Endovascular Stenting of the Ascending Aorta for Type A Aortic Dissections in Patients at High Risk for Open Surgery

Physician Modification to Shorten a TAG Thoracic Endoprosthesis for Treatment of a Pseudoaneurysm in the Ascending Aorta

Purpose:To report initial use of a physician-modified Gore TAG Thoracic Endoprosthesis for the treatment of pseudoaneurysm in the ascending aorta. Technique: This technique is demonstrated in a 42-year-old man with a pseudoaneurysm of the ascending aorta after a Bentall operation. The treatable length extending from the sinotubular junction to the anastomotic aneurysm edge was only 5 cm. A 45×100-mm TAG endograft for the pseudoaneurysm was modified on a back table to shorten its length. The delivery shaft was incised, and the 2 threads that fasten the top and bottom portions of the stent-graft to the sleeve were pulled out. The unfolded half of the stent-graft was cut back after pulling out the strand for the back half. Next, this custom-made graft was deployed via a transcarotid approach with cardiopulmonary bypass; no endoleak was observed. Postoperative computed tomography showed a minute type Ib endoleak. The patient was doing well at postoperative month 6. Conclusion: Physician modification of a TAG endograft facilitated effective management of this ascending aortic lesion by shortening the length of aortic coverage.

Type A aortic dissection model to improve endovascular research and technologies

OBJECTIVE

Type A aortic dissection is a life-threatening disease requiring immediate surgical treatment. With emerging catheter-based technologies, endovascular stent-graft implantation to treat aneurysms and dissections has become a standardized procedure. However, endovascular treatment of the ascending aorta remains challenging. Thus we designed an ascending aortic dissection model to allow simulation of endovascular treatment.

METHODS

Five formalin-fixed human aortas were prepared. The ascending aorta was opened semicircularly in the middle portion and the medial layer was separated from the intima. The intimal tube was readapted using running monofilament sutures. The preparations were assessed by 128-slice computed tomography. A bare-metal stent was implanted for thoracic endovascular aortic repair in 4 of the aortic dissection models.

RESULTS

Separation of the intimal and medial layer of the aorta was considered to be sufficient because computed tomography showed a clear image of the dissection membrane in each aorta. The dissection was located 3.9 ± 1.4 cm proximally from the aortic annulus, with a length of 4.6 ± 0.9 cm. Before stent implantation, the mean distance from the intimal flap to the aortic wall was measured as 0.63 ± 0.163 cm in the ascending aorta. After stent implantation, this distance decreased to 0.26 ± 0.12 cm.

CONCLUSION

This model of aortic dissection of the ascending human aorta was reproducible with a comparable pathological and morphological appearance. The technique and model can be used to evaluate new stent-graft technologies to treat type A dissection and facilitate training for surgeons.

Chronic Type A Aortic Dissection: Two Cases and a Review of Current Management Strategies

Stanford Type A aortic dissection is a rapidly progressing disease process that is often fatal without emergent surgical repair. A small proportion of Type A dissections go undiagnosed in the acute phase and are found upon delayed presentation of symptoms or incidentally. These chronic lesions may have a distinct natural history that may have a better prognosis and could potentially be managed differently then those presenting acutely. The method of repair depends on location and extent of the false lumen, as well as involvement of critical structures and branch arteries. Surgical repair techniques similar to those employed for acute dissection management are currently first-line therapy for chronic cases that involve the aortic valve, sinuses of Valsalva, coronary arteries, and supra-aortic branch arteries. In patients with high-risk for surgery, endovascular repairs have been successful, and active development of delivery systems and grafts will continue to enhance outcomes. We present two cases of chronic Type A aortic dissection and review the current literature.

Percutaneous thoracic endovascular aortic repair for ascending aortic pseudoaneurysm after prosthetic aortic valve repair

Ascending aortic pseudoaneurysms are an uncommon and challenging surgical problem that requires intervention to avoid rupture and hemorrhage. Preceding cardiac procedures often compound the high rate of morbidity and mortality associated with open repair. A case is described of an iatrogenic pseudoaneurysm in a patient with a recently placed prosthetic aortic valve and a clinical course precluding repeat open operative procedure. An endovascular approach was used, with placement of a thoracic aorta endograft with temporary cardiac pacing and a double-curved Lunderquist wire to avoid instrumenting the prosthetic aortic valve. At 9 months of follow-up, the patient returned to his baseline activity status, and at 24 months, had no symptoms or signs of infection, and a computed tomography angiogram demonstrated pseudoaneurysm exclusion with no graft migration.

Endovascular Repair of Type A Aortic Dissection: Current Experience and Technical Considerations

Dissection of the ascending aorta, type A aortic dissection (TAAD), represents a surgical emergency with high morbidity and mortality. Current open surgical techniques, although state-of-the-art procedures and having improved outcomes for patients with TAAD over the last decades, confer significant risk of complications and death. Recently, endovascular techniques for repair of both the abdominal and thoracic aorta have gained acceptance within the vascular and cardiovascular surgical communities as a useful tool in select pathologies and patient populations. As development of endovascular technology proceeds ever closer to the aortic valve, thoracic endovascular repair for TAAD deserves special investigation. A comprehensive literature search for studies reporting outcomes of endovascular repair in the ascending aorta was performed. In this review, we compile the worldwide experience of thoracic endovascular repair for TAAD as well as imaging studies for patient selection and the use of hybrid (open plus endovascular) techniques. The authors discuss the remaining challenges that preclude its broader adoption in this role, namely patient selection and device specificity.

Thoracic Endovascular Aortic Repair in the Ascending Aorta

Thoracic endovascular aortic repair has become an attractive alternative treatment option for thoracic aortic disease. New devices and advanced image-guided procedures are continuously expanding the indications. This article focuses on technical aspects of transapical stent graft deployment for ascending aortic pathologies. With improving device technology, diverse available stent grafts, and imaging modalities, thoracic endovascular aortic repair has become safer and holds promising potential to expand treatment options, especially for high-risk patients requiring ascending aorta treatment.

Endovascular Repair of Saccular Ascending Aortic Aneurysm After Orthotopic Heart Transplantation Using an Investigational Zenith Ascend Stent-Graft

Purpose: To report the use of an investigational stent-graft to treat an ascending aortic aneurysm in a patient with a heart transplant. Case Report: A 48-year-old man presented with a 3.5×1.5-cm saccular aneurysm in the mid anterior ascending aorta, abutting the sternum. The patient’s history was notable for placement of a left ventricular assist device followed by orthotopic heart transplantation 2 years prior to treat end-stage familial dilated cardiomyopathy. Under compassionate use, a custom-designed ascending aortic stent-graft (Zenith Ascend) was successfully delivered via an 18-F system and deployed just distal to the origin of the left main coronary artery under pulmonary artery catheter–guided rapid ventricular pacing. The patient was discharged the next day, and 6-month follow-up was unremarkable. Imaging at 5 months showed an excluded aneurysm sac with no endoleak or migration. Conclusion: The ideal ascending aortic stent-graft should be low profile, conformable to the arch anatomy, with short tip delivery system and a stepwise deployment mechanism that allows precise placement relative to the ostia of the coronary arteries and the innominate artery. This case illustrates the advancement of endovascular techniques to the most challenging segment of the aorta to decrease morbidity and mortality in high-risk patients.

Computed tomography-based study exploring the feasibility of endovascular treatment of type A aortic dissection in the Chinese population

PURPOSE

To characterize type A aortic dissection (TAAD) in the Chinese population using high-resolution computed tomography (CT) and explore potential candidacy for endovascular repair of TAAD.

METHODS

The imaging studies and medical records of all 302 patients presenting with TAAD at two Chinese hospitals from 2010 to 2013 were reviewed. Of these, 221 patients were excluded because of missing/inadequate preoperative CT scans. The remaining 91 patients (64 men; mean age 51.1±7.5 years) had CT data adequate to assess anatomical suitability for endovascular treatment. Entry tears were identified using multiplanar reconstructions, while morphological measurements were based on a centerline of flow (CLF) technique. Suitability for endovascular treatment was based on a proximal landing zone ≥20 mm long, a true lumen aortic diameter ≤38 mm, and a total aortic diameter ≤46 mm; no coronary bypass grafts originating from the ascending aorta; no malfunctioning aortic valve; and good cerebral and cardiac perfusion.

RESULTS

In the 91 patients, the precise location of the primary proximal entry tear could be identified in only 34 (37.4%) patients; in these patients, the identifiable intimal tears were located 36.4±41.0 mm distal to the closest coronary artery. The CLF was successfully generated in the CT scans of all patients; the mean lumen and total aortic lumen diameters at the entry tear level were 37.6±6.3 and 44.3±13.3 mm, respectively. Based on the CT measurements, stent-graft repair would have been anatomically feasible in 35 (38.5%) patients. No proximal landing zone (n=23), large aortic diameter (n=15), abnormal aortic valve (n=10), previous coronary bypass graft surgery (n=5), and poor cerebral and cardiac perfusion (n=3) were obstacles that affected the suitability for this treatment.

CONCLUSION

Based on high-resolution CT scans, our pilot study suggested that 38% of Chinese patients with TAAD could potentially be treated by stent-grafting based on the anatomical characteristics of the proximal dissection.

Midterm results of endovascular stent grafts in the proximal aortic arch (zone 0): an imaging perspective

BACKGROUND

Endovascular options to repair the arch and ascending aorta are rapidly evolving. Little is known about the durability of endovascular devices deployed at this location. This report describes a single-centre experience with the novel application of thoracic endovascular aortic repair (TEVAR) by examining clinical and radiological outcomes.

METHODS

A retrospective review was performed for a cohort of patients undergoing TEVAR of the arch or ascending aorta, or both, at a single centre from November 2008-July 2012.

RESULTS

Sixteen patients were included in the study, with mean imaging follow-up of 38 months (range, 15-72 months). Two complications at the proximal landing zone in the ascending aorta were identified: 1 endoleak and 1 infolding identified at 3 and 24 months postoperatively, respectively. Clinically, both these complications were attributed to the bird-beak configuration at the proximal landing zone site. At up to 72 months of follow-up, there were no cases of retrograde dissection of the native sinus of Valsalva. There were no cases of stent graft migration, graft fracture, open surgical reintervention for aortic pathologic conditions, or late mortality.

CONCLUSIONS

Early outcomes suggest that the current generation of thoracic aortic endografts can be placed in the complex anatomy of the ascending aorta and aortic arch without a high incidence of early graft fracture or migration. Future endeavors will need to focus on techniques to achieve optimal apposition with the curves of the ascending aorta. These findings are important as indications for endovascular aortic therapies expand to address proximal aortic pathologic conditions.

Thoracic endovascular aortic repair: are we approaching total endovascular solutions for thoracic aortic disease?

Thoracic endovascular aortic repair (TEVAR) has become an attractive alternative treatment option for thoracic aortic disease. New devices and advanced image-guided procedures are continuously expanding the indications. This article focuses on currently available endovascular solutions for thoracic aortic disease and future 'all endovascular' directions of TEVAR. Currently available endovascular solutions, such as hybrid operations, chimney stent grafting and transapical stent graft deployment, for ascending aortic pathologies are presented. Additionally, the impact of upcoming new technologies, such as endovascular treatment of Stanford Type A dissections of the ascending aorta, is elaborated. With improving device technology, diverse available stent grafts and imaging modalities, TEVAR has become safer and holds promising potential to expand treatment options, especially for the ascending aorta and the aortic arch.