A Descriptive Analysis of Coronary Computed Tomography Angiography Results among Patients Presenting with Chest Pain...

Chest pain is a frequent reason for evaluation at military treatment facilities in the deployed setting. Deployed persons are generally at low risk of coronary disease as the underlying cause for these symptoms; however, morbidity and mortality from acute coronary syndrome in an austere environment can be catastrophic. For theaters with access to computed tomography (CT), Coronary CT Angiography (CCTA) offers a diagnostic modality to effectively rule out this high-risk diagnosis in low to intermediate risk patients. The researchers present a descriptive analysis of CCTA use at a deployed Role 3 over a deployment rotation spanning 8 months.

The researchers devised a CCTA protocol and delivered this diagnostic modality at a deployed Role 3 MTF. They included patients presenting with chest pain and stratified by the treating cleinician as intermediate risk given a history, electrocardiogram, age, cardiac risk factors, Troponin T, HEART score, and bedside echo when available. The CT scanner used by the researchers was a Siemens SOMATOM go, Top 128 slice, 70 cm bore, equipped with hardware to perform electrocardiography (ECG) gated studies and postprocessing. The researchers beta blocked patients to a target heart rate of 50-60 prior to each study, and administered a single 0.4 mg tab of sublingual nitroglycerin 4-7 minutes prior to starting angiography. They performed pre-angiography unenhanced CCTA to determine calcium score. Later, they performed ECG gated CCTA following intravenous (IV) contrast administration.

The researchers performed four CCTA studies on symptomatic patients, each of whom also received a pre-angiogram CT calcium score. All four patients successfully completed the protocol. All four patients had a calcium score of 0. CCTA was low risk without any visible coronary disease for two patients and non-diagnostic for the remaining two patients. There was no major adverse event. One patient experienced a small volume IV access site infiltration at the end of the contrast bolus injection which did not limit that respective exam. The remaining patients did not experience any minor or major adverse events.

The initial data of this study is proof of concept that CCTA is feasible for assessing intermediate risk patients presenting with acute chest pain in the deployed setting, to rule our coronary pathology. The researchers' initial evaluation shows promise and suggests that this is a useful modality to continue to utilize and study in this environment.