Performance of the 2-hour Accelerated Diagnostic Protocol Within the American College of Radiology Imaging Network PA 4005 Cohort

ObjectivesThe 2-hour accelerated diagnostic protocol (ADAPT) is a decision rule designed to identify emergency department (ED) patients with chest pain for early discharge. Previous studies in the Asia-Pacific region demonstrated high sensitivity (97.9% to 99.7%) for major adverse cardiac events (MACE) at 30days. The objective of this study was to determine the validity of ADAPT for risk stratification in a cohort of U.S. ED patients with suspected acute coronary syndrome (ACS). MethodsA secondary analysis of participants enrolled in the American College of Radiology Imaging Network (ACRIN) PA4005 trial was conducted. This trial enrolled 1,369 patients at least 30years old with symptoms suggestive of ACS. All data elements were collected prospectively at the time of enrollment. Each patient was classified as low risk or at risk by ADAPT. Early discharge rate and sensitivity for MACE, defined as cardiac death, myocardial infarction (MI), or coronary revascularization at 30days, were calculated. ResultsOf 1,140 patients with complete biomarker data, MACE occurred in 31 patients (2.7%). Among 551 of the 1,140 (48.3%, 95% confidence interval [CI]=45.4% to 51.3%), ADAPT identified for early discharge; five of the 551 (0.9%, 95% CI=0.3% to 2.1%) had MACE at 30days. ADAPT was 83.9% (95% CI=66.3% to 94.5%) sensitive, identifying 26 of 31 patients with MACE. Of the five patients identified for early discharge by ADAPT with MACE, there were no deaths, one patient with MI, and five with revascularizations. ConclusionsIn this first North American application of the ADAPT strategy, sensitivity for MACE within 30days was 83.9%. One missed adverse event was a MI, with the remainder representing coronary revascularizations. The effect of missing revascularization events needs further investigation.