Aortic remodeling after endovascular treatment of complicated type B aortic dissection with the use of a composite device design

Volumetric analysis demonstrates that true and false lumen remodeling persists for 12 months after thoracic endovascular aortic repair

A 62-year-old man underwent an elephant trunk procedure followed by thoracic endovascular aortic repair (TEVAR). Computed tomography angiography-based models were built to quantify volume of the whole aorta and true and false lumens preoperatively, before TEVAR, after TEVAR, and at follow-up at 3, 6, and 12 months. With TEVAR, descending aortic true lumen volume increased by 54%, then increased additionally by 60% during 12 months. The descending aortic false lumen volume regressed continuously for 12 months following TEVAR, with the most rapid rate from 6 to 12 months at 16 cm3/month. TEVAR immediately increased true lumen volume and continued to remodel the true and false lumens throughout the following 12 months.

Fenestrated endografting after bare metal dissection stent implantation

PURPOSE

To present a case that demonstrates the ability to deploy a 4-fenestrated endograft in an aorta previously treated with an endovascular graft and additional distal bare stents for acute type B dissection.

CASE REPORT

Five years ago, a 61-year-old man had a Zenith TX2 endovascular graft and 2 distal bare metal stents deployed for acute type B dissection. In follow-up, a distal extension endograft was deployed below the bare stent for false lumen reperfusion and aortic growth. The ascending aorta and the arch were replaced surgically at 3 years, with the distal end of the graft sewn to the existing endograft. At the current admission, a Crawford type III thoracoabdominal aortic aneurysm was found and excluded with a 4-fenestration endograft. Using 3-dimensional fusion imaging, there was no major conflict with the struts of the bare dissection stent during catheterization and bridging stent placement. A distal bifurcated endograft was also implanted. The total procedure time was 240 minutes, the radiation dose was 8066 cGy·cm(2), and the contrast volume was 100 mL. The patient was discharged on the sixth postoperative day and continues to do well at 9 months.

CONCLUSION

Prior dissection stent deployment within the thoracoabdominal segment does not preclude further fenestrated endograft placement. Intraoperative fusion imaging can be very helpful to the successful completion of these complex procedures.

Biomechanical Changes After Thoracic Endovascular Aortic Repair in Type B Dissection

Thoracic endovascular aortic repair (TEVAR) has evolved into an established treatment option for type B aortic dissection (TBAD) since it was first introduced 2 decades ago. Morbidity and mortality have decreased due to the minimally invasive character of TEVAR, with adequate stabilization of the dissection, restoration of true lumen perfusion, and subsequent positive aortic remodeling. However, several studies have reported severe setbacks of this technique. Indeed, little is known about the biomechanical behavior of implanted thoracic stent-grafts and the impact on the vascular system. This study sought to systematically review the performance and behavior of implanted thoracic stent-grafts and related biomechanical aortic changes in TBAD patients in order to update current knowledge and future perspectives.

Endovascular repair of Stanford B aortic dissection using two stent grafts with different sizes

OBJECTIVE

The objective of this study was to introduce a novel strategy for thoracic endovascular aortic repair of Stanford B aortic dissection using two-stent graft implantation (TSI), in which the proximal stent and distal stent with different sizes are sequentially deployed, and to summarize our experience with this technique.

METHODS

A retrospective study was conducted of 72 consecutive patients (61 men; mean age, 55 ± 7 years; range, 41-67 years) with Stanford type B aortic dissection who underwent TSI treatment between January 2012 and May 2013. Among all patients, 43 (59.7%) involved the infrarenal aorta and 29 (40.3%) involved the whole thoracic and abdominal aorta; mean aortic involvement length was 226 ± 13 mm (range, 182-312 mm). Eight cases were for acute dissection (within 2 weeks from onset of symptoms), 11 cases were for chronic dissection (>3 months after initial dissection), and 53 cases were for subacute dissection (between 2 weeks and 3 months). Twenty-two cases (30.6%) were uncomplicated type and 50 cases (69.4%) were complicated type. Follow-up was performed postoperatively at 1 month, 6 months, and yearly thereafter. Technique success, aorta morphology, and procedure-related complications were evaluated.

RESULTS

Technical success was achieved in 100%; 72 pairs of stent grafts (144 thoracic stent grafts) and 10 left subclavian artery chimney stents were used. The mean aortic length coverage by the stent grafts was 197.6 ± 20.3 mm, and mean taper diameter span was 7.5 ± 1.8 mm. All patients were followed up from 6 to 16 months (mean, 10 ± 4 months); 95.8% (69 of 72) had a thrombosed false lumen in the aortic coverage, and the true lumen expanded on average 57% ± 11% (23%-100%). No significant changes were found in aortic diameters of the proximal and distal ends of the two stent grafts and the angles between centerlines of the distal end of the stent and the aorta during follow-up. Procedure-related complications included transient paraplegia (coverage of the left subclavian artery without revascularization and extensive coverage of aorta >220 mm) due to acute spinal cord ischemia (n = 1) and malapposition of the distal stent (primary tear closed, true lumen expansion led to oversize rate insufficient in distal stent diameter; n = 1). No death or malperfusion complications were observed during the perioperative period and follow-up.

CONCLUSIONS

Short-term outcomes showed TSI to be a flexible and effective approach to accurately repair Stanford B aortic dissection that could potentially address the limitations of currently available stent grafts. Further prospective clinical studies are warranted to evaluate its long-term efficacy.

Current Treatment Strategies for Acute Type B Aortic Dissection

Acute type B aortic dissection (ATBAD) is a medical emergency that is a common occurrence in patients with atherosclerotic disease. The presentation is usually severe, with tearing pain that radiates to the back, and various levels of end-organ ischemia and malperfusion, even rupture, may occur. Everyone agrees that prompt and aggressive blood pressure control with β-blockers and nitroprusside is imperative, but when to surgically intervene is still not well characterized. However, the advent of minimally invasive stent graft placement has reshaped our thoughts regarding therapeutic intervention for ATBAD. This review is an attempt to define the current surgical indications for treating ATBAD.