Radiation Dose Reduction Comparing Dual Axis Rotational Coronary Angiography against Conventional Coronary Angiography in a Population with 100% Suspected Coronary Artery Disease: A Randomized Trial

Objective: We sought to compare the radiation dose, contrast volume, and procedure time between dual-axis rotational coronary angiography (DARCA) and conventional coronary angiography (CCA) techniques in a setting characterized by a prevalence of 100% suspected coronary artery disease. Background: Previous studies have shown a reduction in radiation dose and contrast volume using DARCA, but these results have not been replicated in coronary artery disease (CAD) populations. Methods: All-comers, prospective, randomized, open-label trial. Cine acquisition dose-area product (DAP), cumulative Air Kerma (AK), effective dose (E), fluoroscopic time, contrast volume, AK, cine acquisition DAP (CADAP), fluoroscopic DAP (F-DAP) and total DAP were compared between DARCA and CCA groups. Results: We included 503 consecutive patients with suspected CAD, 252 assigned to DARCA and 251 to CCA. Stable coronary artery disease in 465 cases and non-ST elevation acute coronary syndrome in 38. Mean age: 61.88 ± 11.2 years, male gender 70.2%. DARCA arm patients showed lower total E dose (6.85 (4.55-10.83) vs. 7.91 (5.5811.94) Sv; p = 0.0023), and cine E (3.00 (2.00-4.00) vs. 4.00 (3.00-5.00) Sv; p < 0.0001). Total DAP was also lower (40.3 (26.8-63.7) vs. 46.5 (32.8-70.2) Gycm2; p = 0.0023, as a consequence of a lower CADAP (16.3 (10.5-22.9) vs. 23.4 (17.4-32.0) Gycm2; p < 0.0001, with lower AK (367 (2481497) vs. 497 (381-1827) mGy; p < 0.0001, with less contrast medium used (90 (60.0-106.0) vs. 100 (75.0-120.0) ml; p = 0.014. Conclusion: In a population with 100% suspected coronary artery disease, DARCA reduces contrast material volume and radiation dose compared with CCA. Abbreviations CCA: Conventional Coronary Angiography; DARCA: DualAxis Rotational Coronary Angiography; CAD: Coronary Artery Disease; CAG: Coronary Angiography; VTG: Ventriculography; AK: Air Kerma; DAP: Dose-Area Product; CADAP: Cine Acquisition Dose-Area Product 15 ISSN: 2572-3235 DOI: 10.23937/2572-3235.1510054 Szarfer. Int J Radiol Imaging Technol 2019, 5:054 • Page 2 of 5 • second on 27 cm magnification, whereas CCA acquisition was obtained at 15 frames per second on 22 cm magnification. Five experienced operators participated in the study and were encouraged to not modify their usual coronary angiography routines. Data collection and study endpoints Radiation doses were automatically recorded as dose area product (DAP) in Gycm2 and as cumulative Air Kerma (AK) in mGy, at procedure time. DAP is a surrogate measurement for the entire amount of energy delivered to the patient by the x-ray beam and is most often utilized in estimating stochastic risk [14]. Kerma is an acronym for “kinetic energy released in material”; AK represents the energy extracted from the x-ray beam per unit of mass of air in a small-irradiated air volume. Approaches to patient dosimetry are different for procedures that involve the use of fluoroscopy equipment. During these examinations, the tube amps and Kilovolts change continuously because of changes in attenuation through the patient. This means that it is difficult to monitor maximum entrance surface dose (ESD) directly. In these circumstances, DAP or AK area product are assessed and they are easy to measure and to correlate with risk. Additionally, they are independent of the distance from the X-ray tube [15,16]. We use here the dose-area product (DAP), equivalent to air kerma-area product (KAP) proposed by the International Commission on Radiological Units (ICRU 2005) [17]. The dose delivered to the patient is typically measured as “effective dose” (E) in Sievert units (Sv). The International Commission on Radiation Units and Measurements recommends that stochastic and deterministic risks associated with medical exposures be assessed from a detailed knowledge of organ doses, absorbed dose distribution, age and sex [17]. Effective dose is not considered suitable for this purpose by the ICRU. Since, many authors used effective dose as a surrogate quantity to assess patient exposures despite its limitations, in part because it is convenient to use, the latter has been used in this report for purposes of comparison with previous publications. The DAP obtained at procedure time was converted into E using a conversion factor of 0.17 mSv/ Gycm2, as validated by the National Radiological Protection Board (NRPB) [15]. The primary endpoint of this study was to compare the radiation dose measured by cine acquisition DAP and cumulative AK between DARCA and CCA during elective diagnostic CAG and CAG + VTG. Effective dose in Sv, fluoroscopic time (FT) in minutes, contrast volume in ml, AK, cine acquisition DAP (CADAP), fluoroscopic DAP (F-DAP) and total DAP were compared between groups. Baseline demographics and access site were also recorded. Statistical analysis Categorical variables were expressed as numbers or using only 2 acquisitions. Previous studies have shown a reduction in radiation dose and contrast volume using DARCA [11-13], but these results have not been replicated in specific studies in a population with a high prevalence of coronary artery disease. Therefore, we sought to compare the radiation dose, contrast volume, and procedure time between the DARCA and CCA techniques in a setting characterized by a high prevalence of CAD.