Debranching Thoracic Endovascular Aortic Repair Combined with Ascending Aortic Aortoplasty
Surgical treatment of aortic arch lesions remains a significant challenge for cardiac surgeons due to the complexity of the procedures involved. Traditional open arch replacement, while effective, is often unsuitable for high-risk patients due to the associated morbidity and mortality. For such patients, debranching thoracic endovascular aortic repair (d-TEVAR) has emerged as a viable alternative. However, d-TEVAR is not without its complications, the most concerning of which is retrograde type A aortic dissection (RTAD). RTAD is a potentially fatal complication that has limited the application of d-TEVAR, particularly in low-risk patients. This paper describes a modified approach to d-TEVAR that incorporates ascending aortic aortoplasty using artificial blood vessels to minimize the risk of RTAD and expand the applicability of d-TEVAR to a broader patient population.
The procedure is designed for patients with lesions involving part or all of the aortic arch but not the ascending aorta. The surgery is performed under general anesthesia, beginning with a median sternotomy to access the thoracic cavity. The three arch vessels—the innominate artery, the left common carotid artery, and the left subclavian artery—are mobilized. The aorta is then clamped using a side wall clamp, and an appropriately sized incision is made. A Y-shaped artificial blood vessel (Vascutek, 16 x 8 mm; Vascutek Terumo, Inc., Scotland, UK) is used to reconstruct the aortic arch vessels. The main artery of the Y-shaped graft is anastomosed to the sidewall of the ascending aorta.
The innominate artery is subsequently blocked and cut. The proximal end of the artery is sutured, while the distal end is anastomosed to one branch of the Y-shaped artificial blood vessel. After de-airing, the block is opened to restore blood flow to the artery. The same procedure is repeated for the left common carotid artery, which is anastomosed to the corresponding position of the other branch of the Y-shaped graft in an end-to-side fashion. Finally, the left subclavian artery is blocked, cut, and anastomosed to the distal end of another Y-shaped artificial blood vessel branch. Throughout this process, no cardiopulmonary bypass is required, which reduces the complexity and risk of the procedure.
Following the reconstruction of the arch vessels, a straight artificial blood vessel (InterGard; InterVascular S.A. MAQUET Cardiovascular, La Ciotat, France or Vascutek, Inchinnan, UK) is wrapped around the ascending aorta. Both ends of the artificial vessel are marked with a titanium clip to ensure proper placement. Aortic angiography is then performed to confirm the positioning of the stent-graft. The proximal end of the stent-graft is positioned in the ascending aorta, which has been wrapped with the artificial vessel. The stent is then released to close the lesion. The surgery is completed with a repeat angiography to confirm the success of the procedure.
The modified d-TEVAR procedure offers a new option for treating aortic arch lesions, particularly in patients who are not candidates for traditional open arch replacement. However, the use of d-TEVAR has been limited to high-risk patients due to the high incidence of serious complications, such as RTAD. RTAD occurs primarily for three reasons: (1) side-clamping injury of the ascending aorta, (2) damage to the arterial wall caused by catheter angiography and wire manipulation, and (3) compliance mismatch between the rigid stent-graft and the highly compliant ascending aorta. The first two reasons can be mitigated through meticulous surgical techniques, while the third reason can be addressed by wrapping the ascending aorta with an artificial vessel.
The ascending aorta undergoes both radial expansion-contraction and wall translational motion with each heartbeat, resulting in high compliance. In contrast, the stent-graft is much stiffer. The slight back-and-forth motions of the stiff endograft with the cardiac cycle increase the risk of RTAD. Some researchers suggest that when the ascending aorta is less than 40 mm in diameter, it can be directly used as the anchoring zone for the stent-graft. However, when the ascending aorta exceeds 40 mm in diameter, it should be replaced before TEVAR. The authors of this paper argue that regardless of the diameter of the ascending aorta, it is unsafe to use the fragile and frequently moving ascending aorta as an anchoring zone. Instead, they propose that only an artificial blood vessel after ascending aortic replacement or an ascending aorta wrapped with an artificial vessel should be used as an anchoring zone.
Wrapping the ascending aorta with an artificial vessel enhances the strength of the aortic wall and limits the radial expansion-contraction movement with the cardiac cycle. This reduces the compliance mismatch between the anchoring zone and the proximal end of the stent, thereby minimizing the risk of RTAD. The authors have performed this modified d-TEVAR procedure combined with ascending aortic aortoplasty on four patients who were not considered high-risk. The average follow-up duration was three months, and none of the patients developed RTAD.
While the results are promising, further research with a larger sample size and long-term follow-up is necessary to validate the efficacy of this approach. The addition of ascending aortic aortoplasty to d-TEVAR appears to provide a new method for preventing RTAD and expanding the use of d-TEVAR to low-risk patients. This could significantly reduce the challenges associated with aortic arch replacement and improve outcomes for patients with complex aortic arch lesions.
In conclusion, the modified d-TEVAR procedure combined with ascending aortic aortoplasty represents a significant advancement in the treatment of aortic arch lesions. By addressing the key factors that contribute to RTAD, this approach offers a safer and more effective alternative to traditional open arch replacement and standard d-TEVAR. As further research is conducted, this technique has the potential to become a standard treatment option for patients with aortic arch lesions, regardless of their risk profile.
doi.org/10.1097/CM9.0000000000000408
Was this helpful?
0 / 0