CT Coronary Angiography in Patients With Chest Pain
CT Coronary Angiography in Patients With Chest Pain
Current European Society of Cardiology guidelines state that in troponin-negative acute coronary syndrome with no ST-segment change on electrocardiogram (ECG), a stress test is recommended. In the UK, exercise tolerance testing (ETT) is currently the most common first-line test. The high proportion of false-positive and inconclusive results often mandates second-line tests. We compared the diagnostic accuracy and cost implication of computed tomography coronary angiography (CTCA) as first-line investigation compared with ETT. We hypothesised that CTCA would outperform ETT because of its excellent negative-predictive value.
Our results suggest that it is feasible to use CTCA to investigate patients with acute low-to-intermediate likelihood chest pain in place of ETT at no extra cost. Moreover, this cost analysis only took into consideration the actual cost of investigation. Three US clinical trials have shown that CTCA in the emergency room can substantially reduce patient length of stay, reducing overall cost further. CTCA also recognises non-obstructive coronary atheroma, which, combined with clinical risk factors, may prompt the physician to initiate secondary prevention medication earlier.
Multi-detector computed tomography coronary angiography (CTCA) is becoming increasingly available in UK Hospitals. The National Institute for Health and Clinical Excellence (NICE) clinical guideline 95, released in 2010, recommended the use of calcium score ± CTCA in patients with low likelihood chest pain of recent onset. American College of Cardiology (ACC)/American Heart Association (AHA) appropriateness criteria for CTCA recommend its use in patients with low or intermediate likelihood chest pain. The rationale for the recommendations of CTCA is its excellent negative-predictive value. A further important point is that functional imaging tests may exclude the presence of ischaemia but not the presence of coronary artery disease (CAD). CTCA will rule out significant CAD (<50%) reliably, but may demonstrate the presence of milder degrees of CAD in some of the patients. Recent data from the Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry (CONFIRM) registry demonstrated that these patients are at an increased risk of future events and, hence, should benefit from secondary prevention.
Current European Society of Cardiology (ESC) guidelines state that in troponin-negative acute coronary syndrome with no ST-segment change on electrocardiogram (ECG), a stress test is recommended. In patients with significant ischaemia during the stress test, invasive coronary angiography (ICA) and subsequent revascularisation is recommended. The guidelines also recommend CTCA as an alternative to functional testing. In the UK, exercise tolerance testing (ETT) is the most common first-line test in patients presentingwith troponin-negative acute chest pain. The high proportion of false-positive and inconclusive results often mandates second-line tests. We evaluated the diagnostic accuracy and cost implications of CTCA as a first-line investigation in a cohort of patients admitted to our district general hospital (DGH) emergency medical service, with troponin-negative acute onset chest pain, and low-to-intermediate risk as defined by Thrombolysis in Myocardial Infarction (TIMI) score. We compared them with a similar cohort of patients who were investigated with ETT prior to the introduction of CTCA in our DGH. We hypothesised that CTCA would outperform ETT because of its excellent negative-predictive value.
Abstract and Introduction
Abstract
Current European Society of Cardiology guidelines state that in troponin-negative acute coronary syndrome with no ST-segment change on electrocardiogram (ECG), a stress test is recommended. In the UK, exercise tolerance testing (ETT) is currently the most common first-line test. The high proportion of false-positive and inconclusive results often mandates second-line tests. We compared the diagnostic accuracy and cost implication of computed tomography coronary angiography (CTCA) as first-line investigation compared with ETT. We hypothesised that CTCA would outperform ETT because of its excellent negative-predictive value.
Our results suggest that it is feasible to use CTCA to investigate patients with acute low-to-intermediate likelihood chest pain in place of ETT at no extra cost. Moreover, this cost analysis only took into consideration the actual cost of investigation. Three US clinical trials have shown that CTCA in the emergency room can substantially reduce patient length of stay, reducing overall cost further. CTCA also recognises non-obstructive coronary atheroma, which, combined with clinical risk factors, may prompt the physician to initiate secondary prevention medication earlier.
Introduction
Multi-detector computed tomography coronary angiography (CTCA) is becoming increasingly available in UK Hospitals. The National Institute for Health and Clinical Excellence (NICE) clinical guideline 95, released in 2010, recommended the use of calcium score ± CTCA in patients with low likelihood chest pain of recent onset. American College of Cardiology (ACC)/American Heart Association (AHA) appropriateness criteria for CTCA recommend its use in patients with low or intermediate likelihood chest pain. The rationale for the recommendations of CTCA is its excellent negative-predictive value. A further important point is that functional imaging tests may exclude the presence of ischaemia but not the presence of coronary artery disease (CAD). CTCA will rule out significant CAD (<50%) reliably, but may demonstrate the presence of milder degrees of CAD in some of the patients. Recent data from the Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry (CONFIRM) registry demonstrated that these patients are at an increased risk of future events and, hence, should benefit from secondary prevention.
Current European Society of Cardiology (ESC) guidelines state that in troponin-negative acute coronary syndrome with no ST-segment change on electrocardiogram (ECG), a stress test is recommended. In patients with significant ischaemia during the stress test, invasive coronary angiography (ICA) and subsequent revascularisation is recommended. The guidelines also recommend CTCA as an alternative to functional testing. In the UK, exercise tolerance testing (ETT) is the most common first-line test in patients presentingwith troponin-negative acute chest pain. The high proportion of false-positive and inconclusive results often mandates second-line tests. We evaluated the diagnostic accuracy and cost implications of CTCA as a first-line investigation in a cohort of patients admitted to our district general hospital (DGH) emergency medical service, with troponin-negative acute onset chest pain, and low-to-intermediate risk as defined by Thrombolysis in Myocardial Infarction (TIMI) score. We compared them with a similar cohort of patients who were investigated with ETT prior to the introduction of CTCA in our DGH. We hypothesised that CTCA would outperform ETT because of its excellent negative-predictive value.
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