The need to cover the left subclavian artery during thoracic endovascular aortic repair remains one of the main technical challenges of TEVAR. Although fully endovascular solutions have developed considerably in recent years, left carotid-subclavian bypass continues to represent a widely used strategy supported by clinical guidelines to preserve left subclavian artery perfusion and reduce neurological and ischaemic complications. The study by Murana and colleagues analyses the experience of a high-volume centre over nearly two decades, with particular focus on mid- and long-term patency of carotid-subclavian bypass associated with TEVAR, as well as its complications and need for reintervention.

Coverage of the left subclavian artery is required in approximately one quarter of TEVAR procedures to achieve an adequate proximal landing zone. However, intentional subclavian artery coverage without revascularization has been associated with an increased risk of stroke, spinal cord ischaemia, and upper limb ischaemia. For this reason, European and American guidelines recommend routine left subclavian artery revascularization in elective procedures and individualized consideration in urgent scenarios.

In this setting, left carotid-subclavian bypass has historically been the reference technique. However, the emergence of in situ fenestration, chimney techniques, and especially new thoracic fenestrated/branched endografts has partially reduced its prominence. Even so, the available evidence on the true durability of the bypass and its long-term outcomes remains limited, with relatively small series and heterogeneous follow-up.

Murana et al. present a single-centre retrospective study including 161 patients treated between 2005 and 2025 with TEVAR associated with left carotid-subclavian bypass. The cohort included both elective and urgent procedures, with the latter accounting for 22.3% of the sample. The primary objective was to analyse survival, bypass patency, and the need for reintervention during follow-up. All patients underwent serial CT angiography, with a median follow-up of 33 months. The authors also performed a comparative analysis between elective and urgent patients.

The results are particularly relevant because of the excellent durability observed. Overall in-hospital mortality was 3.7%, with no significant differences between elective and urgent procedures. The incidence of stroke was low (1.8%), although it tended to be higher in the urgent group. Bypass-related complications occurred in 7.4% of cases and included recurrent laryngeal nerve palsy, brachial plexus injuries, cervical haematomas, and two bypass thromboses. Overall bypass patency during follow-up reached 97.4%, with an estimated 5-year patency of 99%. Five-year survival was 87.4%, and freedom from reintervention was 88.5%.

The authors conclude that carotid-subclavian bypass remains a safe, effective, and remarkably durable technique, even in urgent scenarios.

COMMENTARY:

The main value of this study lies in providing robust evidence on the durability of carotid-subclavian bypass in real-world clinical practice. In an era defined by the rapid development of complex endovascular solutions, it is particularly interesting to see that a “classic” technique continues to deliver excellent outcomes, with patency rates that are difficult to improve upon and a very low rate of graft-related reintervention.

The current landscape is undoubtedly changing quickly. The introduction of thoracic endografts with branches or fenestrations to preserve the left subclavian artery is reshaping the approach to zone 2 TEVAR. Among these platforms, Castor® was one of the first branched endografts to become clinically available for this purpose, with subsequent developments such as Cratos® broadening the therapeutic spectrum and refining the design of single-branched thoracic endografting. Similarly, the Gore TAG Thoracic Branch Endoprosthesis (TBE)® has represented an important advance, particularly in the United States, as an FDA-approved off-the-shelf solution for endovascular repair while preserving flow to a supra-aortic branch vessel. Nevertheless, its use should be interpreted with appropriate caution, particularly after the recent field safety notice regarding the side-branch component and reports of catheter separation during clinical use.

These considerations do not diminish the value of branched endografts, but they do remind us that technological innovation requires time, accumulated experience, and robust follow-up before it can fully displace established surgical strategies. Early and mid-term results with dedicated branched devices are promising, with high rates of technical success and progressive expansion of indications. However, relevant limitations remain, including anatomical constraints, device availability, learning curve, stroke risk, endoleak, branch occlusion, cannulation difficulties, and delivery system-related events.

This technological evolution should therefore be interpreted with balance. Fully endovascular solutions require immediate device availability, advanced planning, specific expertise, and favourable anatomy. In daily clinical practice, particularly in urgent scenarios or in centres without immediate access to certain devices, carotid-subclavian bypass remains an extremely versatile, reproducible, and effective tool. It also allows complex procedures to be simplified, reduces the number of branches or fenestrations required, and preserves hybrid strategies that remain highly competitive from the standpoint of clinical outcomes.

This is probably where the most important message of the article lies: the emergence of new technologies should not be interpreted as the disappearance of surgical bypass, but rather as an expansion of the therapeutic armamentarium. Centres with greater experience in aortic disease will probably be those capable of individualizing each case and combining both strategies according to the anatomical, clinical, and logistical context. While branched endografts continue to consolidate their results, improve their availability, and accumulate longer-term evidence, carotid-subclavian bypass continues to demonstrate excellent durability and maintains a fundamental role in the hybrid treatment of the thoracic aorta.

REFERENCE:

Murana G, Nocera C, Di Marco L, Buia F, Garofalo R, Aksit G, et al. Long-Term Outcomes and Patency of Left Carotid-Subclavian Bypass in Thoracic Endovascular Aortic Repair. Eur J Cardiothorac Surg. 2025;67(11):ezaf391. doi:10.1093/ejcts/ezaf391.