From the Faculty of Medicine, Department of Laboratory Medicine, Children's and Women's Health (KSB, VV), Department of Circulation and Medical Imaging (RS, AW), Norwegian University of Science and Technology, Department of Cardiothoracic Anaesthesia and Intensive Care (RS, HP), Department of Cardiothoracic Surgery (AW) and Department of Immunology and Transfusion Medicine (HP, VV), St Olav's University Hospital, Trondheim, Norway.
Several models for predicting acute kidney injury following cardiac surgery have been published, and various end-point definitions have been used.
Our aim was to investigate how acute kidney injury following cardiac surgery could be most accurately predicted.
Single-centre prospective observational study.
St Olav's University Hospital, Trondheim, Norway, from 2000 to 2007.
All 5029 adult patients undergoing cardiac surgery were considered eligible for participation. Patients who required preoperative dialysis and patients with missing information on preoperative or maximum postoperative serum creatinine concentration were excluded (n=51). A total of 4978 patients were entered into the statistical analyses.
Logistic regression with bootstrapping methods was applied for model development and validation, together with the area under the receiver operating characteristic curve and Hosmer-Lemeshow test. We tested different end-points, exchanged serum creatinine concentration with creatinine clearance or estimated glomerular filtration rate and added intraoperative variables. The main end-point was at least 50% increase in serum creatinine concentration, an increase in concentration by at least 26.4 µmol l(-1) (0.3 mg dl(-1)) or a new requirement for dialysis after surgery.
The final model consisted of 11 preoperative predictors of acute kidney injury: age, BMI, lipid-lowering treatment, hypertension, peripheral vascular disease, chronic pulmonary disease, haemoglobin concentration, serum creatinine concentration, previous cardiac surgery, emergency operation and operation type. The area under the receiver operating characteristic curve was 0.819 (95% confidence interval 0.801 to 0.837), and the Hosmer-Lemeshow test P value was 0.17. Exchanging serum creatinine concentration with glomerular filtration rate or creatinine clearance slightly reduced model discrimination and the addition of intraoperative variables improved discrimination somewhat. Slight end-point definition changes had little impact.
The risk of acute kidney injury can be accurately predicted using preoperative variables. Serum creatinine concentration was more accurate than estimated glomerular filtration rate or creatinine clearance. Intraoperative variables slightly improved the model, but did not seem to outweigh the advantages of a preoperative model.
Accurate models for prediction of a prolonged intensive care unit (ICU) stay following cardiac surgery may be developed using Cox proportional hazards regression. Our aims were to develop a preoperative and intraoperative model to predict the length of the ICU stay and to compare our models with published risk models, including the EuroSCORE II.
Models were developed using data from all patients undergoing cardiac surgery at St. Olavs Hospital, Trondheim, Norway from 2000-2007 (n = 4994). Internal validation and calibration were performed by bootstrapping. Discrimination was assessed by areas under the receiver operating characteristics curves and calibration for the published logistic regression models with the Hosmer-Lemeshow test.
Despite a diverse risk profile, 93.7% of the patients had an ICU stay
Oxidative stress following ischaemia and reperfusion, as well as inflammation, are thought to be important for the development of cardiac dysfunction after cardiac surgery. Our main objective was to investigate whether the inflammatory biomarkers C-reactive protein (CRP), lactoferrin, neopterin and the terminal complement complex (TCC) were associated with cardiac dysfunction after cardiac surgery. Another objective was to assess whether the biomarkers could improve prediction of postoperative cardiac dysfunction compared with clinical variables only.
Blood samples and clinical data from 1018 consecutive patients undergoing cardiac surgery from 1 April 2008 to 19 April 2010 at St. Olavs University Hospital, Trondheim, Norway, were collected prospectively. The end-point was postoperative cardiac dysfunction, defined as the need for more than one inotropic agent or an intra-aortic balloon pump occurring after the operation and until the patient was discharged from the department. CRP, lactoferrin, neopterin and TCC were analysed in plasma, and we used logistic regression to evaluate the association of the biomarkers with postoperative cardiac dysfunction. We adjusted for the following clinical variables previously associated with postoperative cardiac dysfunction: urgent operation, operation type, previous cardiac surgery, chronic heart failure, pulmonary hypertension, previous myocardial infarction and haemoglobin. The likelihood ratio test, the integrated discrimination improvement and receiver operating characteristic (ROC) curves were used to assess whether the biomarkers could improve prediction of postoperative cardiac dysfunction compared with clinical variables alone.
Neopterin was the only biomarker significantly associated with postoperative cardiac dysfunction (odds ratio 2.73, 95% confidence interval 1.65-4.51) after adjustment for clinical variables. Neopterin improved risk prediction of cardiac dysfunction following heart surgery compared with clinical variables alone according to the likelihood ratio test (P
To assess long-term survival and mortality in adult cardiac surgery patients.
8,564 consecutive patients undergoing cardiac surgery in Trondheim, Norway from 2000 until censoring 31.12.2014 were prospectively followed. Observed long-term mortality following surgery was compared to the expected mortality in the Norwegian population, matched on gender, age and calendar year. This enabled assessment of relative survival (observed/expected survival rates) and relative mortality (observed/expected deaths). Long-term mortality was compared across gender, age and surgical procedure. Predictors of reduced survival were assessed with multivariate analyses of observed and relative mortality.
During follow-up (median 6.4 years), 2,044 patients (23.9%) died. The observed 30-day, 1-, 3- and 5-year mortality rates were 2.2%, 4.4%, 8.2% and 13.8%, respectively, and remained constant throughout the study period. Comparing observed mortality to that expected in a matched sample from the general population, patients undergoing cardiac surgery showed excellent survival throughout the first seven years of follow-up (relative survival = 1). Subsequently, survival decreased, which was more pronounced in females and patients undergoing other procedures than isolated coronary artery bypass grafting (CABG). Relative mortality was higher in younger age groups, females and patients undergoing aortic valve replacement (AVR). The female survival advantage in the general population was obliterated (relative mortality ratio (RMR) 1.35 (1.19-1.54), p
The aim was to compare the relative effects of red blood cell (RBC) transfusion and preoperative anaemia on 5-year mortality following open-heart cardiac surgery using structural equation modelling. We hypothesized that patient risk factors associated with RBC transfusion are of larger importance than transfusion itself.
This prospective cohort study, part of the Cardiac Surgery Outcome Study at St. Olavs University Hospital, Trondheim, Norway, included open-heart on-pump cardiac surgery patients operated on from 2000 through 2017 (n?=?9315). Structural equation modelling, which allows for intervariable correlations, was used to analyse pathway diagrams between known risk factors and observed mortality between 30?days and 5?years postoperatively. Observation times between 30?days and 1?year, and 1-5?years postoperatively were also compared with the main analysis.
In a simplified model, preoperative anaemia had a larger effect on 5-year mortality than RBC transfusion (standardized coefficients: 0.17 vs 0.09). The complete model including multiple risk factors showed that patient risk factors such as age (0.15), anaemia (0.10), pulmonary disease (0.11) and higher creatinine level (0.12) had larger effects than transfusion (0.03). Results from several sensitivity analyses supported the main findings. The models showed good fit.
Preoperative anaemia had a larger impact on 5-year mortality than RBC transfusion. Differences in 5-year mortality were mainly associated with patient risk factors.
The aim of this study was to compare long-term mortality in patients undergoing primary isolated coronary artery bypass grafting who received =1 units of red blood cells (RBCs) or no RBCs. We hypothesized that a possible difference in long-term mortality was due to preoperative morbidity and/or postoperative morbidity.
This prospective cohort study, part of the Cardiac Surgery Outcome Study (CaSOS) at St. Olavs University Hospital, Trondheim, Norway, included patients operated on from 2000 through 2014 (n?=?4014) and excluded those with large intra- or postoperative blood loss or 30-day mortality. Observed mortality from 30?days to 15?years postoperatively was compared between patients who received RBC transfusion and those who did not. Cox regression analysis was performed with unadjusted models, adjusting for pre- and intraoperative covariates, and with further adjustment for postoperative complications. Sensitivity analyses were performed with propensity score matching or including 30-day mortality.
The unadjusted hazard ratio (HR) for long-term mortality was 2.10 (1.81-2.43; P?