Pilot Safety Study of Coronary CTA for the Diagnosis of Acute Coronary Syndrome in the Emergency Room

Design and Aim: This is a prospective pilot study to evaluate the role of multidetector row computed tomography angiography (CTA) to rule out Acute Coronary Syndrome among patients presenting to the ER with chest pain complaints, non-diagnostic ECG and normal troponins and intermediate pre-test probability for significant CAD.

Methods: Following the initial clinical evaluation and the results of initial ECG, blood test and X-ray, patients meeting the inclusion criteria will be randomized to undergo either a CTA scan or a Exercise Stress Echocardiogram to rule out significant coronary artery disease.

CTA will be carried out in a 64 or 128 slice-CT Scanner (SIEMENS,Somaton Sensation 64 or 128-Flash Definition)following iv administration of iodinated contrast (bolus: 5cc x acquisition time (seg)+ 10 cc). Images will be interpreted by two experienced physicians (radiologist and cardiologist)

Stress Echocardiography will be performed and interpreted by an experienced Echocardiographer (cardiologist).

Clinical decision making: Patients with a positive or inconclusive test in each arm will be admitted to the hospital for treatment or further additional testing, while patients with negative results will be discharged from the ER.

Safety issues: A phone call and chart review will be performed one month and 6 months follow-up to register the occurrence of any major adverse cardiac events, as well as new consultation for chest pain.

Inclusion criteria

• Patient is in Sinus Rhythm
• Typical or atypical chest pain lasting more than 5 min in the last 24 hs.
• Estimated pre-test probability of significant coronary artery disease more than 15%.
• Absence of ECG changes suggestive of myocardial ischemia (ST-segment deviation >1 mm or T Wave inversion > 4 mm in at least two contiguous leads).
• Negative initial troponins I at admission (<0.05 ng/ml)

Exclusion criteria

• Known allergy to iodinated contrast.
• Known renal insufficiency or Creatinine >1.5 mg/dl at admission.
• History of known coronary artery disease or prior myocardial revascularization
• Any of the following:hemodynamic instability, persistent chest pain despite treatment, Systolic blood pressure <100 mm Hg.
• Cardiac arrhythmia with rapid or irregular ventricular response.
• Inability to perform an exercise test.
• Patient is incapable of providing informed consent.