Neurophysiologic Intraoperative Monitoring During Endovascular Stent Graft Repair of the Descending Thoracic Aorta

Prevention of Spinal Cord Injury during Thoracoabdominal Aortic Aneurysms Repair: What the Anaesthesiologist Should Know

Thoraco-abdominal aortic repair is a high-risk surgery for both mortality and morbidity. A major complication is paraplegia-paralysis due to spinal cord injury. Modern thoracic and abdominal aortic aneurysm repair techniques involve multiple strategies to reduce the risk of spinal cord ischemia during and after surgery. These include both surgical and anaesthesiologic approaches to optimize spinal cord perfusion by staging the procedure, guaranteeing perfusion of the distal aorta through various techniques (left atrium-left femoral artery by-pass) by pharmacological and monitoring interventions or by maximizing oxygen delivery and inducing spinal cord hypothermia. Lumbar CSF drainage alone or in combination with other techniques remains one of the most used and effective strategies. This narrative review overviews the current techniques to prevent or avoid spinal cord injury during thoracoabdominal aortic aneurysms repair.

Current state of hybrid solutions for aortic arch aneurysms

Since its inception in the early 2000s, hybrid arch repair (HAR) has evolved from a novel approach to a well-established treatment modality for aortic arch pathology in appropriately selected patients. HAR procedures have been proposed as a means to circumvent the perioperative morbidity and mortality associated with open total arch replacement. These procedures, all of which remain off-label applications of approved endograft technology, combine more conventional open surgical techniques, to create endograft landing zones, with thoracic endovascular aortic repair to exclude the aortic pathology from the circulation. The current classification system for HAR was proposed in 2013 and consists of three types, designated by the Roman numerals I, II and III. The current system has become outdated, however, with the advent of newer technologies, and herein we propose a new, updated classification system that is more encompassing with regards to the broad array of options available to treat aortic arch disease. Likewise, an institutional algorithm to guide patient and operative selection for HAR is presented. Patients are considered for HAR if they have either high-risk comorbidities or high-risk anatomy, with an important feature of the algorithm being that any decisions about repair strategy should be made by a surgical team with expertise in both open and endovascular techniques. Despite being performed for nearly two decades, the evidence around HAR consists mainly of single center series (level B-C evidence) with no randomized controlled trials. The data suggest HAR to be a safe alternative to open repair with acceptable short and mid-term results. As we as aortic surgeons continue to move towards less invasive approaches, both conventional open and hybrid techniques will remain important tools in the toolbox for arch repair, although the advent of multi-branched arch endografts will almost certainly reduce the extent of open or hybrid repair in many patients and eliminate it altogether in others.

Permissive Hypertension and Collateral Revascularization May Allow Avoidance of Cerebrospinal Fluid Drainage in Thoracic Endovascular Aortic Repair

BACKGROUND

The utility of cerebrospinal fluid drainage (CSFD) for prevention of spinal cord ischemia (SCI) after thoracic endovascular aortic repair (TEVAR) remains unclear. We previously published our institutional algorithm restricting preoperative CSFD to patients deemed high risk for SCI. Since that publication, our algorithm has evolved with preoperative CSFD avoided in all patients undergoing isolated descending TEVAR with or without arch involvement (+/- arch TEVAR). This study evaluated the updated algorithm in a contemporary cohort.

METHODS

Patients who underwent TEVAR for descending aortic +/-arch pathology between February 2012 and September 2018 at a single center were identified from an institutional aortic surgery database. The algorithm includes left subclavian artery (LSA) revascularization in cases of coverage with no preservation of antegrade flow, permissive hypertension, and use of evoked potential monitoring. The primary end points were SCI or postoperative CSFD.

RESULTS

During the study interval, 225 patients underwent descending +/- arch TEVAR. CSFD was used before TEVAR in 2 patients (0.9%) in violation of the algorithm, and they were excluded from the study cohort. Endograft coverage below T6 occurred in 81%. The LSA was fully covered in 100 patients (47%), all of whom underwent LSA revascularization. Following the updated algorithm, the incidence of temporary or permanent SCI was 0%. No patient required postoperative CSFD.

CONCLUSIONS

A restrictive lumbar CSFD algorithm, including permissive hypertension and LSA revascularization in the setting of descending +/- arch TEVAR, appears safe, with a 0% incidence of SCI in 223 consecutive patients treated during a 6.5-year interval. We recommend consideration of further prospective study to evaluate this algorithm.

Spinal cord injury after thoracic endovascular aortic aneurysm repair

PURPOSE

Thoracic endovascular aortic aneurysm repair (TEVAR) has become a mainstay of therapy for aneurysms and other disorders of the thoracic aorta. The purpose of this narrative review article is to summarize the current literature on the risk factors for and pathophysiology of spinal cord injury (SCI) following TEVAR, and to discuss various intraoperative monitoring and treatment strategies.

SOURCE

The articles considered in this review were identified through PubMed using the following search terms: thoracic aortic aneurysm, TEVAR, paralysis+TEVAR, risk factors+TEVAR, spinal cord ischemia+TEVAR, neuromonitoring+thoracic aortic aneurysm, spinal drain, cerebrospinal fluid drainage, treatment of spinal cord ischemia.

PRINCIPAL FINDINGS

Spinal cord injury continues to be a challenging complication after TEVAR. Its incidence after TEVAR is not significantly reduced when compared with open thoracoabdominal aortic aneurysm repair. Nevertheless, compared with open procedures, delayed paralysis/paresis is the predominant presentation of SCI after TEVAR. The pathophysiology of SCI is complex and not fully understood, though the evolving concept of the importance of the spinal cord's collateral blood supply network and its imbalance after TEVAR is emerging as a leading factor in the development of SCI. Cerebrospinal fluid drainage, optimal blood pressure management, and newer surgical techniques are important components of the most up-to-date strategies for spinal cord protection.

CONCLUSION

Further experimental and clinical research is needed to aid in the discovery of novel neuroprotective strategies for the protection and treatment of SCI following TEVAR.

Neurophysiological Intraoperative Monitoring During Aortic Arch Surgery

Circulatory management during replacement of the aortic arch is complex and involves a period of circulatory arrest to provide a bloodless field during arch vessel anastomosis. To guard against ischemic brain injury, tissue metabolic demand is reduced by systemically cooling the patient prior to circulatory arrest. Neurophysiological intraoperative monitoring (NIOM) is often used during the course of these procedures to provide contemporaneous assessment of brain status to help direct circulatory management decisions and detect brain ischemia. In this review, we discuss the characteristics of electrocerebral activity through the process of cooling, circulatory arrest, and rewarming as depicted through commonly used NIOM modalities, including electroencephalography and peripheral nerve somatosensory-evoked potentials. Attention is directed toward the role NIOM has traditionally played during deep hypothermic circulatory arrest, where it is used to define the point of electrocerebral inactivity or maximal cerebral metabolic suppression prior to initiating circulatory arrest while also discussing the evolving utility of NIOM when systemic circulatory arrest is initiated at more moderate degrees of hypothermia in conjunction with regional brain perfusion. The use of cerebral tissue oximetry by near-infrared spectroscopy as an alternative NIOM modality during surgery of the aortic arch is addressed as well. Finally, special considerations for NIOM and the detection of spinal cord ischemia during hybrid aortic arch repair and emerging operative techniques are also discussed.

Complementary roles of open and hybrid approaches to thoracoabdominal aortic aneurysm repair

OBJECTIVE

Thoracoabdominal aortic aneurysm (TAAA) repair remains a significant challenge with considerable perioperative morbidity and mortality. A hybrid approach utilizing visceral debranching with endovascular aneurysm exclusion has been used to treat high-risk patients and therefore allow repair in more patients. Limited data exist regarding long-term outcomes with this procedure as well as comparison to conventional open repair. This study describes our institutional algorithmic approach to TAAA repair using both open and hybrid techniques.

METHODS

Hybrid and open TAAA repairs performed between July 2005 and August 2015 were identified from a prospectively maintained institutional aortic surgery database. Perioperative morbidity and mortality, freedom from reintervention, and long-term and aorta-specific survival were calculated and compared between the two groups.

RESULTS

During the study period, 165 consecutive TAAA repairs were performed, including 84 open repairs and 81 hybrid repairs. Patients in the hybrid repair group were significantly older, were more frequently female, and had a generally greater comorbid disease burden, including significantly more chronic kidney disease. Despite the older and sicker cohort, there was no difference in in-hospital mortality between the two groups (9.9% hybrid vs 7.1% open; P = .59). Major morbidity rates differed by procedure, with patients undergoing open repair having a significantly higher rate of postoperative stroke (9.5% open vs 0% hybrid; P = .017), whereas patients undergoing hybrid repair had a higher rate of new permanent dialysis (14.8% hybrid vs 3.6% open; P = .043). There was no difference between groups in the rate of postoperative permanent paraplegia/paresis (8.3% open vs 7.4% hybrid; P = .294). There was a significantly increased rate of reintervention in the hybrid repair group (12.3% hybrid vs 1.2% open, P = .004), with all hybrid reinterventions performed because of endoleak. One-year survival was similar between groups at 69% in hybrid repairs vs 77% in open repairs. Long-term survival was worse in the hybrid group (5-year survival, 32% hybrid vs 56% open), although late survival appeared to be influenced mainly by comorbid disease burden, given the similar long-term aorta-specific survival between groups.

CONCLUSIONS

Use of an algorithmic approach whereby higher risk patients with TAAA are treated by a hybrid approach and lower risk patients with conventional open repair yields satisfactory short- and long-term outcomes. The availability of multiple options for TAAA repair within a single center likely allows repair in more patients with consequent decrease in the risk of aorta-related death, at the expense of increased reinterventions for endoleak.

Five-year results for endovascular repair of acute complicated type B aortic dissection

INTRODUCTION

Despite a current lack of U.S. Food and Drug Administration approval for the indication, thoracic endovascular aortic repair (TEVAR) has replaced open surgical management for acute complicated type B aortic dissection due to promising short- and midterm data. However, long-term results, with a view toward durability and need for secondary procedures, are limited. As such, the objective of the present study is to report long-term outcomes of TEVAR for acute (≤ 2 weeks from symptom onset) complicated type B dissection.

METHODS

Between July 2005 and September 2012, 50 consecutive patients underwent TEVAR for management of acute complicated type B dissection at a single referral institution. Patient records were retrospectively reviewed from a prospectively maintained clinical database.

RESULTS

Indications for intervention included rupture in 10 (20%), malperfusion in 24 (48%), and/or refractory pain/impending rupture in 17 (34%). One patient (2%) had both rupture and malperfusion indications. Ten (20%) patients required one or more adjunctive procedures, in addition to TEVAR, to treat malperfusion syndromes. In-hospital and 30-day rates of death were both 0%; 30-day/in-hospital rates of stroke, permanent paraplegia/paraparesis, and new-onset dialysis were 2% (n = 1), 2% (n = 1), and 4% (n = 2), respectively. Median follow-up was 33.8 months [interquartile range, 12.3-56.6 months]. Overall survival at 5 and 7 years was 84%, with no deaths attributable to aortic pathology. Thirteen (26%) patients required a total of 17 reinterventions over the study period for type I endoleak (n = 5), metachronous aortic pathology (n = 5), persistent false lumen pressurization via distal fenestrations (n = 4), type II endoleak (n = 2), or retrograde acute type A aortic dissection (n = 1). Median time to first reintervention was 4.5 months (range, 0 days-40.3 months). Of the 17 total reinterventions, six (35%) were performed using open techniques and 11 (65%) with endovascular or hybrid methods; there was no difference in survival between patients who did or did not require reintervention.

CONCLUSIONS

This study confirms the excellent short-term outcomes of TEVAR for acute complicated type B dissection and demonstrates the results to be durable and sustained over long-term follow-up. Although aortic reinterventions were required in one-quarter of patients, no aortic-related deaths were observed. These data support the use of TEVAR for acute complicated type B aortic dissection but also highlight the importance of life-long aortic surveillance by an experienced aortic referral center in order to identify and treat complications of the underlying disease process and treatment, as well as new aortic pathologies, as they arise.

Thoracoabdominal aortic aneurysm: hybrid repair outcomes

BACKGROUND

Thoracoabdominal aortic aneurysms (TAAA) remain amongst the most formidable of surgical challenges, particularly degenerative aneurysms in the elderly population with concomitant pulmonary disease. This report presents an update of our robust single-institution experience with "hybrid" TAAA repair including complete visceral debranching and endovascular aneurysm exclusion in high-risk patients.

METHODS

Between March 2005 and June 2012, 58 patients underwent extra-anatomic debranching of all visceral vessels followed by aneurysm exclusion via endovascular means at a single institution. The median number of visceral vessels bypassed was 4. The debranching and endovascular portions of the procedure were performed as a single stage in the initial 33 patients and as a staged approach in the most recent n=25 cases.

RESULTS

Median patient age was 69.0 years; 50% were female. All had significant co-morbidity and were considered suboptimal candidates for conventional open surgical repair. Mean aortic diameter was 6.7¡À1.2 cm. Thirty-day/in-hospital rates of death, stroke, and permanent paraparesis/paraplegia were 9%, 0%, and 4%, respectively; in the most recent 25 patients undergoing staged repair these rates were 4%, 0%, and 0%. Over a mean follow-up of 26¡À21 months, visceral graft patency is 95.3%; all occluded limbs were to renal vessels and none resulted in permanent dialysis. Two patients (3%) have required re-intervention, one for type Ib and one for type III endoleak. Five-year freedom from re-intervention was 94%. Kaplan-Meier overall survival was 78% at 1 year and 62% at 5 years, with a 5-year aorta-specific survival of 87%.

CONCLUSIONS

These updated results continue to support hybrid TAAA repair via complete visceral debranching and endovascular aneurysm exclusion as a good option for elderly high-risk patients less suited to conventional open repair. A staged approach to debranching and endovascular aneurysm exclusion appears to yield optimal results.

Results with an algorithmic approach to hybrid repair of the aortic arch

OBJECTIVE

Hybrid repair of the transverse aortic arch may allow for aortic arch repair with reduced morbidity in patients who are suboptimal candidates for conventional open surgery. We present our results with an algorithmic approach to hybrid arch repair, based on the extent of aortic disease and patient comorbidities.

METHODS

Between August 2005 and January 2012, 87 patients underwent hybrid arch repair by three principal procedures: zone 1 endograft coverage with extra-anatomic left carotid revascularization (zone 1; n = 19), zone 0 endograft coverage with aortic arch debranching (zone 0; n = 48), or total arch replacement with staged stented elephant trunk completion (stented elephant trunk; n = 20).

RESULTS

The mean patient age was 64 years, and the mean expected in-hospital mortality rate was 16.3% as calculated by the EuroSCORE II. Of operations, 22% (n = 19) were nonelective. Sternotomy, cardiopulmonary bypass, and deep hypothermic circulatory arrest were required in 78% (n = 68), 45% (n = 39), and 31% (n = 27) of patients to allow for total arch replacement, arch debranching, or other concomitant cardiac procedures, including ascending with or without hemiarch replacement in 17% (n = 8) of patients undergoing zone 0 repair. All stented elephant trunk procedures (n = 20) and 19% (n = 9) of zone 0 procedures were staged, with 41% (n = 12) of patients undergoing staged repair during a single hospitalization. The 30-day/in-hospital rates of stroke and permanent paraplegia or paraparesis were 4.6% (n = 4) and 1.2% (n = 1). Of 27 patients with native ascending aorta zone 0 proximal landing zone, three (11.1%) experienced retrograde type A dissection after endograft placement. The overall in-hospital mortality rate was 5.7% (n = 5); however, 30-day/in-hospital mortality increased to 14.9% (n = 13) owing to eight 30-day out-of-hospital deaths. Native ascending aorta zone 0 endograft placement was found to be the only univariate predictor of 30-day in-hospital mortality (odds ratio, 4.63; 95% confidence interval, 1.35-15.89; P = .02). Over a mean follow-up period of 28.5 ± 22.2 months, 13% (n = 11) of patients required reintervention for type 1A (n = 4), type 2 (n = 6), or type 3 (n = 1) endoleak. Kaplan-Meier estimates of survival at 1 year, 3 years, and 5 years were 73%, 60%, and 51%.

CONCLUSIONS

Hybrid aortic arch repair can be tailored to patient anatomy and comorbid status to allow complete repair of aortic pathology, frequently in a single stage, with acceptable outcomes. However, endograft placement in the native ascending aorta is associated with high rates of retrograde type A dissection and 30-day/in-hospital mortality and should be approached with caution.

Staged total abdominal debranching and thoracic endovascular aortic repair for thoracoabdominal aneurysm

OBJECTIVE

Thoracoabdominal aortic aneurysms (TAAAs) occur most commonly in elderly individuals, who are often suboptimal candidates for open repair because of significant comorbidities. The availability of a hybrid option, including open visceral debranching with endovascular aneurysm exclusion, may have advantages in these patients who are at high-risk for conventional repair. This report details the evolution of our technique and results with complete visceral debranching and endovascular aneurysm exclusion for TAAA repair in high-risk patients.

METHODS

Between March 2005 and June 2011, 47 patients (51% women) underwent extra-anatomic debranching of all visceral vessels, followed by aneurysm exclusion by endovascular means at a single institution. A median of four visceral vessels were bypassed. The debranching procedure was initially performed through a partial right medial visceral rotation approach, leaving the left kidney posterior in the first 22 patients, and in the last 25 by a direct anterior approach to the visceral vessels. The debranching and endovascular portions of the procedure were performed in a single operation in the initial 33 patients and as a staged procedure during a single hospital stay in the most recent 14.

RESULTS

Median patient age was 71.0 ± 9.8 years. All had significant comorbidity and were considered suboptimal candidates for conventional repair: 55% had undergone previous aortic surgery, 40% were American Society of Anesthesiologists (ASA) class 4, and baseline serum creatinine was 1.5 ± 1.3 mg/dL. The 30-day/in-hospital rates of death, stroke, and permanent paraparesis/plegia were 8.5%, 0%, and 4.3%, respectively, but 0% in the most recent 14 patients undergoing staged repair. These patients had significantly shorter combined operative times (314 vs 373 minutes), decreased intraoperative red blood cell transfusions (350 vs 1400 mL), and were more likely to be extubated in the operating room (50% vs 12%) compared with patients undergoing simultaneous repair. Over a median follow-up of 19.3 ± 18.5 months, visceral graft patency was 97%; all occluded limbs were to renal vessels and clinically silent. There have been no type I or III endoleaks or reinterventions. Kaplan-Meier overall survival is 70.7% at 2 years and 57.9% at 5 years.

CONCLUSIONS

Hybrid TAAA repair through complete visceral debranching and endovascular aneurysm exclusion is a good option for elderly high-risk patients less suited to conventional repair in centers with the requisite surgical expertise with visceral revascularization. A staged approach to debranching and endovascular aneurysm exclusion during a single hospitalization appears to yield optimal results.

Results with a selective revascularization strategy for left subclavian artery coverage during thoracic endovascular aortic repair

BACKGROUND

The need for routine left subclavian artery (LSCA) revascularization when this vessel is covered during thoracic endovascular aortic repair remains controversial. We report our results with a selective LSCA revascularization strategy during thoracic endovascular aortic repair.

METHODS

Between May 2002 and March 2010, 287 thoracic endovascular aortic repair procedures were performed at our institution. LSCA coverage occurred in 145 (51%), which form the basis of this report.

RESULTS

Left subclavian artery revascularization was performed in 32 patients (22%) through a left common carotid-LSCA bypass. Indications for selective LSCA revascularization included spinal cord protection in 10, patent pedicled left internal mammary artery graft in 9, left arm ischemia after LSCA coverage in 5, origin of the left vertebral artery from the arch in 4, dialysis access in the left arm in 2, and vertebrobasilar insufficiency in 2. There were no instances of dominant left vertebral artery. The revascularized and non-revascularized groups had similar rates of death (6.3% vs 1.8%; p=0.21), stroke (3.1% vs 3.5%; p>0.99), permanent paraplegia or paraparesis (3.1% vs 0%; p=0.22), and type II endoleak (4.3% vs 6.5%; p>0.99). There were no instances of ischemic stroke related to left posterior circulation hypoperfusion. Four complications of carotid-subclavian bypass occurred in 3 patients (9.4%).

CONCLUSIONS

Selective LSCA revascularization is safe and does not appear to increase the risk of neurologic events. Further, subclavian revascularization is not without complications, which should be considered with regards to a nonselective revascularization strategy.

Total aortic replacement in Loeys-Dietz syndrome

Loeys-Dietz syndrome (LDS) is a recently identified genetic complex characterized in part by rapidly progressive aortic and branch vessel disease. We now describe total aortic replacement using an open Extent II thoracoabdominal repair followed by second-stage redo-sternotomy for a valve-sparing aortic root replacement and hybrid aortic arch repair in a patient with this syndrome. 

Midterm results with thoracic endovascular aortic repair for chronic type B aortic dissection with associated aneurysm

OBJECTIVE

Thoracic endovascular aortic repair for chronic type B aortic dissection with associated descending thoracic aneurysm remains controversial. Concerns include potential ischemic complications due to branch vessel origin from the chronic false lumen and continued retrograde false lumen/aneurysm sac pressurization via fenestrations distal to implanted endografts. The present study examines midterm results with thoracic endovascular aortic repair for chronic (>2 weeks) type B aortic dissection with associated aneurysm to better understand the potential role of thoracic endovascular aortic repair for this condition.

METHODS

Between March 2005 and December 2009, 51 thoracic endovascular aortic repair procedures were performed at a single institution for management of chronic type B dissection. The indication for thoracic endovascular aortic repair was aneurysm in all cases. A subset of 7 patients (14%) underwent placement of the EndoSure wireless pressure measurement system (CardioMEMS, Inc, Atlanta, Ga) in the false lumen adjacent to the primary tear for monitoring aneurysm sac/false lumen pulse pressure after thoracic endovascular aortic repair.

RESULTS

Mean patient age was 57±12 years (range, 30-82 years); 14 patients (28%) were female. Mean aortic diameter was 6.2±1.4 cm. There were no in-hospital/30-day deaths, strokes, or permanent paraplegia/paresis. There were no complications related to compromise of downstream branch vessels arising from the false lumen. Two patients (3.9%) who had preexisting ascending aortic dilation had retrograde acute type A aortic dissection; both were repaired successfully. Median postoperative length of stay was 4 days. Mean follow-up is 27.0±16.5 months (range, 2-60 months). Actuarial overall survival is 77.7% at 60 months with an actuarial aorta-specific survival of 98% over this same time period. Actuarial freedom from reintervention is 77.3% at 60 months. All patients with the EndoSure wireless pressure measurement system exhibited a decrease in aneurysm sac/false lumen pulse pressure indicating a depressurized false lumen. The aneurysm sac/false lumen pulse pressure ratio decreased from 52%±27% at the predischarge measurement to 14%±5% at the latest follow-up reading (P=.029).

CONCLUSIONS

Thoracic endovascular aortic repair for chronic type B dissection with associated aneurysm is safe and effective at midterm follow-up. Aneurysm sac/false lumen pulse pressure measurements demonstrate a significant reduction in false lumen endotension, thus ruling out clinically significant persistent retrograde false lumen perfusion and provide proof of concept for a thoracic endovascular aortic repair-based approach. Longer-term follow-up is needed to determine the durability of thoracic endovascular aortic repair for this aortic pathology.

Endovascular repair of descending thoracic aneurysms: results with "on-label" application in the post Food and Drug Administration approval era

BACKGROUND

Most studies of thoracic endovascular aortic repair (TEVAR) published since the technology gained US Food and Drug Administration (FDA) approval in March 2005 have included multiple applications including dissection, trauma, and "hybrid" approaches, all of which are currently "off-label." However, little post-approval data exist for the only FDA-approved application, namely descending thoracic aneurysm (DTA). The purpose of this study was to examine our experience with TEVAR for aneurysms limited to the descending thoracic aorta.

METHODS

Between March 23, 2005 (date of initial FDA approval) and April 6, 2009, 210 TEVAR procedures were performed at our institution. Of these, 79 (38%) were for saccular (n = 31) or fusiform (n = 48) DTA and form the basis of this report. Patients requiring "hybrid" approaches other than carotid-subclavian bypass were excluded. Devices utilized were Gore TAG (W. L. Gore Associates, Flagstaff, AZ) (n = 67; 85%), Zenith TX2 (Cook Medical Incorporated, Bloomington, IN) (n = 10; 13%), and Medtronic Talent (Medtronic, Inc, Santa Rosa, CA) (n = 5; 6%); 3 (4%) patients received more than one type of device.

RESULTS

Median patient age was 73 +/- 4 years; 35 (44%) were female. Mean aortic diameter was 5.8 +/- 1.8 cm. Twenty-four (30%) procedures were urgent-emergent. Thirty-day in-hospital rates of death, stroke, and permanent paraplegia-paresis were 5.1% (n = 4; 1.9% elective mortality), 2.5% (n = 2), and 1.3% (n = 1), respectively. The median postoperative length of stay was 3.0 days (25th and 75th percentiles = 2 and 6, respectively). At a mean follow-up of 23 +/- 17 months (range, 6 to 55), there were 2 (2.5%) late aortic deaths from graft infection (n = 1) and aneurysm rupture (n = 1). Overall actuarial midterm survival is 73% at 55 months, with an aorta-specific actuarial survival of 86% during this same time interval. Five patients (6.3%) required late (>30 days) secondary endovascular re-intervention for type I (n = 4) or type II (n = 1) endoleak; re-intervention was successful in 4 of 5.

CONCLUSIONS

Despite the advanced age, comorbid conditions, and significant incidence of urgent-emergent status of patients presenting with DTA, on-label application of TEVAR yields excellent 30-day and midterm outcomes, especially when compared with historic rates of morbidity and mortality with open repair. However, "on-label" applications represent a minority of current TEVAR use, likely due to the relative scarcity of DTA. These data appear to support the increasing utilization of TEVAR as a treatment strategy for this pathology.

"Hybrid" repair of aneurysms of the transverse aortic arch: midterm results

BACKGROUND

Aneurysms of the transverse aortic arch, especially those involving the mid to distal arch, are technically challenging to repair with conventional open techniques. We present our results with a combined open/endovascular approach ("hybrid repair") in such patients.

METHODS

From August 11, 2005, to September 18, 2008, 28 patients underwent hybrid arch repair. For patients (n = 9) with distal arch aneurysms but 2 cm or more of proximal landing zone (PLZ) distal to the innominate artery, right to left carotid-carotid bypass was performed to create a PLZ by covering the left carotid origin. For patients (n = 12) with mid arch aneurysms but 2 cm or more of PLZ in the ascending aorta, proximal ascending aorta-based arch debranching was performed. For patients (n = 7) with arch aneurysms with no adequate PLZ ("mega aorta") but adequate distal landing zone, a stage 1 elephant trunk procedure was performed to create a PLZ. For the first two groups, endovascular aneurysm exclusion and debranching were performed concomitantly, whereas the procedures were staged for the group undergoing an initial elephant trunk procedure.

RESULTS

Mean patient age was 64 +/- 13 years. Primary technical success rate was 100%. Thirty-day/in-hospital rates of death, stroke, and permanent paraplegia/paresis were 0%, 0%, and 3.6% (n = 1), respectively. At a mean follow-up of 14 +/- 11 months, there have been no late aortic-related events. Two patients (7%) required secondary endovascular reintervention for a type 1 endovascular leak. No patient has a type 1 or 3 endovascular leak at latest follow-up.

CONCLUSIONS

Hybrid repair of transverse aortic arch aneurysms appears safe and effective at midterm follow-up and may represent a technical advance in the treatment of this pathology.

Endovascular stenting of thoracic aortic aneurysm

In 2005, the findings of the multicenter Gore Tag study led to United States Food and Drug Administration approval for endovascular repair of thoracic aortic aneurysms (TEVAR). TEVAR provides a therapeutic option for patients who have thoracic aortic aneurysm and for the treatment of type B aortic dissection with malperfusion. Spinal cord ischemia and stroke are recognized neurologic complications of TEVAR. Identification of high-risk patients combined with targeted anesthetic and perioperative management may decrease the risk of neurologic complications after TEVAR.

Use of custom Dacron branch grafts for "hybrid" aortic debranching during endovascular repair of thoracic and thoracoabdominal aortic aneurysms

OBJECTIVES

A significant number of patients with thoracic and thoracoabdominal aortic aneurysms are unsuitable for endovascular repair owing to the absence of graft seal zones. "Hybrid" techniques, including open aortic debranching procedures, allow creation of proximal and/or distal landing zones and expand the potential applications of endovascular repair. We report our experience with aortic arch and thoracoabdominal debranching using custom fabricated Dacron branch grafts, which greatly simplify aortic debranching by providing inflow via a single anastomosis and incorporate a side arm for introduction of the stent graft.

METHODS

Between November 14, 2005, and December 18, 2006, a total of 53 thoracic endograft procedures were performed at our institution. Of these, 13 (25%) involved either open aortic arch or abdominal debranching to create proximal or distal landing zones for endovascular repair. Patients undergoing arch debranching (n = 7) had aneurysms involving the transverse arch with less than 2 cm of proximal landing zone distal to the innominate artery, necessitating stent graft coverage of both the innominate and left common carotid arteries. Patients undergoing complete abdominal debranching (n = 6) had either thoracoabdominal aortic aneurysms (extent II, n = 1; extent V, n = 3) or visceral button false aneurysms after prior open thoracoabdominal aortic aneurysm repair (n = 2). In all cases, endovascular aneurysm exclusion was performed at the same operation.

RESULTS

Mean patient age was 63 +/- 11 years (range 46-83 years); all patients had significant comorbidities, including prior open aortic surgery in 8 (62%). There were no perioperative (30 day) deaths and no permanent neurologic deficits, either cerebrovascular accident or paraparesis/paraplegia. At a mean follow-up of 7.5 +/- 6.0 months, there has been no late mortality and all debranching bypass grafts remain patent without need for further intervention. Computed tomographic scans demonstrate no type I or III endoleaks, and all aneurysms are thrombosed with stable (n = 4) or decreasing aortic dimensions (n = 9).

CONCLUSIONS

"Hybrid" aortic debranching using custom fabricated Dacron branch grafts with a single inflow source combined with endovascular aneurysm exclusion appears to be a safe alternative to conventional open repair for thoracoabdominal and arch aneurysms and avoids the need for cardiopulmonary bypass and aortic crossclamping. This technique may be ideally suited to patients with significant comorbidity or prior open aortic surgery. Longer term follow-up is needed to determine the durability of this approach.