Low-Dose Coronary Computed Tomographic Angiography for Early Triage of Acute Chest Pain

Study Overview
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Brief Summary
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This study is to see whether the low-dose coronary computed tomographic angiography (CCTA) protocol is as safe and efficacious as conventional-dose protocol in early triage of acute chest pain.

Detailed Description
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Currently, CCTA is a valuable tool for early triage of low to intermediate risk acute chest pain patients in emergency department. However, it has been criticized for causing unnecessary radiation exposure in the population where its majority has no coronary lesion. A low-dose CCTA protocol comprised with 1) dedicated cardiac imaging protocol (rather than triple rule-out protocol), 2) prospective gating and 3) without additional imaging for calcium scoring will be used to implement the low-dose imaging. We hypothesized that the low-dose CCTA protocol will be as safe and efficacious as conventional dose protocol while decreasing the amount of radiation exposure significantly.

Official Title
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Safety and Efficacy of Implementing Low-Dose Coronary Computed Tomographic Angiography for Early Triage of Acute Chest Pain in Emergency Department

Conditions
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Chest Pain

Intervention / Treatment
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* Other: Low-dose Cardiac CT protocol
* Other: Conventional cardiac CT protocol


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - Patients visiting emergency department for A) acute onset (<12hr) chest pain or equivalent symptoms B) aged between 25-55, C) that requires to rule out acute coronary syndrome. Exclusion Criteria: Known coronary artery disease and/or any related intervention (STENT, CABG) Elevated cardiac biomarkers (CK-MB, Troponin I) Ischemic ECG changes Documented evidence of low LV systolic function (ejection fraction ≤ 45%) TIMI risk >4 Unstable vital sign (e.g. hypoxemia, shock) Patients with contraindication to iodinated contrast and/or beta blockers including renal failure or reactive airway diseases such as COPD or asthma Atrial fibrillation on initial ECGs Active renal disease, serum creatinine ≥1.5 mg/dl Negative coronary angiography or CCTA within 6 months Modified Wells criteria >4 or D-dimer > 0.5ug/mL Suspicious of aortic dissection or D-dimer > 0.5ug/mL

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Low-dose cardiac CT<br>Patients randomized to this group will be assessed by low-dose cardiac CT protocol. | Other: Low-dose Cardiac CT protocol<br>* A cardiac CT protocol modified for reduction of radiation exposure Prospective gating Range: dedicated imaging (below carina to heart base)<br>|
| Other: Conventional cardiac CT<br>Patients randomized to this group will be assessed by conventional cardiac CT protocol. | Other: Conventional cardiac CT protocol<br>* Conventional CCTA protocol Retrospective gating with tube current modulation Range: dedicated imaging (below carina to heart base)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of patients having hard events (death, MI) after negative low-dose CCTA findings |  | Within one month after discharge from emergency department | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Direct comparison of accuracy (sensitivity, specificity, PPV, NPV) for between low-dose and conventional cardiac CT | The diagnostic accuracy of detecting ACS will be assessed using patient chart review and telephone interview (48-72 hours and one month after discharge) as appropriate. ACS event (and MACE) will be adjudicated by independent cardiologists. | One month after discharge from emergency department | 
| Direct comparison of frequency and overall cost of additional tests such as echocardiography, treadmill test, myocardial SPECT and coronary angiography |  | During 1) index ED visit, which will be an average of 1 day and 2) one-month follow-up period after discharge | 
| Total radiation dose exposed by index CT imaging and additional tests including SPECT and invasive angiography |  | During 1) index ED visit, which will be an average of 1 day and 2) one-month follow-up period after discharge | 
| Total length of ED and hospital stay |  | Time spent for index ED visit, which will be an average of 24 hours and total hospital stay until discharge, which will be an average of 7 days. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Radiation dose reduction, Medical radiation exposure, Acute coronary syndrome, Cardiac computed tomographic angiography