Hybrid Repair of Type B Aortic Dissection With Thoracoabdominal Aortic Aneurysmal Degeneration in the Setting of Marfan Syndrome

Case Report

A 34-year-old African American male with a history of hypertension and tobacco abuse presented to a rural community hospital with back pain; computed tomography angiography (CTA) demonstrated an acute type B aortic dissection. He was treated conservatively with antihypertensives, but after 1 year, his pain recurred. Repeat CTA revealed interval development of an extent II thoracoabdominal aneurysm (TAAA) with a greatest cross-sectional diameter of 4.9 cm. He was referred to our Vascular Surgery clinic where a genetic aortopathy was suspected. There was aneurysmal degeneration extending to the origin of the left subclavian artery (LSA) prohibiting adequate proximal seal zone of 2 cm. The left CCA was in close proximity to the LSA, and a LSA bypass or transposition for zone 2 thoracic endovascular aortic repair (TEVAR) would also provide inadequate seal. After a multidisciplinary discussion with cardiac surgery, the decision was made for a staged hybrid technique (HT) with zone 1 TEVAR; the thoracic endograft could serve as a bridge if future ascending aortic arch or thoracoabdominal aortic aneurysmal degeneration mandated open repair. For aortic arch debranching, a left-to-right carotid-carotid transposition (CCT) was chosen as an autologous option for cervical debranching with shunt placement for cerebral perfusion. Two days later, a zone 1 TEVAR to the celiac axis with retrograde LSA stent graft in parallel configuration was performed after placement of a prophylactic spinal drain. From an operative standpoint, 31 mm and 28 mm thoracic endografts converted this TAAA from an extent II to an extent IV, requiring a less extensive open repair in the event of further thoracoabdominal degeneration. The retrograde LSA snorkel preserved antegrade left arm access to the thoracoabdominal aorta for staged or future endovascular TAAA repair. He underwent genetic analysis by our medical hereditary aortic specialist, revealing the underlying pathology of Marfan syndrome (MFS). Although the initial HT surgery was successful, over the next year the patient’s back pain recurred. He underwent serial imaging every 2 to 3 months, and despite a lack of evidence of an endoleak, CTA imaging revealed continued growth of the abdominal component of the TAAA to 6 cm (Figure 1). After genetic counseling and addition of an angiotensin receptor blocker, the patient underwent open extent IV TAAA repair with individual prosthetic bypass to the celiac axis, superior mesenteric artery, bilateral renal arteries, and bilateral common iliac arteries. The proximal and distal extents of the Coselli graft were sutured to the distal end of the thoracic endograft with a felt pledget strip and the bilateral common iliac arteries, respectively (Figure 2). The thoracic aneurysm was closed over the proximal suture line. The patient’s postoperative course was complicated by retroperitoneal and left femoral hematomas, blood transfusion, subclinical acute kidney injury, and a non-occlusive left common femoral vein thrombosis which was treated with systemic therapeutic anticoagulation. He was discharged to a rehabilitation facility on post-operative day 16. The patient has remained asymptomatic on follow-up. There was progressive aortic remodeling on serial CTAs (Figure 3).

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Figure 1.

Initial 6 month post-TEVAR follow-up CTA of the chest with 3-D volumetric reconstruction in the anterior projection (A) and lateral projection (B) demonstrating Zone 1 thoracic stent graft (thick white arrows) with retrograde left subclavian stent graft (white arrowhead) and carotid-carotid transposition (thin white arrow) showing retropharyngeal course. Residual aneurysm sac (teal) extends from the left subclavian artery to the hiatus.

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Figure 2.

Open TAAA repair with Coselli graft sutured proximally to distal end of thoracic endograft and distally to the bilateral common iliac arteries.

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Figure 3.

20-month post-TEVAR CTA of the chest, abdomen and pelvis with 3-D volumetric reconstruction shows significant remodeling of the aneurysm sac (teal) which has decreased in size and extent (thick white arrows). Coselli thoracoabdominal graft (white overlay and arrowheads) with individual bypasses of the celiac, superior mesenteric, and bilateral renal arteries.

Discussion

MFS is an autosomal dominant connective tissue disorder arising from a mutation of the fibrillin gene. ¹ The leading cause of death in this population is cardiovascular pathology, including aortic dissection with subsequent aneurysm formation and rupture. ² Aneurysmal degeneration of the thoracoabdominal aorta in chronic aortic dissection occurs secondary to a connective tissue disorder or continued perfusion of the false lumen. ² Historically, patients underwent open TAAA repair. Furthermore, greater morbidity and mortality was associated with increasing degrees of thoracoabdominal aorta involvement. In open repair of extent II TAAA, spinal cord ischemia (SCI) ranged from 7% to 32%, while death occurred in 10% to 42%. ³ Comparatively, less TAAA involvement in extent III and IV TAAAs were associated with lower risk of SCI 9% and 1.5%, respectively. ⁴

Given the significant sequela of open surgery, endovascular surgery became an increasingly frequent treatment modality for TAAA. Endovascular technique is associated with improved short-term outcomes with justifiable long-term risks, most notably endoleak and progression of underlying aortic disease. ⁵ Furthermore, it allows remodeling of the aorta to the endograft as well as thrombosis of the false lumen.^6,7 Its utilization in connective tissue disorders has been controversial, stemming from concern over the radial force of an endograft. Geisbusch et al. demonstrated patients with MFS undergoing TEVAR had an elevated although acceptable risk of endoleak and progression of underlying aortic disease compared to patients without connective tissue disorders. ⁸

Staged hybrid repair is an alternative approach to extensive TAAA, utilizing TEVAR to convert extent I/II TAAA to extent III/IV TAAA followed by open repair. Similar to our case, the distal thoracic endograft serves as a prosthetic bridge for an open prosthetic reconstruction. Furthermore, the proximal thoracic endograft provides a similar function if there is future need for open repair of ascending aortic arch degeneration. As previously discussed, open repair of extent III/IV TAAAs is associated with lower morbidity and mortality. Gawenda et al. reported 6 staged hybrid repairs of TAAA with no deaths, endoleak, or SCI without prophylactic placement of spinal drains at median follow-up of 12 months. ⁹ Half of the patients required zone 2 TEVAR; there was no LSA revascularization. ⁹ Johnston et al. described 10 patients with extensive TAAAs who underwent staged hybrid repair without mortality or SCI with prophylactic spinal drain. ⁶ Morbidity included 4 endoleaks (n = 1, type IA; n = 3, type II) in which 3 underwent endovascular reintervention with median follow-up of 35 weeks. ⁶ Subsequent long-term data of 19 patients with 3 year median follow-up described no deaths, strokes, or chronic renal failure. ⁷ There were 3 endoleaks (type Ia, n = 1; type Ib, n = 1; type II, n = 1) necessitating endovascular reintervention before open repair. ⁷ 50% of these patients underwent zone 2 TEVAR with LSA revascularization. ⁷ There were no further endoleak or TAAA reintervention after open repair. ⁷ Within this cohort, 4 patients had MFS. ⁷ Furthermore, there are case reports of patients with MFS undergoing hybrid repair of TAAA with similar success.^10,11

Our preferred technique for aortic arch debranching in zone 1 TEVAR is CCT, previously reported by Egaña et al, and retrograde LSA stent snorkel at the time of TEVAR for preservation of antegrade arm access. ¹² We demonstrate that shunt placement is effective in cerebral perfusion during CCT.

Conclusions

Aneurysmal degeneration of aortic dissection in the setting of MFS historically mandates open aortic repair. We present a case in which a type B aortic dissection with aneurysmal progression in MFS was managed successfully with staged HT comprised of autologous aortic debranching by CCT, zone 1 TEVAR, and preservation of antegrade LSA access by parallel stent grafting, followed 1 year later by open extent IV TAAA repair.