Background: An Acute Myocardial Infarction (AMI) is a medical emergency caused by a clot that interrupts blood supply to an area of the heart. It requires prompt intervention to save life and prevent disabling sequelae. The treatment interventions are thrombolysis or Primary Percutaneous Coronary Intervention (PPCI). Thrombolysis involves intravenous injection of medication to dissolve the clot, while PPCI is an invasive treatment method, undertaken in hospitals that have specialised cardiac catheterisation facilities, which aims to restore blood supply to the effected area. Health outcomes are dependent upon ischemic time, but several meta-analyses have provided evidence that especially stroke and death rates are improved when patients are treated with PPCI. There is limited evidence on the cost effectiveness of this intervention from an Australian perspective.
Aims: To conduct an economic evaluation, specifically a cost utility analysis, comparing PPCI with thromobolysis in the treatment of AMI. A government perspective was used based upon facilities that are currently in operation.
Methods: A decision tree model was constructed to estimate the health consequences from AMI intervention, at 30 days, with thrombolysis versus PPCI. The target population was those suffering AMI, stratified into subgroups based upon time to presentation since the onset of symptoms, which was used as a proxy for ischemic time. The incidence of AMI was taken from the recently released 2003 Australian Burden of Disease Study. The outcomes, survival rate and stroke rate, were taken from two meta-analyses, one by Boersma (2006) the other by Keeley et al (2003). Prices were taken from the National Hospital Cost Data Collection, the Pharmaceutical Benefits Scheme (2003) and Queensland Health wage rates. Uncertainty was included within the model, calculated by Monte Carlo simulation, as where several sensitivity analyses.
Results: Treating the population with PPCI compared to thromobolysis was estimated to result in improved outcomes at an increased cost to the government. The incremental cost effectiveness ratio calculated was estimated to be $17 000 (95% uncertainty interval, 4 000, 9 000) per health adjusted life year.
Discussion: These results show that at a threshold of $50 000 per health adjusted life year treating patients who present to a hospital with cardiac catheterisation facilities was cost effective. The results were robust to a range of sensitivity analyses, therefore, the policy implication was that ppeI was cost effective, hence, should be the treatment of choice for those AMI patients who present to a hospital with cardiac catheterisation.
Key Words: Economic evaluation, Cost effectiveness analysis, Cost utility analysis, Acute Myocardial Infarction, Thrombolysis, Primary percutaneous transelumenal angioplasty, Ischemic Heart Disease.