Economic Evaluation of National Patient Blood Management Clinical Guidelines in Cardiac Surgery.

OBJECTIVES: To the best of our knowledge, no published clinical guidelines have ever undergone an economic evaluation to determine whether their implementation represented an efficient allocation of resources. Here, we perform an economic evaluation of national clinical guidelines designed to reduce unnecessary blood transfusions before, during, and after surgery published in 2012 by Australia's sole public blood provider, the National Blood Authority (NBA). METHODS: We performed a cost analysis from the government perspective, comparing the NBA's cost of implementing their perioperative patient blood management guidelines with the estimated resource savings in the years after publication. The impact on blood products, patient outcomes, and medication use were estimated for cardiac surgeries only using a large national registry. We adopted conservative counterfactual positions over a base-case 3-year time horizon with outcomes predicted from an interrupted time-series model controlling for differences in patient characteristics and hospitals. RESULTS: The estimated indexed cost of implementing the guidelines of A$1.5 million (2018-2019 financial year prices) was outweighed by the predicted blood products resource saving alone of A$5.1 million (95% confidence interval A$1.4 million-A$8.8 million) including savings of A$2.4 million, A$1.6 million, and A$1.2 million from reduced red blood cell, platelet, and fresh frozen plasma use, respectively. Estimated differences in patient outcomes were highly uncertain and estimated differences in medication were financially insignificant. CONCLUSIONS: Insofar as they led to a reduction in red blood cell, platelet, and fresh frozen plasma use during cardiac surgery, implementing the perioperative patient blood management guidelines represented an efficient use of the NBA's resources.

The Real-World Cost-Effectiveness of Coronary Artery Bypass Surgery Versus Stenting in High-Risk Patients: Propensity Score-Matched Analysis of a Single-Centre Experience.

BACKGROUND: There are limited economic evaluations comparing coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) for multi-vessel coronary artery disease (MVCAD) in contemporary, routine clinical practice. OBJECTIVE: The aim was to perform a cost-effectiveness analysis comparing CABG and PCI in patients with MVCAD, from the perspective of the Australian public hospital payer, using observational data sources. METHODS: Clinical data from the Melbourne Interventional Group (MIG) and the Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) registries were analysed for 1022 CABG (treatment) and 978 PCI (comparator) procedures performed between June 2009 and December 2013. Clinical records were linked to same-hospital admissions and national death index (NDI) data. The incremental cost-effectiveness ratios (ICERs) per major adverse cardiac and cerebrovascular event (MACCE) avoided were evaluated. The propensity score bin bootstrap (PSBB) approach was used to validate base-case results. RESULTS: At mean follow-up of 2.7 years, CABG compared with PCI was associated with increased costs and greater all-cause mortality, but a significantly lower rate of MACCE. An ICER of $55,255 (Australian dollars)/MACCE avoided was observed for the overall cohort. The ICER varied across comparisons against bare metal stents (ICER $25,815/MACCE avoided), all drug-eluting stents (DES) ($56,861), second-generation DES ($42,925), and third-generation of DES ($88,535). Moderate-to-low ICERs were apparent for high-risk subgroups, including those with chronic kidney disease ($62,299), diabetes ($42,819), history of myocardial infarction ($30,431), left main coronary artery disease ($38,864), and heart failure ($36,966). CONCLUSIONS: At early follow-up, high-risk subgroups had lower ICERs than the overall cohort when CABG was compared with PCI. A personalised, multidisciplinary approach to treatment of patients may enhance cost containment, as well as improving clinical outcomes following revascularisation strategies.

The burden and implications of preoperative atrial fibrillation in Australian heart valve surgery patients.

BACKGROUND: Atrial fibrillation (AF) is the most common preoperative arrhythmia in heart valve surgery patients and its prevalence is rising. This study aims to investigate the impact of AF on valve surgery early complications and survival and on valve disease of different aetiologies and populations with particular reference to Indigenous Australians with rheumatic heart disease (RHD). METHODS: The Australian and New Zealand Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database was analysed to determine the association between preoperative AF and valve surgery outcome. Its association with demographics, co-morbidities, preoperative status and short and long term outcome was assessed. RESULTS: Outcome of 1594 RHD and 19,029 non-RHD-related surgical procedures was analysed. Patients with preoperative AF were more likely to be older, female, Indigenous, to have RHD and to bear a greater burden of comorbidities. Patients with RHD and preoperative AF had a longer hospital stay and were more likely to require reoperation. Adjusted short (OR 1.4, 95% CI 1.2-1.7) and long term (HR 1.5, 95% CI 1.3-1.7) survival was inferior for patients with non-RHD preoperative AF but was no different for Indigenous and non-Indigenous Australians with RHD. CONCLUSIONS: In this prospective Australian study, patients with valve disease and preoperative AF had inferior short and long term survival. This was particularly the case for patients with non-RHD valve disease. Earlier intervention or more aggressive AF management should be investigated as mechanisms for enhancing postoperative outcomes. This may influence treatment choice and the need for ongoing anticoagulation.

When is 'Urgent' Really Urgent and Does it Matter? Misclassification of Procedural Status and Implications for Risk Assessment in Cardiac Surgery.

BACKGROUND: Many patients classified as "urgent" in Australia New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) registry contradict the prescribed definition (surgery within 72hours of angiogram or unplanned admission). The aim was to examine the impacts of this misclassification on the prediction of 30-day mortality following cardiac surgery. METHODS: The 'reported clinical status' was compared with a 'corrected clinical status' following reclassification based on the standard definition calculated from raw data. Observed-to-predicted risk ratios (OPRs) of 30-day mortality were calculated for the model using reported status and corrected status and compared. A Bland-Altman plot was generated to examine the level of agreement between the two OPRs. RESULTS: Of 18496 cases reported as urgent, 49.9% were operated after 72hours, leading to misclassification of 14.6% in the registry. Misclassified patients had significantly higher mortality (3.5%) than true urgent patients (2.9%). Underweight (OR:1.6,CI:1.2-2.1), dialysis (OR:1.4,CI:1.1-1.7), endocarditis (OR:2.1,CI:1.7-2.5), shock (OR:1.6,CI:1.3-2.0) and poor ejection fraction (OR:1.2,CI:1.1-1.4) were significant predictors of misclassification. Bland- Altman plot demonstrates significant disagreement between two risk estimates (P<0.001). Misclassification results in overestimation of risk by 9.1%. Observed-to-predicted risk increased with corrected definition (0.8975 vs 0.9875), suggesting poorer calibration with reported status. CONCLUSIONS: In the ANZSCTS database, misclassification prevalence is 14.6%. Misclassification compromises the discrimination capacity and calibration of the model and results in overestimation of mortality risk.

AusSCORE II in predicting 30-day mortality after isolated coronary artery bypass grafting in Australia and New Zealand.

OBJECTIVES: To update the Australian System for Cardiac Operative Risk Evaluation (AusSCORE) model for operative estimation of 30-day mortality risk after isolated coronary artery bypass grafting in the Australian population. METHODS: Data were collected by the Australian and New Zealand Society of Cardiac and Thoracic Surgeons registry from 2001 to 2011 in 25 hospitals. A total of 31,250 patients underwent isolated coronary artery bypass grafting and the outcome was 30-day mortality. A total of 2154 (6.9%) patients had 1 or multiple missing values. Missing values were estimated assuming missing completely at random and logistic regression with a generalized estimating equation was used to address within-hospital variance. Bootstrapping methods were used to construct and validate the updated model (AusSCORE II). Also the model was validated on an out-of-creation sample of 4700 patients who underwent bypass surgery in 2012. RESULTS: The average age of the patients was 65.6±12.9 years and 78.6% were male. Thirteen variables were selected in the updated model. The bootstrap discrimination and calibration of the AusSCORE II was very good (receiver operating characteristics [ROC], 82.0%; slope calibration, 0.987). The overall observed/AusSCORE II predicted mortality was 1.63% compared with the original AusSCORE predicted mortality of 1.01%. The validation of the AusSCORE II on the out-of-sample data also showed a high performance of the model (ROC, 84.5%; Hosmer-Lemoshow P value, .7654). CONCLUSIONS: The AusSCORE II model provides improved prediction of 30-day mortality and successfully stratifies patient risk. The model will be useful to improve the preoperative consultation regarding risk stratification in terms of 30-day mortality.