Hybrid repair of Kommerell diverticulum associated with severe aberrant left subclavian artery stenosis and poststenotic aneurysmal degeneration: 2-year outcomes

Abstract

A 79-year-old man with a right-sided aortic arch was found to have progressive enlargement of an aberrant left subclavian artery aneurysm arising from a Kommerell diverticulum and associated with high-grade ostial narrowing on computed tomography angiography. Serial imaging demonstrated growth from 2.4 to 4.1 cm over 12 years. The patient underwent hybrid repair with left carotid-subclavian bypass, proximal subclavian occlusion, and thoracic endovascular aortic repair. Completion angiography demonstrated successful exclusion of the diverticulum and aneurysm without endoleak. Two-year surveillance imaging confirmed durable aneurysm exclusion, bypass patency, and absence of endoleak. This case highlights the feasibility and durability of hybrid repair for Kommerell diverticulum associated with severe aberrant left subclavian artery stenosis and poststenotic aneurysmal degeneration.

Kommerell diverticulum (KD) is a rare congenital aortic arch anomaly characterized by aneurysmal dilation at the origin of an aberrant subclavian artery, resulting from incomplete regression of the fourth primitive dorsal arch, and is associated with an increased risk of dissection and rupture related to cystic medial degeneration of the diverticular wall¹; a right-sided arch with an aberrant left subclavian artery is rare, with an estimated prevalence under 0.1%.^2,3 Progressive enlargement may result in compressive symptoms, dissection, rupture, or thromboembolic complications.⁴

Management remains challenging because of the rarity of the condition, diverse anatomic presentations, and the absence of prospective data to guide treatment selection. Advances in endovascular technology have expanded the role of hybrid repair strategies combining supra-aortic debranching with thoracic endovascular aortic repair (TEVAR), particularly in elderly patients with complex arch anatomy. We report the case of a right-sided aortic arch with KD associated with severe aberrant left subclavian artery stenosis and poststenotic aneurysmal degeneration, successfully treated with hybrid repair and demonstrating durable exclusion at 2-year follow-up.

Case report

A 79-year-old man with atrial fibrillation, chronic kidney disease stage III, obstructive sleep apnea requiring continuous positive airway pressure therapy, hypertension, hyperlipidemia, hypothyroidism, and a known right-sided aortic arch was referred for evaluation of an enlarging aberrant left subclavian artery aneurysm that had been under radiographic surveillance for more than 15 years. Several months before presentation, noncontrast computed tomography during evaluation of chest pain unrelated to the aneurysm demonstrated interval enlargement from 2.4 cm, documented 12 years earlier, to 4.1 cm. In contrast, the KD remained relatively stable, measuring 2.3 × 2.2 cm on computed tomography angiography (CTA). He denied upper-extremity claudication, neurologic symptoms, dysphagia, dyspnea, or other manifestations of compressive pathology. Dysphagia and other compressive symptoms were specifically assessed during serial surveillance visits and remained absent despite progressive enlargement of the poststenotic aneurysm.

Physical examination showed intact upper-extremity motor and sensory function with symmetric radial and ulnar pulses. CTA revealed a type II right-sided aortic arch with sequential branching of the left common carotid, right common carotid, and right subclavian arteries, and an aberrant left subclavian artery arising from a 2.3 × 2.2 cm KD with high-grade ostial narrowing on CTA and a 4.1 × 3.8 cm poststenotic aneurysm (Figs 1 and 2), without intraluminal thrombus. Preoperative centerline CTA planning demonstrated a 22.1-mm segment of healthy, parallel descending thoracic aorta between the right subclavian artery and the diseased origin of the aberrant left subclavian artery, providing an adequate proximal landing zone for TEVAR. The left vertebral artery was chronically occluded; the right was dominant.

Fig 1.

Preoperative computed tomography angiography (CTA): complex arch anatomy. Preoperative three-dimensional reconstructed CTA demonstrating a type II right-sided aortic arch with sequential branching of the left common carotid artery (LCCA), right common carotid artery (RCCA), and right subclavian artery (RSCA). An aberrant left subclavian artery (LSCA) arises from a Kommerell diverticulum (KD) and demonstrates severe ostial stenosis with associated poststenotic aneurysmal degeneration.

Fig 2.

Sagittal computed tomography angiography demonstrating a right-sided aortic arch with a Kommerell diverticulum (KD), severe ostial stenosis of the aberrant left subclavian artery (LSCA), and poststenotic aneurysmal degeneration. Arrowhead, KD; white arrow, severe LSCA stenosis; black arrow, poststenotic aneurysm.

Duplex ultrasound guidance showed patent left upper-extremity arterial inflow with biphasic waveforms, and carotid duplex showed no significant stenosis. Given the enlarging aneurysm, KD, and complex arch anatomy, the case was reviewed at a multidisciplinary vascular and cardiothoracic conference. As treatment required excluding both the diverticulum and aneurysmal aberrant subclavian artery while maintaining cerebral and upper-extremity perfusion, a hybrid approach—left carotid-subclavian bypass, proximal subclavian occlusion, and TEVAR—was recommended, and the patient consented to proceed.

A hybrid repair was performed under general anesthesia. Through a left supraclavicular incision, the left common carotid and subclavian arteries were exposed with preservation of the phrenic and vagus nerves. A left carotid-subclavian bypass was constructed using an 8-mm ringed polytetrafluoroethylene graft end-to-side with running 5-0 polypropylene sutures, with restoration of a palpable left radial pulse.

To exclude inflow into the aneurysmal aberrant left subclavian artery, the left subclavian artery was accessed retrograde through the bypass hood. Angiography confirmed chronic occlusion of the left vertebral artery origin, and an 8-mm vascular plug was deployed proximal to the takeoff; completion angiography demonstrated complete proximal left subclavian occlusion without retrograde filling of the aneurysmal segment or KD and a patent carotid-subclavian bypass.

Attention then turned to TEVAR. The right common femoral artery was accessed percutaneously and preclosed with two ProGlide devices (Abbott Vascular). After systemic heparinization, a 22F DrySeal sheath (W. L. Gore & Associates) was advanced over a Lunderquist wire (Cook Medical). Intravascular ultrasound guidance and angiography delineated the right-sided arch anatomy, including the KD and arch vessel origins. A 37 × 37 × 100 mm conformable Gore TAG thoracic endograft (W. L. Gore & Associates) was deployed across the aberrant subclavian origin, excluding the diverticulum while preserving flow to the bilateral carotid and right subclavian arteries (Fig 3).

Fig 3.

Schematic illustration of the patient's right-sided aortic arch anatomy and hybrid repair. A, Preoperative anatomy demonstrating sequential arch branching of the (1) left common carotid artery (LCCA), (2) right common carotid artery (RCCA), (3) right subclavian artery (RSCA), and (4) aberrant left subclavian artery (LSCA) arising from a Kommerell diverticulum (KD) with severe ostial stenosis and poststenotic aneurysmal degeneration. B, Postoperative anatomy after left carotid-subclavian bypass, thoracic endovascular aortic repair (TEVAR), and proximal LSCA occlusion with exclusion of the KD and aneurysm. Arch vessels are depicted as a mirror-image schematic and are not drawn to anatomic scale.

Completion angiography confirmed exclusion of the diverticulum and aneurysmal aberrant subclavian artery without endoleak, with a widely patent bypass and no retrograde filling. The femoral access site was closed with the preclose sutures, and distal pulses remained unchanged from baseline (Fig 4).

Fig 4.

Intraoperative angiography. A, Predeployment angiography demonstrating opacification of the Kommerell diverticulum and poststenotic aneurysmal degeneration of the aberrant left subclavian artery. B, Completion angiography after carotid-subclavian bypass (black arrow), proximal vascular plug occlusion of the aberrant left subclavian artery (arrowhead), and thoracic endovascular aortic repair (TEVAR), demonstrating successful exclusion of the Kommerell diverticulum and aneurysm without endoleak.

The patient’s postoperative course was uncomplicated; he was discharged home on postoperative day 1. At the 40-day follow-up, he remained asymptomatic, and follow-up CTA demonstrated complete thrombosis of the aneurysm and diverticulum without endoleak, a widely patent bypass, and a well-positioned endograft.

At the 2-year follow-up, surveillance imaging demonstrated durable aneurysm exclusion, bypass patency, and absence of endoleak (Fig 5). The patient provided informed consent for publication of this case report and accompanying images. This case report was exempt from Institutional Review Board oversight per institutional policy for single patient case reports.

Fig 5.

Two-year postoperative computed tomography angiography (CTA) demonstrating durable exclusion of the Kommerell diverticulum and aberrant left subclavian artery (LSCA) aneurysm. A, Three-dimensional reconstruction demonstrating stable thoracic endovascular aortic repair (TEVAR) with persistent exclusion of the diverticulum and aneurysm. B, Axial CTA demonstrating a patent right-sided TEVAR graft (white arrow) and thrombosed LSCA aneurysm sac (arrowhead) without evidence of endoleak. C, Coronal CTA demonstrating a patent left carotid-subclavian bypass graft (white arrow) with continued exclusion of the aneurysm and no evidence of endoleak. LCCA, Left common carotid artery.

Discussion

A notable feature of this case was the coexistence of a KD, high-grade ostial narrowing on CTA of an aberrant left subclavian artery, and marked poststenotic aneurysmal degeneration. This uncommon anatomy created a unique technical challenge because durable treatment required exclusion of both the diverticulum and distal aneurysm while preserving cerebral, vertebral, and upper-extremity perfusion. To our knowledge, reports describing hybrid repair of a KD associated with severe aberrant left subclavian artery stenosis and poststenotic aneurysmal degeneration are exceedingly rare.

Although consensus recommendations exist, indications for intervention remain individualized because of the heterogeneous anatomy and limited evidence base. The Society for Vascular Surgery recommends repair when the diverticulum exceeds 30 mm or the adjacent aorta exceeds 50 mm.⁵ Although this patient’s 2.3-cm diverticulum fell below that threshold, progressive enlargement of the poststenotic aberrant subclavian aneurysm—a distinct indication not captured by diverticulum-size criteria alone—supported intervention; treatment should be individualized to anatomy, symptoms, and operative risk.⁶

Historically, KD was treated by open repair through thoracotomy, which is durable but carries substantial morbidity, particularly in elderly patients requiring extensive arch exposure.^7,8 Advances in endovascular technology have since expanded treatment options toward hybrid approaches combining supra-aortic debranching with TEVAR.^2,7,9,10

Left carotid-subclavian bypass established durable revascularization of the left upper extremity before exclusion of the aberrant vessel. Proximal subclavian occlusion was performed to prevent retrograde aneurysm perfusion while preserving vertebral circulation. TEVAR subsequently excluded the KD and origin of the aberrant left subclavian artery. Completion angiography confirmed successful exclusion of both the diverticulum and aneurysm without endoleak, and 2-year surveillance imaging demonstrated durable aneurysm exclusion and bypass patency.

Several contemporary series have demonstrated favorable early and midterm outcomes following hybrid repair of KD. Yang et al² demonstrated effective aneurysm exclusion with lower perioperative morbidity than open reconstruction, and Idrees et al5, 10 reported excellent technical success with hybrid strategies in older patients with complex arch anatomy.5, 10 Bath et al¹¹ reported 87% survival and 95% to 96% subclavian patency at a median follow-up of 41 months, supporting durability. Rodríguez-Pérez et al¹² reported a similar case of KD with proximal aberrant subclavian stenosis and poststenotic degeneration successfully managed with a hybrid approach, underscoring both the rarity of this pathology and the feasibility of less invasive treatment. Given this patient’s age, comorbidities, and complex anatomy, a hybrid approach offered a less invasive alternative to open reconstruction while achieving durable exclusion.

This case demonstrates that hybrid repair can provide durable exclusion of both a KD and associated poststenotic aberrant subclavian aneurysm while preserving cerebral and upper-extremity perfusion.

Conclusions

Hybrid repair with carotid-subclavian bypass, proximal subclavian occlusion, and TEVAR provided durable exclusion of a KD and associated poststenotic aberrant left subclavian artery aneurysm. This approach represents a feasible and durable treatment strategy for selected patients with similarly complex aortic arch anatomy.

Funding

None.

Declaration of generative AI and AI-assisted technologies in the writing process

During the preparation of this work, the authors used ChatGPT by OpenAI to assist with language refinement. After using this tool, the authors reviewed and edited the content as needed and take full responsibility for the content of the publication.

Disclosures

The authors declare no conflicts of interest.