Does CT Coronary Angiography Have a Role in CABG?
Does CT Coronary Angiography Have a Role in CABG?
Multi-detector computed tomography coronary angiography (CTCA) is now an established highly effective non-invasive test in patients with chest pain and a low-to-intermediate pre-test likelihood of having coronary artery disease (CAD), as it has excellent sensitivity and negative predictive value (NPV). The limiting factors for CTCA are fast or irregular heart rate, a very high body mass index (BMI), the presence of extensive calcium in the coronary arteries and radiation. Recent introduction of prospectively gated acquisition in CTCA, where the acquisition is limited to 10% of the cardiac cycle at end-diastole, has dramatically reduced the radiation dose to 2–3 mSv for CTCA of the native coronary arteries, but this is only possible in patients with a regular rhythm below 60 bpm. Otherwise, retrospectively gated CTCA with electrocardiographically controlled tube current modulation (ECTCM) during the cardiac cycle keeps the dose below 10 mSv. The CTCA scan range in patients with coronary artery bypass grafts (CABG) is from the level of the subclavian arteries to below the diaphragm, which is twice the length of a CTCA for the native coronary arteries, and, hence, doubles the radiation dose. However, while the low-dose prospectively gated CTCA technique may not be possible in all patients having CTCA of the native coronary arteries, the minimal motion of the grafts means that CABG patients can be adequately imaged even with higher or irregular heart rates or higher BMI with the low-dose technique. The American College of Cardiology (ACC) has recently published appropriateness criteria for the use of CTCA, which included the use in patients with recurrent symptoms after CABG.
Abstract and Introduction
Introduction
Multi-detector computed tomography coronary angiography (CTCA) is now an established highly effective non-invasive test in patients with chest pain and a low-to-intermediate pre-test likelihood of having coronary artery disease (CAD), as it has excellent sensitivity and negative predictive value (NPV). The limiting factors for CTCA are fast or irregular heart rate, a very high body mass index (BMI), the presence of extensive calcium in the coronary arteries and radiation. Recent introduction of prospectively gated acquisition in CTCA, where the acquisition is limited to 10% of the cardiac cycle at end-diastole, has dramatically reduced the radiation dose to 2–3 mSv for CTCA of the native coronary arteries, but this is only possible in patients with a regular rhythm below 60 bpm. Otherwise, retrospectively gated CTCA with electrocardiographically controlled tube current modulation (ECTCM) during the cardiac cycle keeps the dose below 10 mSv. The CTCA scan range in patients with coronary artery bypass grafts (CABG) is from the level of the subclavian arteries to below the diaphragm, which is twice the length of a CTCA for the native coronary arteries, and, hence, doubles the radiation dose. However, while the low-dose prospectively gated CTCA technique may not be possible in all patients having CTCA of the native coronary arteries, the minimal motion of the grafts means that CABG patients can be adequately imaged even with higher or irregular heart rates or higher BMI with the low-dose technique. The American College of Cardiology (ACC) has recently published appropriateness criteria for the use of CTCA, which included the use in patients with recurrent symptoms after CABG.
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