Thoracic Endografts: Procedural Steps, Technical Pitfalls and How to Avoid Them

Stent graft treatment for transverse arch and descending thoracic aorta aneurysms

PURPOSE OF REVIEW

The aim of this article is to review the recent relevant literature on endovascular repair of thoracic aortic aneurismal disease.

RECENT FINDINGS

The introduction of endovascular stent graft technology has ushered in a new era in therapy for diseases of the aortic arch and descending thoracic aorta. The technical challenges of stent graft deployment in the descending thoracic aorta, such as proximity to the great vessels and arch tortuosity, have been and remain a device engineering focus. More recently, repair of aortic arch aneurysms has been accomplished using both 'hybrid' (open and endovascular) and totally endovascular techniques.

SUMMARY

Endovascular stent grafting of aneurismal disease processes of the thoracic aorta is feasible and relatively safe. Exquisite judgment is essential for good results. These results generally rest on a broad knowledge base of thoracic aortic disease processes and experience in both open and endovascular surgery. Careful attention to patient anatomy and device specifications must be maintained. The key to the successful implementation of this technology lies in careful preoperative planning, intraoperative execution with safe device delivery, and prevention of central nervous system injury. Routine follow-up imaging is imperative to better understand the long-term results and indications for these new procedures.

Strategies for prevention and operative treatment of aortic lesions related to spinal interventions

STUDY DESIGN

A retrospective analysis of a case series was performed.

OBJECTIVE

To give recommendations for the prevention and operative treatment of thoracic and thoracoabdominal aortic lesions in association with spinal interventions.

SUMMARY OF BACKGROUND DATA

Aortic lesions after spinal interventions for traumatic vertebral fractures, segmental spondylodiscitis, or vertebral metastasis are fortunately rare, but associated with a high perioperative mortality rate and absolute numbers are unknown. Therefore, preventive strategies to avoid perioperative major vessel injuries and recommendations for the operative treatment of aortic lesions related to spinal surgery are required.

METHODS

The clinical course of 10 patients with an acute aortic hemorrhage or an increased intraoperative risk for aortic injuries in association with primary or secondary spinal interventions is reported. All patients were evaluated before surgery by orthopedic trauma surgeons, vascular surgeons, and diagnostic radiologists.

RESULTS

Five patients had preventive vascular interventions to avoid major aortic injuries during spinal reinterventions, and 5 patients were treated as an emergency for acute intraoperative hemorrhage related to spinal interventions. The operative treatment was performed by direct aortic sutures (n = 3), segmental alloplastic reconstructions (n = 2), or endovascular stent graft implantations (n = 3). Prophylactic banding of the thoracic aorta during thoracotomy or a femoral access for possible aortic balloon blockade was performed in patients with an estimated lower risk for an aortic laceration caused by malpositioned pedicle screws. No perioperative mortality was observed in patients treated by this interdisciplinary concept, but 1 patient treated under emergency condition for spondylodiscitis with an initially unrecognized aortic lesion died.

CONCLUSION

In patients with complex spinal trauma, spondylodiscitis or difficult vertebral reinterventions, and an increased risk of major vessel injury, a preoperative interdisciplinary evaluation is recommended, even under emergency conditions. Endovascular stent graft technique is an additional option for prevention and treatment of suspected or acute aortic injuries of thoracic and infrarenal aortic lesions, whereas injuries to the visceral aortic segment still require advanced vascular reconstructions.

Caring for patients with traumatic injuries of the thoracic aorta

Trauma is a major cause of mortality and morbidity in the United States, with blunt traumatic injuries of the thoracic aorta continuing to occur despite the increased use of seatbelts and airbags. Emerging from crash analysis are effective interventions and provides increased awareness of the occult nature of these types of injuries. This article describes those interventions that healthcare providers must embed throughout the continuum of care for patients experiencing thoracic aortic injuries. Outcomes will be dependent upon the healthcare provider's knowledge of the physics of the event and the urgency of the diagnosis, as well as the ability to assess and manage all the variables involved. Current procedural issues are delineated and case studies are used to illustrate the processes of care needed by these patients.

Anatomic factors associated with acute endograft collapse after Gore TAG treatment of thoracic aortic dissection or traumatic rupture

OBJECTIVE

The potentially devastating complication of total or near total thoracic endoprosthesis collapse has been described with the TAG device (W. L. Gore & Associates, Flagstaff, Ariz). This rare complication has resulted in a warning to clinicians and speculation about the etiology of this problem. This report evaluates potential causative anatomic factors that may increase the probability of endoprosthesis collapse in patients undergoing endovascular thoracic aneurysm repair (TEVAR).

METHODS

Preoperative and postoperative computed tomography scans were collected worldwide representing six patients who had experienced radiologically confirmed TAG endoprosthesis collapse. These were compared with a matched cohort of five patients with a TAG endoprosthesis in the same anatomic position in which no collapse occurred. Anatomic variables of aortic arch angulation, apposition, intraluminal lip length, proximal aortic diameter, distal aortic diameter, intragraft aortic diameter, percentage of oversizing, and angle of the proximal endograft to the aortic arch were compared between groups. Differences between groups were determined using the Student t test, with P < .05 considered significant.

RESULTS

The two groups (collapse vs no collapse) were evenly matched demographically, and all underwent endoluminal treatment with the TAG device, with no differences in gender, graft position in the aorta, operative indication, or age (P = NS). Distal sealing zone aortic diameter +/- standard deviation of 18.9 +/- 1.7 mm vs 22.7 +/- 2.7 mm and minimum aortic diameter within the endograft of 18.6 +/- 1.7 mm vs 22.4 +/- 3.1 mm predicted collapse (P < .05). Proximal aortic diameter, apposition, intraluminal lip length, aortic arch angle, and angle of proximal endograft to aortic arch did not predict collapse (P = NS).

CONCLUSION

Thoracic endograft collapse is an exceedingly rare event. In this series, endoprosthesis collapse occurred in patients who were treated outside the manufacturer's instructions for use for minimum required aortic diameter. Although distal aortic diameter and minimum intragraft aortic diameter predicted collapse, other variables may also influence this complication but were not significant owing to potential type II statistical errors. In the future, caution should be exercised when contemplating TEVAR in patients with small (<23 mm) aortic diameters.

Stent-graft versus open-surgical repair of the thoracic aorta: Mid-term results

OBJECTIVE

Pivotal and comparative trial data are emerging for stent graft (SG) vs open repair of the thoracic aorta. We reviewed procedure-related perioperative morbidity, mortality, and mid-term outcomes in a contemporary series of patients treated with SG of the thoracic aorta. The data were compared with those of a patient cohort concurrently treated with open surgical repair confined to the descending aorta.

METHODS

A review of patients undergoing SG procedures and open surgery of the thoracic aorta from January 1, 1996, to November 30, 2005, was performed from a prospectively compiled database. Study end points included perioperative complications, late survival, freedom from reinterventions, and graft-related complications. Multivariate methods were used to assess variables potentially associated with study end points; late outcomes were compared with actuarial methods.

RESULTS

In 105 patients (mean age, 70 years; 66 male [62.9%]) SG repairs were done for 68 degenerative aneurysms (64.7%), 12 penetrating ulcers (11.4%), 15 pseudoaneurysms (14.3%), 9 traumatic tears (8.6%), and 1 acute dissection (0.9%). Mean follow-up was 22 months (range, 0 to 101 months). Eighty-nine (84.8%) SG patients were asymptomatic at presentation and underwent elective repair, whereas 16 (15.2%) presented with acute conditions and underwent urgent repair. Perioperative mortality was 7.6% (8/105), and actuarial survival at 48 months was 54% +/- 7%. The perioperative mortality rate among SG patients treated for degenerative pathology was 10.4% (8/77). Seven (6.7%) of 105 patients experienced spinal cord ischemic complications, including 2 patients with transient paraparesis that resolved by the time of discharge. Reinterventions were performed in 10.5% of patients (11/105), with freedom from reintervention approaching 81% by 48 months. Over the same interval, 93 patients were treated with open-surgical repair for descending thoracic aneurysm (anastomosis cephalad to the celiac axis). Perioperative mortality in the open cohort was 15.1% (14/93; P = .09 vs SG repair), and the 48-month actuarial survival was 64% +/- 6%. The incidence of spinal cord ischemic complications was 8.6% (8/93), including 4 patients with transient paraparesis (P = .44 vs SG repair). Nine patients (9.7%) required surgical reintervention during the follow-up period, with 48-month freedom from reintervention approaching 79% (P = .73 vs SG repair).

CONCLUSIONS

Operative mortality was halved with SG, with similar late survival for both cohorts. Reinterventions were required at a nearly identical rate for open repair and SG, and both groups experienced similar rates of spinal cord ischemic complications.