Rule Out Myocardial Infarction by Computer Assisted Tomography

Study Overview
=================
Brief Summary
-----------------
The goal of this research is to determine noninvasively whether detection of coronary stenosis and plaque by multidetector computed tomography (MDCT) in patients with acute chest pain suspected of acute coronary syndrome (ACS) enhances triage, reduces cost and is cost effective. Among the 5.6 million patients with ACP presenting annually in emergency departments (ED) in the United States, a subgroup of two million patients is hospitalized despite normal initial cardiac biomarker tests and electrocardiogram (ECG). This subgroup is at low (20%) risk for ACS during the index hospitalization. Most (80-94%) patients with a diagnosis of ACS have a significant epicardial coronary artery stenosis ( >50% luminal narrowing). However, in -10% of patients non-stenotic coronary plaque triggers events, i.e. vasospasms, leading to myocardial ischemia. Since the absence of plaque excludes a coronary cause of chest pain, these patients could in theory be discharged earlier reducing unnecessary hospital admissions. Recent publications demonstrate high sensitivity and specificity of MDCT for the detection of significant coronary stenosis compared with coronary angiography and the detection of coronary plaque as validated with intravascular ultrasound. Using 64- slice MDCT we propose to study 400 patients with ACP, negative initial cardiac biomarkers and non-diagnostic ECG. We will analyze MDCT images for the presence of significant coronary artery stenosis and plaque and correlate the data with the clinical diagnosis of ACS (AHA guidelines) during the index hospitalization to determine the sensitivity and specificity. MDCT data, risk factors, and the results of standard diagnostic tests available at the time of MDCT will be used to generate a multivariate prediction function and derive a clinical decision rule. Based on this decision rule we will compare the diagnostic accuracies and cost effectiveness of competing strategies. We hypothesize that an MDCT- based diagnostic strategy will reduce the time to diagnosis of ACS, number of hospitalizations, and absolute cost of management of patients with acute chest pain compared to standard clinical care and is cost effective.

Official Title
-----------------
Accuracy of Contrast Enhanced Multidetector Computed Tomography to Identify Cardiac Cause of Symptoms in Patients With Intermediate Likelihood of Acute Coronary Syndrome (ACS) - A Comparison to Standard Care

Conditions
-----------------
Acute Coronary Syndrome, Myocardial Infarction, Unstable Angina Pectoris

Intervention / Treatment
-----------------
* Radiation: Cardiac Computed Tomography


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients with any episode > five minutes of chest pain being admitted to rule out acute coronary syndrome Exclusion Criteria: Positive initial troponin or CK-MB tests Diagnostic ECG changes (ST- segment elevation or horizontal ST- segment depression in more than two contiguous leads) Unstable clinical condition (hemodynamically unstable, ventricular tachycardia, persistent chest pain despite adequate therapy) Creatinine Clearance <50 mL/min Known allergy to iodinated contrast agents Patients on metformin therapy unable or unwilling to discontinue therapy for 48 hours after CT scan procedure Known asthma, reactive airway disease Patients currently in atrial fibrillation Previous intolerance to beta blocker Patients that are referred for coronary angiography/PCI by their PCP or cardiologist.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Acute Chest Pain<br>Patients who presented to the emergency department with acute chest pain, with negative initial biomarkers and normal or non-ischemic ECG | Radiation: Cardiac Computed Tomography<br>* Localization of the heart position in a projectional topographic scan of the chest. Determination of contrast agent transit time: 10 ml contrast agent. CT coronary angiography: CT scan in spiral acquisition mode with 330 ms rotation time, 32 x 0.6 mm collimation, a pitch of 2.8 mm/rotation, tube voltage of 120 kVp, and maximum tube current of 850 mA. 80 ml of contrast agent, followed by 40 ml saline solution will be injected at a rate of 4 ml/s. The mean breath hold duration for this acquisition is approximately 13 seconds.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Accuracy of CT derived features of coronary artery disease and LV function for ACS |  | ED presentation to hospital discharge | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Major adverse cardiac events (MACE) - defined as death, myocardial infarction or coronary revascularization |  | Follow up at 6 months and 2 year after index hospitalization | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
acute chest pain, emergency department, cardiac computed tomography