Figura 1. Angiographic image showing the dissection flap distal to the left subclavian artery.

Figura 2. Deployment of the Ankura® thoracic endoprosthesis in the aortic arch. Follow-up contrast-...

Introduction

Type B aortic dissection is a vascular emergency that involves a tear of the aortic intima, generating a false lumen that can extend distally and compromise blood flow to vital organs. Its management depends on the presence of complications such as rupture, organ ischemia, or progressive dilation. Endovascular repair has gained prominence over conventional surgery due to its lower morbidity and mortality, and fast dissection control. In cases where the left subclavian artery must be covered, in-situ fenestration emerges as a useful technique to preserve its flow without the need for additional surgical approaches.

Case description

A 46-year-old man reports onset of intermittent epigastric pain radiating to the back with an intensity of 6/10 following dietary indiscretion, with approximately 48 hours of evolution. Due to persistent and exacerbated pain, he visits the emergency room in his hometown. An abdominal ultrasound is performed, revealing an abdominal aortic dissection with a mobile false lumen. Urgent referral is requested, and he arrives at our institution with a trend towards hypertension. He is admitted through the Emergency Department, where thoracic and abdominal CT angiography of the aorta is conducted. It shows the presence of an apparent false lumen starting from the ascending aorta, extending through the entire arterial tree, dissecting down to the distal left iliac artery, without involvement of the renal arteries (Figure 1).

Past medical history: No reported comorbidities; passive smoker.

Usual medications: Losartan 50 mg every 12 hours, amlodipine 5 mg every 12 hours, hydrochlorothiazide 25 mg, carvedilol 25 mg every 12 hours.

Family history: Father deceased at age 35 from unknown cause.

The patient is admitted to the Coronary Care Unit (CCU). There, the studies below are performed.

Chest multislice CT angiogram: An aortic dissection flap is identified starting immediately posterior to the origin of the left subclavian artery and extending along the descending aorta; this is consistent with Stanford type B dissection, reaching both iliac arteries without renal involvement. Both the true and false lumens are patent. The descending aorta has regular walls. Valve annulus: 25.2 mm. Sinus portion: 42 mm. Sinotubular junction: 32.2 mm. The aortic valve is trileaflet, without any thickening of the leaflets. The coronary artery calcium score is 0 Agatston units. Coronary dominance is right. Given the persistence of pain and favorable anatomical characteristics, endovascular repair is decided. Using the Vessel Navigator® system (Philips, Netherlands) for guidance, an Ankura® prosthesis (Lifetech, Shenzhen, China) is deployed. The Ankura® thoracic endoprosthesis is introduced via the transfemoral access over a support wire, in this case, an extra support 0.035” Lunderquist® Extra-Stiff Wire Guide (Cook Medical, Bloomington, Indiana, USA), until its proximal end is positioned immediately distal to the ostium of the left carotid artery, under fluoroscopic control and with imaging fusion support (Vessel Navigator®). A large-bore introducer sheath is used (22 Fr, according to the selected device diameter), and the controlled delivery system allows for gradual prosthesis deployment. The device is deployed in two stages. Initial controlled deployment phase: The endoprosthesis is positioned respecting the orientation of proximal and distal radiopaque markers. The proximal portion is gradually deployed, allowing for the expansion of the self-expanding anchor in the thoracic aorta. Full deployment phase: After confirming proper alignment with the supra-aortic vessels, the prosthetic body is fully deployed. The seamless design with proximal bare stents facilitates proximal sealing without compromising the supra-aortic branches when correctly aligned (Figure 2). In this case, since the prosthesis covers the ostium of the left subclavian artery, in situ fenestration is subsequently performed using the Futhrough® system. Through left humeral access, a fenestration is made in the prosthesis and, using a 0.035” metallic guide, an 8 × 59-mm stent graft is placed to maintain perfusion of the left upper limb without the need for extra-anatomic bypass. Once the endoprosthesis is implanted, the delivery system is carefully removed, and digital angiography is performed to confirm exclusion of the false lumen and adequate flow in the true lumen. The patient is discharged 48 hours later, asymptomatic and with excellent clinical evolution.

Discussion

Type B aortic dissection is a potentially lethal vascular emergency that requires rapid assessment and precise therapeutic decision-making1. While in the past two decades medical therapy has been the initial approach in uncomplicated cases, the evolution of endovascular techniques has changed the therapeutic paradigm in complicated cases or those at high anatomical risk.

The case presented involved an acute type B dissection complicated by persistent pain and extensive flap extension, which justified intervention. The finding of an extensive false lumen with potential involvement of visceral and peripheral branches increased the risk of aneurysmal degeneration or late rupture, especially in young patients.

Thoracic endovascular aortic repair (TEVAR) allows for the sealing of the proximal entry tear, promoting favorable remodeling and preventing progression. Dake et al.2 and Nienaber et al.4 documented the superiority of TEVAR in terms of false lumen thrombosis, aortic remodeling, and reduction of complications compared to medical therapy alone.

Covering the left subclavian artery represents a challenge, as it may compromise vertebral, coronary (in patients with myocardial infarction revascularized using the mammary artery), or upper limb perfusion3. In situ fenestration, as in this case, avoids the need for cervical surgical approaches. Its success depends on operator experience and prior planning with 3D reconstruction, such as that enabled by Vessel Navigator®.

This technique offers advantages such as shortening procedure times, avoiding the use of multiple access routes, and reducing perioperative risks. Recent studies5, 6 suggest that its efficacy is comparable to hybrid techniques, with lower morbidity.

Prior anatomical planning using transesophageal echocardiography and CT angiography with multiplanar reconstructions allowed for the precise definition of the deployment site and prevention of complications. The use of 3D navigation software was decisive for precise and safe fenestration.

It is important to emphasize that these procedures must be performed in centers with experience and structured follow-up protocols, given the risk of endoleak, prosthesis migration, false lumen persistence, or new rupture.

Finally, this case exemplifies the importance of multidisciplinary collaboration among imaging diagnostics, vascular surgery, cardiology, and interventional teams, with the common goal of providing the patient with an effective and minimally invasive solution.

Conclusions

In this case, endovascular treatment of this complicated type B dissection using techniques such as in situ fenestration and imaging-guided navigation tools was a modern, safe, and effective therapeutic option. Precise anatomical planning and multidisciplinary teamwork are fundamental to ensure successful and durable outcomes.

1. Hong JC, Le Huu A, Preventza O. Medical or endovascular management of acute type B aortic dissection. J Thorac Cardiovasc Surg. 2021;162(4):1211-1218.

2. Dake MD, Kato N, Mitchell RS, et al. Endovascular stent-graft placement for the treatment of acute aortic dissection. N Engl J Med. 1999;340(20):1546-1552.

3. Mertens R, Valdés F, Krämer A, et al. Tratamiento Híbrido del Aneurisma Tóraco-Abdominal: Revascularización Extra-Anatómica e Inserción de Endoprótesis. Rev Méd Chile. 2007;135:153-159.

4. Nienaber CA, Fattori R, Lund G, et al. Nonsurgical reconstruction of thoracic aortic dissection by stent-graft placement. N Engl J Med. 1999;340(20):1539-1545.

5. Rylski B, Branchetti E, Bavaria JE, Vallabhajosyula P. Modeling aortic growth in acute type B aortic dissection. J Thorac Cardiovasc Surg. 2014;148(4):1200-1207.

6. Lombardi JV, Hughes GC, Appoo JJ, et al. Society for Vascular Surgery (SVS) and Society of Thoracic Surgeons (STS) reporting standards for type B aortic dissections. J Vasc Surg. 2020;71(3):723-747.

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In-situ fenestration and endograft for complicated type B aortic dissection: a minimally invasive endovascular strategy

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