Left subclavian artery management in endovascular repair of thoracic aortic aneurysms and aortic dissections

How I do it: Established and novel methods for left subclavian revascularization with thoracic endovascular aortic repair

Left subclavian artery revascularization at the time of thoracic endovascular aortic repair has been the subject of discussion for over a decade. Contemporary viewpoints suggest that revascularization should be performed where possible to decrease the risk of perioperative stroke, spinal cord ischemia, and, to a lesser degree, loss of upper extremity function. In this article, we present traditional methods as well as descriptions of newer options and technology for preservation of left subclavian artery flow during thoracic endovascular aortic repair.

Atypical presentation of subclavian steal syndrome with left sided sensorineural deafness

We present a rare manifestation of a common pathology: left sided sensorineural hearing loss secondary to subclavian steal syndrome after thoracic endovascular aortic repair for complicated acute aortic dissection. We describe the vascular physiology that can result in unilateral hearing loss and provide a brief review of subclavian steal syndrome. This case report highlights the importance of avid clinical recognition of an atypical presentation of a common vascular disease.

CT of Postoperative Repair of the Ascending Aorta and Aortic Arch

While many of the classic open surgical repairs are still used to repair the ascending aorta, management of the aortic arch has become more complex via implementation of newer open surgical and endovascular techniques. Furthermore, techniques are often combined in novel repairs or to allow extended anatomic coverage. As such, a framework that rests on understanding the expected postoperative appearance is necessary for the diagnostic radiologist to best interpret CT studies in these patients. After reviewing the imaging appearances of the common components used in proximal aortic repair, the authors present a structured approach that focuses on the key relevant questions that diagnostic radiologists should consider when interpreting CT studies in these patients. For repair of the ascending aorta, this includes determining whether the aortic valve has been repaired, whether the sinuses of Valsalva have been repaired, and how the coronary arteries were managed, when necessary. In repairs that involve the aortic arch, the relevant considerations relate to management of the arch vessels and the distal extent of the repair. In focusing on these questions, the diagnostic radiologist will be able to identify and describe the vast majority of repairs. Understanding these questions will also facilitate improved understanding of novel repairs, which often use these basic building blocks. Finally, complications-which typically involve infection, noninfectious repair breakdown, hemorrhage, problems with endografts, or disease of the remaining adjacent aorta-will be identifiable as deviations from the expected postoperative appearance. Online supplemental material is available for this article. ^©RSNA, 2021.

Clinical Application of an Original Flexible MK Stent-Graft for Nonruptured Thoracic Aortic Aneurysms: Early Experience

Objective

To obtain early MK stent-grafting results for nonruptured thoracic aortic aneurysms and thoracoabdominal aortic aneurysms.

Methods

The authors analyzed 47 patients who underwent treatment using MK stent-grafting. All patients (40 men and 7 women; mean age, 70.8 years) underwent elective procedures. Straight, curved, or tapered MK stents were constructed from a nitinol wire and covered with seamless, cylindrical woven polyester fabric grafts. The mean stent-graft diameter was 24 to 48 mm. In cases where the aneurysm had a short proximal neck (under 15 mm), supraaortic arch artery bypass surgery was planned to lengthen the neck.

Results

Simple stent-grafting without bypass was performed in 26 patients, whereas stent-grafting with supraaortic arch artery bypass was performed in 21 patients. An 18 or 20 F sheath was used as the delivery system in 46 patients (96%). In all 47 patients, the stent-grafts were successfully deployed. Two patients died while in hospital, and another 2 patients suffered a stroke. No other perioperative complications were observed. Postoperative computed tomography after 3 months showed complete thrombus formation in 42 patients (93.3%; 42/45 patients).

Conclusions

Forty-seven patients with thoracic aortic aneurysm were treated with our original flexible MK stent-graft system. Using a small sheath system, straight or curved M-K stent-grafts could be deployed to adequately fit to the aorta as planned. Furthermore, simultaneous bypass surgery widened the application of stent-grafting. However, careful long-term observation is necessary, and further studies are needed to assess such stent-grafting with bypass surgery.

Outcomes of carotid-subclavian bypass performed in the setting of thoracic endovascular aortic repair

BACKGROUND

Subclavian artery revascularization is frequently performed in the setting of thoracic endovascular aortic repair (TEVAR). However, there is little information on the short- and long-term outcomes of patients undergoing carotid to subclavian artery bypass in this clinical setting. As such, this study sought to define the early and late outcomes associated with this procedure.

METHODS

Patients undergoing carotid-subclavian bypass in conjunction with TEVAR between June 2005 and September 2016 were retrospectively identified from a prospectively maintained, single-center aortic surgery database. The 30-day outcomes specific to the carotid-subclavian bypass procedure were analyzed, including cervical plexus nerve injury, bleeding complications, and local vascular complications. All preoperative and postoperative chest radiographs were carefully analyzed to assess for hemidiaphragm elevation indicative of phrenic nerve palsy. Long-term outcomes included primary graft patency and anastomotic complications.

RESULTS

Of 579 consecutive patients undergoing TEVAR during this time interval, 112 patients (19%) underwent concomitant carotid-subclavian bypass. The cohort was 38% female (n = 43), with a mean age of 65 ± 14 years. The majority of conduits were 8-mm polytetrafluoroethylene grafts (n = 107 [95.5%]), with a minority being reversed saphenous vein (n = 4 [3.6%]) or Dacron (n = 1 [0.9%]) grafts. The bypass procedure was done concurrently at the time of TEVAR in 91% (n = 102) of cases. The short-term complication rate attributed specifically to the carotid-subclavian bypass was 29% (n = 33). These complications included phrenic nerve palsy in 25% (n = 27), recurrent laryngeal nerve palsy in 5% (n = 6), axillary nerve palsy in 2% (n = 2), and neck hematoma requiring re-exploration in 1% (n = 1) of patients. The 30-day in-hospital all-cause mortality rate was 5% (n = 6), and the rate of permanent paraparesis or paraplegia was 0.9% (n = 1). Of the operative survivors (n = 106), follow-up imaging of the bypass graft was available in 87% (n = 92) of patients. Actuarial primary graft patency was 97% at 5 years. There were three patients (3%) with bypass graft occlusions, two of which were clinically silent and detected on follow-up imaging. The third was detected because of symptoms of subclavian steal and required repeated revascularization. Two patients (2%) developed a late anastomotic pseudoaneurysm requiring either endovascular (n = 1) or surgical (n = 1) intervention.

CONCLUSIONS

Carotid-subclavian bypass for revascularization of the subclavian artery performed in the setting of TEVAR is durable, although the true complication rate is likely higher than is generally reported in the literature because of a not insignificant rate of phrenic nerve palsy. These data should serve well as "gold standard" comparison data for emerging branch graft devices.

Association of left subclavian artery coverage without revascularization and spinal cord ischemia in patients undergoing thoracic endovascular aortic repair: A Vascular Quality Initiative® analysis

Objectives

Investigate the impact of left subclavian artery coverage without revascularization on spinal cord ischemia development in patients undergoing thoracic endovascular aortic repair.

Methods

The Vascular Quality Initiative thoracic endovascular aortic repair module (April 2011–July 2014) was analyzed. Patients undergoing left subclavian artery coverage were divided into two groups according to revascularization status. The association between left subclavian artery revascularization with the primary outcome of spinal cord ischemia and the secondary outcome of stroke was assessed with multivariable analysis adjusting for between-group baseline differences.

Results

The left subclavian artery was covered in 508 (24.6%) of the 2063 thoracic endovascular aortic repairs performed. Among patients with left subclavian artery coverage, 58.9% underwent revascularization. Spinal cord ischemia incidence was 12.1% in the group without revascularization compared to 8.5% in the group undergoing left subclavian artery revascularization (odds ratio (95%CI): 1.48(0.82–2.68), P = 0.189). Multivariable analysis adjustment identified an independent association between left subclavian artery coverage without revascularization and the incidence of spinal cord ischemia (adjusted odds ratio (95%CI): 2.29(1.03–5.14), P = 0.043). Although the incidence of stroke was also higher for the group with a covered and nonrevascularized left subclavian artery (12.1% versus 8.5%), this difference was not statistically significant after multivariable analysis (adjusted odds ratio (95%CI): 1.55(0.74–3.26), P = 0.244).

Conclusion

For patients undergoing left subclavian artery coverage during thoracic endovascular aortic repair, the addition of a revascularization procedure was associated with a significantly lower incidence of spinal cord ischemia.

Type II Endoleaks, Left-Arm Complications, and Need of Revascularization after Left Subclavian Artery Coverage for Thoracic Aortic Aneurysms Endovascular Repair: A Systematic Review

BACKGROUND

The status of the left arm, the need of revascularization, and the occurrence of type II endoleakes from de left subclavian artery (LSA) after intention LSA coverage for thoracic aortic aneurysm endovascular repair need to be better understood. This systematic review was developed for contributing with such issue.

METHODS

Systematic literature review of studies published from January 2000 through December 2015 identified 7 studies comprising 201 patients submitted to elective endovascular repair for thoracic aortic aneurysms requiring intentional LSA coverage. Outcomes of interest included left-arm complications (ischemia, symptoms of claudication, and subclavian steal syndrome [SSS]) requiring postoperative revascularization of LSA, as well as endoleaks from the subclavian artery requiring postoperative embolization of LSA.

RESULTS

Left-arm complication rate was 4.5% (9 patients), requiring postoperative revascularization of LSA in 1 case (0.5%) of SSS. Type II endoleaks from the subclavian artery requiring postoperative embolization of LSA were reported in 2 cases (1.0%).

CONCLUSIONS

Low-quality evidence suggests very low rates of arm complications with need of LSA revascularization and of type II endoleaks requiring embolization in elective endovascular treatment of thoracic aortic aneurysms with intentional coverage of LSA without prophylactic revascularization of LSA.

Techniques for Preserving Vertebral Artery Perfusion During Thoracic Aortic Stent Grafting Requiring Aortic Arch Landing

Thoracic endografting offers many advantages over open repair. However, delivery of the device can be difficult and may necessitate adjunctive procedures. We describe our techniques for preserving perfusion to the left subclavian artery despite endograft coverage to obtain a proximal seal zone. We reviewed our experience with the Talent thoracic stent graft (Medtronic, Santa Rosa, CA). From 1999 to 2003, 49 patients received this device (29 men, 20 women). Seventeen patients required adjunctive procedures to facilitate proximal graft placement. We performed left subclavian-to-left common carotid artery transposition (6), left common carotid-to-left subclavian artery bypass with ligation proximal to the vertebral artery (7), and left common carotid-to-left subclavian artery bypass with proximal coil embolization (4). Patients who had anatomy unfavorable to transposition or bypass with proximal ligation (large aneurysms or proximal vertebral artery origin) were treated with coil embolization of the proximal left subclavian artery in order to prevent subsequent type II endoleaks. Technical success rate of the carotid subclavian bypass was 100%. Patient follow-up ranged from 3 to 48 months with a mean of 12 months. Six patients had follow-up <6 months owing to recent graft placement. Primary patency was 100%. No neurologic events occurred during the procedure or upon follow-up. One patient had a transient chyle leak that spontaneously resolved in 24 hours. Another patient had a phrenic nerve paresis that resolved after 3 weeks. We believe that it is important to maintain patency of the vertebral artery specifically when a patent right vertebral system and an intact basilar artery is not demonstrated. Furthermore, we describe a novel technique of coil embolization of the proximal left subclavian artery in conjunction with left common carotid-to-left subclavian artery bypass. This circumvents the need for potentially hazardous mediastinal dissection and ligation of the proximal left subclavian artery in cases of large proximal aneurysms or unfavorable vertebral artery anatomy.

Aortic Arch Aneurysm and Patent Left Internal Mammary Artery: Technique of Transposition of Supra-aortic Vessels and Embolization of the Subclavian Artery

Endovascular treatment of aortic arch aneurysms poses unique problems because of vascularization of the carotid arteries.

Transposition of supra-aortic vessels is becoming an established and accepted strategy for expanding the applicability of stent graft repair. left subclavian artery (LSA) is not usually transposed because its overstenting does not produce relevant complications. Nevertheless, some selected cases need high-pressure revascularization of the LSA, such as in the presence of a patent left internal mammary artery. We present a technique of revascularization of supra-aortic vessels and “balloon protected” embolization of the origin of the LSA.

Left Subclavian Artery Fenestration: A Novel Treatment Strategy for Acute Type A Aortic Dissection

BACKGROUND

The optimal surgical strategy for the left subclavian artery (LSA) during total arch replacement combined with stented elephant trunk implantation for acute type A aortic dissection remains a challenge. The objective of the study is to report a novel surgical technique aiming to simplify the revascularization procedure of total aortic arch replacement combined with stented elephant trunk implantation.

METHODS

We retrospectively reviewed the result of 167 patients who underwent total aortic arch replacement combined with stented elephant trunk implantation between January 2000 and December 2012. Of the 167 patients, 51 were selected to undergo the simplified revascularization, which is to fenestrate a stent graft of the descending aorta instead of performing reconstruction of the LSA. Before performing the new LSA revascularization, we had performed the elephant trunk procedure whereby the tubular material completely covered the LSA. The ensuing revascularization was modified by removing a patch of the polyester fabric of the elephant trunk that was located at the origin of the LSA. Both perioperative variables and postoperative outcome of the surgery were assessed.

RESULTS

The indication for adopting the LSA fenestration was under the circumstance of absence of dissection at the origin of the LSA. The nosocomial mortality of the 51 patients was 7.8% (multiorgan failure 2, renal failure 1, infection 1). During a mean follow-up period of 51.3 ± 27.6 months, the survival rate of the 47 patients was 100%, 90.8%, and 70.2% at 1, 5, and 10 years, respectively. No stroke and left limb ischemia were observed. No patients required reintervention because of anastomotic leak between the LSA and the descending aorta during follow-up.

CONCLUSIONS

The LSA fenestration technique during total arch replacement combined with stented elephant trunk implantation for acute type A aortic dissection is reliable and effective for patients who have no dissection at the LSA. Furthermore, because the simplified surgical procedure largely shortens the time of operation, it effectively improves the patient's prognosis.

Hybrid arch debranching and proximal endograft extension to repair a type I endoleak after endovascular thoracic aneurysm repair

Endovascular repair of complex aortic disease has emerged over the past decade as an alternative to traditional open repair, especially for patients with significant medical comorbidities and/or anatomic challenges, such as reoperative fields. However, the possibility of graft migration and endoleak mandates long-term follow-up of these grafts. We present a patient who underwent hybrid repair after stent graft migration and proximal type I endoleak after thoracic endovascular aneurysm repair. This approach allowed us to avoid extensive surgery that would also necessitate circulatory arrest.

Routine revascularization is unnecessary in the majority of patients requiring zone II coverage during thoracic endovascular aortic repair: A longitudinal outcomes study using United States Medicare population data

Objective

We aimed to evaluate outcomes of thoracic endovascular aortic repair (TEVAR) with left subclavian artery (LSA) coverage without bypass (TEVAR + SUB) to TEVAR with coverage of the LSA with a bypass at the time of the initial procedure or later at a separate procedure (TEVAR + SUB + BYPASS).

Methods

The Centers for Medicare & Medicaid Services inpatient claims for 2006–2007 were queried using Current Procedural Terminology codes for TEVAR, TEVAR + SUB, TEVAR + SUB + BYPASS or later as a separate procedure.

Results

A total of 2676 patients underwent TEVAR; 869 (32.5%) underwent TEVAR + SUB and 49 (5.6%) TEVAR + SUB + BYPASS. At the time of the initial procedure, TEVAR + SUB + BYPASS was associated with a higher incidence of stroke compared to TEVAR + SUB (12.8% vs. 3.8 %; p = 0.0033). Among TEVAR + SUB, only 1.93% (50 patients) had a subsequent bypass performed during a one-year follow-up. Overall rates of morbidity ( p = 0.004) and mortality ( p = 0.011) trended towards significance in favor of TEVAR + SUB.

Conclusions

TEVAR + SUB were associated with lower rates of mortality and complications. Only a small percentage of TEVAR + SUB required a bypass at one year after procedure. Our data suggest that routine LSA bypass during TEVAR is unnecessary and associated with increase morbidity and mortality.

A Case Series of a Hybrid Approach to Aortic Arch Disease

<p><b>Objective:</b> Debranching of the aortic arch and endovascular stent placement as a combination therapy for complex aortic arch pathology has emerged over the past few years as an alternative to traditional repair. This hybrid approach is a viable option for patients who would not tolerate conventional arch replacement, as well as for patients with a failed stent graft of the descending aorta and a subsequent type I endoleak.</p><p><b>Methods:</b> We retrospectively reviewed the preoperative characteristics and postoperative outcomes of 5 patients who underwent debranching of the aortic arch and implantation of an endovascular stent across the aortic arch between 2008 and 2011. Data were analyzed with the Student t test and the Kaplan-Meyer method.</p><p><b>Results:</b> The mean age was 70.6 � 18 years; 4 men and 1 woman were evaluated. One patient had previous aortic surgery for dissection. The preoperative morbidities included arrhythmia (1 patient), chronic obstructive pulmonary disease (2 patients), cerebrovascular accident (1 patient), diabetes mellitus (2 patients), coronary artery disease (2 patients), and active angina (1 patient). One patient had a myocardial infarction 3 weeks before surgery. The primary technical-success rate was 100%, and none of the patients died in the perioperative phase. The mean follow-up time was 22 � 18.4 months, and the median follow-up time was 13.8 months (range, 7.13-50.7 months). Two patients died during follow-up. The pathology of the aorta in the patients who died was arch aneurysm; the 3 remaining patients are alive and regularly followed at our institution.</p><p><b>Conclusion:</b> The combination of surgery and simultaneous endovascular stenting in the operating room is an alternative approach for patients who are poor candidates for traditional arch repair under circulatory arrest.</p>

Evaluation of the vertebrobasilar system in thoracic aortic surgery

BACKGROUND

We evaluated the probability of vertebrobasilar system malperfusion due to occlusion of the left subclavian artery as assessed by preoperative magnetic resonance angiography in patients scheduled to undergo thoracic aortic surgery.

METHODS

(Study 1) From January 2000 through March 2009, we studied variations of vertebral arteries in 301 patients scheduled to undergo thoracic aortic surgery. We classified vertebral artery variations into 3 categories according to the findings on preoperative magnetic resonance angiography: connection type, interrupted right vertebral artery, and interrupted left vertebral artery. (Study 2) From February 2007 through January 2010, we evaluated the cerebral complication in 41 patients who had occlusion of the left subclavian artery with a stent graft.

RESULTS

(Study 1) On preoperative magnetic resonance angiography, the vertebral artery was classified as connection type in 247 patients, interrupted right vertebral artery in 34, and interrupted left vertebral artery in 20. (Study 2) We performed subclavian obstruction test, left-right subclavian artery bypass, or left subclavian artery-left common carotid artery bypass to the 3 patients with interrupted right vertebral artery, respectively. Forty patients (98%) out of 41 patients had no complication after occlusion of the left subclavian artery.

CONCLUSIONS

Preoperative magnetic resonance angiography is useful for detection of the patients with high risk of vertebrobasilar system malperfusion due to occlusion of the left subclavian artery.

"Hybrid" approach for the treatment of aortic arch aneurysm

BACKGROUND

High mortality and morbidity rates are associated with the conventional surgery for aortic arch aneurysm because of cardiopulmonary bypass and deep hypothermic circulatory arrest. In this report, we describe a "hybrid" treatment for aortic arch aneurysm that combines the surgical debranching procedure and the stenting technique.

METHODS

A surgical bypass graft is created from the ascending aorta to every main branch of the aortic arch. Subsequently, an endovascular stent graft is deployed retrogradely through the femoral artery with the aid of digital subtraction angiography.

RESULT

The patient was discharged on postoperative day 7. A computed tomography scan was routinely performed at 1 week postoperatively to confirm the good patency of all grafts and the stent.

CONCLUSION

The feasibility and the benefit of the hybrid treatment for aortic arch aneurysm are confirmed.

Electromagnetic navigation for thoracic aortic stent-graft deployment: a pilot study in swine

PURPOSE

To determine the feasibility of electromagnetic tracking as a method to augment conventional imaging guidance for the safe delivery, precise positioning, and accurate deployment of thoracic aortic endografts.

MATERIALS AND METHODS

Custom guide wires were fabricated, and the delivery catheters for thoracic aortic endoprostheses were retrofitted with integrated electromagnetic coil sensors to enable real-time endovascular tracking. Preprocedure thoracic computed tomographic (CT) angiograms were obtained after the placement of fiducial skin patches on the chest wall of three anesthetized swine, enabling automatic registration. The stent-graft deployment location target near the subclavian artery was selected on the preprocedure CT angiogram. Two steps were analyzed: advancing a tracked glidewire to the aortic arch and positioning the tracked stent-graft assembly by using electromagnetic guidance alone. Multiple CT scans were obtained to evaluate the accuracy of the electromagnetic tracking system by measuring the target registration error, which compared the actual position of the tracked devices to the displayed "virtual" electromagnetic-tracked position. Postdeployment CT angiography and necropsy helped confirm stent-graft position and subclavian artery patency.

RESULTS

A stent-graft was successfully delivered and deployed in each of the three animals by using real-time electromagnetic tracking alone. The mean fiducial registration error with autoregistration was 1.5 mm. Sixteen comparative scans were obtained to determine the target registration error, which was 4.3 mm +/- 0.97 (range, 3.0-6.0 mm) for the glidewire sensor coil. The mean target registration error for the stent-graft delivery catheter sensor coil was 2.6 mm +/- 0.7 (range, 1.9-3.8 mm). The mean deployment error for the stent-graft, defined as deployment deviation from the target, was 2.6 mm +/- 3.0.

CONCLUSIONS

Delivery and deployment of customized thoracic stent-grafts with use of electromagnetic tracking alone is feasible and accurate in swine. Combining endovascular electromagnetic tracking with conventional fluoroscopy may further improve accuracy and be a more realistic multimodality approach.

Acute traumatic aortic injuries: posttherapy multidetector CT findings

Acute traumatic aortic injury is a life-threatening entity that requires emergent treatment. Treatment was once performed with left thoracotomy, resection of the damaged aortic segment, and placement of an interposition graft. Within the past decade, endovascular therapy has gained increased acceptance, primarily because of a significant decrease in mortality and morbidity compared with those of surgery. The authors reviewed the experience with management of acute traumatic aortic injuries at their institution, as well as that reported in the literature. Complications after endovascular repair include endoleak, endograft collapse, stroke, upper extremity ischemia, paraplegia, graft infection, endograft structural failure, missed injury or stent migration, and access site complications. After surgical repair, paraplegia and ischemia to other organs, graft dehiscence, graft infection, and graft stenosis may occur. With the growing use of endovascular management of acute traumatic aortic injuries and the increased likelihood of patient survival, the radiologist will be expected to be familiar with the findings in these patients and is positioned to play a critical role in early recognition of potential complications. Early diagnosis of the complications of therapy for aortic injury is imperative for reduction of mortality and morbidity.

Management of left subclavian artery in endovascular stent-grafting for distal aortic arch disease

BACKGROUND

Although the left subclavian artery (LSA) is simply covered to exclude distal aortic arch aneurysm during endovascular stent-grafting, this technique is potentially harmful.

METHODS AND RESULTS

Between January 2001 and April 2005, 40 cases of stent-grafting were performed for distal aortic arch diseases. For all 31 elective cases, the LSA occlusion test using a balloon catheter was preoperatively performed to predict critical complications secondary to LSA coverage by a stent graft and this revealed 2 cases in which the LSA was crucial for brain circulation (6.5%). The LSA was saved by using a hand-made fenestrated stent graft without bypass-grafting to the LSA in 22 cases. Bypass-grafting to LSA was performed in 5 cases. The LSA was simply occluded in 13 cases. Hospital mortality rates for the elective and emergency cases were 3.2% and 30.0%, respectively. One elective patient had a cerebral infarction (2.5%). LSA patency was successfully maintained in all 22 cases using a fenestrated stent graft.

CONCLUSION

The LSA plays an important role in brain circulation in some patients and so a preoperative LSA occlusion test is helpful when aortic stent-grafting is proposed. Fenestrated stent graft saved the LSA in more than 50% of the present cases.

Balloon angioplasty with stenting to correct a functionally interrupted aorta: A case report with three-year follow-up

A 16-year-old male presenting with upper extremity hypertension was found to have a severe form of discrete coarctation with complete luminal obliteration, causing a functional interruption of the thoracic aorta. Fluoroscopically guided perforation of the obstruction and creation of a neo-aortic lumen was performed. This was followed by balloon angioplasty and stent placement, successfully relieving the coarctation. The procedural method, acute and late follow-up results, and a discussion of the potential risks and benefits are presented.

Endovascular treatment of aortic arch aneurysms

BACKGROUND: Endovascular approach to the aortic arch is an appealing solution for selected patients. OBJECTIVE: To compare the technical and clinical success recorded in the different anatomical settings of endografting for aortic arch disease. METHODS: Between June 1999 and October 2006, among 178 patients treated at our institution for thoracic aorta disease with a stent-graft, the aortic arch was involved in 64 cases. According to the classification proposed by Ishimaru, aortic zone 0 was involved in 14 cases, zone 1 in 12 cases and zone 2 in 38 cases. A hybrid surgical procedure of supra-aortic debranching and revascularization was performed in 37 cases. RESULTS: Zone 0. Proximal neck length: 44±6 mm. Initial clinical success was 78.6%: two deaths (stroke), one type Ia endoleak. At a mean follow-up of 16.4±11 months the midterm clinical success was 85.7%. Zone 1. Proximal neck length: 28±5 mm. Initial clinical success was 66.7%: 0 deaths, four type Ia endoleaks. At a mean follow-up of 16.9±17.2 months the midterm clinical success was 75.0%. Zone 2. Proximal neck length: 30±5 mm. Initial clinical success was 84.2%: two deaths (one cardiac arrest, one multiorgan embolization), three type Ia endoleaks, one case of open conversion. Two cases of delayed transitory paraparesis/paraplegia were observed. At a mean follow-up of 28.0±17.2 months the midterm clinical success was 89.5%. CONCLUSIONS: This study and a literature review demonstrated that hybrid procedure for aortic arch pathology is feasible in selected patients at high risk for conventional surgery. Our experience is still limited by the relatively small sample size. We propose to reserve zone 1 for patients unfit for sternotomy or in cases with aortic neck length > 30 mm following left common carotid artery debranching. We recommend to perform complete aortic rerouting of the aortic arch in cases with lesser comorbidities and shorter aortic neck.

Can the Left Subclavian Artery be Safely Covered during Endovascular Repair of the Descending Thoracic Aorta?

Objective

Routine preoperative carotid-subclavian bypass or transposition is frequently recommended in patients undergoing endovascular repair of the descending thoracic aorta (DTA). We reviewed our comprehensive thoracic endografting experience with regards to coverage of the left subclavian artery (LSA) to assess whether mandatory preoperative carotid-subclavian bypass or transposition is necessary.

Methods

Between February 2000 and November 2005, 255 patients were successfully treated with an endoluminal graft (ELG) to the DTA. Indications for intervention included atherosclerotic aneurysms (109/255, 42.7%), acute and chronic dissections (75/255, 29.4%), miscellaneous (41/255, 16.1%), and penetrating aortic ulcers (30/255, 11.8%). There were 151 males (151/255, 59.2%) and 104 females (104/255, 40.8%) with a mean age of 71 years (range, 23–91 years).

Results

The LSA was completely covered with an ELG in 71 patients (71/255, 27.8%) and partially covered in 47 patients (47/255, 18.4%). In patients who had complete coverage of the LSA, 30 patients (30/71, 42.3%) had acute or chronic Type B dissections, 26 patients (26/71, 36.6%) had aneurysms, 11 patients (11/71, 15.5%) had miscellaneous aortic pathologies, and 4 patients (4/71, 5.6%) had pseudoaneurysms associated with prior coarctation repair. Fifteen patients (15/255, 5.9%) underwent preoperative carotid-subclavian bypass or transposition and subsequently underwent complete coverage of the LSA with an ELG. One patient (1/56, 1.8%) with complete coverage of the LSA required elective postoperative carotid-subclavian bypass secondary to left arm claudication.

Conclusions

Routine preoperative carotid-subclavian bypass is not necessary, except in select patients with a patent left internal mammary artery to the left anterior descending artery bypass graft or contralateral vertebral artery disease.

Stent Grafting–Related Acute Type B Redissection

The purpose of this article is to report two distal dissections resulting as a complication of endovascular aneurysm repair (EVAR) in two cases of type B aortic dissection (TBAD) and its relationship with prosthetic alignment at the distal landing zone. Two patients affected by aneurysm formation of a chronic type B dissection underwent EVAR. During postoperative follow-up, at 48 and 39 months, respectively, a new chest pain episode recommended a new computed tomographic angiography examination. New false lumen reperfusion and increased aortic diameter distally to the prosthesis were demonstrated. The distal end of each stent graft showed an angulated alignment to the proximal descending aorta at the point of the secondary entry site. Both patients were successfully treated after deployment of a distal endograft. Prosthetic alignment with the aortic axis is important to avoid wall stress and secondary perforation in patients treated for TBAD. The distal landing point at the descending aortic straight segment is recommended.

Reevaluating the Need for Left Subclavian Artery Revascularization With Thoracic Endovascular Aortic Repair

BACKGROUND

With increased utilization of thoracic endovascular aortic repair (TEVAR), the anatomic limitations of proximal device landing zones are being challenged. As our experience has grown with TEVAR involving exclusion of the left subclavian artery (LSA), the need for selective revascularization of the LSA appeared to be more common than we initially anticipated. We hypothesize that for patients undergoing TEVAR requiring coverage of the LSA, the need for LSA revascularization is higher than reported in the literature.

METHODS

The charts of all patients undergoing TEVAR performed at a single tertiary care center from 1999 to 2006 were reviewed. The review included the preoperative radiographic evaluations, the assessment of comorbidities, the anatomic position of the proximal and distal landing zones, outcomes, complications, and the need for preoperative or postoperative subclavian artery revascularization.

RESULTS

Sixty-four patients underwent TEVAR and 27 (42%) of these patients required exclusion of the LSA from the thoracic aorta. Seven of these 27 patients (25.9%) required preoperative LSA revascularization. Four patients developed late symptoms, necessitating LSA revascularization. No patients died or developed paraplegia, but three adverse neurological events occurred unrelated to the posterior fossa circulation. No patient developed any left arm disability.

CONCLUSIONS

The TEVAR coverage of the LSA with selective revascularization was safe for patients, but greater than 11 of 27 (40.7%) required either preoperative or postoperative LSA revascularization. Although this study represents our early experience with TEVAR, these data suggest that selective revascularization after TEVAR exclusion of the origin of the LSA may be required more frequently than previously reported.

Endovascular Treatment of Acute and Chronic Thoracic Aortic Injury

Our aim is to present midterm results after endovascular repair of acute and chronic blunt aortic injury. Between December 1999 and December 2005, 13 patients were endovascularly treated for blunt aortic injury. Ten patients, 8 men and 2 women, mean age 38.7 years, were treated for acute traumatic injury in the isthmus region of thoracic aorta. Stent-graftings were performed between the fifth hour and the sixth day after injury. Three patients (all males; mean age, 66 years; range, 59-71 years) were treated due to the presence of symptoms of chronic posttraumatic pseudoaneurysm of the thoracic aorta (mean time after injury, 29.4 years, range, 28-32). Fifteen stent-grafts were implanted in 13 patients. In the group with acute aortic injury one patient died due to failure of endovascular technique. Lower leg paraparesis appeared in one patient; the other eight patients were regularly followed up (1-72 months; mean, 35.6 months), without complications. In the group with posttraumatic pseudoaneurysms all three patients are alive. One patient suffered postoperatively from upper arm claudication, which was treated by carotidosubclavian bypass. We conclude that the endoluminal technique can be used successfully in the acute repair of aortic trauma and its consequences. Midterm results are satisfactory, with a low incidence of neurologic complications.

Incidence of neurological complications following overstenting of the left subclavian artery

OBJECTIVE

Aortic endovascular stent-graft implantation is associated with low morbidity and mortality rates. Overstenting of the left subclavian artery may be necessary to create a satisfactory proximal 'landing zone' for the stent-graft. Few cases have been published reporting adverse neurological events after overstenting of the left subclavian artery. We thus evaluated whether this procedure is associated with a higher rate of neurological complications by focusing on the management of the supra-aortic vessels.

METHODS

Twenty patients suffering from aortic arch aneurysms (n=3), descending aortic aneurysms (n=7), acute (n=6) and chronic (n=4) type-B aortic dissections underwent stent-graft repair with complete (n=14) or partial (n=6) overstenting of the left subclavian artery. Three patients underwent overstenting of the entire aortic arch with ascending aortic-bi-carotid bypass grafting. One patient with right carotid and vertebral artery occlusion underwent initial carotid-to-subclavian bypass. All patients subsequently underwent neurological examination and Doppler ultrasound for detection of neurological and peripheral vascular complications.

RESULTS

Aortic stent-graft repair was successful in all patients without acute neurologic complications. Two patients developed late central adverse neurological events: right-sided vertebral artery occlusion with brainstem infarction (n=1) and impaired binocular vision combined with dizziness (n=1), necessitating secondary subclavian transposition in one patient. Peripheral symptoms related to occlusion of the left subclavian artery were observed in five patients as sensory and motoric deficits of the left hand and arm.

CONCLUSIONS

Overstenting of the left subclavian artery as treatment of aortic pathologies in high-risk patients is feasible but associated with the risk of neurological complications and peripheral symptoms. Side effects were mild or transient in most of our patients. Detailed preoperative exploration of vascular anatomy and pathology via Doppler ultrasound, CT- or MRI scan is mandatory to avoid adverse neurological events. Prior surgical revascularization of the left subclavian artery is essential in patients with high-grade stenoses, occlusions, or anatomic variants of the supra-aortic branches. Delayed surgical revascularization is necessary only in patients with relevant subclavian steal syndrome or severe peripheral vascular symptoms.