Identifying Patient Risk: The Basis for Rational Discharge Planning After Acute Myocardial Infarction

Variations in the management of patients with chest pain and acute myocardial infarction (MI) can significantly affect hospital length of stay and cost. Risk stratification of such patients, combined with data about effective therapies, provides the basis for developing rational guidelines for patient care that can improve efficiency while maintaining quality of care. Such standardized management approaches are often referred to as pathways or CareMaps. To be most effective in guiding hospital course and early discharge planning, risk stratification strategies must be applied early in a patient's course with continuous updating. The process of identifying risk in a patient with acute chest pain occurs in two segments: assessing the risk of acute MI at presentation, and subsequently assessing the morbidity and mortality risk of patients diagnosed with acute MI. Identification of patient risk at presentation has been the object of intense investigation. The history, physical exam, initial electrocardiogram, and cardiac enzymes are the mainstays of the process, but because of inherent weaknesses in this approach (>25% of acute MIs missed initial screening), several risk stratification models have been developed. To date these models have not been widely employed, however. Very sensitive early cardiac markers, such as troponin T, and the use of diagnostic echocardiography or cardiolite perfusion imaging during pain are also being investigated. Chest pain observation units are an alternate strategy and have obviated the need to admit many low- to moderate-risk chest pain patients. In these protocol-driven units, continuous physiologic monitoring and serial cardiac enzymes and electrocardiography over a 9-12 hour period refine the risk assessment. For the majority who "rule out," the risk of subsequent MI or death is very low. Cost savings due to reduced length of stay and more efficient resource utilization are 63-76% compared with conventional word or cardiac care unit management. For patients with acute MI, baseline characteristics, complications, and laboratory and diagnostic testing help define the risk of morbidity and mortality and guide management through the immediate post-MI phase and long term. Many models incorporating these features have been proposed for risk stratification after acute MI, and they have implications for both timing of discharge and necessary diagnostic testing. Savings by employing risk stratification to guide hospital course and discharge planning could be 30-44% in some patient groups. In conclusion, risk stratification models can facilitate early discharge planning, potentially reducing hospital stay, improving resource utilization, and reducing costs.