Right-sided aortic arch with anomalous coronary artery origin and concomitant Stanford type A dissection: A rare case report

Abstract

Congenital anomalies of the aortic arch are rare and may be incidentally discovered or present with life-threatening complications. We report a case of a 58-year-old man with hypertension and a remote history of smoking, who presented with sudden, severe chest pain radiating to the back, hypotension, tachycardia, and pallor. Bedside ultrasound revealed moderate pericardial effusion and raised suspicion of aortic dissection. ECG-gated CT angiography (CTA) confirmed a Stanford type A aortic dissection with a right-sided aortic arch (RAA) and anomalous origin of the right coronary artery from the left main coronary artery. Despite supportive management and preparation for emergent surgery, the patient developed progressive shock and died. This case highlights the importance of rapid recognition of rare aortic arch anomalies and concomitant coronary anomalies using advanced imaging, which is critical for surgical planning in acute settings.

Introduction

Congenital anomalies of the aortic arch are rare malformations, often associated with other congenital cardiovascular abnormalities, with an estimated prevalence of 0.05%-0.1% in the general population [1,2]. Kommerell first described an aortic arch anomaly involving an aberrant right subclavian artery [3].

These anomalies result from incomplete regression of the fourth primitive dorsal aortic arch during embryogenesis. Edwards’ classification describes 3 major types of right-sided aortic arch (RAA) based on embryological development:

• •Type 1: mirror-image branching
• •Type 2: aberrant left subclavian artery (aLSA)
• •Type 3: isolated left subclavian artery (iLSA)

In 20%-60% of type 2 cases, the aLSA originates from Kommerell’s diverticulum, a saccular dilation predisposing to aneurysm or dissection. Intracardiac and extracardiac anomalies, including tetralogy of Fallot and truncus arteriosus, may coexist. Genetic aberrations, notably 22q11 microdeletion, have also been implicated [[4], [5], [6]].

RAA is usually asymptomatic; symptoms arise from esophageal or tracheal compression or, rarely, from dissection. Dissections associated with type 2 RAA and Kommerell’s diverticulum are well documented [7]. We report a rare case of a 58-year-old man presenting with type 1 RAA, anomalous right coronary artery origin, and acute Stanford type A aortic dissection.

Case presentation

A 58-year-old male with a 10-year history of hypertension and a remote history of smoking (quit 20 years ago) presented to the emergency department with sudden, severe chest pain radiating to the back, accompanied by profuse sweating and nausea. On initial examination, he was hypotensive (BP 90/60 mmHg), tachycardic (110 bpm), and pale. His past surgical history was unremarkable, and his father had died from myocardial infarction at age 62.

Bedside ultrasound revealed moderate pericardial effusion and suspicion of aortic dissection. Laboratory tests showed leukocytosis (WBC 14,000/µL), mildly elevated troponin (0.08 ng/mL, normal <0.04), and normal renal function (creatinine 1.1 mg/dL).

Given high clinical suspicion for acute aortic pathology, an ECG-gated CT angiography (CTA) of the thorax and abdomen was performed. Imaging demonstrated a Stanford type A aortic dissection involving a RAA, with anomalous origin of the right coronary artery from the left main coronary artery, coursing pre-pulmonarily. Three-dimensional reconstructions clearly visualized both the coronary anomaly and the dissection flap (Fig. 1, Fig. 2, Fig. 3).

Fig. 1.

(A, B) Computed tomography: sub-sequential axial CT shows circumferential pericardial effusion with mean density of 62 HU. Green arrow in image A shows enlarged ascending aorta, with thin hyperdense membrane suspect of dissection.

Fig. 2.

(A, B, C, D) Computed tomography angiography, MPR, and MIP reconstruction. It is possible to see a Stanford A dissection in a type 1 RAA. Dissection does not involve epiaortic vessels or the abdominal one.

Fig. 3.

(A, B) Subsequent axial plane CTA. Even if images are of suboptimal quality for coronary evaluation, it is possible to see the right coronary artery (green arrow). It originates from the left main coronary and, with a pre-pulmonary course, passes along the right coronary sulcus.

The patient received hemodynamic stabilization in the emergency department and was prepared for emergent surgical repair. Unfortunately, despite interventions, he developed progressive shock and died. Written consent for publication was obtained from the patient’s next of kin, in accordance with local regulations for retrospective studies.

Discussion

Congenital aortic arch anomalies are uncommon, but detection has increased due to advanced imaging modalities such as CTA and MRI. Embryologically, the aortic arch develops from 6 paired primitive aortic arches connecting the dorsal and ventral aortae. The fourth arches form the definitive aortic arch and subclavian arteries, while the sixth arches contribute to the pulmonary arteries and ductus arteriosus [4,5,7].

RAA results from failure of the right fourth arch to regress. Type 1 RAA, or mirror-image branching, mirrors the normal left-sided arch and is often asymptomatic, though it may coexist with congenital heart disease. Acute aortic dissection in type 1 RAA is extremely rare [5,8].

Type 2 RAA, with an aberrant left subclavian artery from Kommerell’s diverticulum, carries a higher risk of aneurysm and dissection, often related to cystic medial necrosis. Surgical intervention is indicated for symptomatic patients or those with aneurysmal dilation >30 mm, using open, endovascular, or hybrid approaches [[5], [6], [7],9,8,[10], [11], [12], [13], [14]].

Our case is notable for type 1 RAA with an anomalous right coronary artery originating from the left main coronary artery and acute Stanford type A aortic dissection. Recognizing coronary anomalies is crucial for surgical planning. ECG-gated CTA with 3D reconstruction enabled precise delineation of both the dissection and coronary anatomy, highlighting the value of multimodal imaging. Early bedside ultrasound also aided rapid suspicion of aortic dissection in this hemodynamically unstable patient (Fig. 4, Fig. 5) [15].

Fig. 4.

(A) Initial development of the “six arches system” according to “Edward’s theory”. (B) Definitive aortic arch system; one of the first 3 arches forms the carotid system; the fourth arch forms the right side of the RSA, on the left the aortic arch; the sixth arches form the pulmonary arteries. 1-6: aortic arches; 7: aortic sac; 8: ventral aorta; 9: dorsal aorta; ECA, external carotid artery.

Fig. 5.

Diagram of possible aortic anomalies according to “Edward’s theory”. Normally the atrophy of right arch from RSA to DAo determines a correct left aortic arch; Alternatively may be observed the atrophy of left arch from LSA to DAo causing RAA with mirror image branching (type 1); RAA with aberrant LSA (type 2) derives from a selective atrophy of left arch between LCA and LSA; RAA with isolated LSA (type 3) depends from a regression of left arch in 2 different points, between LCA and LSA and between LSA and Dao; in this case LSA is isolated, not connected to Aorta, but connected to PA; If both arches persist there may be observed a DAA. RSA, right subclavian artery; LSA, left subclavian artery; RCA, right carotid artery; LCA, left carotid artery; AAo, ascending aorta; DAo, descending aorta; PA, pulmonary arteries; LAA, left aortic arch; RAA, right aortic arch; DAA, double aortic arch; Tr, Trachea; E, Esophagus; CA, internal carotid artery; RSA, right subclavian artery; LSA, left subclavian artery; AAo, ascending aorta; AArch, aortic arch; Dao, descending aorta; PA, pulmonary arteries; DA, ductus arteriosus.

Radiologists should carefully assess coronary origins when reporting RAAs, especially in acute dissections, as anomalies may significantly influence management.

Conclusion

RAA with mirror-image branching is rare but may present with life-threatening Stanford type A aortic dissection. Coexistence with coronary anomalies, such as right coronary artery arising from the left main coronary artery, is exceptionally uncommon. Rapid recognition using ECG-gated CTA and 3D reconstructions is essential to guide acute management and surgical planning, highlighting the importance of multimodal imaging in emergent cardiovascular care.

Patient consent

Written consent was obtained from the patient for publication of relevant medical information within the manuscript.