Predicting the Risk of Paraplegia After Thoracic and Thoracoabdominal Aneurysm Repair

Sizing the Frozen Elephant Trunk Based on Aortic Pathology and the Importance of Pre-Operative Imaging

The frozen elephant trunk is a formidable tool for the aortovascular surgeon. An appreciation of how to size the graft in different pathologies is key in achieving optimal results. Herein, we demonstrate worked examples of how imaging can be used to plan for a frozen elephant trunk and discuss the nuisances and uncertainties of sizing using three index cases: Type A aortic dissection, distal thoracic aortic aneurysm and chronic dissection.

Computational fluid dynamics simulate optimal design of segmental arteries reattachment: Influence of blood flow stagnation

Objectives

This study aimed to simulate blood flow stagnation using computational fluid dynamics and to clarify the optimal design of segmental artery reattachment for thoracoabdominal aortic repair.

Methods

Blood flow stagnation, defined by low-velocity volume or area of the segmental artery, was simulated by a 3-dimensional model emulating the systolic phase. Four groups were evaluated: direct anastomosis, graft interposition, loop-graft, and end graft. Based on contemporary clinical studies, direct anastomosis can provide a superior patency rate than other reattachment methods. We hypothesized that stagnation of the blood flow is negatively associated with patency rates. Over time, velocity changes were evaluated.

Results

The direct anastomosis method led to the least blood flow stagnation, whilst the end-graft reattachment method resulted in worse blood flow stagnation. The loop-graft method was comparatively during late systole, which was also influenced by configuration of the side branch. Graft interposition using 20 mm showed a low-velocity area in the distal part of the side graft. When comparing length and diameter of an interposed graft, shorter and smaller branches resulted in less blood flow stagnation.

Conclusions

In our simulation, direct anastomosis of the segmental artery resulted in the most efficient design in terms of blood flow stagnation. A shorter (<20 mm) and smaller (<10 mm) branch should be used for graft interposition. Loop-graft is an attractive alternative to direct anastomosis; however, its blood flow pattern can be influenced.

Outcomes of Secondary Endovascular Aortic Repair After Frozen Elephant Trunk

OBJECTIVE

The aim of this study was to evaluate the midterm outcomes of secondary extension of frozen elephant trunk (FET) by means of thoracic endovascular aortic repair (TEVAR).

METHODS

This single-center prospective study was conducted in a tertiary aortic center on consecutive patients having undergone TEVAR with an endograft covering most of the 10 cm FET module with 2 to 4 mm oversizing. All patients were monitored by computerized tomography angiography (CTA) at sixth month and yearly thereafter.

RESULTS

From January 2015 to July 2022, among 159 patients who received FET, 30 patients (18.8%) underwent a TEVAR procedure (13 for a thoracoabdominal aneurysm, 11 for a chronic aortic dissection and 6 for an emergency procedure). All connections were successfully achieved with 2 postoperative deaths (6.6%) and 1 paraplegia (3.3%). At a median follow-up of 21 months (interquartile range [IQR], 4.2-34.7), 5 patients (25%) required a fenestrated-branched endovascular aortic repair (F-BEVAR) extension followed by 4 patients with 5 reinterventions, 3 for a Type 3 endoleak due to disconnection between FET and TEVAR endograft, and 2 unrelated to the FET for a secondary Type 1C endoleak. All reinterventions were successful, without mortality or morbidity.

CONCLUSIONS

In this series, FET connection with a TEVAR endograft was effective with low postoperative morbidity but with a risk of aortic reintervention related to disconnection between the FET and TEVAR endograft. These results suggest the need for annual CTA monitoring with no time limit in patients following connection of the FET with a TEVAR endograft.

CLINICAL IMPACT

In this series of 30 patients, midterm outcomes of secondary extension of frozen elephant trunk (FET) by thoracic endovascular repair (TEVAR) showed 3 disconnections (10%) with a Type 3 endoleak between FET and TEVAR. These findings suggest the need for annual CTA monitoring with no time limit. But so far, only a few studies provide some information after one year while the risk of disconnection increases over time and becomes a concern after 3 years. This is the new message brought by our study.

Thoracoabdominal aortic aneurysm life-altering events following endovascular aortic repair in the Vascular Quality Initiative

OBJECTIVE

Endovascular aortic aneurysm repair has lower rates of postoperative mortality and morbidity when compared with open repair. However, endovascular repair still carries the risk of postoperative dialysis, paralysis, and stroke. This study examined the rates of postoperative mortality and morbidity stratified by type of endovascular aortic aneurysm repair.

METHODS

All patients who underwent endovascular aortic aneurysm repair in the Vascular Quality Initiative registry from January 2011 - May 2022 were identified. Patients were stratified by repair type: infrarenal endovascular aortic repair (EVAR), complex EVAR, thoracic endovascular aortic repair (TEVAR), extent I-III thoracoabdominal aortic aneurysm (TAAA) repair, or aortic arch repair. The primary outcome was postoperative thoracoabdominal aortic aneurysm life-altering events (TALE) across the different treatment groups. TALE was defined as a composite outcome of postoperative mortality, dialysis, paralysis, and/or stroke. Mixed effect logistic regression modeling was used to identify procedural and anatomic factors that were independently associated with TALE.

RESULTS

A total of 52,592 EVARs, 3,768 complex EVARs, 3,899 TEVARs, 1,139 extent I-III TAAA repairs, and 479 arch repairs were identified. TALE was observed in 1.2% of EVARs, 4.8% of complex EVARs, 6.0% of TEVARs, 10% of extent I-III TAAA repairs, and 14% of arch repairs. More proximal landing zone was associated with higher odds of TALE after complex EVAR (OR 1.9 [1.2-3.1]; p=.008), TEVAR (OR 2.2 [1.4-3.5]; p=.001), and extent I-III TAAA repair (OR 2.7 [1.5-4.9]; p=.001). Aortic diameter >65mm was associated with higher odds of TALE after infrarenal EVAR (OR 1.8 [1.4-2.3]; p<.001), complex EVAR (OR 1.6 [1.1-2.3]; p=.010), TEVAR (OR 2.7 [2.0-3.8]; p<.001), and arch repair (OR 2.4; [1.3-4.4]; p=.007). The use of parallel grafting technique (chimney/snorkel/periscope) during extent I-III TAAA repair was also associated with higher odds of TALE (OR 1.8 [1.1-3.2]; p=.032). Preoperative chronic kidney disease was also associated with higher odd of TALE after infrarenal EVAR (OR 4.3 [3.0-5.7]; p<.001), complex EVAR (OR 5.2 [3.3-8.2]; p<.001), TEVAR (OR 4.5 [2.8-7.1]; p<.001), and extent I-III TAAA repair (OR 3.2 [1.6-6.7]; p=.001).

CONCLUSION

While TALE was originally described for thoracoabdominal aortic aneurysm repairs, TALE may occur after complex EVAR, TEVAR, and arch repairs as well. Therefore, TALE and its component parts should be used to evaluate the efficacy of all aortic repairs and for preoperative counseling. Additionally, surgeons should be aware of anatomic and procedural characteristics that are associated with higher odds of TALE. The anticipated need for such interventions during aortic repair should be factored into preoperative risk assessment of patients.

Risk Factors Associated with Spinal Cord Ischemia During Aortic Aneurysm Repair

BACKGROUND

The risk of spinal cord ischemia (SCI) with aortic aneurysm repair can cause significant neurological morbidity. Prevention of SCI is critical. We sought to identify risk factors that predispose to SCI that may guide strategies to mitigate the occurrence of SCI during and following these procedures.

METHODS

This study includes all adults who underwent atraumatic, unruptured, thoracic, and suprarenal aortic aneurysm repairs (endovascular or open) at our institution over 11 years (2010-2020). Our database included patient demographics, aneurysm anatomic features, and operative characteristics and an extreme gradient boost (XGB) machine method was used to develop a predictive model for SCI. The model was trained on an 80% randomly stratified cohort of the data and tested on the remaining 20% testing cohort. Shapley values were used to determine the most important predictive factors of SCI and decision trees were used to identify risk factor threshold values and highest risk factor combinations.

RESULTS

Information was collected for 174 adult patients undergoing thoracic and suprarenal aortic repair from 2010 to 2020. Fifty eight percent of the patients were male. Ninety seven (55.7%) patients had open aortic repair and 87 (44.3%) had endovascular repair. Twenty seven (15%) of all patients had major complications and were considered to have SCI. The XGB model converged over the training cohort with a testing cohort accuracy of 0.841 [Sensitivity = 75%, Specificity = 68%] and area under the curve of receiver operating characteristic of 0.774. The XGB model identified older age (> 65 years), history of neurologic disease, hyperlipidemia, diabetes, coronary artery disease, heart failure, poor renal function, < 6 months since last aortic repair, chronic anticoagulant use, preoperational anemia (Hemoglobin < 9), thrombocytopenia (platelet < 90,000), coagulopathy (prothrombin time > 15s and activated partial thromboplastin time > 40s), hypotension (mean arterial pressure < 70 mm Hg), longer operations (> 100 min), aneurysms longer than 5 cm, and anatomic location of aneurysm caudal to T-11 as risk factors for SCI in all types of aortic repair. Diabetic and heart failure patients undergoing longer operations (> 100 min) with thrombocytopenia or aneurysms longer than 5 cm were at the highest risk.

CONCLUSIONS

The XGB model accurately identified risk factors of SCI with aortic aneurysm repair that may guide patient selection, timing of surgery, and strategies to minimize the risk of SCI.

Evaluation and Management of Complications of Endovascular Aneurysm Repair of the Thoracic Aorta

Thoracic endovascular aortic repair (TEVAR) has become the standard of care for descending thoracic aortic pathology as the procedure has a historically low rate of reintervention and a high rate of success. However, TEVAR can be associated with complications such as endoleak, upper extremity limb ischemia, cerebrovascular ischemia, spinal cord ischemia, and post-implantation syndrome. An 80-year-old man with a history of complex thoracic aortic aneurysms underwent repair of a large thoracic aneurysm with a frozen elephant trunk procedure in 2019 at an outside institution. The proximal aortic graft extended to the arch and the innominate and left carotid artery were implanted into the distal portion of the graft. The endograft, extending from the proximal graft to the descending thoracic aorta, was fenestrated to maintain left subclavian artery flow. In an attempt to gain a seal at the fenestration, a Viabahn graft (Gore, Flagstaff, AZ, USA) was inserted. A type III endoleak was identified postoperatively at the fenestration, and a second Viabahn graft was required to gain a seal during the initial hospitalization. In 2020, an endoleak persisted at the fenestration on follow-up imaging, but the aneurysmal sac was stable. No intervention was recommended. The patient later presented to our institution with three days of chest pain. A type III endoleak at the level of the subclavian fenestration persisted with significant enlargement of the aneurysm sac. The patient underwent an urgent repair of the endoleak. This consisted of covering the fenestration with an endograft and left carotid to subclavian bypass. Subsequently, the patient developed a transient ischemic attack (TIA) due to kinking and extrinsic compression by the large aneurysm sac of the proximal left common carotid artery, requiring a right carotid to left carotid-axillary graft bypass. This report with a literature review discusses TEVAR complications and outlines methods to approach them. TEVAR complications and their management should be firmly understood to improve overall treatment outcomes.

Neuronal Pre- and Postconditioning via Toll-like Receptor 3 Agonist or Extracorporeal Shock Wave Therapy as New Treatment Strategies for Spinal Cord Ischemia: An In Vitro Study

Spinal cord ischemia (SCI) is a devastating and unpredictable complication of thoracoabdominal aortic repair. Postischemic Toll-like receptor 3 (TLR3) activation through either direct agonists or shock wave therapy (SWT) has been previously shown to ameliorate damage in SCI models. Whether the same applies for pre- or postconditioning remains unclear. In a model of cultured SHSY-5Y cells, preconditioning with either poly(I:C), a TLR3 agonist, or SWT was performed before induction of hypoxia, whereas postconditioning treatment was performed after termination of hypoxia. We measured cytokine expression via RT-PCR and utilized Western blot analysis for the analysis of signaling and apoptosis. TLR3 activation via poly(I:C) significantly reduced apoptotic markers in both pre- and postconditioning, the former yielding more favorable results through an additional suppression of TLR4 and its downstream signaling. On the contrary, SWT showed slightly more favorable effects in the setting of postconditioning with significantly reduced markers of apoptosis. Pre- and post-ischemic direct TLR3 activation as well as post-ischemic SWT can decrease apoptosis and proinflammatory cytokine expression significantly in vitro and might therefore pose possible new treatment strategies for ischemic spinal cord injury.

Results of cryopreserved arterial allograft replacement for thoracic and thoracoabdominal aortic infections

BACKGROUND

Primary and secondary thoracic aortic infections are rare but associated with high morbidity and mortality. There is currently no consensus on their optimal treatment. Arterial allografts have been shown to be resistant to bacterial colonization. Complete excision of infected material, especially synthetic grafts, combined with in situ aortic repair is considered the best treatment of abdominal aortic infections. The aim of this study was to assess the management of thoracic and thoracoabdominal aortic infections using arterial allografts.

METHODS

Between January 2009 and December 2017, all patients with thoracic and thoracoabdominal aortic native or graft infections underwent complete excision of infected material and in situ arterial allografting. The end points were the early mortality and morbidity rates and early and late rates of reinfection, graft degeneration, and graft-related morbidity.

RESULTS

Thirty-five patients with a mean age of 65.6 ± 9.2 years were included. Twenty-one (60%) cases experienced graft infections and 14 (40%) experienced native aortic infections. Eight (22.8%) patients had visceral fistulas: 5 (14.4%) prosthetic-esophageal, 1 (2.8%) prosthetic-bronchial, 1 (2.8%) prosthetic-duodenal, and 1 (2.8%) native aortobronchial. In 12 (34.3%) cases, only the descending thoracic aorta was involved; in 23 (65.7%) cases, the thoracoabdominal aorta was involved. Fifteen (42.8%) patients died during the first month or before discharge: 5 of hemorrhage, 4 of multiorgan failure, 3 of ischemic colitis, 2 of pneumonia, and 1 of anastomotic disruption. Eleven (31.5%) patients required early revision surgery: 6 (17.1%) for nongraft-related hemorrhage, 3 (8.6%) for colectomy, 1 (2.9%) for proximal anastomotic disruption, and 1 (2.9%) for tamponade. One (2.9%) patient who died before discharge experienced paraplegia. One (2.9%) patient experienced stroke. Six (17.1%) patients required postoperative dialysis. Among them, four died before discharge. The mean length of stay in the intensive care unit was 11 ± 10.5 days; the mean length of hospital stay was 32 ± 14 days. During a mean follow-up of 32.3 ± 23.7 months, three allograft-related complications occurred in survivors (15% of late survivors): one proximal and one distal false aneurysm with no evidence of reinfection and one allograft-enteric fistula. The 1-year and 2-year survival rates were 49.3% and 42.5%, respectively.

CONCLUSIONS

Although rare, aortic infections are highly challenging. Surgical management includes complete excision of infected tissues or grafts. Allografts offer a promising solution to aortic graft infection because they appear to resist reinfection; however, the grafts must be observed indefinitely because of the risk of late graft complications.

Spinal Cord Protection of Aorto-Iliac Bypass in Open Repair of Extent II and III Thoracoabdominal Aortic Aneurysm

BACKGROUND

Spinal cord injury (SCI) is one of the serious complications of thoracoabdominal aortic aneurysm (TAAA) repair. Cardiopulmonary bypass (CPB) and left heart bypass (LHB) are well-established extracorporeal circulatory assistance methods to increase distal aortic perfusion and prevent spinal cord ischaemia in TAAA repair. Aorto-iliac bypass, a new surgical adjunct offering distal aortic perfusion without the need of complex perfusion skills, was developed as a substitute for CPB and LHB. However, its spinal cord protective effect is unknown.

METHODS

The perioperative data of 183 patients who had elective open Crawford extent II and III TAAA repair at our aortic centre from July 2011 to May 2019 were retrospectively analysed. Spinal cord protection was compared between the aorto-iliac bypass group (n=106) and the extracorporeal circulatory assistance group (n=77 [65 CPB, 12 LHB]), and the risk factors for SCI in these patients were explored.

RESULTS

Eleven (11) patients had postoperative SCI: five (6.5%) in the extracorporeal circulatory assistance group (four with CPB and one with LHB), and six (5.7%) in the aorto-iliac bypass group. The incidence of SCI was 6.0% (11/183 cases). There was no difference between the aorto-iliac bypass group and the extracorporeal circulatory assistance group (p=1.0), while operation time, proximal aortic clamp time, intercostal artery clamp time, and length of intensive care unit stay were all increased in the latter group. Multivariate logistic regression analysis showed that cerebrospinal fluid pressure (odds ratio [OR], 1.270; 95% confidence interval [CI], 1.092-1.478 [p=0.002]) and lowest haemoglobin on the first postoperative day (OR, 0.610; 95% CI, 0.416-0.895 [p=0.011]) were the independent predictors of SCI in TAAA repair.

CONCLUSIONS

Spinal cord protection of aorto-iliac bypass is comparable to that of CPB and LHB in open TAAA repair.

Thoracic Trauma: Aortic Injuries

Thoracic aortic injuries caused by high impact trauma are life-threatening and require emergent diagnosis and management. With improvement in the acute care services, an increasing number of such injuries are being managed such that patients survive to undergo definitive therapies. A high index of clinical suspicion is required to order appropriate imaging. Computed tomography angiography is used to classify the injuries and guide treatment strategy. While low-grade injuries might be managed conservatively, high-grade injuries require urgent surgical or endovascular intervention. Over the past decade, endovascular repair of the thoracic aorta with or without a surgical bypass has become the preferred treatment with reduced mortality and morbidity. Rapid advancements in the stent graft technology have reduced the anatomic barriers to endovascular therapy and increased the confidence of the operators. Detailed planning prior to the procedure, understanding of the anatomy, correct choice of hardware, and adherence to technical protocol are essential for a successful endovascular procedure. These patients are often young and the limited data on the long-term outcome of aortic stent grafts make a case for a robust follow-up protocol.

Stent Graft Modification to Preserve Intercostal Arteries Using Thoracoabdominal Off-the-Shelf Multibranched (t-Branch) Endograft

Purpose: To demonstrate an off-the-shelf multibranched (t-Branch) modification to allow intercostal arteries preservation during juxtarenal, pararenal, paravisceral, and extent IV thoracoabdominal aortic aneurysm repair. Technique: The t-Branch is an off-the-shelf device not customized for specific patient anatomy and may be offered for urgent endovascular repair for patients with complex aortic aneurysms. However, a concern when treating patients who do not aneurysms extending above the celiac axis is that the more proximal extension which is required with this device may render patients at high risk for spinal cord injury. We report a novel technique with t-Branch modification performing a 180° fabric back windows at the first 2 sealing stents that allow perfusion to the intercostal arteries. Conclusion: T-Branch-PIA (preserving intercostal arteries) modification limits intercostal arteries coverage while optimizing proximal seal zone in juxtarenal, pararenal, paravisceral, and extent IV thoracoabdominal aneurysms, thereby may decrease the risk of spinal cord injury.

Update on graft infections in thoracoabdominal aortic aneurysm surgery

The incidence of an aortic graft infection following the repair of thoracoabdominal aortic aneurysm, is a rare yet insidious complication which requires prompt recognition and management. The decision-making framework for management encompasses the choice or antimicrobial therapy alone versus pursuing surgical intervention, which can then also lead to considering the potential for allografts. The current literature on the matter is heavily burdened by limitations of the reported retrospective experiences consisting of small patient cohorts. Studies have reported the favored approach of surgical intervention, although statistical significance is not reached. There is a clear recognized impact that the event surrounding the initial repair has on the occurrence of graft infection itself; with emergency repairs, and incidence of nosocomial infection being associated with higher rates of graft infection. We must consider the influencers of this ominous complications, which go back to the perioperative events itself, whether the initial intervention was elective or an emergency, the impact of nosocomial infections, the choice of open versus endovascular for initial repair. Only with the appropriate management strategy that encompasses all these factors, will allow the best treatment to be provided for patients. A sound understanding and appreciation for the aforementioned can allow the stratification of the risk associated with the occurrence of an aortic graft infection, leading to surveillance opportunities to provide the crucial ability to rapidly recognize this complication.

Comparison between Arch Zones in Modified Frozen Elephant Trunk Procedure for Complex Thoracic Aortic Diseases

Introduction

The aim of this study is to compare postoperative outcomes and follow-up of two different modifications facilitating surgical technique of frozen elephant trunk (FET) procedure for complex thoracic aortic diseases - zone 0 (fixation with total arch debranching) and zone 3 (fixation with islet-shape arch repair).

Methods

From May 2012 to December 2018, data were collected from 139 patients who had been treated with FET procedure for complex thoracic aortic diseases. According to Ishimaru arch map, patients with proximal anastomotic site of hybrid graft at zone 0 and zone 3 were grouped as Group A (n=58, 41.7%) and Group B (n=81, 58.3%), respectively. Mean age of study population was 54.7±11.4 years, and 111 patients were male (79.9%).

Results

In-hospital mortality was observed in 20 (14.4%) patients (n=12, acute type A aortic dissection, and n=4, previous aortic dissection surgery). There was no significant difference between both groups in terms of in-hospital mortality. Four patients from Group A and three patients from Group B had permanent neurological deficit (P=0.32). Three patients from both groups had transient spinal cord ischemia (P=0.334). Although mean total perfusion time was longer in Group A, duration of visceral ischemia, when compared with Group B, was shorter (P<0.001). Five-year survival rate was 82.8% in Group A and 81.5% in Group B (P=0.876).

Conclusion

FET procedure is a feasible repair technique in the treatment of complex aortic diseases, providing satisfactory early results. Because of its advantageous aspects, zone 0 fixation with debranching is the preferred technique in our clinic.

Total arch replacement and frozen elephant trunk for acute type A aortic dissection

OBJECTIVE

The present study aimed to evaluate the outcomes of total aortic arch replacement with proximalization of distal anastomosis using the frozen elephant trunk technique with the J Graft FROZENIX (Japan Lifeline, Tokyo, Japan) and Gelweave Lupiae (Vascutek Terumo Inc, Scotland, United Kingdom) graft (distal anastomosis performed in zones 1 and 2) in patients with acute Stanford type A acute aortic dissection.

METHODS

A total of 50 patients underwent total aortic arch replacement using the frozen elephant trunk technique, deploying the J Graft FROZENIX into zone 1 or 2 (zone 1: n = 17, zone 2: n = 33) in combination with the Gelweave Lupiae graft for acute Stanford type A acute aortic dissection. Patient characteristics, intraoperative data, and early and midterm outcomes were analyzed.

RESULTS

The overall in-hospital mortality rate was 4% (2 patients). The in-hospital mortality rate in patients with visceral malperfusion was 11% (1/9). There were no patients with paraplegia and stent graft-induced new entry. Resection or closure of the most proximal entry tear was achieved in 100% of 42 patients who had postoperative computed tomography. The overall survival was 87.9%, 84.1%, and 84.1% at 1, 2, and 3 years, respectively. However, 1 patient required endovascular extension for the dilatation of the descending thoracic aorta 4 months after the initial surgery.

CONCLUSIONS

Total aortic arch replacement with the frozen elephant trunk technique (zone 1-2) and Gelweave Lupiae graft was safe and effective in simplifying surgery for acute Stanford type A acute aortic dissection.

Normothermic iliac perfusion improves early outcomes after thoraco-abdominal aortic aneurysm repair

OBJECTIVES

The aim of this study is to evaluate the safety and efficacy of thoraco-abdominal aortic aneurysm repair with normothermic iliac perfusion.

METHODS

One hundred and ninety patients who underwent aortic replacement for the Crawford type II thoraco-abdominal aortic aneurysm between January 2005 and June 2017 were assigned to 2 groups: normothermic iliac perfusion (group A, n = 75) and deep hypothermic circulatory arrest (group B, n = 115). We selected 58 pairs of patients for propensity score matching. We analysed early operative death, a composite of complications and mid-term survival.

RESULTS

After propensity score matching, no early operative death occurred in group A (0.0%), and group B had 4 cases of early operative death (6.9%), with a statistically significant difference (P = 0.047). The composite of complications was reported in 11 patients in group A (21.0%) and in 21 patients in group B (36.2%) (P = 0.038). Age >50 years [odds ratio (OR) 6.50, 95% confidence interval (CI) 2.32-16.36; P = 0.020], deep hypothermia (OR 12.13, 95% CI 1.64-23.13; P = 0.003) and chronic renal insufficiency (OR 8.21, 95% CI 2.34-43.33; P < 0.001) were independent risk factors for early operative death. The 3-year, 5-year and 7-year survival rates were 98.3%, 98.3% and 86.9% in group A and 86.9%, 86.9% and 86.9% in group B, respectively (P = 0.471). The 7-year cumulative incidence function rates for reintervention were 0.026% in group A and 0.048% in group B (P = 0.625).

CONCLUSIONS

Normothermic iliac perfusion provides a viable alternative for thoraco-abdominal aortic aneurysm repair, which reduced early operative death and composited complications.

Delayed-Onset Postoperative Paraplegia in Acute Type A Aortic Dissection

In patients with operated type A aortic dissections, irreversible spinal cord injury (SCI) may result from several factors: prolonged circulatory arrest, extension of replacement, and hypoperfusion of segmental arteries secondary to aortic false lumen thrombosis. Careful neuroprotective strategies and shorter operative times are crucial to reduce SCI incidence. Despite optimal perioperative management, delayed-onset SCI occurs in rare cases in response to subacute aortic remodeling. This report describes the case of a 77-year-old woman who underwent ascending aorta and hemiarch replacement for type A aortic dissection and had delayed paraplegia that developed on postoperative day 12.

Unilateral Nerve Root Ligation for Multilevel Vertebral Column Resection After Fixed Post-infectious Deformity

Kyphotic deformity is a well-recognized complication of thoracic vertebral osteomyelitis, often requiring multi-level vertebral column resection for mobilization of the spine and reduction of the deformity. We present a case of severe post-infectious kyphosis treated with multi-level vertebral column resection via a unilateral approach. We obtained excellent decompression and deformity correction without neurologic decline. We review relevant literature regarding spinal cord blood supply and known potential complication of nerve root ligations.

Current status of endovascular treatment for thoracoabdominal aortic aneurysms

Open surgical repair (OSR) for thoracoabdominal aortic aneurysms (TAAAs) is maximally invasive and associated with high rates of operative mortality and perioperative complications including spinal cord ischemia (SCI), despite improvements in surgical techniques and perioperative care. Elderly patients, patients with a history of aortic surgery, and patients with severe comorbidities are often considered ineligible for this surgery and endovascular treatment may be their only treatment option. Total endovascular aneurysm repair (t-EVAR) without debranching surgery does not require thoracotomy and laparotomy and could improve the outcomes of these patients. t-EVAR includes fenestrated EVAR (f-EVAR), multi-branched EVAR (b-EVAR), and physician-modified fenestration endograft (PMFG). Although these techniques have achieved lower mortality rates than OSR, there are concerns about perioperative complications including limb ischemia, SCI, and long-term outcomes such as endograft migration and endoleaks (ELs). This article provides an overview of available endovascular devices for TAAAs and reviews the short and mid-term results of t-EVAR, as well as alternative options.

Spinal ischaemia after thoracic endovascular aortic repair with left subclavian artery sacrifice: is there a critical stent graft length?

OBJECTIVES

Thoracic endovascular aortic repair (TEVAR) is used for treatment of thoracic aortic pathologies, but the covered stent graft can induce spinal ischaemia depending on the length used. The left subclavian artery contributes to spinal cord collateralization and is frequently occluded by the stent graft. Our objective was to investigate the impact of covered stent graft length on the risk of spinal ischaemia in the setting of left subclavian artery sacrifice.

METHODS

Twenty-six pigs (German country race, mean body weight 36 ± 4 kg) underwent simulated descending aortic TEVAR via left lateral thoracotomy, with left subclavian artery and thoracic segmental artery occlusion in normothermia. Animals were assigned to treatment groups according to simulated stent graft length: TEVAR to T8 (n = 4), TEVAR to T9 (n = 4), TEVAR to T10 (n = 4), TEVAR to T11 (n = 7) and TEVAR to T12 (n = 1) and a sham group (n = 6). End points included spinal cord perfusion pressure, cerebrospinal fluid pressure and spinal cord blood flow using fluorescent microspheres.

RESULTS

There were no group differences in spinal cord perfusion pressure drop or in spinal cord perfusion pressure regeneration potential at 3 h after the procedure: from a baseline average of 75 mmHg (95% confidence interval 71-83 mmHg) to 73 mmHg (67-75 mmHg) at 3 h in Group T10 versus from a baseline average of 67 mmHg (95% CI 50-81 mmHg) to 65 mmHg (95% confidence interval 48-81 mmHg) in Group T8. There were no differences in the spinal cord blood flow courses over time in the different groups nor was there any difference in cerebrospinal fluid pressure levels and cerebrospinal fluid pressure dynamics between groups. However, we did observe local blood flow distribution to the spinal cord that was inhomogeneous depending on the distance between the simulated stent graft end and the first thoracic anterior radiculomedullary artery.

CONCLUSIONS

The risk of spinal ischaemia after serial segmental artery occlusion does not depend on the distal extent of the aortic repair alone. Future attempts to allow patient risk stratification for spinal ischaemia need to focus on anterior radiculomedullary artery anatomy together with the extent of planned aortic repair.

Paraplegia prevention in aortic aneurysm repair by thoracoabdominal staging with 'minimally invasive staged segmental artery coil embolisation' (MIS²ACE): trial protocol for a randomised controlled multicentre trial

INTRODUCTION

Spinal cord injury (SCI) including permanent paraplegia constitutes a common complication after repair of thoracoabdominal aortic aneurysms. The staged-repair concept promises to provide protection by inducing arteriogenesis so that the collateral network can provide a robust blood supply to the spinal cord after intervention. Minimally invasive staged segmental artery coil embolisation (MIS²ACE) has been proved recently to be a feasible enhanced approach to staged repair.

METHODS AND ANALYSIS

This randomised controlled trial uses a multicentre, multinational, parallel group design, where 500 patients will be randomised in a 1:1 ratio to standard aneurysm repair or to MIS²ACE in 1-3 sessions followed by repair. Before randomisation, physicians document whether open or endovascular repair is planned. The primary endpoint is successful aneurysm repair without substantial SCI 30 days after aneurysm repair. Secondary endpoints include any form of SCI, mortality (up to 1 year), length of stay in the intensive care unit, costs and quality-adjusted life years. A generalised linear mixed model will be used with the logit link function and randomisation arm, mode of repair (open or endovascular repair), the Crawford type and the European System for Cardiac Operative Risk Evaluation (euroSCORE) II as fixed effects and the centre as a random effect. Safety endpoints include kidney failure, respiratory failure and embolic events (also from debris). A qualitative study will explore patient perceptions.

ETHICS AND DISSEMINATION

This trial has been approved by the lead Ethics Committee from the University of Leipzig (435/17-ek) and will be reviewed by each of the Ethics Committees at the trial sites. A dedicated project is coordinating communication and dissemination of the trial.

TRIAL REGISTRATION NUMBER

NCT03434314.

Comparison of early patency rate and long-term outcomes of various techniques for reconstruction of segmental arteries during thoracoabdominal aortic aneurysm repair

OBJECTIVES

This study aimed to analyse the early patency rate and long-term outcomes of reattached segmental intercostal arteries using graft interposition, single-cuff anastomosis or island reconstruction.

METHODS

We selected 172 consecutive patients who underwent open surgery for the thoracoabdominal aorta with reattachment of segmental arteries between October 1999 and March 2018. The early patency of segmental arteries was analysed using enhanced computed tomography. Segmental arteries were reconstructed using graft interposition (n = 111), single-cuff anastomosis (n = 38) or island reconstruction (n = 23).

RESULTS

The hospital mortality was 6.4%. Twenty patients developed spinal cord ischaemic injury (permanent, n = 12 or transient, n = 8). Spinal cord injury was found in 16, 3 and 1 patients in the graft interposition, single-cuff anastomosis and island reconstruction groups, respectively. Overall, 475 segmental arteries were reattached (mean number per patient 2.8 ± 1.3). The overall early patency rate was 63.4%. The patency rates in island reconstruction (91.2%) and single-cuff anastomosis (77.1%) were significantly better than that in graft interposition (54.0%; P < 0.01). However, 6 patients with island reconstruction of segmental arteries had an aneurysm formation at the intercostal artery reconstruction site, of whom 4 patients underwent reoperation during follow-up. None of the patients with graft interposition or single-cuff reattachment had a patch aneurysm in segmental arteries.

CONCLUSIONS

Island reconstruction and single-cuff anastomosis might offer better patency rates and prevent spinal cord ischaemic injury than graft interposition. Because some patients with island reconstruction required reoperation for patch aneurysms in segmental arteries, single-cuff anastomosis is preferable in terms of early- and long-term outcomes.

Electroacupuncture pretreatment attenuates spinal cord ischemia-reperfusion injury via inhibition of high-mobility group box 1 production in a LXA4 receptor-dependent manner

Paraplegia caused by spinal cord ischemia is a severe complication following surgeries in the thoracic aneurysm. HMGB1 has been recognized as a key mediator in spinal inflammatory response after spinal cord injury. Electroacupuncture (EA) pretreatment could provide neuroprotection against cerebral ischemic injury through inhibition of HMGB1 release. Therefore, the present study aims to test the hypothesis that EA pretreatment protects against spinal cord ischemia-reperfusion (I/R) injury via inhibition of HMGB1 release. Animals were pre-treated with EA stimulations 30min daily for 4 successive days, followed by 20-min spinal cord ischemia induced by using a balloon catheter placed into the aorta. We found that spinal I/R significantly increased mRNA and cytosolic protein levels of HMGB1 after reperfusion in the spinal cord. The EA-pretreated animals displayed better motor performance after reperfusion along with the decrease of apoptosis, HMGB1, TNF-α and IL-1β expressions in the spinal cord, whereas these effects by EA pretreatment was reversed by rHMGB1 administration. Furthermore, EA pretreatment attenuated the down-regulation of LXA₄ receptor (ALX) expression induced by I/R injury, while the decrease of HMGB1 release in EA-pretreated rats was reversed by the combined BOC-2 (an inhibitor of LXA₄ receptor) treatment. In conclusion, EA pretreatment may promote spinal I/R injury through the inhibition of HMGB1 release in a LXA₄ receptor-dependent manner. Our data may represent a new therapeutic technique for treating spinal cord ischemia-reperfusion injury.

Left heart bypass for thoracoabdominal aortic aneurysm repair: technical aspects

There are different surgical techniques for providing circulatory support during the repair of thoracoabdominal aortic aneurysms. They all aim at reducing the afterload of the heart and the preservation of distal organ perfusion. Partial or total extracorporeal circulation with or without cooling and left heart bypass (LHB) are actually the most used surgical approaches. The objective of this study was to describe and comment on the technical aspects of the LHB. We briefly describe our results and put them into perspective based on the current literature.

Early Experience of Endovascular Repair of Post-dissection Aneurysms Involving the Thoraco-abdominal Aorta and the Arch

OBJECTIVES

Outcomes are reported in management of post-dissection aneurysms involving the aortic arch and/or thoraco-abdominal segment (TAAA) treated with fenestrated and branched (complex) endografts.

METHODS

This report includes all patients with chronic post-dissection aneurysms >55 mm in diameter, deemed unfit for open surgery, treated using complex endografts between October 2011 and March 2015. When appropriate, staged management strategies including left subclavian artery revascularization, thoracic endografting, dissection flap fenestration or tear enlargement, and other endovascular procedures were performed at least 3 weeks prior to definitive complex endovascular repair. The following outcome data were collected prospectively at discharge, 12 months and annually thereafter: technical success, endoleaks, target vessel patency, false lumen patency, aneurysm diameter, major and minor complications, re-interventions, and mortality.

RESULTS

The cohort comprised 23 patients with a median age of 65 years. Staged procedures were performed in 14 patients (61%). Seven patients with dissections involving the arch were treated with inner branched endografts, and 16 TAAA patients were treated with fenestrated or branched endografts. The technical success rate was 71% following arch repair and 100% following TAAA repair. During early follow up, one of the arch group patients died and one in the TAAA group suffered spinal cord ischemia. The median follow up was 12 months (range 3-48), during which time one patient died of causes unrelated to aneurysm or treatment. Two early re-interventions were performed in the arch group to correct access vessel complications and there were a further two late re-interventions in the TAAA group to treat endoleaks. All target vessels (n = 72) remained patent.

CONCLUSIONS

This experience indicates that complex endovascular repair of post-dissection aneurysms is a viable alternative to open repair in patients deemed unfit for open surgery. There are insufficient data to allow comparison with the outcome of open surgery in anatomically similar, but fit, patients.

Planned Staged Repair of Thoracoabdominal Aortic Aneurysms to Minimize Spinal Cord Injury: A Proof of Concept

Management of thoracoabdominal aortic aneurysms (TAA) can lead to spinal cord injury. A variety of clinical adjuncts have proven to decrease the incidence of paraplegia; however, at least 10% patients remain at risk of developing paraplegia. Experimentally and in sporadic clinical experiences, the staged repair of TAAs can lead to better neurologic outcomes. We present two clinical cases with extensive TAA in which a deliberate staged repair leads to excellent neurologic outcomes.

Midterm Outcomes of Open Descending Thoracic Aortic Repair in More Than 5,000 Medicare Patients

BACKGROUND

Diseases involving the descending thoracic aorta (DTA) represent a heterogeneous substrate with a variety of therapeutic options. Although thoracic endovascular aortic repair has been increasingly applied to DTA disease, open surgical repair is ostensibly more durable.

METHODS

A total of 5,578 patients who underwent open DTA repair (Current Procedural Terminology code 33875) from 1999 to 2010 were identified from the Medicare database; 5,489 patients had complete data. Survival was assessed with Kaplan-Meier analysis. Cox regression determined predictors of death. Hospital and surgeon volume and variability were modeled, and their association with survival assessed.

RESULTS

Median survival after open DTA repair was only 4.3 years (95% confidence interval: 4.0 to 4.6). The likelihood of death varied significantly by certain aortic diseases: aortic rupture and acute aortic dissection patients had the highest early mortality. Survival beyond 180 days was best for patients with acute aortic dissection and isolated thoracic aortic aneurysm, and lowest for patients with thoracoabdominal aneurysm and aortic rupture. Hospital and surgeon volume, as well as interhospital and intersurgeon variability, had associations with overall survival.

CONCLUSIONS

Open DTA repair has treated a spectrum of aortic diseases in Medicare beneficiaries. Overall mortality was high, predominately confined to the initial postoperative hazard phase. Independent hospital and surgeon effects, hospital and surgeon volume, and a more recent date of surgery correlated with improved survival, while increased operative urgency and complexity correlated with worse outcomes. These observations argue for regionalization of DTA treatment for Medicare patients in specialized centers to concentrate expertise, which should translate into better outcomes.

Neuroprotective Strategies Can Prevent Permanent Paraplegia in the Majority of Patients Who Develop Spinal Cord Ischaemia After Endovascular Repair of Thoracoabdominal Aortic Aneurysms

OBJECTIVES

Spinal cord ischaemia (SCI) following endovascular thoracoabdominal aortic aneurysm (TAAA) repair is a devastating and unpredictable complication. This study describes a single unit's experience of SCI in patients who have had endovascular TAAA repair.

METHODS

A prospectively maintained database of patients having endovascular TAAA repair using branched and fenestrated stent grafts between 2008 and 2014 at a single high volume centre was reviewed. Patients who developed neurological symptoms and signs related to SCI were identified and factors associated with onset and recovery of neurology were analysed.

RESULTS

Sixty-nine patients (median age 73 years, 52 male; Crawford classification type I [n = 4], type II [n = 11], type III [n = 33], type IV [n = 14], type V [n = 7]) underwent endovascular TAAA repair. Twelve patients developed neurological symptoms/signs related to SCI but this was successfully reversed in eight patients, leaving four (5.8%) with permanent paraplegia. The median length of aorta covered was not significantly different in the 12 patients who developed SCI compared with the cohort that did not. Eleven of the patients who developed SCI had an intraoperative mean arterial pressure (MAP) below 80 mmHg. Cutaneous atheroemboli were noted in half of the patients in the SCI group compared with 11% of the non-SCI group (p < .05). Strategies used to reverse SCI included raising MAP, cerebrospinal fluid drainage, angioplasty of stenosed internal iliac arteries, and restoring perfusion to the aneurysm sac.

CONCLUSIONS

This series highlights some of the risk factors associated with the development of SCI after endovascular repair of TAAAs. It also illustrates the importance of a dedicated institutional protocol aimed at ensuring the early diagnosis of SCI and prompt intervention to reverse permanent paraplegia in the majority of cases.

Spinal cord injury following thoracic and thoracoabdominal aortic repairs

Objective

To discuss the currently available approaches to prevent spinal cord injury during thoracic and thoracoabdominal aortic repairs.

Methods

We carried out a PubMed search up to 2013 using the Medical Subject Headings: “aortic aneurysm/surgery” and “spinal cord ischemia”; “aortic aneurysm, thoracic/surgery” and “spinal cord ischemia”; “aneurysm/surgery” and “spinal cord ischemia/cerebrospinal fluid”; “aortic aneurysm/surgery” and “paraplegia”. All 190 original articles satisfying our inclusion criteria were analyzed for incidence, predictors, and other pertinent variables related to spinal cord injury, and we compared the results in recent publications with those in earlier reports.

Results

The mean age of the 38,491 patients was 65.3 ± 4.9 years. The overall incidence of paraplegia and/or paraparesis was 7.1% ± 6.1% (range 0%–32%). The incidence of spinal cord injury before 2000, from 2001 to 2007, and 2008–2013 was 9.0% ± 6.7%, 7.0% ± 6.1%, and 5.9% ± 5.2%, respectively ( p = 0.019). Various predictors of spinal cord injury were identified, extent of disease being the most common. Modification of surgical techniques, use of adjuncts, and better understanding of spinal cord perfusion physiology were attributed to the decrease in postoperative spinal cord injury in recent years.

Conclusions

Spinal cord injury after thoracic and thoracoabdominal aortic repair poses a real challenge to cardiovascular surgeons. However, with evolving surgical strategies, identification of predictors, and use of various adjuncts over the years, the incidence of spinal cord injury after thoracic/thoracoabdominal aortic repair has declined. Embracing a multimodality approach offers a good insight into combating this grave complication.

[Aneurysms of the thoracic and thoracoabdominal aorta]

The incidence and operations of thoracic and thoracoabdominal aortic aneurysms have significantly increased. The indications for repair are considered to be a diameter of 6 cm or more and 5.5 cm for patient groups with increased risk of rupture. Complex open surgical repair is associated with significant mortality and complication rates. Total or hybrid endovascular repair seems to reduce early postoperative complications and mortality. The endovascular approach has evolved to be a good and predominant alternative to open repair of these aneurysms for older and high-risk patients as well as for aneurysms with optimal morphological suitability. Notwithstanding, at present a complete paradigm shift from open to endovascular repair for all patients, especially those with complex aneurysms, cannot yet be established.

Long-term outcomes in thoracoabdominal aortic aneurysm repair for chronic type B dissection

INTRODUCTION

Open repair for chronic aortic dissection remains a challenging surgical option. Different centers report diverse experiences and outcomes pertaining to thoracoabdominal aortic aneurysm repair (TAAAR) for chronic type B dissection. We highlight our center's experience and results on a background of published literature and current evidence.

METHODS

We reviewed 214 open TAAAR performed between October 1998 and February 2014. Of these, chronic type B dissection was present in 62 (29.0%) patients. We reviewed these patients in terms of demographics, operative characteristics and outcomes. Thirteen (21.0%) patients had surgery on the descending thoracic aorta [Category A =2 (3.2%), B =0 (0%), C =11 (17.7%)] and 49 (79.0%) in the thoracoabdominal thoracic aorta [Crawford extent I =5 (8.1%), extent II =39 (62.9%), extent III =4 (6.5%), extent IV =1 (1.6%)]. Left heart bypass was used in 12 (19.4%) patients.

RESULTS

The composite in-hospital endpoint, adverse outcome-defined as operative death, renal failure necessitating dialysis at discharge, stroke, or permanent paraplegia or paraparesis-occurred after 28 (45.2%) procedures. There were 14 (22.6%) operative deaths. In-hospital mortality was seven (16.3%) out of 43 elective patients, and increased to seven (36.8%) of the 19 non-elective ones. Permanent paraplegia or paraparesis occurred after two (3.2%) cases, stroke occurred after seven (11.3%) and renal failure requiring dialysis occurred after 16 (25.8%). Mean follow-up time was 3.2 years and actuarial 5-year mortality was 27.4% [nine (14.5%) elective and eight (12.9%) non-elective patients].

CONCLUSIONS

TAAAR in chronic type B dissection carries a substantial risk of early adverse outcomes. The results could be well alleviated with cases directed towards specialized regional and supra-regional centers. Although the endovascular approaches offer relatively low mortality and morbidity, there is a lack of long-term data and guidelines on their use. There is a need for a multidisciplinary international registry on the management of thoracoabdominal aortic aneurysms and dissection. This would provide a degree of guidance on relevant clinical and surgical judgments and outcomes.