Intra-atrial right coronary artery on dual-source CT: prevalence and characteristics

Abstract

Intra-atrial, intracameral or intracavitary right coronary artery (IARCA) is a rare anomaly in which a segment of the right coronary artery (RCA) courses through the right atrial chamber. Radiologically, IARCA is defined as a segment of RCA that is entirely surrounded by intracavitary contrast in all phases of the cardiac cycle. It was initially described only in post mortem specimens and during cardiac surgeries with an incidence varying between ~0.1% and 1.8% (1, 2). Although current evidence points to it being a benign and incidental anomaly, its importance lies in its identification prior to ablative procedures for arrhythmias, catheterization of the right-sided chambers, and pacemaker implantation. With the indications for patients requiring the above procedures expanding rapidly, it is imperative to identify this anomaly pre-procedurally, as the risk of injury to the intracavitary coronary arterial segment is high. The injury can be thermal damage due to proximity to the ablation tip or due to entanglement during catheterization. IARCA can be detected reliably by using computed tomography coronary angiography (CTCA) and recent studies using CTCA have consistently detected a relatively higher prevalence rate as opposed to earlier studies due to its superior and improved image resolution (3, 4). As we increasingly shift from invasive coronary angiographies to non-invasive cross-sectional modalities, their diagnosis is bound to increase. The advent of dual-source CT scanners has led to tremendous developments in the field of cardiac imaging due to their higher temporal and spatial resolution. The purpose of this study was to identify the prevalence and characteristics of IARCA in the adult population undergoing CTCA on a dual-source CT scanner. PURPOSEWe aimed to determine the prevalence rate and radiological characteristics of intra-atrial right coronary artery (IARCA) in an adult population undergoing computed tomography coronary angiography (CTCA) on a dual-source CT scanner. METHODSOverall, 7114 consecutive CTCAs acquired using a dual-source CT scanner in a high-volume, specialized cardiac care facility were retrospectively analyzed for the presence of IARCA. We scrutinized the CTCA datasets to determine the prevalence rate of IARCA and also to characterize its various imaging features including its length, depth from right atrial wall, segment involved, and presence and absence of atherosclerosis within the involved segment and in the rest of the right coronary artery (RCA). RESULTSThe prevalence of IARCA was 0.29% (21/7114) in our study population. The mean length and depth of the intra-atrial segment was 14.85 mm and 2.57 mm, respectively. The mid-RCA was the most common segment to be involved, and no significant atherosclerosis was noted either in the intra-atrial segment or the rest of the RCA. CONCLUSIONThe prevalence rate of the incidental IARCA in the adult subjects undergoing CTCA is higher than previously reported for anatomical series, as seen in our study using a dual-source scanner. This under...

Intramyocardial and Intra-atrial courses in the Right Coronary Artery: Prevalence and characteristics

“…Consistently, our study con rmed right coronary dominance across all instances, aligning with the extant observations on coronary dominance dynamics in IARCA presentations. [8,11,28]. Our ndings are similar to the literature in this respect.…”

“…Although the literature includes case reports detailing IARCA instances, research series quantifying its prevalence remain scarce. Initially detected solely in post-mortem specimens and during heart surgeries, its observed frequency ranges from 0.1-1.8% [10,11,25]. IARCA's prevalence, as reported in autopsy or surgical cohorts is notably minimal [11].…”

“…Initially detected solely in post-mortem specimens and during heart surgeries, its observed frequency ranges from 0.1-1.8% [10,11,25]. IARCA's prevalence, as reported in autopsy or surgical cohorts is notably minimal [11]. MacAlpine et al quanti ed a 0.1% prevalence in a thousand autopsy evaluations, and [29].…”

“…Initially identi ed in postmortem specimens and during cardiac surgeries, the prevalence of IARCA ranges from approximately 0.1-1.8% [8]. Despite being considered a benign and incidental anomaly, the importance of IARCA lies in its identi cation prior to ablative procedures for arrhythmias, catheterization of the right-sided chambers, and pacemaker implantation [11].…”

Questions about “Intra-atrial right coronary artery on dual-source CT”

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I read with great interest the article by P Ganga et al 1 , "Intra-atrial right coronary artery on dual-source CT: prevalence and characteristics, " published in Diagnostic and Interventional Radiology in the September-October 2021 issue. The authors described the prevalence and radiological features of the intra-atrial course of the right coronary artery (IA-RCA) in adults on coronary computed tomography angiography (CCTA).

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