correlation between predicted and observed mortality compared to coronary cohort. In the EuroSCORE model, predicted mortality was 1.4% for 0-2% risk, 4.0% for 3-5% risk, 6.7% for 6-8% risk, 9.7% for 9-11% risk, 13% for 12% plus risk, and 5.3% for overall patients. Actual mortality was 0, 1.5, 6.8, 11, 21, and 4.5%, respectively. Each of the thoracic aorta, valve, and coronary cohort indicated good correlation between predicted and observed mortality. Areas under the ROC curves were 0.72 in Parsonnet and 0.82 in EuroSCORE. CONCLUSIONS: The EuroSCORE additive model yielded good predictive value for hospital mortality of Japanese patients undergoing not only cardiac but also thoracic aortic surgery.     

Performance of EuroSCORE II compared to EuroSCORE I in predicting operative and mid-term mortality of patients from a single center after combined coronary artery bypass grafting and aortic valve replacement

Objective

The performance comparison of the recently introduced European System for Cardiac Operative Risk Evaluation II in predicting operative as well as mid-term mortality, with its previous version in patients after combined aortic valve replacement and coronary artery bypass grafting surgery.

Methods

This retrospective analysis included 216 patients operated on at one institution from 01/1999 to 12/2005. Accuracy and calibration of EuroSCORE I and II were assessed by plotting the areas under the receiver operator curves and comparing observed and predicted mortalities.

Results

EuroSCORE II showed, regarding early mortality, a slightly higher discriminatory accuracy with an area under the receiver operator curve of 0.77, while additive and logistic EuroSCORE I areas were 0.749, 0.75, respectively. The highest specificity and sensitivity level was approached for EuroSCORE II at a predicted mortality of 4.4 %. Receiver operator curves concerning mid-term mortality revealed areas for additive, logistic EuroSCORE and EuroSCORE II of 0.745, 0.739 and 0.718 with the highest accuracy levels at predicted mortalities of 6.5, 6.48 and 3.88 %, respectively. Mean predicted mortalities by logistic EuroSCORE and EuroSCORE II were 8.35 and 3.99 %, respectively, while overall observed operative mortality was 6.3 %. In “high-risk” patients (EuroSCORE > 13), EuroSCORE II underestimated early and mid-term outcomes.

Conclusions

Regarding operative mortality, EuroSCORE II showed in this study a slightly higher discriminatory accuracy than EuroSCORE I. There were no significant differences in the calibration of the two model versions in “low-” and “moderate-risk” patients regarding early as well as mid-term mortality. Analyses in larger patient populations will contribute to further model improvement.     

Comparison of short-term mortality risk factors for valve replacement versus coronary artery bypass graft surgery

BACKGROUND: Risk factors for 30-day operative (short-term) mortality following coronary artery bypass graft (CABG only) procedures are well established. However, little is known about how the risk factors for short-term mortality following valve replacement procedures (with or without a CABG procedure performed) compare with CABG only risk factors. METHODS: Department of Veterans Affairs (VA) records (65,585 records) were collected from October 1991 through March 2001 and analyzed. Risk factors for short-term mortality were compared across three subgroups of patients: CABG only surgery (n = 56,318), aortic valve replacement (AVR) with or without CABG (n = 7450), and mitral valve replacement (MVR) with or without CABG (n = 1817). Multivariable logistic regression analyses were used to compare the relative magnitude of risk for 19 candidate predictor variables across subgroups. RESULTS: Only three patient baseline characteristics differed significantly in magnitude of risk between the procedure groups. Partially or totally dependent functional status significantly increased the risk of short-term mortality for AVR patients (odds ratio [OR] 1.64, 95% confidence interval [CI] 1.29-2.09) and MVR patients (OR 2.21, 95% CI 1.48-3.30), but not for CABG only patients (OR 1.04, 95% CI 0.93-1.16). Conversely, previous heart surgery and New York Heart Association functional class III or IV symptoms conferred greater magnitude of risk for CABG only patients compared with the valve subgroups. CONCLUSIONS: Overall, the risk factors for short-term mortality following valve replacement and CABG surgery appear to be relatively consistent. However, clinicians should be aware of the importance of preoperative functional status as a unique predictor of mortality following valve surgery.     

非体外循环冠状动脉旁路移植术后早期死亡风险预测——SinoSCORE与EuroSCORE评分的对比

目的 比较中国冠状动脉旁路移植手术评分系统(SinoSCORE)和欧洲心脏外科手术风险评分系统(EuroSCORE)对中国人群非体外循环冠状动脉旁路移植(OPCAB)术后早期死亡风险的预测价值.方法 OPCAB病人资料来自中国心血管外科注册登记研究2004-2005年数据库,观察终点为术后院内死亡.分别用SinoSCORE和logistic EuroSCORE两种模型计算病人预计病死率,并与实际病死率比较.校准度采用Hosmer-Lemeshow拟合优度检验,利用 ROC曲线下面积(AUC)评价模型的区分度.结果 4920例病人中73例发生院内死亡,实际病死率1.48%,SinoSCORE模型和EuroSCORE模型预测的病死率分别为2.73%、4.13%.SinoSCORE模型Hosmer-Lemeshow拟合优度检验P=0.636,AUC=0.794;EuroSCORE模型Hosmer-Lemeshowrny拟合优度检验P=0.01,AUC=0.756.SinoSCORE和logistic EuroSCORE两种模型的区分度均较好,但SinoSCORE的校准度明显优于后者,即两种模型均能预测术后死亡,但SinoSCORE对术后病死率的预测更加准确.结论 SinoSCORE模型比EuroSCORE模型更适用于中国非体外循环冠状动脉旁路移植病人术后早期死亡预测.     

Application of European system for cardiac operative risk evaluation (EuroSCORE) in coronary artery bypass surgery for Taiwanese

The applicability for Taiwanese cardiac surgery is unclear. The preliminary goal of our study was to evaluate the validity of EuroSCORE in coronary artery bypass surgery (CABG). From January 1999 to January 2004, 801 consecutive adult patients who received primary or re-operative off- and on-pump CABG in our institute were collected. Both simple additive and logistic scores were calculated. Patients were categorized into low-risk group (simple additive score 0-2), medium-risk group (simple additive score 3-5), and high-risk group (simple additive score 6 plus). Mean age was 68.0+/-10.1 years. Patients aged 75 or more were 27.6%. Male-to-female ratio was 3.8:1. The mean simple additive and logistic scores of all patients were 5.0+/-3.5 and 8.0+/-11.9, respectively. The observed overall average mortality rate was 10.6%. There were 18.6% of patients in low-risk group, 40.0% in medium-risk group, and 41.4% in high-risk group. The mortality rate was 3.3% in low-risk group, 5.3% in medium-risk group, 19.0% in high-risk group. The area under the curve (c-index) was 0.75 for the simple additive score and 0.74 for the logistic score. Our results suggest that despite demographic differences, our study demonstrates preliminarily that EuroSCORE is valid in CABG for Taiwanese.     

Risk stratification analysis of operative mortality in isolated coronary artery bypass graft patients in Pakistan: comparison between additive and logistic EuroSCORE models

We compared the performances of the additive and logistic EuroSCORE in predicting mortality in patients undergoing isolated coronary artery bypass grafting at a single institution in Pakistan. Both models were applied to 2004 patients, operated upon at the Aga Khan University Hospital from January 2006 to July 2010. The actual mortality (3.8%) was significantly different from the additive (4.35%) and the logistic (6.41%) estimates. On the basis of degree of risk, actual mortality was 0.6% in the low-risk (additive EuroSCORE 0-4), 4.2% in the medium-risk (EuroSCORE 5-9) and 19.1% in the high-risk (EuroSCORE 10-19) group. With the low risks, both systems slightly overestimated mortality, with the logistic EuroSCORE being more accurate. At a EuroSCORE of between 10 and 19, the additive EuroSCORE underestimated and logistic EuroSCORE overestimated mortality. Both models satisfactorily discriminated outcomes (receiver operating characteristics areas of 0.866 and 0.859 for the additive and the logistic model, respectively). The Hosmer-Lemeshow test showed that calibration was good for the additive model (P=0.424) but turned out to be inadequate for the logistic model (P<0.001). We conclude that the additive EuroSCORE is a more accurate model for risk assessment compared to the logistics model in the Pakistani population.     

Off pump coronary artery bypass grafting in EuroSCORE high and low risk patients.

OBJECTIVE: Off pump coronary artery bypass grafting (OPCAB) is claimed to reduce the operative morbidity and mortality in high risk patients. It was the aim of the study to compare the outcome of OPCAB patients classified as high- and low risk according to the EuroSCORE. METHODS: Medical records of patients undergoing off pump coronary artery bypass grafting (n=126) at our institution between 1998 and 2001 were retrospectively reviewed. We classified them into two subgroups: low risk (EuroSCORE < or = 5, n=72, male 58 (81%), female 14 (19%), age 61 (37-78) years) and high risk (EuroSCORE >5, n=54, male 32 (59%), female 22 (41%), age 73 (42-83) years). RESULTS: EuroSCORE high risk patients showed significantly higher rates of blood transfusion (70 vs 31%; P<0.0001), intraaortic balloon pump insertion (16 vs 3%; P=0.013), atrial fibrillation (43 vs 22%; P=0.014), and renal failure (13 vs 3%; P=0.028). ICU length of stay was significantly longer in the high risk group (25 vs 22 h; P=0.002). There was also a higher perioperative mortality in the high risk group (9 vs 0%; P=0.008). CONCLUSION: From these data we conclude that using off pump coronary artery bypass grafting results as predicted by the EuroSCORE can be achieved. OPCAB is safe for low risk patients. Major complications seem to occur preferentially in the high risk group.