Pseudocoarctation-associated aneurysm in a young female: surgical resection and histological evidence of aortic fragility with five-year surveillance

Abstract

Background

Pseudocoarctation of the aorta is a rare congenital anomaly characterized by elongation and kinking of the aortic arch without significant pressure gradient. While often asymptomatic, it may be associated with aneurysmal degeneration, necessitating surgical intervention.

Case presentation

We report the case of a woman in her 30s who was referred after an abnormal shadow was detected on chest imaging during a routine health checkup. Contrast-enhanced computed tomography revealed elongation and kinking of the distal aortic arch with an associated saccular aneurysm in the descending thoracic aorta. An aberrant left vertebral artery originated independently from the aortic arch. The patient underwent surgical resection and Dacron graft replacement under partial cardiopulmonary bypass. Histopathological examination revealed medial thinning, elastic fiber disruption, and reduced smooth muscle content not only in the aneurysmal segment but also in macroscopically normal adjacent aortic tissue within approximately 10 mm from the aneurysmal margin. No aneurysm recurrence or new aortic pathology was observed during five years of postoperative follow-up.

Conclusions

This case suggests that aortic tissue adjacent to pseudocoarctation-associated aneurysms may exhibit localized histological fragility despite a normal gross appearance. Although pseudocoarctation cannot be defined as a distinct aortopathy based on a single case, careful intraoperative assessment and selection of the anastomotic site are essential. No aneurysm recurrence or new aortic pathology was observed during five years of postoperative follow-up, highlighting the importance of long-term imaging surveillance.

Background

Pseudocoarctation of the aorta, first described by Souders in 1951 [1], is a rare anomaly resulting from elongation and kinking of the aortic arch without significant hemodynamic obstruction. While typically benign, aneurysmal changes have been observed in some cases [2–4]. The precise mechanism of aneurysm formation in pseudocoarctation is unclear, but hemodynamic stress and congenital wall fragility are considered contributing factors [5–7]. Here we report a case of surgically treated pseudocoarctation with descending aortic aneurysm, including histological findings suggestive of diffuse aortic fragility, and document a stable five-year postoperative course.

Case presentation

A woman in her 30s was referred to our institution following detection of a mediastinal abnormality on routine chest X-ray. Contrast-enhanced computed tomography (CT) showed a mildly aneurysmal descending thoracic aorta (25 mm) just distal to a left subclavian artery. There was notable elongation and kinking of the distal aortic arch (Fig. 1), consistent with pseudocoarctation [2, 6–8]. The minimum lumen diameter at the kink was 9.8 mm, with the adjacent normal aorta measuring 18 mm. No signs of coarctation, such as systemic hypertension or upper-limb-to-lower-limb pressure gradient, were noted and the ankle-brachial pressure index (ABPI) was within normal range; the systolic blood pressure difference between upper and lower extremities was no greater than 18 mmHg. Transthoracic echocardiography revealed normal left ventricular wall thickness, with no evidence of left ventricular hypertrophy, suggesting an absence of chronic pressure overload.

Fig. 1.

Preoperative CT images of the aortic arch and descending aorta. (A) Axial contrast-enhanced CT image showing a focal narrowing of the aortic arch due to a bending configuration, without significant luminal stenosis. (B) Straight curved planar reconstruction (CPR) image generated using VINCENT software also clearly demonstrates the same narrowing, depicting the presence of this anatomical bend. (C, D) Three-dimensional volume-rendered images from anterior (C) and posterior (D) perspectives demonstrate elongation of the aortic arch with findings consistent with pseudocoarctation. No collateral circulation is observed

In spite of normal pressure, given the presence of aneurysmal degeneration, surgical repair was indicated. Endovascular repair was considered as a treatment option; however, it was deemed suboptimal in this case due to concerns regarding long-term durability in a young patient and the presence of anomalous aortic arch anatomy. Given the patient’s young age, the incision line was carefully planned along the natural breast contour to optimize cosmetic outcomes. The descending thoracic aorta was exposed through a left third intercostal thoracotomy before the proximal and distal aorta adjacent to the aneurysm, the left subclavian artery, and a fibrous ligament consistent with the ligamentum arteriosum arising from the contralateral wall of the aneurysmal segment were individually encircled and controlled with vessel tapes. No collateral circulation was identified around the descending aorta. Intraoperatively, the aortic wall within the aneurysmal segment appeared thin and translucent. After systemic heparinization, partial cardiopulmonary bypass was initiated and the descending thoracic aorta was resected as described below. The aorta was resected from just distal to the origin of the left subclavian artery to approximately 15 mm distal to the aneurysmal segment. The resected segment was replaced with an 18-mm Dacron graft, with an interposition graft length of approximately 50 mm. Both proximal and distal anastomoses were reinforced with felt strips on the aortic side and completed using continuous 3 − 0 polypropylene sutures.

Histopathological examination of the resected segment demonstrated severe medial thinning, fragmentation of elastic fibers, decreased smooth muscle content, and compensatory collagen proliferation (Fig. 2). Similar but milder histological changes were also observed in the macroscopically normal-appearing adjacent descending aorta extending approximately 10 mm from the aneurysmal margin, whereas the aortic wall beyond this region showed preserved medial architecture.

Fig. 2.

Representative histological images of the resected aortic wall stained with Elastic Van Gieson (EVG) and Hematoxylin and Eosin (HE). Left column: (A) Aneurysmal segment (EVG), (B) Adjacent macroscopically normal segment (EVG), (C) Distant normal aortic segment (EVG). Right column: (D) Aneurysmal segment (HE), (E) Adjacent macroscopically normal segment (HE), (F) Distant normal aortic segment (HE). Note the thinning and fragmentation of elastic fibers in the aneurysmal wall and adjacent segment (A, B), while the distant segment (C, F) shows preserved architecture. All images are shown at original magnification × 40 with 1000 μm scale bars

Postoperative recovery was uneventful. Serial CT imaging over a five-year period has shown no evidence of recurrence or new aneurysm formation (Fig. 3). No recurrence or new aneurysm formation has been detected during a five-year postoperative follow-up. The patient met radiologic diagnostic criteria for pseudocoarctation, including kinking without significant narrowing, lack of collateral circulation, and arch elongation [3, 9]. Notably, the distance between the left common carotid and subclavian arteries was increased, consistent with an embryologic failure of dorsal aortic regression [3, 8, 9].

Fig. 3.

Three-dimensional computed tomography (3D CT) imaging following surgical repair of aortic kinking and aneurysm. (A, B) 3D CT images obtained immediately after surgery, showing successful open surgical graft replacement with restoration of aortic geometry. Anterior and posterior views are displayed. (C, D) 3D CT images obtained five years postoperatively, demonstrating maintained graft position and stable aortic anatomy. There is no evidence of aneurysmal recurrence or graft-related complications. Anterior and posterior views are displayed

Discussion

The novelty of this report lies not in the rarity of pseudocoarctation itself, but in the detailed histological assessment of macroscopically normal adjacent aortic tissue combined with documented long-term postoperative stability.

Differentiating pseudocoarctation from true coarctation or arch hypoplasia is critical to avoid unnecessary intervention. As Singh et al. systematically reviewed, pseudocoarctation typically lacks a significant pressure gradient, does not demonstrate collateral circulation, and is characterized by elongation and kinking of the arch without true luminal narrowing [10]. Recent evidence by Ito et al. demonstrated the utility of four-dimensional flow Magnetic Resonance Imaging (4D flow MRI) in assessing pseudocoarctation-associated saccular aneurysms. Their report highlighted abnormal wall shear stress and vortex flow in the kinked aortic segment, suggesting that hemodynamic forces may play a role in aneurysm formation even in the absence of overt inflammation or trauma [5].

Thus, the diagnosis of pseudocoarctation in this case is supported by the fulfillment of classical diagnostic criteria: (1) abnormal mediastinal shadow on chest X-ray, (2) absence of a significant pressure gradient between the upper and lower extremities with an ABPI within the normal range, (3) lack of collateral circulation as confirmed by contrast-enhanced CT, and (4) elongation and kinking of the aortic arch and proximal descending aorta demonstrated on reconstructed CT imaging. These findings distinguish pseudocoarctation from true coarctation and confirm characteristic anatomical and hemodynamic features.

In bicuspid aortic valve–associated aortopathy, Marfan syndrome, Loeys–Dietz syndrome, and sporadic thoracic aortic aneurysms, histological degeneration has been reported or suggested even in aortic segments that appear morphologically normal or non-dilated on imaging [11–13]. Although such findings have not been systematically documented in pseudocoarctation, the congenital nature of this anomaly raises the possibility that a similar aortopathy may underlie aneurysm formation. In this context, the histological changes observed in the macroscopically normal adjacent aorta in our case may support the concept of intrinsic aortic wall vulnerability in pseudocoarctation, underscoring the importance of careful anastomotic site selection rather than reliance on macroscopic appearance alone. In the present case, histological analysis demonstrated significant medial degeneration even in non-aneurysmal aortic segments, while no aneurysmal progression or new aortic pathology was observed during five years of postoperative follow-up. These findings underscore the importance of long-term imaging surveillance in patients with pseudocoarctation-associated aneurysms, particularly when underlying histological fragility is present, and even in the absence of radiographic dilation.

Of particular interest was the transitional aortic tissue between normal and abnormal areas. These abnormal-adjacent segments appeared grossly preserved, but they were located near the aneurysmal lesion and exhibited mild histological changes, such as focal thinning of elastic fibers. In contrast, histological evaluation of normal aortic wall specimens revealed intact elastic lamellae and preserved medial architecture. As these findings suggest that visual inspection alone may not reliably identify structurally compromised tissue, thorough histopathological examination of any segments adjacent to anomalous aortic tissue is essential for preventing pseudocoarctation-associated aneurysms. Additionally, as in our case, it is crucial to establish anastomoses on a segment of the descending thoracic aorta sufficiently distal from the aneurysmal lesion to maintain wall thickness. This approach allows secure graft attachment to histologically normal aortic tissue, minimizing the risk of suture line complications.

Conclusion

We report a rare case of pseudocoarctation of the aorta complicated by aneurysmal degeneration, successfully treated by surgical resection and graft replacement with no aneurysm recurrence or new aortic pathology during five years of postoperative follow-up. Histopathological examination revealed medial degeneration not only in the aneurysmal segment but also in the adjacent aorta that appeared macroscopically normal, suggesting localized intrinsic aortic wall vulnerability. Long-term imaging surveillance remains warranted in patients with pseudocoarctation associated with aneurysmal change.

Abbreviations

3D CT

Three-dimensional computed tomography

4D flow MRI

Four-dimensional flow magnetic resonance imaging

ABPI

Ankle-brachial pressure index

CPR

Curved planar reconstruction

CT

computed tomography

EVG

Elastic van gieson

HE

Hematoxylin and eosin

Author contributions

TT performed the surgery and drafted the manuscript.MO supervised the surgery and provided critical revisions.YI assisted in the surgery and contributed to data collection.BM reviewed and edited the manuscript for language and clarity.YS critically reviewed and edited the manuscript for language and clarity.HS provided critical revisions to the manuscript.All authors read and approved the final manuscript.

Funding

No funding was received for this study.

Data availability

Not applicable.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Written, informed consent was obtained from the patient for publication of this case report and accompanying images. Institutional review board approval was not required for this single case report.

Competing interests

The authors declare no competing interests.