Evaluating and Managing Low-Risk Chest Pain in the ED
Evaluating and Managing Low-Risk Chest Pain in the ED
Coronary computed tomography angiography (CCTA) is a test that can rapidly and accurately visualize significant coronary artery stenosis and coronary atherosclerotic plaques. The relationship between such findings and acute coronary syndrome, however, has not been established. The authors of this observational study investigated the utility of CCTA in assessing patients with low to intermediate risk for ACS who present to the ED with acute chest pain.
This was a prospective observational cohort study of patients without established CAD who presented to the ED with a chief complaint of acute chest pain for greater than 5 minutes during the last 24 hours. All patients had a normal initial troponin and an ECG that was negative for ischemic changes. If enrolled, patients underwent a contrast-enhanced CCTA prior to admission to the hospital floor using a 64-slice CT scanner. Images were reconstructed and read by 2 experienced investigators in search of coronary plaque and stenosis. Significant stenosis was defined as a luminal narrowing greater than 50%. If a consensus was not reached, a third expert reader made the final diagnosis. All physicians caring for the patient remained blind to the result of the CCTA. The two clinical endpoints established for the study included ACS during hospitalization and MACE within the 6-month follow-up.
The study enrolled 368 patients, of which 31 were diagnosed with ACS. Of the 337 subjects without ACS, zero suffered a MACE at 6 months. Of the 368 enrolled subjects, 183 were found to have no CAD by CCTA or ACS giving the test a negative predictive value of 100% when completely negative. A plaque with no significant stenosis was found in 117 patients, and 34 were read as positive for stenosis greater than 50%. The specifics of finding plaque and significant stenosis on CCTA were calculated to be 54% and 87% respectively for ACS.
This study demonstrates that CCTA can be utilized for ruling out ACS in low-risk patients presenting with acute chest pain. In the future CCTA may also improve management of acute chest pain as the presence and extent of CAD is considered a powerful predictor of future cardiovascular events. The strength of CCTA, however, is the high NPV for ACS and the fact that half of the patients in the studied population had no CAD detected. Low risk chest pain patients with a negative CCTA can be directly discharged from the ED without further diagnostic testing or hospital admission.
One restraint to this approach in low risk chest pain patients is the associated radiation exposure and its potential long-term affects. The study has limited generalizability because it was at a single center, had a dedicated research team who performed the CCTA exams, and highly experienced personnel to interpret the images. Nonetheless, lack of plaque and stenosis on CCTA can negatively predict ACS independent of cardiovascular risk factors or TIMI risk score. Given the large number of patients with low to intermediate risk of ACS presenting to the ED with chest pain, early CCTA has the potential to significantly improve patient management in the ED.
Coronary Computed Tomography Angiography for Early Triage of Patients With Acute Chest Pain: The Rule Out Myocardial Infarction using Computer Assisted Tomography (ROMICAT) Trial. Hoffmann U, Bamberg F, Chae CU, Nichols JH, Rogers IS, Seneviratne SK, Truong QA, Cury RC, Abbara S, Shapiro MD, Moloo J, Butler J, Ferencik M, Lee H, Jang IK, Parry BA, Brown DF, Udelson JE, Achenbach S, Brady TJ, Nagurney JT. J Am Coll Cardiol. 2009 May 5;53(18):1642-50.
Coronary computed tomography angiography (CCTA) is a test that can rapidly and accurately visualize significant coronary artery stenosis and coronary atherosclerotic plaques. The relationship between such findings and acute coronary syndrome, however, has not been established. The authors of this observational study investigated the utility of CCTA in assessing patients with low to intermediate risk for ACS who present to the ED with acute chest pain.
This was a prospective observational cohort study of patients without established CAD who presented to the ED with a chief complaint of acute chest pain for greater than 5 minutes during the last 24 hours. All patients had a normal initial troponin and an ECG that was negative for ischemic changes. If enrolled, patients underwent a contrast-enhanced CCTA prior to admission to the hospital floor using a 64-slice CT scanner. Images were reconstructed and read by 2 experienced investigators in search of coronary plaque and stenosis. Significant stenosis was defined as a luminal narrowing greater than 50%. If a consensus was not reached, a third expert reader made the final diagnosis. All physicians caring for the patient remained blind to the result of the CCTA. The two clinical endpoints established for the study included ACS during hospitalization and MACE within the 6-month follow-up.
The study enrolled 368 patients, of which 31 were diagnosed with ACS. Of the 337 subjects without ACS, zero suffered a MACE at 6 months. Of the 368 enrolled subjects, 183 were found to have no CAD by CCTA or ACS giving the test a negative predictive value of 100% when completely negative. A plaque with no significant stenosis was found in 117 patients, and 34 were read as positive for stenosis greater than 50%. The specifics of finding plaque and significant stenosis on CCTA were calculated to be 54% and 87% respectively for ACS.
This study demonstrates that CCTA can be utilized for ruling out ACS in low-risk patients presenting with acute chest pain. In the future CCTA may also improve management of acute chest pain as the presence and extent of CAD is considered a powerful predictor of future cardiovascular events. The strength of CCTA, however, is the high NPV for ACS and the fact that half of the patients in the studied population had no CAD detected. Low risk chest pain patients with a negative CCTA can be directly discharged from the ED without further diagnostic testing or hospital admission.
One restraint to this approach in low risk chest pain patients is the associated radiation exposure and its potential long-term affects. The study has limited generalizability because it was at a single center, had a dedicated research team who performed the CCTA exams, and highly experienced personnel to interpret the images. Nonetheless, lack of plaque and stenosis on CCTA can negatively predict ACS independent of cardiovascular risk factors or TIMI risk score. Given the large number of patients with low to intermediate risk of ACS presenting to the ED with chest pain, early CCTA has the potential to significantly improve patient management in the ED.
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