Background: Coronary computed tomography angiography (CCTA) accurately identifies coronary artery disease (CAD). However, its use in ED patients with acute chest pain (CP) is controversial. We instituted a HEART (history, ECG, age, risk factors, troponin) score-based protocol to reduce unnecessary advanced testing in ED patients with CP. We hypothesized that the new protocol would reduce the number of CTCAs and increase the percentage of CCTAs demonstrating obstructive CAD.
Methods: Study Design: Before and after study. Setting: Large academic suburban ED. Patients: ED patients with CP undergoing CCTA for suspected acute coronary syndrome (ACS) six months before (1/17-6/17) and six months after (1/18-6/18) instituting the HEART protocol. Interventions: A joint ED-cardiology working group implemented an institutional protocol in July 2017 to identify low risk CP patients (HEART score 3 or less and 2 negative contemporary cardiac troponins at least 3 hours apart) that could be discharged from the ED without further testing. These patients were then seen by cardiology within 72 hours for further evaluation. A random sample (12.5%) of CCTAs were selected from each study period and reviewed.
Outcomes: Percentage of adult ED patients undergoing CCTA and percentage of CCTAs demonstrating obstructive (>50% stenosis) CAD.
Data Analysis: Percentages of CCTAs and percentages of obstructive CCTAs before and after new protocol compared with chi-square tests.
Results: There were 37,365 and 36,173 adult ED visits and 1217 and 1123 CCTAs before and after the new protocol respectively. The percentage of ED patients undergoing CCTA before and after the intervention were 3.3% (95%CI 3.1 to 3.4) and 3.1% (95%CI, 2.9 to 3.3) respectively; mean difference 0.1% (95%CI, -0.1 to 0.4; P=0.25). Among the 300 randomly selected sample of patients undergoing CCTA , mean age was 53 years and females were 53%. The percentage of CCTAs that demonstrated obstructive CAD before and after intervention were 14.7% (95%CI 9.9 to 21.1) and 17.3% (95%CI, 12.1 to 24.2) respectively; mean difference 2.7% (95%CI, -5.7 to 11.0; P=0.53).
Conclusion: Introduction of a HEART score-based protocol did not significantly reduce the percentage of ED patients undergoing CCTA or increase the percentage of CTCAs with obstructive CAD.