ASSENCE (assessment of cost-effectiveness of several strategies of early diagnosis in patients with acute chest pain and non-conclusive electrocardiogram).

Clinical, economical, organizative, and medico-legal issues raised by management of citizens who come to Emergency Department with acute chest pain and non diagnostic electrocardiogram are well known. Data from the Italian Health Ministry show that, in 1996, 37,444 patients had been discharged from Italian hospitals with the main diagnosis of chest pain. To obtain this "non-diagnosis", it was needed a mean hospital stay of 4.2 days with estimated costs close to $57,000,000. The ASSENCE study is a randomized, multicenter, international trial aimed at comparing three strategies of handling citizens presenting to emergency department for unexplained chest pain in terms of cost/effectiveness ratio and quality of patients' life. The three strategies that will be compared are: 1. current clinical protocols, prescribing an in-hospital observation period and discharge after several hours/days; 2. performing a dobutamine-atropine stress echocardiography between 0 and 18 hours after randomization (at 6 hours after index chest pain onset) and discharging the patients (if negative) immediately thereafter; 3. performing an electrocardiographic exercise stress test between 0 and 18 hours after randomization and discharging the patients (if negative) immediately thereafter. The main ASSENCE study end-point will be assessment of cost/effectiveness of the 3 strategies tested. Costs will be assessed taking into account: hospital stay length, performed diagnostic procedures and treatments during index admission, in-hospital and 2-month follow-up events (cardiac death, myocardial infarction, definite unstable angina, coronary angioplasty, by-pass surgery, re-admission to hospital for chest-pain). A secondary ASSENCE study end-point will be to assess the effect on patient quality of life of the use of the 3 strategies tested. Sample size estimation calculated in order to detect an absolute difference of at least 10% and based on a 30% expected rate of events, was of 186 patients for each strategy tested.