Author + information
- Marisa Lubbers, MD∗ ( and )
- Koen Nieman, MD, PhD
- ↵∗Department of Cardiology, Erasmus University Medical Center, ’s-Gravendijkwal 230, Room Ca-207a, 3015 CE Rotterdam, the Netherlands
We thank Dr. Desiderio and colleagues for their thoughtful comments in response to our report on radiation exposure of downstream testing in the evaluation of suspected coronary artery disease (1). The skewed distribution of radiation doses required comparison of median values, but as noted, this reflects only part of the exposure to X-ray radiation associated with the respective diagnostic strategies. Whereas, according to protocol, all except 1 patient in the computed tomography (CT) group (99%) of the CRESCENT-II (Comprehensive Cardiac CT Versus Exercise Testing in Suspected Coronary Artery Disease II) trial were exposed to X-radiation, standard care involved X-ray exposure in only 51 of 138 patients (37%) as exercise electrocardiography (ECG) was the predominant initial test. The mean cumulative radiation exposure was 6.6 ± 8.3 mSv for the CT group and 4.3 ± 6.6 mSv for the functional testing group. Although exposure to X-rays represents a drawback of CT, as well as several other diagnostic tests, contemporary CT technology offers various means to reduce dose, including prospective ECG-triggered axial scan protocols, low-kV scanning, and iterative reconstruction. In the CRESCENT-II trial, patients with a low probability of coronary artery disease (CAD), who were more often young and female, underwent triage by calcium imaging, which resulted in lower overall exposure in those most vulnerable to radiation exposure. Although the radiation exposure from dynamic CT myocardial perfusion imaging was 10.6 ± 6.3 mSv, use of CT in selected patients with CAD demonstrated by angiography resulted in an overall median cumulative exposure from CT of 3.1 mSv, which is lower than the median cumulative dose of 10.0 mSv reported in the PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) trial or the 4.1-mSv dose for CT angiography alone reported in the SCOT-HEART (Scottish COmputed Tomography of the HEART) trial (2,3). In our opinion, for patients with suspected CAD, the objective should be to rule out CAD accurately in most patients by relatively simple and low-risk means while reserving a more comprehensive assessment for those patients who may benefit from revascularization.
Please note: This work was supported by the Erasmus University Medical Center and ZonMw. Dr. Lubbers is supported by Dutch Heart Foundation grant NHS 2014T061. Dr. Nieman is supported by Dutch Heart Foundation grant NHS 2014T061; has received institutional research support from Siemens, General Electric Healthcare, Bayer, and HeartFlow; and has received speakers fees from Siemens.
- 2018 American College of Cardiology Foundation