John Au

The logistic EuroSCORE in cardiac surgery: How well does it predict operative risk?

Objectives: To study the ability of the logistic EuroSCORE to predict operative risk in contemporary cardiac surgery. Design: Retrospective analysis of prospectively collected data. Setting: All National Health Service centres undertaking adult cardiac surgery in northwest England. Patients: All patients undergoing cardiac surgery between April 2002 and March 2004. Main outcome measures: The predictive ability of the logistic EuroSCORE was assessed by analysing how well it discriminates between patients with differing observed risk by using the area under the receiver operating characteristic (ROC) curve and studying how well it is calibrated against observed in-hospital mortality. The performance of the EuroSCORE was examined in the following surgical subgroups: all cardiac surgery, isolated coronary artery surgery, isolated valve surgery, combined valve and coronary surgery, mitral valve surgery, aortic valve surgery and other surgery. Results: 9995 patients underwent surgery. The discrimination of the logistic EuroSCORE was good with a ROC curve area of 0.79 for all cardiac surgery (range 0.71–0.79 in the subgroups). For all operations, the predicted mortality was 5.7% and observed mortality was 3.3%. The logistic EuroSCORE overpredicted observed mortality for all subgroups but by differing degrees (p  =  0.02) Conclusions: The logistic EuroSCORE is a reasonable overall predictor for contemporary cardiac surgery but overestimates observed mortality. Its accuracy at predicting risk in different surgical subgroups varies. The logistic EuroSCORE should be recalibrated before it is used to gain reassurance about outcomes. Caution should be exercised when using it to compare hospitals or surgeons with a different operative case mix.

Has the publication of cardiac surgery outcome data been associated with changes in practice in northwest England: an analysis of 25 730 patients undergoing CABG surgery under 30 surgeons over eight years

Objectives: To study changes in coronary artery surgery practice in the years spanning publication of cardiac surgery mortality data in the UK. Methods: A retrospective analysis of prospectively collected data from all National Health Service centres undertaking adult cardiac surgery in northwest England was carried out. Patients undergoing coronary artery surgery for the first time between April 1997 and March 2005 were included. Changes in observed, predicted and risk adjusted mortality (EuroSCORE) were studied. Evidence of risk-averse behaviour was looked for by examining the number of patients at low risk (EuroSCORE 0–5), high risk (6–10), and very high risk (11 or more), before and after public disclosure. Results: 25 730 patients underwent coronary artery surgery during the study period. The observed mortality decreased from 2.4% in 1997–8 to 1.8% in 2004–5 (p = 0.014). The expected mortality (EuroSCORE) increased from 3.0 to 3.5 (p<0.001). The observed to expected mortality ratio decreased from 0.8 to 0.51 (p<0.05). The total number and percentage of patients who were at low risk, high risk and very high risk was 2694 (84.6%), 449 (14.1%) and 41 (1.3%) before and 2654 (81.7%), 547 (16.8%) and 47 (1.4%) after public disclosure, respectively, demonstrating a significant increase in the number and proportion of high risk patients undergoing surgery (p<0.001). Conclusions: Publication of cardiac surgery mortality data in the UK has been associated with decreased risk adjusted mortality on retrospective analysis of a large patient database. There is no evidence that fewer high risk patients are undergoing surgery because mortality rates are published.

Repair of post-infarct ventricular septal defect with or without coronary artery bypass grafting in the northwest of England: a 5-year multi-institutional experience.

OBJECTIVE To present the 5-year experience of the northwest of Englands surgical repair of post myocardial infarction (MI) ventricular septal defects (VSD). Our primary aim was to evaluate the effect of concomitant coronary artery bypass grafting (CABG) on mid-term survival and also to identify prognostic indicators. METHODS A multi-centre regional observational study involving clinical data from 65 consecutive patients who underwent post MI VSD repair in the northwest of England between April 1997 and March 2002. Both prospective and retrospective collection of preoperative, operative and postoperative information was performed. Patient follow-up was performed by linking their records to the National Strategic Tracing Service database. Multivariate logistic regression and Cox proportional hazards analyses were used to identify independent risk factors for poor prognosis. RESULTS Of the 65 patients included in the study, 42 (64.6%) underwent concomitant CABG with a median of two grafts. The majority of patients who had their coronary arteries grafted had multivessel disease (92.9%). Overall 30-day mortality was 23.1%. Predictors of poor prognosis included preoperative inotropes (P<0.001) and total occlusion of infarct related artery (P=0.03). The crude hazard ratio (HR) of mid-term mortality for concomitant CABG patients was 0.82 [95% confidence interval (CI) 0.38-1.78; P=0.62]. After adjustment for differences in patient and disease characteristics, the adjusted HR of mid-term mortality for concomitant CABG patients was 0.17 (95% CI 0.04-0.74; P=0.019). The adjusted freedom from death in the concomitant CABG patients at 30 days, 1, 2, and 4 years was 96.2%, 91.6%, 88.8%, and 82.8%, respectively, compared with 79.1%, 58.8%, 49.1%, and 32.2% for the non-concomitant CABG patients. CONCLUSION These data provide evidence that concomitant CABG is significantly beneficial to mid-term mortality rates. We recommend that patients who present with post MI VSD who have multivessel disease should be routinely revascularised.

The effect off-pump coronary artery bypass surgery on in-hospital mortality and morbidity.

OBJECTIVE Off-pump coronary artery bypass (OPCAB) surgery is being increasingly reported to show better outcomes compared to conventional on bypass grafting. We examined the effect of OPCAB on in-hospital mortality and morbidity, while adjusting for patient and disease characteristics, in four institutions in the North West of England. METHODS Between April 1997 and March 2001, 10,941 consecutive patients underwent isolated coronary artery bypass surgery at these four institutions. Of these, 7.7% were performed off-pump. We used logistic regression to examine the effect of OPCAB on in-hospital mortality and morbidity after adjusting for potentially confounding variables. RESULTS The crude odds ratio (OR) for death (off-pump versus on-pump coronary bypass grafting) was 0.48 (95% confidence interval, CI 0.26-0.92; P=0.023). After adjustment for all major risk factors, the OR for death was 0.59 (95% CI 0.31-1.12; P=0.105). Off-pump patients had a substantially reduced risk of post-operative stroke (0.6 versus 2.3%, respectively; adjusted OR 0.26 (95% CI 0.09-0.70; P=0.008) and a significant reduction in post-operative hospital stay. Other morbidity outcomes were similar in both groups. CONCLUSIONS Off-pump coronary artery bypass incurs no increased risk of in-hospital mortality. In contrast, there is a significant reduction in morbidity in patients undergoing off-pump coronary bypass grafting when compared to that performed on cardiopulmonary bypass.

Improving mortality of coronary surgery over first four years of independent practice: retrospective examination of prospectively collected data from 15 surgeons

Abstract Objective To study the “learning curve” associated with independent practice in coronary artery surgery. Design Retrospective analysis of prospectively collected data. Setting All NHS centres in north west England that carry out cardiac surgery in adults. Participants 18 913 patients undergoing coronary artery surgery for the first time between April 1997 and March 2003, 5678 of whom were operated on by 15 surgeons in the first four years after their consultant appointment. Main outcome measures Observed and predicted mortality (EuroSCORE) for surgeons in their first, second, third, and fourth years after appointment as a consultant compared with figures for established surgeons. Results Overall mortality decreased over the six years of study (P = 0.01). Of the patients operated on by established surgeons or newly appointed consultants, 265/13 235 (2.0%) and 109/5678 (1.9%), respectively, died (P = 0.71). There was a progressive decrease in observed mortality with time after appointment as a consultant from 2.2% in the first year to 1.2% in the fourth year (P = 0.049). This result remained significant after adjustment for time and case mix (P = 0.019). Conclusions Mortality in patients operated on by newly appointed consultant surgeons is similar to mortality in patients operated on by established surgeons. There are significant decreases in crude and risk adjusted mortality in the four years after appointment. These findings should influence the nature of practice in newly appointed surgeons.

Social deprivation and prognostic benefits of cardiac surgery: observational study of 44 902 patients from five hospitals over 10 years

Objective To assess the effects of social deprivation on survival after cardiac surgery and to examine the influence of potentially modifiable risk factors. Design Analysis of prospectively collected data. Prognostic models used to examine the additional effect of social deprivation on the end points. Setting Birmingham and north west England. Participants 44 902 adults undergoing cardiac surgery, 1997-2007. Main outcome measures Social deprivation with census based 2001 Carstairs scores. All cause mortality in hospital and at mid-term follow-up. Results In hospital mortality for all cardiac procedures was 3.25% and mid-term follow-up (median 1887 days; range 1180-2725 days) mortality was 12.4%. Multivariable analysis identified social deprivation as an independent predictor of mid-term mortality (hazard ratio 1.024, 95% confidence interval 1.015 to 1.033; P<0.001). Smoking (P<0.001), body mass index (BMI, P<0.001), and diabetes (P<0.001) were associated with social deprivation. Smoking at time of surgery (1.294, 1.191 to 1.407, P<0.001) and diabetes (1.305, 1.217 to 1.399, P<0.001) were independent predictors of mid-term mortality. The relation between BMI and mid-term mortality was non-linear and risks were higher in the extremes of BMI (P<0.001). Adjustment for smoking, BMI, and diabetes reduced but did not eliminate the effects of social deprivation on mid-term mortality (1.017, 1.007 to 1.026, P<0.001). Conclusions Smoking, extremes of BMI, and diabetes, which are potentially modifiable risk factors associated with social deprivation, are responsible for a significant reduction in survival after surgery, but even after adjustment for these variables social deprivation remains a significant independent predictor of increased risk of mortality.

Does the choice of risk adjustment model influence the outcome of surgeon specific mortality analysis: a retrospective analysis of 14,637 patients under 31 surgeons

Objectives: To compare implications of using the logistic EuroSCORE and a locally derived model when analysing individual surgeon mortality outcomes. Design: Retrospective analysis of prospectively collected data. Setting: All NHS hospitals undertaking adult cardiac surgery in northwest England. Patients: 14 637 consecutive patients, April 2002 to March 2005. Main outcome measures: We have compared the predictive ability of the logistic EuroSCORE (uncalibrated), the logistic EuroSCORE calibrated for contemporary performance and a locally derived logistic regression model. We have used each to create risk-adjusted individual surgeon mortality funnel plots to demonstrate high mortality outcomes. Results: There were 458 (3.1%) deaths. The expected mortality and receiver operating characteristic (ROC) curve values were: uncalibrated EuroSCORE −5.8% and 0.80, calibrated EuroSCORE −3.1% and 0.80, locally derived model −3.1% and 0.82. The uncalibrated EuroSCORE plot showed one surgeon to have mortality above the northwest average, and no surgeon above the 95% control limit (CL). The calibrated EuroSCORE plot and the local model showed little change in surgeon ranking, but significant differences in identifying high mortality outcomes. Two of three surgeons above the 95% CL using the calibrated EuroSCORE revert to acceptable outcomes when the local model is applied but the finding is critically dependent on the calibration coefficient. Conclusions: The uncalibrated EuroSCORE significantly overpredicted mortality and is not recommended. Instead, the EuroSCORE should be calibrated for contemporary performance. The differences demonstrated in defining high mortality outcomes when using a model built for purpose suggests that the choice of risk model is important when analysing surgeon mortality outcomes.

A validated rule for predicting patients who require prolonged ventilation post cardiac surgery

OBJECTIVE Prolonged ventilation post surgery causes logistic problems on cardiac surgical intensive care units (CSU). We thus sought to derive and validate a clinical decision rule to predict patients at high risk of prolonged ventilation, so that the timing of operations on high risk patients can be optimised in the context of the workload of the CSU. METHODS The North Staffordshire Royal Infirmary (NSRI) Open Heart Registry was analysed from April 1998 to May 2002. Prolonged ventilation was defined as that which was longer than 24 h. The Parsonnet score was assessed for its ability to predict these patients. Univariate analysis was first performed to identify predictive variables. Recursive partitioning and logistic regression was then performed to identify the optimal decision rule. This rule was then validated on the Blackpool Victoria Hospital (BVH) Open Heart Registry. RESULTS A total of 3,070 patients were analysed of whom 201 were ventilated for more than 24 h. A Parsonnet score of 10 predicted 49% of high risk patients but 618 low risk patients are misclassified. Our rule that uses Parsonnet score over 7, ejection fraction, operation status, PA pressure and age, to identify high risk patients identifies 50% of those needing prolonged ventilation and only incorrectly identifies 282 of the 2869 patients with normal ventilation times giving a specificity of over 90%. Validation in the BVH database demonstrated similar findings. CONCLUSION Our rule identifies 14% of all our patients as high risk and 50% of these required prolonged ventilation. Such a rule allows more efficient use of scarce CSU resources by appropriate surgical scheduling.

Derivation and validation of a clinical scoring system to predict the need for an intra-aortic balloon pump in patients undergoing adult cardiac surgery.

The spectrum of patients receiving cardiac surgery are increasing in age and severity of illness. With the reduction of complications caused by the placement of an intra-aortic balloon pump (IABP) there is increasing interest in the placement of an IABP prophylactically. We sought to derive a scoring system to guide the placement of IABPs. A total of 3927 patients from the Blackpool Victoria Open Heart Registry were used to derive a range of clinical decision scores using a range of established and novel statistical techniques. This database included 127 patients who received an IABP. The derived scores and rules were then validated on the North Staffordshire Open Heart Registry, containing 3070 patients, and 161 patients who received an IABP. We derived and validated a clinical score that has a sensitivity of 50% and a specificity of 96.5% in the prediction of those patients requiring an IABP. This was robust in the validation dataset and outperformed the Parsonnet score in this context. Our validated clinical scoring system will be useful both to guide individual clinical decision making and to compare variation of IABP usage among institutions.

Does video-assisted thoracoscopic decortication in advanced malignant mesothelioma improve prognosis?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was: Does video-assisted thoracoscopic (VATS) decortication in advanced malignant mesothelioma improve prognosis? Altogether more than 25 papers were found using the reported search, of which five represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that VATS decortication is useful as a palliative measure in advanced malignant mesothelioma. VATS provides a diagnostic tool, yielding tissue for histological diagnosis. Secondly, drainage of effusion and pleurectomy/decortication improves the quality of life and may increase survival as well.