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.

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.

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.

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.

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.

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.

Preparing the spinal cord - priming or preconditioning? A systematic review of experimental studies.

Objectives. Paraplegia is devastating complication associated with thoracic and thoracoabdominal aortic aneurysm repair. Vast evidence has been gathered on pre-, peri- and postoperative protective adjuncts aiming to minimize spinal cord ischemia. This review focuses on the pretreatment phase of open surgical or endovascular aortic procedures and gathers the experimental data on the interventional preconditioning and priming methods that increase the spinal cord ischemic tolerance. Design. By the start of March 2021, a systematic review was performed in PubMed, Scopus and Web of Science core collection to identify the articles that reported (i) either an ischemic preconditioning, remote ischemic preconditioning or priming method prior to (ii) experimental spinal cord ischemia performed in endovascular or open surgical fashion mimicking either thoracic, abdominal or thoracoabdominal aortic aneurysm procedures. (iii) The outcomes were reported via neurological, motor-evoked potential, somatosensory-evoked potential, histopathological, immunohistochemical, physiological analysis, or in different combinations of these measurements. Results. The search yielded 7802 articles, and 57 articles were included in the systematic review. The articles were assessed by the evaluated species, the utilized pretreatment, the measured protective effects, and the suggested underlying mechanisms. Conclusions. The reviewed articles showed several possible mechanisms in ischemic and remote ischemic preconditioning for prevention of spinal cord ischemia. The main suggested method for priming was arteriogenetic stimulus. Future studies should confirm these hints of arteriogenetic stimulus with more precise quantification of the protective recruitment process.

A Novel Bypass Technique to Prevent Vexing Spinal Cord Ischemia in Endovascular Thoracoabdominal Aortic Intervention.

BACKGROUND: Spinal cord ischemia remains a devastating complication when treating patients with complex thoracoabdominal aortic aneurysms using fenestrated endovascular aortic repair. This approach is progressively deployed. However, to date, no strategy has been identified to reduce the feared risk of spinal cord ischemia. OBJECTIVE: To introduce a novel bypass technique using a customized composite graft to create a direct extra-anatomic revascularization before fenestrated endovascular aortic repair in patients with high-risk of spinal cord ischemia. METHODS: To demonstrate this novel concept, we present here a clinical case that reports the strategy of this novel concept in detail. An 83-year-old man with medical history of endovascular repair of an abdominal aortic aneurysm and thoracic aorta presented with a type IA endoleak, located along the posterior superior aspect of the aortic stent graft adjacent to the lumbar arteries. A multidisciplinary plan was developed, which included a novel bypass from the profunda femoris to the left L1 radicular artery before fenestrated endovascular aortic repair to prevent spinal cord ischemia. RESULTS: The patient successfully receives the novel extra-anatomic revascularization bypass before fenestrated endovascular aortic repair. During the first implementation of this strategy, no intraoperative difficulties and postoperative complications were observed. CONCLUSION: This case demonstrates a novel surgical technique before fenestrated endovascular aortic repair for prevention of spinal cord ischemia. In addition, this concept provides a promising direction to not only complement the existing surgical techniques but also to generate more future innovations.

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.

Spinal drain for aortic aneurysm repairs: tool or toy?

PURPOSE OF REVIEW: Spinal cord injury (SCI) is one of the biggest complications in open and endovascular aortic repairs. Historically, cerebrospinal fluid drains (CSFD) have been one of the most effective modalities in reducing SCI and one of the most studied. CSFD placement also carries its' own set of procedural risks. This editorial intends to evaluate recent literature to determine whether CSFDs remain a valuable tool in aortic repair. RECENT FINDINGS: As the surgical management of thoracic aortic aneurysms has evolved, there has been an increasing number of endovascular repairs. Current recommendations emphasize prophylactic CSFD placement in endovascular repair cases deemed 'high risk.' However, several meta-analyses differ on whether prophylactic CSFD placement reduced the risk of SCI. The incidence of SCI decreased between 2014 and 2018, despite a similar rate of prophylactic CSFD placement suggesting other techniques are being performed and may be effective in spinal cord protection as well. SUMMARY: There has been conflicting data on whether CSFDs have a role in reducing the risk of SCI in endovascular aortic repair. Some studies suggest that there is no benefit to placement while others suggest that routine prophylactic drains should be placed for all endovascular cases. Despite this, efforts have been made to selectively place CSFDs in those patients deemed at 'high risk' for SCI. CSFDs also remain a part of rescue treatment for postoperative SCI. This suggests that CSFDs continue to be a valuable tool that we need to better comprehend. Future research is necessary to better understand how patient risk factors can be balanced with perioperative management to help identify patients who may benefit from CSFD placement.

Temporary Reperfusion of the Aneurysm Sac as a Prevention of Spinal Cord Ischemia After Endovascular Treatment of Thoracoabdominal Aortic Aneurysm: Systematic Review and Meta-analysis.

BACKGROUND: Spinal cord ischemia (SCI) is still a feared complication for patients suffering from thoracoabdominal aortic aneurysm (TAAA) who undergo endovascular treatment. The aims of this work are to review the available literature on different reperfusion methods of the aneurysm sac, and to analyze whether the different reperfusion methods, also in combination with other factors, are effective in reducing SCI risk and if the impact varies with the patient's age. METHODS: PubMed/MEDLINE library was searched for studies published until November 2020 concerning TAAA, endovascular repair, and SCI preventive measures. Systematic review and meta-analysis were conducted according to Preferred Reporting Items for Systematic reviews and Meta-Analyses criteria. Primary outcome consisted of correlation between endovascular repair techniques (type A: single step; type B: staged approach with reperfusion branches; type C: staged sequential approach with positioning of the thoracic component). A logistic-weighted regression for each event (SCI, transient, and permanent) was then performed with type of treatment, age, and interaction between them as input factors. Finally, another logistic-weighted regression was performed to analyze the other relevant factors for which observations are available together with the endovascular technique. RESULTS: Data from 53 studies with a total of 3095 patients were analyzed. Type A, type B, and type C endovascular strategies were adopted in 75%, 13%, and 12% of studied patients, respectively. Data showed that both type B and type C treatments are associated with lower risk of SCI, with a higher reduction of type C with respect to type B, although this positive trend is limited for elder patients. Moreover, a greater aortic diameter, a reduced aneurysm extent, and the absence of cerebrospinal fluid drainage positioning contribute to lower the risk of SCI. Concerning permanent SCI, both type B and type C are effective in reducing percentages for all ages, with type C treatment more beneficial for younger patients and type B for elder ones. CONCLUSION: According to the anatomy and the endovascular repair feasibility criteria, staged endovascular treatment appears to offer relevant advantages over single-step treatment in reducing the risk of SCI, regardless of the reperfusion method adopted.

Reappraisal of the role of motor and somatosensory evoked potentials during open distal aortic repair.

OBJECTIVE: Intraoperative motor and somatosensory evoked potentials have been applied to monitor spinal cord ischemia during repair. However, their predictive values remain controversial. The purpose of this study was to evaluate the impact of motor evoked potentials and somatosensory evoked potentials on spinal cord ischemia during open distal aortic repair. METHODS: Our group began routine use of both somatosensory evoked potentials and motor evoked potentials at the end of 2004. This study used a historical cohort design, using risk factor and outcome data from our department's prospective registry. Univariate and multivariable statistics for risk-adjusted effects of motor evoked potentials and somatosensory evoked potentials on neurologic outcome and model discrimination were assessed with receiver operating characteristic curves. RESULTS: Both somatosensory evoked potentials and motor evoked potentials were measured in 822 patients undergoing open distal aortic repair between December 2004 and December 2019. Both motor evoked potentials and somatosensory evoked potentials were intact for the duration of surgery in 348 patients (42%). Isolated motor evoked potential loss was observed in 283 patients (34%), isolated somatosensory evoked potential loss was observed in 18 patients (3%), and both motor evoked potential and somatosensory evoked potential loss were observed in 173 patients (21%). No spinal cord ischemia occurred in the 18 cases with isolated somatosensory evoked potential loss. When both signals were lost, signal loss happened in the order of motor evoked potentials and then somatosensory evoked potentials. Immediate spinal cord ischemia occurred in none of those without signal loss, 4 of 283 (1%) with isolated motor evoked potential loss, and 15 of 173 (9%) with motor evoked potential plus somatosensory evoked potential loss. Delayed spinal cord ischemia occurred in 12 of 348 patients (3%) with intact evoked potentials, 24 of 283 patients (8%) with isolated motor evoked potentials loss, and 27 of 173 patients (15%) with motor evoked potentials + somatosensory evoked potentials loss (P < .001). Motor evoked potentials and somatosensory evoked potentials loss were each independently associated with spinal cord ischemia. For immediate spinal cord ischemia, no return of motor evoked potential signals at the conclusion of the surgery had the highest odds ratio of 15.87, with a receiver operating characteristic area under the curve of 0.936, whereas motor evoked potential loss had the highest odds ratio of 3.72 with an area under the curve of 0.638 for delayed spinal cord ischemia. CONCLUSIONS: Somatosensory evoked potentials and motor evoked potentials are both important monitoring measures to predict and prevent spinal cord ischemia during and after open distal aortic repairs. Intraoperative motor evoked potential loss is a risk for immediate and delayed spinal cord ischemia after open distal aortic repair, and somatosensory evoked potential loss further adds predictive value to the motor evoked potential.

Spinal cord protection in open and endovascular approaches to thoracoabdominal aortic aneurysms.

Despite advancements in surgical and postoperative management, spinal cord injury has been a persistent complication of both open and endovascular repair of thoracoabdominal and descending thoracic aortic aneurysm. Spinal cord injury can be explained with an ischemia-infarction model which results in local edema of the spinal cord, damaging its structure and leading to reversible or irreversible loss of its function. Perfusion of the spinal cord during aortic procedures can be enhanced by several adjuncts which have been described with a broad variety of evidence in their support. These adjuncts include systemic hypothermia, cerebrospinal fluid drainage, extracorporeal circulation and distal aortic perfusion, segmental arteries reimplantation, left subclavian artery revascularization, and staged aortic repair. The Authors here reviewed and discussed the role of such adjuncts in preventing spinal cord injury from occurring, pinpointing current evidence and outlining future perspectives.