Impact of proximal seal zone length and intramural hematoma on clinical outcomes and aortic remodeling after thoracic endovascular aortic repair for aortic dissections.

OBJECTIVE: Thoracic endovascular aortic repair (TEVAR) has become standard treatment of complicated type B aortic dissections (TBADs). Whereas adequate proximal seal is a fundamental requisite for TEVAR, what constitutes "adequate" in dissections and its impact on outcomes remain unclear. The goal of this study was to describe the proximal seal zone achieved with associated clinical outcomes and aortic remodeling. METHODS: A retrospective review was performed of TEVARs for TBAD at a single institution from 2006 to 2016. Three-dimensional centerline analysis of preoperative computed tomography was used to identify the primary entry tear, dissection extent, distances between arch branches, and intramural hematoma (IMH) involvement of the proximal seal zone. Patients were categorized into group A, those with proximal extent of seal zone in IMH/dissection-free aorta, and group B, those with landing zone entirely within IMH. Clinical outcomes including retrograde type A dissection (RTAD), death, and aortic reinterventions were recorded. Postoperative computed tomography scans were analyzed for remodeling of the true and false lumen volumes of the thoracic aorta. RESULTS: Seventy-one patients who underwent TEVAR for TBAD were reviewed. Indications for TEVAR included malperfusion, aneurysm, persistent pain, rupture, uncontrolled hypertension, and other. Mean follow-up was 14 months. In 26 (37%) patients, the proximal extent of the seal zone was without IMH, whereas 45 (63%) patients had proximal seal zone entirely in IMH. Proximal seal zone of 2-cm IMH-free aorta was achieved in only six (8.5%) patients. Review of arch anatomy revealed that to create a 2-cm landing zone of IMH-free aorta, 31 (43.7%) patients would have required coverage of all three arch branch vessels. Postoperatively, two patients developed image-proven RTADs requiring open repair, and one patient had sudden death. All three of these patients had TEVAR with the proximal seal zone entirely in IMH. No RTADs occurred in patients whose proximal seal zone involved healthy aortic segment. At 24 months, overall survival was 93% and freedom from aorta-related mortality was 97.4%. Complete thoracic false lumen thrombosis was seen in 46% of patients. Aortic remodeling, such as true lumen expansion, false lumen regression, and false lumen thrombosis, was similar in both groups of patients. CONCLUSIONS: Whereas achieving 2 cm of IMH-free proximal seal zone during TEVAR for TBAD would often require extensive arch branch coverage, failure to achieve any IMH-free proximal seal zone may be associated with higher incidence of RTAD. The length and quality of the proximal seal zone did not affect the subsequent aortic remodeling after TEVAR.

Anatomic suitability for "off-the-shelf" thoracic single side-branched endograft in patients with type B aortic dissection.

OBJECTIVE: Treatment of type B aortic dissections with thoracic endovascular aortic repair (TEVAR) has been adopted in many centers with the goal of covering the proximal entry tear. Coverage of the left subclavian artery (LSCA) is commonly required to achieve a dissection-free proximal seal zone. A novel thoracic single side-branched (TSSB) endograft device offers a potential off-the-shelf option to achieve total endovascular incorporation of LSCA during zone 2 TEVAR. The aim of this study was to determine what percentage of patients with type B aortic dissection who require zone 2 TEVAR meet the anatomical requirements for this device. METHODS: All consecutive patients undergoing TEVAR for type B aortic dissections at a single institution from 2006 to 2016 were evaluated. Three-dimensional centerline reconstruction of preoperative computed tomography angiography was performed to identify the diameter of the aorta, distances between branch vessels, diameter of the target branch vessel, and location of the primary entry tear. Only patients who met criteria for zone 2 TEVAR were included in the analysis. The primary outcome was percentage of patients that meet all anatomical requirements for TSSB. Individual criteria were evaluated independently, and results were stratified by dissection chronicity. RESULTS: Eighty-seven patients who underwent TEVAR for Stanford type B aortic dissections were reviewed. Fifty-seven (66%) would have required zone 2 TEVAR. Indications for TEVAR were malperfusion (12), aneurysm (15), persistent pain (22), rupture (3), uncontrolled hypertension (5), and other (3). Mean follow-up was 19 months (range, 1-72 months). Only 16 of the 57 patients (28%) met all the requirements for anatomic suitability. The primary contributor was that only 49% of patients had sufficient length between arch branches to prevent coverage of a proximal branch. CONCLUSIONS: Although the new TSSB device can allow for a more proximal seal zone and eliminate the need for open aortic arch debranching, only 28% of patients with type B dissection who required zone 2 TEVAR met all the anatomic requirements for this device. Future devices will need to account for the short distance between the left carotid and LSCA to be more broadly applicable.

Multilayered Parallel Endografting for Urgent Endovascular Repair of a Severely Angulated Thoracoabdominal Aortic Aneurysm.

Total endovascular repair of TAAA using branched, fenestrated stent grafts have been performed with promising midterm results. However, severe angulation of the aorta as well as close proximity of the visceral and renal artery ostia pose a significant technical challenge in designing and implanting branched, fenestrated stent grafts. Parallel grafting offers an alternative technique, allowing an urgent, or emergent total endovascular repair of symptomatic, or ruptured TAAA. We describe a technique of 4-vessel incorporation in a total endovascular repair of TAAA, using multilayered parallel endografting via bilateral femoral and unilateral brachial access. A 76-year-old male with severe chronic obstructive pulmonary disease and coronary artery disease presented with a symptomatic 9 cm extent IV thoracoabdominal aortic aneurysm. The thoracic, and paravisceral segments of his aorta, as well as the iliac arteries were severely angulated, whereas the superior mesenteric and the celiac arteries had a common origin. An urgent total endovascular aortic repair was performed. The aorta and the iliac arteries were straightened by placing stiff wires from bilateral femoral arteries in a "buddy" fashion. In addition, a brachiofemoral "body-floss" wire was established. Over this body-floss wire, thoracic stent grafts were deployed in multiple layers, alternating with parallel branch stents into visceral and renal arteries. Distally, a bifurcated modular stent graft was deployed down to the common iliacs, achieving complete aneurysm exclusion. Patient recovered well without complications and was discharged home in 5 days. Postoperative computed tomography scan showed patent visceral and renal stents and complete exclusion of the aneurysm without evidence of endoleak.

Remodeling of abdominal aortic branch perfusion after thoracic endovascular aortic repair for aortic dissections.

OBJECTIVE: The fate of the abdominal aorta and its branches after thoracic endovascular aortic repair for aortic dissection (TEVAR-AD) has not been studied. The objective of this study was to describe the midterm changes in abdominal aortic branch perfusion after TEVAR-AD. METHODS: A retrospective analysis of TEVAR-AD at a single institution from December 1, 2008, to March 31, 2015, was performed. Computed tomography angiography (CTA) images were reviewed to characterize the perfusion pattern changes of the celiac, superior mesenteric, inferior mesenteric, bilateral renal, and common iliac arteries. Risk factors associated with branch interventions were identified. RESULTS: During the study period, 68 patients underwent TEVAR-AD, 46 of whom had pre-TEVAR and post-TEVAR CTA images available for review. For post-TEVAR CTA, the most recent scans were selected for analysis. The mean period between CTA studies was 371 days. Indications for TEVAR-AD were persistent pain (41%), malperfusion (15%), rupture (6%), and aneurysmal degeneration (33%). Twenty-five patients (54%) were treated during the acute phase (<14 days). All patients had dissections extending to the paravisceral aorta. Of the 304 abdominal aortic branches analyzed, 8 required intervention (2.6%). Branch events requiring intervention included malperfusion (two) and aneurysms involving the branches (three). No intervention was performed for one asymptomatic inferior mesenteric artery occlusion. Of the remaining 295 branches, changes in perfusion patterns were observed in 16 (5.4%). Twelve branches (75%) demonstrated an increased true lumen contribution to perfusion. Four branches (25%) had increased false lumen contribution, without clinical evidence of malperfusion. Patients requiring branch interventions were more likely to have severe chronic kidney disease (P = .012) and more extensive aortic zone coverage during TEVAR (P = .003). On multivariable Cox proportional hazards analysis, coverage of four or more zones during TEVAR-AD was associated with branch intervention (odds ratio, 6.44; 95% confidence interval, 1.01-40.8). The estimated intervention-free patency of the abdominal aortic branches was 89% at 5 years. CONCLUSIONS: Perfusion patterns of abdominal aortic branches remain largely stable after TEVAR-AD. The need for branch intervention is rare and associated with extensive aortic coverage.

Successful treatment and survival after gunshot wound to the aortic arch with bullet embolism to superficial femoral artery.

Mortality after gunshot wounds to the thoracic aorta ranges from 92% to 100%. Survival is almost always in patients with injury from low-caliber, low-velocity bullets with hemorrhage contained by the wall of the aorta. Bullet embolization, even rarer with a reported incidence of 0.3% of vascular injuries, is most commonly found during autopsy. We report the successful treatment and survival of a patient who presented with a large-caliber gunshot wound to the aortic arch with contained rupture and bullet embolization from the aortic arch to the superficial femoral artery. The patient remained functionally independent and was discharged without complication.

Treatment of Complex Thoracoabdominal Aortic Disease.

Thoracoabdominal aortic aneurysms are increasing in incidence. Rupture is associated with a high rate of morbidity and mortality. The historic gold standard of open repair can be performed with low rates of complications at centers of excellence. However, these results are not universally achievable, with significantly higher rates of mortality reported from statewide studies. With the advent of endovascular therapy, techniques to mitigate the physiologic stress of open surgery have been developed. Hybrid open/endovascular operations are being undertaken with total visceral debranching followed by endografting. Totally endovascular procedures are now being performed using fenestrated, branched, and parallel endografts.