Frozen Elephant Trunk Procedure for Acute Type a Aortic Dissection: Analysis of Distal Aortic Remodeling According to the Society for Vascular Surgery (SVS)/Society of Thoracic Surgeons (STS) Reporting Standard.

BACKGROUND: To investigate impact of frozen elephant trunk (FET) on long-term distal aortic remodeling in acute A aortic dissection (AAD) according to the latest recommended standards from the Society for Vascular Surgery (SVS)/Society of Thoracic Surgeons (STS). METHODS: Clinical data and imaging of patients who underwent FET to treat acute AAD over the last 8 years were retrospectively reviewed. Patients were included if a pre and postoperative computed angio tomographies at least 30 days from surgery was available for comparison. Contrasted postprocessed imaging were analyzed with Aquarius iNtuition (TeraRecon Inc., Foster City, CA, USA) to analyze long-term positive aortic remodeling, false lumen thrombosis, and aortic expansion according to the SVS or STS recommendations. Secondary endpoints were the rate of in-hospital and long-term mortality, spinal cord ischemia (SCI), and aortic-related reinterventions. RESULTS: Out of 75 patients who underwent FET for type A AAD, n = 41 (54.6%) were included. Significant positive aortic remodeling was reported in Ishimaru zone 1-4 but not in visceral or infrarenal aorta (P < 0.001), and the overall rate of false lumen thrombosis was 95.1% (n = 39). Aortic expansion rates were as follows: 4.9% in zones 1-4, 8.3% in zones 5-6, and 15% in zone 7. The rates of in-hospital mortality and long-term mortality were 7.3% (n = 3) and 9.7% (n = 4), respectively. At a median follow-up of 11 months (range 1-141, reintervention rate was 17.1%. CONCLUSIONS: We report positive aortic remodeling of the distal thoracic aorta in patients who underwent FET for acute AAD according to the SVS or STS reporting standards. The positive effect on the distal aorta is limited to the thoracic segments but not in the visceral aorta.

Postoperative Spinal Cord Ischemia Monitoring: A Review of Techniques Available after Endovascular Aortic Repair.

BACKGROUND: Spinal cord ischemia is one of the complications that can occur after open and endovascular thoracoabdominal aortic repair. This occurs despite various perioperative approaches, including distal aortic perfusion, hybrid procedures with extra anatomical bypasses, motor-evoked potential, and cerebrospinal fluid drainage. The inability to recognize spinal ischemia in a timely manner remains a devastating complication after thoracoabdominal aortic repair.This review aims to look at novel technologies that are designed for continuous monitoring to detect early changes that signal the development of spinal cord ischemia and to discuss their benefits and limitations. METHODS: We conducted a systematic review of the technologies available for continuous monitoring in the intensive care unit for early detection of spinal cord ischemia. Studies were eligible for inclusion if they used different technologies for monitoring spinal ischemia during the postoperative period. All articles that were not available in English were excluded. To ensure that all relevant articles were included, no other significant restrictions were imposed. RESULTS: We identified 59 studies from the outset to December 2022 to be included in our study. New techniques have been studied as potentially useful monitoring tools that could provide simple and effective monitoring of the spinal cord. These include near-infrared spectroscopy, contrast-enhanced ultrasound, magnetic resonance imaging, fiber optic monitoring of the spinal cord, and cerebrospinal fluid biomarkers. CONCLUSIONS: Despite the development of new techniques to monitor for postoperative spinal cord ischemia, their use remains limited. We recommend more future research to ensure rapid intervention for our patients.

Spinal cord ischemia and reinterventions following thoracic endovascular repair for acute type B aortic dissections.

OBJECTIVE: The technical aspects of thoracic endovascular aortic repair (TEVAR) for acute type B aortic dissection (TBAD), specifically the location of proximal seal zone (PSZ) (need to cover the left subclavian artery [LSA]), distal seal zone (DSZ) (length of aortic coverage), benefit of LSA revascularization, and prophylactic lumbar drainage are still debated. Each of these issues has potential benefits but also has known risks. This study aims to identify factors associated with reintervention and spinal cord ischemia (SCI) following TEVAR for acute TBAD with a zone 3 entry tear. METHODS: The Vascular Quality Initiative was queried for TEVARs performed for acute TBAD with zone 3 entry tear, zone 3 proximal zone of disease, treated with TEVAR extending between zone 2 and zone 5. The primary outcomes were SCI and related reintervention. Secondary outcomes were stroke, arm ischemia, and retrograde type A dissection (RTAD). The exposure variables were PSZ 2 vs 3, DSZ 4 vs 5, prophylactic lumbar drain, and LSA revascularization. Univariate analyses were conducted with χ2 analysis, and multivariable logistic regression was used to evaluate association with outcomes. RESULTS: Of 583 patients who met inclusion criteria, 266 had PSZ 2 and 317 had PSZ 3. On univariate analysis, PSZ 2 was associated with a higher rate of reintervention, but PSZ2 was not significant on multivariable analysis after accounting for age, sex, race, smoking, PSZ, DSZ, prophylactic lumbar drain, and LSA patency. PSZ 2 was not associated with SCI, arm ischemia, or RTAD. PSZ 2 was associated with a trend towards a higher rate of stroke. DSZ 4 and DSZ 5 were performed in 161 and 422 TEVARs, respectively, and DSZ 5 was associated with a higher rate of SCI on univariate (3 [1.9%] vs 39 [9.2%]; P = .01) and multivariable (odds ratio, 7.384; 95% confidence interval, 2.193-24.867; P = .001) analyses. Prophylactic lumbar drain placement was not statistically significantly associated with SCI, but lack of postoperative LSA patency was associated with SCI (odds ratio, 2.966; 95% confidence interval, 1.016-8.656; P = .05). CONCLUSIONS: This study found that PSZ 2 was not associated with lower reinterventions or higher rates of SCI but trended towards a higher rate of stroke than PSZ 3. Additionally, DSZ 5 was strongly associated with SCI when compared with DSZ 4, highlighting the importance of limiting aortic coverage to coverage of the proximal entry tear when possible.

Prospective randomized pilot trial comparing prophylactic and therapeutic cerebrospinal fluid drainage during complex endovascular thoracoabdominal aortic aneurysm repair.

BACKGROUND: Endovascular techniques have transformed the management of thoracoabdominal aortic aneurysms (TAAAs). However, spinal cord ischemia (SCI) remains a prevalent and devastating complication. Prophylactic drainage of cerebrospinal fluid (CSF) is among the proposed strategies for prevention of SCI. Although prophylactic CSF drainage is widely used and conceptually attractive, prophylactic CSF drains have not been demonstrated to definitively prevent the occurrence nor mitigate the severity of SCI in endovascular TAAA repair. Whether or not outcomes of prophylactic drains are superior to therapeutic drains remains unknown. This pilot study was performed to determine the feasibility of a randomized clinical trial designed to investigate the role of prophylactic vs therapeutic CSF drains in the prevention of SCI in patients undergoing endovascular TAAA repair using branched and fenestrated endovascular aortic repair (FBEVAR). METHODS: This was a prospective multicenter randomized pilot clinical trial conducted at The University of Alabama at Birmingham and The University of Massachusetts. Twenty patients were enrolled and randomized to either the prophylactic drainage or therapeutic drainage groups, prior to undergoing FBEVAR for extensive TAAAs and arch aortic aneurysms. This was a pilot feasibility study that was not powered to detect statistical differences in clinical outcomes. The primary outcome was feasibility of randomization and compliance with a shared lumbar drain protocol. Secondary outcomes included rate of drain complications and SCI. RESULTS: Twenty patients were enrolled and successfully randomized, without any crossovers, to either the control cohort (n = 10), without prophylactic drains, or the experimental cohort (n = 10), with prophylactic drains. There were no differences in age, comorbidities, or history of prior aortic surgery across the cohorts. All patients were treated with FBEVAR. Aneurysm classifications were as follows: Extent I (10%), Extent II (50%), Extent III (35%), and Extent IV (5%). The average length of aortic coverage was 207 ± 21.6 mm. The length of aortic coverage did not vary across cohorts, nor did procedural times or blood loss volume. Compliance with the SCI prevention protocol was 100% across both groups. Within the prophylactic drain cohort, one patient experienced an adverse event related to lumbar drain placement, manifested as an epidural hematoma requiring laminectomy, without neurologic deficit (n = 1/10; 10%). There was one SCI event (n = 1/20; 5%), which occurred in the prophylactic drain cohort on postoperative day 9 following an episode of hypotension related to a gastrointestinal bleed. CONCLUSIONS: The role of prophylactic CSF drains for the prevention of SCI following endovascular TAAA repair is a topic of ongoing research, with many current practices based on expert opinion and experience, rather than rigorous scientific data. This study demonstrates the feasibility of a multicenter randomized clinical trial to evaluate the role of prophylactic vs therapeutic CSF drains in the prevention of SCI in patients undergoing endovascular TAAA repair.

Usefulness of Motor Evoked Potential Measurement and Analysis of Risk Factors for Spinal Cord Ischaemia from 300 Cases of Thoracic Endovascular Aortic Repair.

OBJECTIVE: This study investigated the usefulness of motor evoked potentials (MEPs) for intra-operative monitoring to detect the risk of spinal cord ischaemia (SCI) during thoracic endovascular aortic repair (TEVAR). Risk factors for SCI in TEVAR were also analysed. METHODS: Among 330 TEVARs performed from February 2009 to October 2018, 300 patients underwent intra-operative MEP monitoring. SCI risk groups were extracted based on MEP amplitude changes using a cutoff value of 50%. When the amplitude decreased to < 50% of the pre-operative value, intra-operative mean arterial pressure (MAP) was increased by about 20 mmHg using noradrenaline, whereas MAP was usually controlled to about 80 mmHg during surgery. Other efforts were also made to increase MEP amplitude by increasing cardiac output, correcting anaemia, and finishing the surgery promptly. Based on MEP amplitude data, SCI risk groups were extracted and risk factors for SCI in TEVAR were analysed. RESULTS: A total of 283 non-SCI risk patients and 17 SCI risk patients by MEP monitoring were extracted; only 1.0% developed immediate paraplegia and none developed delayed paraplegia. Bivariable analysis showed significant differences in chronic kidney disease, haemodialysis, artery of Adamkiewicz closure, and stent graft (SG) covered length ≥ 8 vertebral bodies. Logistic regression analysis showed hyperlipidaemia (odds ratio [OR] 3.55, 95% confidence interval [CI] 1.08 - 11.67; p = .037), SG covered length ≥ 8 vertebral bodies (OR 1.35, 95% CI 1.02 - 1.78; p = .034), and haemodialysis (OR 27.78, 95% CI 6.02 - 128.22; p < .001) were the most influential risk factors for SCI in TEVAR. CONCLUSION: MEPs might be a useful monitoring tool to predict SCI in TEVAR. In addition, hyperlipidaemia, SG covered length ≥ 8 vertebral bodies, and haemodialysis represent key risk factors for SCI during TEVAR.

Systematic review of the effect of cerebrospinal fluid drainage on outcomes after endovascular type B aortic dissection repair.

OBJECTIVE: The aim of the present systematic review was to determine whether prophylactic use of cerebrospinal fluid drainage (CSFD) contributes to a lower rate of spinal cord ischemia (SCI) after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD). METHODS: PubMed, Embase, Web of Science and Cochrane Library databases were systematically searched to identify all relevant studies reported before May 7, 2023. A systematic review was conducted in accordance with PRISMA guidelines (PROSPERO registration no. CRD42023441392). The primary outcome was permanent SCI. Secondary outcomes were temporary SCI and 30-day/in-hospital mortality. The data were presented as the pooled event rates (ERs) and 95% confidence intervals (CIs). RESULTS: A total of 1008 studies were screened, of which 34 studies with 2749 patients were included in the present analysis. The mean Downs and Black quality assessment score was 8.71 (range, 5-12). The pooled rate of permanent SCI with prophylactic CSFD was identical to that without prophylactic CSFD (2.0%; 95% CI, 1.0-3.0; P = 0.445). No statistically significant difference was found between the rates of permanent SCI with routine vs. selective prophylactic CSFD (P = 0.596). The pooled rate of temporary SCI was 1.0% (95% CI, 0.00-1.0%). The pooled rate for 30-day or in-hospital mortality was not significantly different (P = 0.525) in patients with prophylactic CSFD (4.0, 95% CI 2.0-6.0) or without prophylactic CSFD (5.0, 95% CI 2.0-7.0). CONCLUSIONS: The systematic review has shown that prophylactic CSFD was not associated with a lower rate of permanent SCI and 30-day or in-hospital mortality after TEVAR for TBAD.

The combination of hydrogen gas and hydrogen-rich solution does not protect against ischemic spinal cord injury in rabbits.

PURPOSE: This study aimed to determine whether the combination of H2 gas inhalation and administration of hydrogen-rich acetated Ringer's solution (HS) could protect against ischemic spinal cord injury in rabbits. METHODS: In Experiment 1, rabbits were randomly assigned to a 1.2% H2 gas group, HS group, 1.2% H2 gas + HS group (combination group), or control group (n = 6 per group). The H2 concentration of HS was 0.65 mM. H2 was inhaled for 60 min, starting 5 min before reperfusion. HS (20 mL/kg) was divided into six bolus injections at 10-min intervals, starting 5 min before reperfusion. Spinal cord ischemia was produced by occluding the abdominal aorta for 15 min. Neurologic and histopathologic evaluations were performed 7 days after reperfusion. In Experiment 2, H2 concentrations in spinal cord tissue according to the administration of 1.2% H2 gas or HS were compared by measuring the electric current through a platinum needle electrode (n = 2). In Experiment 3, rabbits were assigned to a 2% H2 gas group or control group (n = 6 per group). Spinal cord ischemia was produced and neurologic and histopathologic evaluations were performed as in Experiment 1. RESULTS: There were no significant differences among the groups in the neurologic and histopathologic outcomes in Experiments 1 and 3. Bolus administration of HS (10 mL) transiently increased the current to only 1/30th and 1/27th of the plateau current with 1.2% H2 gas inhalation in two animals. CONCLUSION: These results suggest that the combination of 1.2% H2 gas inhalation and administration of a hydrogen-rich solution does not protect against ischemic spinal cord injury and that the increase in H2 concentration in spinal cord tissue after administration of HS is very low compared to 1.2% H2 gas inhalation.

Descending thoracic aortic mural ulceration is associated with postoperative spinal cord ischemia after branched endovascular aortic aneurysm repair.

OBJECTIVE: Paraplegia is one of the most feared complications after thoracoabdominal aortic aneurysm repair. The purpose of this study is to determine whether aortic thrombus characteristics are associated with spinal cord ischemia (SCI) after branched endovascular aneurysm repair (BEVAR). METHODS: From April 2011 to April 2020, 62 patients underwent elective BEVAR for thoracoabdominal aortic aneurysm and pararenal aortic aneurysms using a low-profile device and had a complete preoperative computed tomography angiography of the aorta from the sinotubular junction to the aortic bifurcation. Aortic thrombus was evaluated for thrombus thickness ≥5 mm, thrombus >2/3 of aortic circumference, and the presence of an ulcer-like thrombus. One point was assigned at each 5 mm axial image if all 3 criteria were met, resulting in a total "shaggy score" for the entire aorta. Data on demographics, procedural details, and outcomes were collected prospectively. All patients underwent a standard spinal cord protection protocol, including routine cerebrospinal fluid drainage. In July 2016, an insulin infusion protocol (IIP) was initiated to maintain postoperative blood glucose levels <120 mg/dL for 48 hours. The primary clinical end point was postoperative SCI. RESULTS: 10 (16%) patients developed postoperative SCI: 6 with transient paraparesis, 2 with persistent paraparesis, and 2 with persistent paraplegia. Patients with SCI were older, had higher shaggy scores, and were less likely to have been on an IIP. There were no significant differences in demographics, aneurysm type, or operative parameters. In a logistic multivariate regression model for SCI, age (odds ratio [OR]: 1.2 [1.1-1.4], P = .02) and shaggy score (OR: 1.2 [1.1-1.4], P = .02) were independently associated with increased risk of SCI, whereas treatment with the IIP was associated with lower risk of SCI (OR: 0.04 [0.006-0.50], P = .05). Of the individual components of the shaggy score, higher descending thoracic aortic ulcer scores were the most strongly associated with postoperative SCI (P = .009). CONCLUSIONS: Preoperative characterization of aortic wall thrombus is an important adjunctive tool for individualized clinical decision-making and patient counseling about the risk of SCI after BEVAR.

Establishment and Validation of a Model for Fetal Neural Ischemia Using Necrotic Core-Free Human Spinal Cord Organoids.

Fetal spinal cord ischemia is a serious medical condition that can result in significant neurological damage and adverse outcomes for the fetus. However, the lack of an appropriate experimental model has hindered the understanding of the pathology and the development of effective treatments. In our study, we established a system for screening drugs that affect fetal spinal cord ischemia using spinal cord organoids. Importantly, we produced necrotic core-free human spinal cord organoids (nf-hSCOs) by reducing the organoid size to avoid potential complications of spontaneous necrosis in large organoids. Exposing nf-hSCOs to CoCl2 as a hypoxia mimetic and hypoglycemic conditions resulted in significant neuronal damage, as assessed by multiple assay batteries. By utilizing this model, we tested chemicals that have been reported to exhibit beneficial effects in brain organoid-based ischemia models. Surprisingly, these chemicals did not provide sufficient benefit, and we discovered that rapamycin is a mild neuroprotective reagent for both axon degeneration and neuronal survival. We propose that nf-hSCO is suitable for large-scale screening of fetal neural ischemia due to its scalability, ease of ischemic induction, implementation of quantifiable assay batteries, and the absence of spontaneous necrosis.

[Prevention and Treatment of Ischemic Spinal Cord Injury].

In recent years, the widespread use of thoracic/thoracoabdominal stent grafting and a better understanding of spinal cord blood supply have led to quite a few change in measures to prevent spinal cord injury. It is essential to understand the characteristics of spinal cord blood flow, which is complicated by collateral pathways, and to strive to maintain spinal cord blood flow during surgery. It is also important to plan staged repair as much as possible in any treatment modality. Particular attention must be paid to the prevention of second attacks, especially after thoracic/thoracoabdominal endovascular aortic repair without segmental artery reconstruction. Systemic circulatory and respiratory management, improvement of anemia, and cerebrospinal fluid drainage with attention to drainage rates, may be effective as preventive and therapeutic measures for spinal cord injury.

Single-Site Review of Spinal Cord Protection Protocols Including the Utilization of Spinal Drains versus Medical Management with Branched Endovascular Aortic Repair.

BACKGROUND: Spinal cord ischemia (SCI) continues to be a devastating complication after repair of thoracoabdominal aortic aneurysms. The objective of this review is to present our single-center outcomes after the implementation of a standardized neuroprotective protocol following branched endovascular aortic repair. METHODS: A standardized neuroprotective protocol including preoperative steroids, acetazolamide, intraoperative hemodynamic parameters, and postoperative treatment goals was initiated in November 2019. Physician-modified branched endovascular repairs were completed at a single center from 2012 to 2021 with outcomes reviewed both before (n = 107) and after (n = 67) the implementation of the neuroprotective protocol. The primary end point was the incidence of any SCI event at 30 days. Secondary end points included all-cause mortality, stroke, myocardial infarction, and renal failure at 30 days. Patients with Crawford extents I-III, renal failure, or necessitating emergent repair were deemed high risk for SCI events and underwent a subset analysis. Survivability after SCI was estimated using Kaplan-Meier tables. RESULTS: Of the 174 consecutive patients treated, the 67 patients treated following implementation of the neuroprotective protocol were more likely to have experienced a prior myocardial infarction (26.9% vs. 14%; P = 0.0466) and have a history of chronic obstructive pulmonary disease (64.3% vs. 45.8%; P = 0.02). This group was more likely to be treated for paravisceral aneurysms (53.7% vs. 24.3%; P = 0.0002). Postprotocol implementation, spinal drain use was lower (6% vs. 38.3%; P = <0.0001) with 100% of these drains placed in urgent or unstaged thoracoabdominal aortic aneurysm repairs as a part of the protocol. Rates of any SCI event among all patients before and after implementation of the protocol were 9.3% (n = 10 of 107) and 6% (n = 4 of 67; P = 0.57), respectively. In comparison, the protocol significantly reduced SCI rates to 0 (0% vs. 17.1%; P = 0.0407) in high-risk patients. Frequency of renal failure was reduced (3% vs. 14%; P = 0.018) after initiation of the protocol. Patients in the postprotocol group had significantly improved 1-year mortality rate (9% vs. 27.1%; P = 0.0035) and renal failure rates (2% vs. 15%; P = 0.018). Regression models indicated that patients in the postprotocol group had lower likelihood of mortality and renal failure than patients in preprotocol group (P < 0.05) and that spinal drain reduced mortality (P < 0.1). CONCLUSIONS: Implementation of a standardized neuroprotective protocol that focuses on medical management and fluid dynamics may significantly reduce risk of SCI after branched endovascular repairs, with the most significant improvement of SCI outcomes involving those at greatest risk for developing SCI. Also noteworthy, there was significant improvement to 1-year survivability after the implementation of this neuroprotective protocol.

Spinal cord ischemia rates and prophylactic spinal drainage in patients treated with fenestrated/branched endovascular repair for thoracoabdominal aneurysms.

OBJECTIVE: Spinal cord ischemia (SCI) is a devastating complication after thoracoabdominal aortic aneurysm (TAAA) repair. The benefit of prophylactic cerebrospinal fluid drainage (pCSFD) to prevent SCI is still under investigation. The aim of this study was to evaluate the SCI rate and the impact of pCSFD following complex endovascular repair (fenestrated or branched endovascular repair [F/BEVAR]) for type I to IV TAAA. METHODS: The STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) statement was followed. A single-center retrospective study was conducted, including all consecutive patients, managed for TAAA type I to IV using F/BEVAR, between January 1, 2018, and November 1, 2022, for degenerative and post-dissection aneurysms. Patients with juxta- or pararenal aneurysms were excluded, as well as cases managed urgently for aortic rupture or acute dissection. After 2020, pCSFD in type I to III TAAAs was abandoned and replaced by therapeutic CSFD (tCSFD), performed only in patients presenting SCI. The primary outcome was the perioperative SCI rate for the entire cohort and the role of pCSFD for type I to III TAAAs. RESULTS: In total, 198 patients were included (mean age, 71.1±3.4 years; 81.8% males), including 50.5% with type I to III TAAA. The primary technical success was 94.9%. The perioperative mortality was 2.5%. and the major adverse cardiovascular event (MACE) rate was 10.6%; 4.5% presented SCI of any type (2.5% paraplegia). When comparing the SCI group with the remaining cohort, patients with SCI presented higher MACE (66.7% vs 7.9%; P < .001) rate and longer intensive care unit stay (3.5 vs 1 day; P = .002). Following type I to III repair, similar SCI, paraplegia, and paraplegia with no recovery rates were reported in the pCSFD and tCSFD groups (7.3% vs 5.1%; P = .66; 4.8% vs 3.3%; P = .72; and 2% vs 0%; P = .37). CONCLUSIONS: The incidence of SCI after TAAA I to IV endovascular repair was low. SCI was associated with significantly increased MACE and intensive care unit stay. The prophylactic use of CSFD in type I to III TAAAs was not associated with lower SCI rates and may not be justified routinely.

Comparison of Landmark-Guided Versus Fluoroscopy-Guided Cerebrospinal Fluid Drain-Related Complications After Aortic Repairs.

OBJECTIVE: Cerebrospinal fluid drains (CSFDs) are efficacious in preventing spinal cord injury after thoracic or thoracoabdominal aortic repair with extensive coverage. Increasingly, fluoroscopy is used to guide placement instead of the traditional landmark-based approach, but it is unknown which approach is associated with fewer complications. DESIGN: A retrospective cohort study. SETTING: In the operating room. PARTICIPANTS: Patients having undergone thoracic or thoracoabdominal aortic repair with a CSFD over a 7-year period at a single center. INTERVENTIONS: No intervention. MEASUREMENTS AND MAIN RESULTS: Groups were reviewed and statistically compared with respect to baseline characteristics, ease of CSFD placement, and major and minor complications directly related to placement. A total of 150 CSFDs were placed with landmark guidance as opposed to 95 with fluoroscopy guidance. Compared to the landmark group, patients with fluoroscopy-guided CSFDs were older (p < 0.008), had lower American Society of Anesthesiologists physical status scores (p = 0.008), required fewer CSFD placement attempts (p = 0.011), had the CSFD in place for longer duration (p < 0.001), and had a similar incidence of CSFD-related complications (p > 0.999). Composites of both major (4.5% of cases) and minor CSFD-related complications (6.1% of cases), the primary outcomes of the study, occurred with similar incidences between the 2 groups (p > 0.999 for both comparisons) after adjusting potential confounders. CONCLUSIONS: In patients undergoing thoracic or thoracoabdominal aortic repairs, there were no significant differences in the risk of major and minor CSFD-related complications between fluoroscopic guidance and the landmark approach. Although the authors' institution is a high-volume center for this type of procedure, the study was limited by a small sample size. Hence, regardless of the technique used for the placement of CSFD, the risks related to the placement should be balanced carefully against the potential benefits resulting from spinal cord injury prevention. Fluoroscopy-aided insertion of CSFD requires fewer attempts and, hence, may be better tolerated by patients.

Systematic Review of the Effect of Cerebrospinal Fluid Drainage on Outcomes After Endovascular Descending Thoracic/Thoraco-Abdominal Aortic Aneurysm Repair.

OBJECTIVE: This study aimed to investigate whether prophylactic use of cerebrospinal fluid (CSF) drainage in endovascular descending thoracic aortic aneurysm (DTAA) and thoraco-abdominal aortic aneurysm (TAAA) repair contributes to a lower rate of post-operative spinal cord ischaemia (SCI). DATA SOURCES: MEDLINE, Embase, and CINAHL. REVIEW METHODS: A literature review was conducted in accordance with PRISMA guidelines (PROSPERO registration no. CRD42021245893). Risk of bias was assessed through the Newcastle-Ottawa scale (NOS), and the certainty of evidence was graded using the GRADE approach. A proportion meta-analysis was conducted to calculate the pooled rate and 95% confidence interval (CI) of both early and late onset SCI. Pooled outcome estimates were calculated using the odds ratio (OR) and associated 95% CI. The primary outcome was SCI, both early and lateonset. Secondary outcomes were complications of CSF drainage, length of hospital stay, and peri-operative (30 day or in hospital) mortality rates. RESULTS: Twenty-eight observational, retrospective studies were included, reporting 4 814 patients (2 599 patients with and 2 215 without CSF drainage). The NOS showed a moderate risk of bias. The incidence of SCI was similar in patients with CSF drainage (0.05, 95% CI 0.03 ‒ 0.08) and without CSF drainage (0.05, 95% CI 0.00 ‒ 0.14). No significant decrease in SCI was found when using CSF drainage (OR 0.67, 95% CI 0.29 ‒ 1.55, p = .35). The incidence rate of CSF drainage related complication was 0.10 (95% CI 0.04 ‒ 0.19). The 30 day and in hospital mortality rate with CSF drainage was 0.08 (95% CI 0.05 ‒ 0.12). The 30 day and in hospital mortality rate without CSF drainage and comparison with late mortality and length of hospital stay could not be determined due to lack of data. The quality of evidence was considered very low. CONCLUSION: Pre-operative CSF drainage placement was not related to a favourable outcome regarding SCI rate in endovascular TAAA and DTAA repair. Due to the low quality of evidence, no clear recommendation on pre-operative use of CSF drainage placement can be made.

Practice of neuromonitoring in open and endovascular thoracoabdominal aortic repair-an international expert-based modified Delphi consensus study.

OBJECTIVES: Spinal cord injury is detrimental for patients undergoing open or endovascular thoracoabdominal aortic aneurysm (TAAA) repair. The aim of this survey and of the modified Delphi consensus was to gather information on current practices and standards in neuroprotection in patients undergoing open and endovascular TAAA. METHODS: The Aortic Association conducted an international online survey on neuromonitoring in open and endovascular TAAA repair. In a first round an expert panel put together a survey on different aspects of neuromonitoring. Based on the answers from the first round of the survey, 18 Delphi consensus questions were formulated. RESULTS: A total of 56 physicians completed the survey. Of these, 45 perform open and endovascular TAAA repair, 3 do open TAAA repair and 8 do endovascular TAAA repair. At least 1 neuromonitoring or protection modality is utilized during open TAAA surgery. Cerebrospinal fluid (CSF) drainage was used in 97.9%, near infrared spectroscopy in 70.8% and motor evoked potentials or somatosensory evoked potentials in 60.4%. Three of 53 centres do not utilize any form of neuromonitoring or protection during endovascular TAAA repair: 92.5% use CSF drainage; 35.8%, cerebral or paravertebral near infrared spectroscopy; and 24.5% motor evoked potentials or somatosensory evoked potentials. The utilization of CSF drainage and neuromonitoring varies depending on the extent of the TAAA repair. CONCLUSIONS: The results of this survey and of the Delphi consensus show that there is broad consensus on the importance of protecting the spinal cord to avoid spinal cord injury in patients undergoing open TAAA repair. Those measures are less frequently utilized in patients undergoing endovascular TAAA repair but should be considered, especially in patients who require extensive coverage of the thoracoabdominal aorta.

Perioperative neuromonitoring during thoracoabdominal aortic aneurysm open repair: a systematic review.

OBJECTIVES: While open surgical repair remains the gold standard for thoracoabdominal aortic aneurysm (TAAA) treatment, there is still no consensus regarding perioperative neuromonitoring technique for prevention of spinal cord ischaemia. METHODS: In this systematic review, we aimed to explore the effects and practices of neuromonitoring during the open TAAA repair. A systematic literature search in PubMed, Embase via Ovid, Cochrane library and ClinicalTrialsGov until December 2022 was performed. RESULTS: A total of 535 studies were identified from the literature search, of which 27 studies including a total of 3130 patients met the eligibility criteria. Most studies (21 out of 27, 78%) investigated the feasibility of motor-evoked potentials (MEP), while 15 analysed somatosensory-evoked potentials (SSEP) and 2 studies analysed near-infrared spectroscopy during open TAAA repair. CONCLUSIONS: Current literature suggest that rates of postoperative spinal cord ischaemia can be kept at low levels after open TAAA repair with the adequate precautions and perioperative manoeuvres. Neuromonitoring with MEP provides the surgeon objective criteria to direct selective intercostal reconstruction or other protective anaesthetic and surgical manoeuvres. Simultaneous monitoring of MEP and SSEP is a reliable method that can rapidly detect important findings and direct adequate protective manoeuvres during open TAAA repair.

Spinal drain-related complications after complex endovascular aortic repair using a prophylactic automated volume-directed drainage protocol.

OBJECTIVE: A common measure to lower the risk for spinal cord ischemia (SCI) during complex endovascular aortic repair (cEVAR) is prophylactic cerebrospinal fluid drainage (CSFD). This method has caused controversy because of drain-related complications. Spinal drains are usually pressure directed. The objective of this study was to evaluate the risk of CSFD-related complications and SCI within the context of an automated volume-directed drain protocol. METHODS: This is a retrospective, single-center study of all cEVARs with CSFD at a tertiary vascular center between January 2014 and December 2020. Demographics, complications, and spinal drain data were recorded. All drainages were volume based using an automatic drainage system (LiquoGuard7; Möller Medical GmbH). Spinal drain complications were categorized as disabling and nondisabling according to the modified Rankin scale. The primary end point was any CSFD-related complication. RESULTS: A total of 448 cEVAR patients were identified, of whom 147 (32.8%) had prophylactic CSFD. The mean age was 69 years (63% male). The most common pathology (61%) was thoracoabdominal aortic aneurysm, and the most common procedure was branched EVAR (55.1%). Eighteen (12.2%) patients developed a CSFD-related complication, whereof three (2%) were disabling. Nineteen (13%) patients developed SCI: 12 (8.4%) paraparetic, 5 (3.4%) paraplegic, and 2 (1.4%) paresthesias. Of these, 13 (68%) had full reversal of symptoms, whereas 6 patients (4%) had residual symptoms and were deemed disabling. Drain-related complications were more common in patients with SCI (31.6%) compared with those without (9.4%, P = .014). In the latter group, only two patients (1.6%) developed a disabling drain-related complication. CONCLUSIONS: Selective use of prophylactic, automated volume-directed CSFD in patients at high risk for SCI was associated with a high incidence of complications and should be used with caution. Among those developing SCI, reversal was achieved frequently with increased CSFD volume, but at the price of more bleeding complications.

Endoplasmic Reticulum Stress is Involved in the Protective Effect of Sivelestat Sodium Hydrate (ONO-5046) in Spinal Cord Ischemia-Reperfusion Injury.

BACKGROUND: Postoperative complications of thoracoabdominal aortic aneurysm include paraplegia due to impaired blood flow in the spinal cord. Sivelestat sodium hydrate (ONO-5046), a specific neutrophil elastase inhibitor, can prevent neuropathy after ischemia-reperfusion of the spinal cord; however, the underlying mechanism remains unclear. Here, we examined whether ONO-5046 elicits its protective effects in spinal cord ischemia by affecting endoplasmic reticulum (ER) stress. METHODS: Forty-five male Japanese white rabbits (weight 2.5-3.0 kg) were assigned to three groups: a sham control group (n = 5), and two other groups (n = 20, respectively; n = 5 each time point) that were subjected to spinal cord ischemia-reperfusion for 15 min and administered saline or ONO-5046 intravenously. From 8 h to 7 d after resumption of blood flow, a neurological evaluation, histological evaluation of the spinal cord, and immunohistochemical evaluation based on the expression of GRP78 and caspase12 were performed. RESULTS: Rabbits treated with ONO-5046 had fewer functional deficits and more surviving motor neurons after ischemia than did rabbits in the saline and control groups. In rabbits treated with ONO-5046, histological findings of the spinal cord showed a high number of viable motor nerves, whereas induction of GRP78, an ER stress response-related protein, was prolonged. Furthermore, caspase12 expression was activated by excessive ER stress and was downregulated in rabbits treated with ONO-5046, as compared with that in rabbits administered saline. CONCLUSIONS: ONO-5046 exerts a protective effect on the spinal cord by relieving ER stress during spinal cord ischemia.

Git1-PGK1 interaction achieves self-protection against spinal cord ischemia-reperfusion injury by modulating Keap1/Nrf2 signaling.

Spinal cord ischemia-reperfusion (IR) injury (SCIRI) is a significant secondary injury that causes damage to spinal cord neurons, leading to the impairment of spinal cord sensory and motor functions. Excessive reactive oxygen species (ROS) production is considered one critical mechanism of neuron damage in SCIRI. Nonetheless, the molecular mechanisms underlying the resistance of neurons to ROS remain elusive. Our study revealed that the deletion of Git1 in mice led to poor recovery of spinal cord motor function after SCIRI. Furthermore, we discovered that Git1 has a beneficial effect on neuron resistance to ROS production. Mechanistically, Git1 interacted with PGK1, regulated PGK1 phosphorylation at S203, and affected the intermediate products of glycolysis in neurons. The influence of Git1 on glycolysis regulates the dimerization of Keap1, which leads to changes in Nrf2 ubiquitination and plays a role in resisting ROS. Collectively, we show that Git1 regulates the Keap1/Nrf2 axis to resist ROS in a PGK1-dependent manner and thus is a potential therapeutic target for SCIRI.