National incidence, mortality outcomes, and predictors of spinal cord ischemia after thoracic endovascular aortic repair

[Trauma-associated vascular injuries and the vascular surgical/interventional options for vascular reconstruction]

AIM

The aim of this work is to illustrate the diversity of vascular injuries in terms of vascular segments or body regions, accident mechanisms and specific patient constellations.

METHOD

A representative case collection was compiled based on current and relevant scientific references in PubMed, own clinical experiences, vascular surgical and novel image-guided interventional options.

RESULTS

The diagnostics of vascular injuries in the context of trauma and fractures are based on a thorough physical examination. In addition, the hard and soft signs preferred by the Western Trauma Association should be included in the decision. Doppler ultrasonography examination is the safest and gentlest noninvasive examination procedure for a suspected vascular injury due to repeatable and comparative measurements. The stabilization of a fracture, ideally using an external fixator, should be performed before vascular reconstruction whenever possible, unless massive bleeding, hypovolemic shock or a rapidly spreading hematoma represent an immediate indication for surgery. In pediatric supracondylar fractures, avascular injury without relevant ischemia has frequently been described (pink pulseless hand). In this case, the fracture should first be reduced as the pulse often recovers. Due to the increasing availability, good technical handling and high technical success rate as well as the relatively limited interventional trauma, endovascular treatment of traumatic vascular injuries has become widely accepted. Traumatic aortic ruptures are associated with a high mortality even at the accident site. Rapid endovascular treatment using a stent prosthesis significantly increases the injured person's chances of survival.

CONCLUSION

Vascular injuries in connection with fractures or multiple injuries require interdisciplinary cooperation between the specialties involved.

Clinical outcomes of celiac artery coverage vs preservation during thoracic endovascular aortic repair

OBJECTIVE

Adequate proximal and distal seal zones are necessary for successful thoracic endovascular aortic repair (TEVAR). Often, the achievement of an adequate distal seal zone requires celiac artery (CA) coverage by endograft with or without preservation of CA blood flow. The outcomes of CA coverage without its flow preservation were studied only in small case series. This study aims to determine the difference in outcomes between CA coverage with vs without preservation of CA blood flow during TEVAR using a multi-institutional national database.

METHODS

The Vascular Quality Initiative database was reviewed for all TEVAR patients distally landing in zone 6. The cohort was divided into TEVAR with vs without CA flow preservation. Demographic, clinical, and perioperative characteristics, as well as postoperative mortality, morbidities, and complications, were compared between the groups. Univariate and multivariate regression analyses were performed.

RESULTS

Of 25,549 reviewed patients, 772 had a distal landing in Zone 6, 212 of which (27.5%) had TEVAR without CA flow preservation, whereas 560 (72.5%) underwent TEVAR with CA flow preservation. Indications for TEVAR were aneurysm in 431 (55.8%), dissection in 247 (32.0%), or other in 94 (12.2%) cases. Patients who underwent TEVAR without CA flow preservation had statistically significantly higher rates of 30-day mortality (11.3% vs 5.9%; P = .010), 30-day disease/treatment-related mortality (8.0% vs 4.3%; P = .039), as well as a tendency of increased intestinal ischemia requiring intervention (1.9% vs 0.5%; P = .077). After adjusting for potential confounders, CA coverage without flow preservation was associated with more than a two-fold increase in the overall 30-day mortality (odds ratio [OR], 2.83; 95% confidence interval [CI], 1.35-5.92; P = .006) and 30-day disease/treatment-related mortality (OR, 2.72; 95% CI, 1.11-6.72; P = .029). In a sub-group analysis based on disease pathology, these results persisted only in the aneurysm group (30-day mortality [OR, 2.36; 95% CI, 1.01-5.48; P = .047]; 30-day disease/treatment-related mortality [OR, 2.88; 95% CI, 1.08-7.67; P = .034]), whereas there was no significant association between CA flow preservation status and the endpoints in the dissection subgroup (30-day mortality [OR, 1.16; 95% CI, 0.22-6.05; P = .856], 30-day disease/treatment-related mortality [OR, 0.90; 95% CI, 0.16-5.19; P = .911]).

CONCLUSIONS

CA coverage during TEVAR without preservation of its blood flow is associated with significantly higher mortality in patients with aortic aneurysm, but not dissection. In patients with aortic aneurysm, CA flow should be preserved during TEVAR whenever feasible, whereas in patients with dissection, it may be safe to cover CA without preservation of its flow. Prospective studies should be done to confirm these findings and compare the open vs endovascular revascularization techniques on outcomes.

A Multicenter Study of the Mid-term Outcomes of Patients with Uncomplicated Type B Aortic Dissection After Distal Porous Talos Stent-Graft Implantation

BACKGROUND

The Talos stent-graft has extended length to improve aortic remodeling, and distal porous design to decrease the rate of spinal cord ischemia (SCI). This study retrospectively analyzed its mid-term outcomes for uncomplicated type B aortic dissection in a multicenter study.

METHODS

The primary safety end point was 30-day major adverse events, including all-cause mortality, dissection-related mortality, conversion to open surgery, and device-related adverse events. The primary efficacy end point was treatment success at 12 months postoperation, defined as no technical failure or secondary dissection-related reintervention. The survival status of the patients was visualized using the Kaplan-Meier curve. Aortic growth was assessed at 4 levels, and SCI was evaluated at 12 months.

RESULTS

113 patients participated with a mean age of 54.4 (11.1) years and 71.7% (81/113) were male. The 30-day mortality was 0.9% (1/113), no conversions to open surgery or device-related adverse events were recorded. The 12-month treatment success rate was 99.1% (112/113), with no dissection-related reinterventions. There was no spinal cord or visceral ischemia at 12 months. At a median of 34 months follow-up, 9 further deaths were recorded and the 3-year survival rate was 91.7%. The percentage of aortic growth was 1.8% (2/111) at the tracheal bifurcation, 3.6% (4/111) below the left atrium, 6.0% (5/83) above the celiac artery, and 12.1% (9/74) below the lower renal artery. The total thrombosis rate of the false lumen at the stented segment was 80.5% (91/113).

CONCLUSIONS

The results showed satisfactory results of Talos stent-graft in terms of safety and efficacy. More data are needed to confirm the long-term performance.

Rescue therapy for symptomatic spinal cord ischemia after thoracic endovascular aortic repair

OBJECTIVE

Spinal cord ischemia (SCI) after thoracic endovascular aortic repair (TEVAR) can cause permanent neurologic deficits and poor long-term survival. Targeted treatment of new SCI symptoms after TEVAR (rescue therapy [RT]) might improve/resolve neurologic symptoms but few data characterize the association of specific interventions with SCI outcomes. We evaluated the effectiveness of post-TEVAR RT at our tertiary aortic center.

METHODS

Our institutional TEVAR database was reviewed for SCI incidence and details of RT. This included cerebrospinal fluid drainage (CSFD), medical therapy, and optimization of spinal cord oxygen delivery. SCI outcomes were categorized at discharge as paralysis/paraparesis and temporary/permanent.

RESULTS

Nine hundred forty-three TEVAR procedures were performed in 869 patients from 2011 to 2020. Post-TEVAR SCI occurred in 7.8% (n = 74) with permanent paraplegia in 1.5%. Older patient age, chronic obstructive pulmonary disease, and previous abdominal aortic surgery were predictive of SCI. Half (n = 37) of SCI episodes resulted in only temporary paralysis/paraparesis. Rescue postoperative cerebrospinal fluid drains were implanted in 3.7% (n = 35) of procedures and was predicted by higher American Society of Anesthesiologists class, lower serum hemoglobin level, elevated international normalized ratio, bilateral iliac artery occlusion, nonelective procedures, and penetrating atherosclerotic ulcer/intramural hematoma indication. The most commonly used RTs were emergent placement of or increased drainage from an existing cerebrospinal fluid drain (87.8%), induced/permissive hypertension (77.0%), corticosteroid bolus (36.5%), and naloxone infusion (33.8%). Neurologic improvement occurred in 68.9% (n = 51/74). New/increased drainage was associated with improved SCI outcome.

CONCLUSIONS

Permanent paraplegia from post-TEVAR SCI is rare (1.5%). Older patients with comorbidities carry greater post-TEVAR SCI risk. SCI symptoms improved/resolved with CSFD and multimodal RT in 68.9% of patients, but no intervention was independently associated with improvement. TEVAR centers should have robust protocols for timely and safe CSFD placement to augment RT strategies for SCI.

How Would I Treat My Own Thoracoabdominal Aortic Aneurysm: Perioperative Considerations From the Anesthesiologist Perspective

A thoracoabdominal aortic aneurysm (TAAA) can be potentially life-threatening due to its associated risk of rupture. Thoracoabdominal aortic aneurysm repair, performed as endovascular repair and/or open surgery, is the recommended therapy of choice. Hemodynamic instability, severe blood loss, and spinal cord or cerebral ischemia are some potential hazards the perioperative team has to face during these procedures. Therefore, preoperative risk assessment and intraoperative anesthesia management addressing these potential hazards are essential to improving patients' outcomes. Based on a presented index case, an overview focusing on anesthetic measures to identify perioperatively and manage these risks in TAAA repair is provided.

Two-year follow-up after treatment of an aortic transection in the presence of an aberrant right subclavian artery

OBJECTIVES

An aberrant right subclavian artery (ARSA) is one of the most common anatomic variants of the aortic arch. The combination of an ARSA and a transection is naturally rare.

METHODS

This case report describes the treatment of a transection in the presence of an ARSA and the follow-up of two years.

RESULTS

We successfully treated the contained rupture with a stentgraft. Both subclavian arteries had to be covered in the emergency setting. At the two-year follow-up, the patient did not suffer from any neurological impairment.

CONCLUSIONS

In emergency settings, primary cover of both subclavian arteries with a stentgraft can be performed in individual cases after risk assessment. Severe complications such as development of upper limb ischaemia, ASAS or reduced perfusion of the posterior cerebral circulation should be considered in treatment planning.

Risk Factors for Spinal Cord Injury during Endovascular Repair of Thoracoabdominal Aneurysm: Review of the Literature and Proposal of a Prognostic Score

Despite recent improvements, spinal cord ischemia remains the most feared and dramatic complication following extensive aortic repair. Although endovascular procedures are associated with a lower risk compared with open procedures, this risk is still significant and must be considered. A combined medical and surgical approach may help to optimize the tolerance of the spinal cord to ischemia. The aim of this review is to describe the underlying mechanism involved in spinal cord injury during extensive endovascular aortic repair, to describe the different techniques used to improve spinal cord tolerance to ischemia-including the prophylactic or curative use of spinal drainage-and to propose our algorithm for spinal cord protection and the rational use of spinal drainage.

Retrospective investigation of >400 patients undergoing thoracic endovascular aortic repair with or without cerebrospinal fluid drainage

OBJECTIVES

The aim of this study was to analyse the risks and benefits of cerebrospinal fluid drainage (CSFD) placement in patients undergoing thoracic endovascular aortic repair.

METHODS

Between 2009 and 2020, 411 patients underwent thoracic endovascular aortic repair in 1 institution where 236 patients (57%) received a preoperative CSFD. Patient and outcome characteristics were retrospectively analysed and compared between patients with and without preoperative CSFD placement.

RESULTS

Preoperative CSFD was performed significantly more frequently in elective patients, especially those undergoing distal stent graft extension following frozen elephant trunk-stent placement (P < 0.001). Significantly fewer CSFD was placed in patients with acute aortic injury (P < 0.001). The incidence of permanent spinal cord ischaemia (SCI) was higher in patients without preoperative CSFD [10 patients (2%) vs 1 patient (0.2%), P = 0.001]. Postoperative CSFD was placed in 3 patients (0.7%). Severe CSFD-associated complications affected 2 patients (0.5%) namely, a subdural spinal haematoma causing permanent paraplegia in one of those 2 patients.

CONCLUSIONS

CSFS placement is associated with low procedural risk and can potentially help to prevent SCI. However, the SCI incidence is most likely also associated with other preoperative factors including the patient's haemodynamics. Hence, a general recommendation for placing a preoperative CSFD cannot be made when relying on the present evidence.

Association of simple renal cysts to aneurysm sac shrinkage in true thoracic aortic aneurysms after thoracic endovascular aortic repair

BACKGROUND

An increased prevalence of thoracic aortic aneurysms (TAA) has been demonstrated in patients with simple renal cysts (SRC); patients with SRC have a less elastic aortic wall than those without SRC. The purpose of this study was to evaluate aneurysm sac shrinkage after thoracic endovascular aortic repair (TEVAR) for true TAA in patients with and without SRC.

METHODS

One hundred three patients with true aneurysms of the thoracic aorta who underwent TEVAR at our university hospital from November 2013 to December 2021 were included in this study. Aneurysm sac size was compared between that on baseline preoperative computed tomography and that on postoperative computed tomography scans at 1 year. A change in aneurysm sac size ≥5 mm was considered to be significant, whether due to expansion or shrinkage.

RESULTS

The patients were divided into two groups: those with SRC (46 patients [45%]) and those without SRC (57 patients [55%]). At 1 year, there was a significant difference in the proportion of aneurysm sac shrinkage between patients with SRC and those without SRC (23.9% vs 59.6%; P < .001). Patients with SRC showed significantly less aneurysm sac shrinkage than those without SRC (-1.8 ± 5.6 mm vs -5.1 ± 6.6 mm; P = .009). Univariable and multivariable analyses showed that the initial sac diameter (odds ratio, 1.08; 95% confidence interval, 1.03-1.14; P = .002) and the presence of SRC (odds ratio, 0.15; 95% confidence interval, 0.06-0.40; P < .001) were positively and negatively associated with aneurysm sac shrinkage after TEVAR, respectively.

CONCLUSIONS

The presence of a SRC was independently associated with failure of aneurysm sac shrinkage after TEVAR for true TAA. This suggests that the presence of a SRC may be a predictor for the failure of aneurysm sac shrinkage after TEVAR.

Thoracic endovascular aortic repair of metachronous thoracic aortic aneurysms following prior infrarenal abdominal aortic aneurysm repair

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) of metachronous thoracic aortic aneurysms (M-TAAs) following previous infrarenal abdominal aortic aneurysm (AAA) repair has been associated with higher spinal cord ischemia (SCI) risk compared with TEVAR of primary thoracic aortic aneurysms (TAAs). However, data on the impact of the type of prior infrarenal aortic repair on outcomes are scarce. In this study, we examined perioperative outcomes and long-term mortality following TEVAR M-TAA compared with primary TEVAR of TAA.

METHODS

We identified all Vascular Quality Initiative (VQI) patients who underwent TEVAR of TAA in the descending thoracic aorta from 2013 to 2022. Only patients undergoing primary TEVAR or TEVAR following infrarenal open (OAR) or endovascular (EVAR) repair were included. We performed univariate analyses to identify differences in baseline and procedural characteristics, and multivariable analyses for perioperative outcomes and 5-year mortality using logistic and Cox regression, respectively.

RESULTS

We included 1493 patients who underwent primary TEVAR (81%) or TEVAR following prior OAR (9.0%) or prior EVAR (9.7%). Compared with primary TEVAR, patients undergoing TEVAR M-TAA were older, more commonly male, white, and had higher rates of hypertension, smoking, and renal dysfunction. Patients with M-TAA were more likely to be asymptomatic and have larger diameters at presentation but were exposed to greater contrast volume and procedural times relative to primary TEVAR patients. Following risk-adjustment, compared with primary TEVAR, TEVAR after prior EVAR was associated with higher perioperative mortality (9.7% vs 3.9%; odds ratio [OR], 5.3; 95% confidence interval [CI], 2.3-12; P < .001) and 5-year mortality (40% vs 24%; hazard ratio [HR], 2.1; 95% CI, 1.4-3.1; P = .001). Specifically, among octogenarians (n = 375; 25%), the perioperative and 5-year mortality differences were even more pronounced (perioperative mortality: 17% vs 8.4%; OR, 6.7; 95% CI, 2.2-21; P = .001; 5-year mortality: 50% vs 27%; HR, 3.0; 95% CI, 1.5-5.7; P = .010). However, in-hospital complications, including SCI (2.6% vs 2.8%; OR, 1.2; 95% CI, 0.33-3.3; P = .77), were not notably different. In contrast, TEVAR after previous OAR was associated with comparable perioperative mortality (4.4% vs 3.9%; OR, 1.2; 95% CI, 0.32-3.8; P = .73), 5-year mortality (28% vs 24%; HR, 1.3; 95% CI, 0.80-2.1; P = .54), and in-hospital complications, including SCI (2.6% vs 0.7%; OR, 0.21; 95% CI, 0.01-1.1; P = .16).

CONCLUSIONS

Patients undergoing TEVAR of M-TAAs after prior EVAR, particularly octogenarians, have higher perioperative and 5-year mortality and therefore, represent a high-risk group. Future efforts should strive to discern the underlying factors leading to these poorer outcomes; meanwhile, these findings emphasize the need for careful patient selection and appropriate preoperative counseling in these high-risk individuals.

Mouse Model of Spinal Cord Hypoperfusion with Immediate Paralysis Caused by Endovascular Repair of Thoracic Aortic Aneurysm

BACKGROUND

A clinically relevant mouse model of thoracic endovascular aortic repair-induced ischemic spinal cord injury has been lacking since the procedure was first employed in 1991. The hypothesis was that ligation of mouse intercostal arteries would simulate thoracic endovascular aortic repair-induced ischemic spinal cord injury and behavioral deficit. The aim was to create a mouse model of thoracic endovascular aortic repair-induced spinal cord hypoperfusion by ligating five pairs of mouse intercostal vessels.

METHODS

Mice were divided into sham (n = 53) and ligation (n = 60) groups. The procedures called for double ligation of three pairs and single ligation of two pairs of thoracic intercostal arteries in adult C57BL/6 mice. A laser Doppler probe was used in vivo on the spinal cords and intercostal arteries to document the extent of arterial ligation and spinal cord hypoperfusion. The Basso Mouse Scale for Locomotion, histological studies, and electron microscopy demonstrated postligation locomotive and histopathological changes.

RESULTS

Ligation induced a significant and instantaneous drop in blood flow in the intercostal arteries (% change; mean = -63.81; 95% CI, -72.28 to -55.34) and the thoracic spinal cord (% change; mean = -68.55; 95% CI, -80.23 to -56.87). Paralysis onset was immediate and of varying degree, with behavioral deficit stratified into three groups: 9.4% exhibited severe paralysis, 37.5% moderate paralysis, and 53.1% mild paralysis at day 1 (n = 32; P < 0.001). Mild and moderate paralysis was transient, gradually improving over time. Severe paralysis showed no improvement and exhibited a higher mortality rate (83%; n = 15 of 18) compared to moderately (33%; n = 6 of 18) and mildly (24%; n = 6 of 25) paralyzed mice (P < 0.001). The overall ligation group survival rate (84%; n = 46 of 55) was significantly lower than the sham group (100%; n = 48 of 48) with P = 0.003.

CONCLUSIONS

The mouse model generates reproducible spinal cord hypoperfusion and accompanying histopathological ischemic spinal cord damage. The resulting anatomical changes and variable behavioral deficits mimic the variability in radiological and clinical findings in human patients.

EDITOR’S PERSPECTIVE

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.

Simultaneous Endovascular Repair Is Not Associated With Increased Risk for Thoracic and Abdominal Aortic Pathologies: Early and Midterm Outcomes

Coexisting multilevel aortic pathologies were caused by atherosclerosis and hypertension and presented in a small subgroup of patients. Endovascular repair is a safe and effective treatment for a variety of aortic pathologies. However, fewer small series and cases were reported using simultaneous thoracic endovascular repair (TEVAR) and endovascular aneurysm repair (EVAR) for both aortic segments. To determine the outcomes of simultaneous and separately TEVAR and EVAR treating for multilevel aortic pathologies. Between 2010 and 2020, 31 patients and 22 patients were treated by one-staged and two-staged repair, respectively at a single center. All patients had the concomitant thoracic and abdominal aortic disease (aortic dissection, aneurysms, and penetrating aortic ulcers). Compared with the patients with two-staged aortic repair, the one-staged repair patients were older (mean age, 68 vs. 57 years; P < 0.001) and had a larger preoperative maximal aortic diameter (67.03 ± 10.65 vs. 57.45 ± 10.36 mm; p = 0.002). The intraoperative and postoperative outcomes show that the procedure times and length of hospital stay (LOS) were longer in the two-staged group. There is no significant difference in postoperative complications between the two groups. In the follow up, the freedom from re–intervention and the mean survival rate for the one-staged group were 100 vs. 100%, 92.4 vs. 95%, and 88 vs. 88% at one, two, and 5 years, respectively, whereas the mean survival rate for the two-staged group was 86.4 vs. 90.5%, 87 vs. 90.5%, and 76 vs. 84% at one, two, and 5 years, respectively, all with no statistical difference. Combined TEVAR and EVAR can be performed successfully with minimal morbidity and mortality. The one-staged repair was not associated with the increased risk for multilevel aortic pathologies treatment.

Safety of Cerebrospinal Fluid Drainage for Spinal Cord Ischemia Prevention in Thoracic Endovascular Aortic Repair

Objective

Spinal cord ischemia (SCI) after thoracic endovascular aortic repair (TEVAR) is associated with permanent neurologic deficit and decreased survival. Prophylactic cerebrospinal fluid (CSF) drainage (CSFD) in TEVAR is controversial. We evaluated the usage of CSFD in TEVAR at our tertiary aortic center.

Methods

Our institutional TEVAR database was reviewed to determine the frequency of CSFD usage/complications. Complications were categorized as mild (headache/CSF leak not requiring intervention, urinary retention), moderate (headache/CSF leak requiring intervention, drain malfunction requiring replacement), or severe (intrathecal hemorrhage, CSFD-attributable neurologic deficit). The relationships between CSFD complications and patient/procedural characteristics, CSFD placement timing, and survival were analyzed.

Results

Nine hundred thirty-six TEVAR procedures were performed in 869 patients from 2011 to 2020. Three hundred ninety CSFD drains were placed in 373 (41.7%) TEVAR patients. Most CSFD drains (89.5%) were pre-TEVAR. Most post-TEVAR drains were placed for new SCI symptoms (n = 21). Twenty-five patients (6.4%) suffered 32 CSFD complications. Most (n = 17) were mild in severity. Severe CSFD complications occurred in 5/432 (1.1% CSF drains) patients. No patient/procedural characteristics were predictive of CSFD complications. Post implant CSFD placement for new SCI symptoms conferred an increased risk of CSFD complication (odds ratio, 6.9; 95% CI, 2.42-19.6; P < .01). The long-term survival of the CSFD complication cohort did not differ from the overall population.

Conclusions

Post-TEVAR CSFD placement for new SCI symptoms was associated with substantially greater risk of CSFD complications. Avoidance of post-implant therapeutic drain placement might be the key to prevention of CSFD complications, favoring a strategy of selective pre-implant drain placement in patients at higher risk for SCI.

Prior Infrarenal Aortic Surgery is Not Associated with Increased Risk of Spinal Cord Ischemia Following Thoracic Endovascular Aortic Repair and Complex Endovascular Aortic Repair

OBJECTIVES

Patients with prior infrarenal aortic intervention represent an increasing demographic of patients undergoing thoracic endovascular aortic repair (TEVAR) and/or complex EVAR. Studies have suggested that prior abdominal aortic surgery is a risk factor for spinal cord ischemia (SCI). However, these results are largely based on single-center experiences with limited multi-institutional and national data assessing clinical outcomes in these patients. The objective of this study was to evaluate the effect of prior infrarenal aortic surgery on SCI.

METHODS

The Society for Vascular Surgery Vascular Quality Initiative database was retrospectively reviewed to identify all patients ≥18 years old undergoing TEVAR/complex EVAR from January 2012 to June 2020. Patients with previous thoracic or suprarenal aortic repairs were excluded. Baseline and procedural characteristics and postoperative outcomes were compared by group: TEVAR/complex EVAR with or without previous infrarenal aortic repair. The primary outcome was postoperative SCI. Secondary outcomes included postoperative hospital length of stay (LOS), bowel ischemia, renal ischemia, and 30-day mortality. Multivariate regression was used to determine independent predictors of postoperative SCI. Additional analysis was performed for patients undergoing isolated TEVAR.

RESULTS

A total of 9506 patients met the inclusion criteria: 8691 (91.4%) had no history of infrarenal aortic repair and 815 (8.6%) had previous infrarenal aortic repair. Patients with previous infrarenal repair were older with an increased prevalence of chronic kidney disease (p=0.001) and cardiovascular risk factors including hypertension, chronic obstructive pulmonary disease, and smoking history (p<0.001). These patients presented with larger maximal aortic diameters (6.06±1.47 cm versus 5.15±1.76 cm; p<0.001) and required more stent grafts (p<0.001) with increased intraoperative blood transfusion requirements (p<0.001), and longer procedure times (p<0.001). Univariate analysis demonstrated no difference in postoperative SCI, postoperative hospital LOS, bowel ischemia, or renal ischemia between the two groups. Thirty-day mortality was significantly higher in patients with prior infrarenal repair (p=0.001). On multivariate regression, prior infrarenal aortic repair was not a predictor of postoperative SCI, while aortic dissection (odds ratio [OR] 1.65; 95% confidence interval [CI] 1.26-2.16, p<0.001), number of stent grafts deployed (OR 1.45; 95% CI 1.30-1.62, p<0.001), and units of packed red blood cells transfused intraoperatively (OR 1.33; 95% CI 1.03-1.73, p=0.032) were independent predictors of SCI.

CONCLUSIONS

Although TEVAR/complex EVAR patients with prior infrarenal aortic repair constituted a sicker cohort with higher 30-day mortality, the rate of SCI was comparable to patients without prior repair. Previous infrarenal repair was not associated with risk of SCI.

Spinal Cord Protection for Thoracoabdominal Aortic Surgery

Open and endovascular repairs of the descending thoracic and thoracoabdominal aorta are associated with a substantial risk of spinal cord injury, namely paraplegia. Endovascular repairs seem to have a lower incidence of spinal cord injury, but there have been no randomized trials comparing outcomes of open and endovascular repairs. Paraplegia occurs when collateral blood supply to the anterior spinal artery is impaired. The risk of spinal cord injury can be mitigated with perioperative protocols that include drainage of cerebrospinal fluid, avoidance of hypotension and anemia, intraoperative neurophysiologic monitoring, and advanced surgical techniques. Drainage of cerebrospinal fluid using a spinal drain decreases the risk of spinal cord ischemia by improving spinal cord perfusion pressure. However, cerebrospinal fluid drainage has risks including neuraxial and intracranial bleeding, and these risks need to be carefully weighed against its potential benefit. This review discusses current surgical management of descending thoracic and thoracoabdominal aortic disease, incidence of and risk factors for spinal cord injury, and elements of spinal cord protection protocols that pertain to anesthesiologists, with a focus on cerebrospinal fluid drainage.

Optimization of factors for the prevention of spinal cord ischemia in thoracic endovascular aortic repair

OBJECTIVES

Spinal cord ischemia following thoracic endovascular aortic repair (TEVAR) is a devastating complication. This study seeks to demonstrate how a standardized protocol to prevent spinal cord ischemia affects incidence in patients undergoing TEVAR.

METHODS

Using CPT codes 33880 and 33881, all TEVAR procedures performed at a single tertiary care center from January 2017 to December 2018 were examined. Patients who had concomitant ascending aortic repairs or a TEVAR for traumatic indications were excluded from analysis, leaving 130 TEVAR procedures. Comorbid conditions, procedural characteristics, extent of coverage, peri-procedural management strategies, and post-operative outcomes were collected and analyzed retrospectively.

RESULTS

One hundred thirty patients undergoing TEVAR were examined for four perioperative variables: postoperative hemoglobin greater than 10 g/dL, subclavian revascularization, preoperative spinal drain placement, and somatosensory evoked potential monitoring (SSEP). All conditions were met in 46.2% (60/130) of procedures; 37.8% (28/74) in emergent/urgent cases and 61.5% (32/52) in elective cases. Of patients who required subclavian coverage, 87.1% (54/62) underwent subclavian revascularization; 70.8% (92/130) of patients received spinal drains preoperatively; 68.5% (89/130) of patients had SSEP monitoring; 73.8% (93/130) of patients obtained a postoperative hemoglobin of >10 g/dL. Out of all patients, two (1.5%) developed spinal cord ischemia.

CONCLUSION

Incidence of spinal cord ischemia in our cohort was low at 1.5% (2/130). Individual and bundled interventions for the prevention of spinal cord ischemia were unable to demonstrate a statistically significant effect given the low rate. Nonetheless, we advocate for a proactive approach for the prevention of spinal cord ischemia given our experience in this complex population.

Short-term and Mid-term Outcomes after Use of the Native Infrarenal Aorta as Distal Landing Zone for Fenestrated-Branched Endovascular Aortic Repair

BACKGROUND

This study aimed to examine outcomes after use of the native infrarenal aorta as distal landing zone for fenestrated-branched endovascular aortic repair (F-BEVAR) of pararenal-thoracoabdominal aortic aneurysms (PRAA-TAAA).

METHODS

All F-BEVAR procedures for treatment of PRAA-TAAA (2011-2019) at 2 aortic centers were examined. The outcomes of interest were as follows: i) technical success, ii) perioperative morbidity, iii) preservation of lumbar arteries and the inferior mesenteric artery, iv) type IB endoleaks, v) reinterventions, vi) survival, vii) aneurysm sac behavior, and viii) infrarenal aortic changes.

RESULTS

Twenty consecutive patients with distal landing in the native infrarenal aorta were included (median age 71 years; 25% men). The median number of visible lumbar arteries at baseline was 7, and a patent inferior mesenteric artery (IMA) before the operation was present in 19 (95%) of the cases. There were no deaths within 30 days. One patient (5%), operated on with a 4-BEVAR for a type 2 TAAA, experienced spinal cord ischemia (permanent paraplegia). The median decrease in the number of visible lumbar arteries at the first postoperative scan was 3 from the baseline value, whereas a patent IMA was preserved in 12 out of 19 patients. Only in one case (5%), a type IB endoleak was noted for an overall technical success rate of 95%, which required a standard EVAR 20 months after the initial operation. The median follow-up duration for the study cohort was 491 days; all patients were alive at the longest available individual follow-up, and no instances of new-onset type IB endoleaks were observed. Another 3 late reinterventions (in addition to the one mentioned previously) were performed during midterm follow-up, all because of target vessel instability. In patients with ≥12 months of follow-up after the index procedure (n = 12, 60% of the entire cohort), no instances of aneurysm sac increase >5 mm were noted; the median largest aortic diameter was 51 mm with a median difference from baseline of -6 mm. The median distal landing zone diameter increase was 4 mm from baseline but never beyond the nominal stent-graft diameter, whereas the median aortic bifurcation diameter differed 1 mm from baseline.

CONCLUSIONS

This preliminary experience shows that the use of the native infrarenal aorta as a distal landing zone for F-BEVAR is safe in the short term and midterm in patients with suitable anatomy, allowing the sparing of collateral vessels. Longer follow-up is warranted to assess durability.

Low-density vulnerable thrombus/plaque volume on preoperative computed tomography predicts for spinal cord ischemia after endovascular repair for thoracic aortic aneurysm

BACKGROUND

Similar to open surgical repair, thoracic endovascular aortic repair (TEVAR) carries a risk of spinal cord ischemia (SCI). However, the generally lower incidence of SCI after TEVAR compared with that after open surgical repair, despite the inability to preserve the intercostal arteries, indicates different pathophysiologic mechanisms with the two procedures. We hypothesized that a microembolism from an aortic mural thrombus is the main cause of SCI. Thus, we evaluated the association between the density of a mural thrombus in the descending thoracic aorta and the development of SCI.

METHODS

A retrospective review of a prospectively assembled database was performed for all patients who had undergone surgery at a single institution from October 2008 to December 2018. Patient demographics and procedure-related variables were collected. The volume and Hounsfield unit (HU) value of mural thrombi in the whole descending thoracic aorta were estimated on preoperative computed tomography using a three-dimensional workstation. Logistic regression analysis was performed to identify the risk factors for SCI development.

RESULTS

Of the 367 patients who had undergone TEVAR during the study period, 155 were excluded because of previous arch surgery (n = 59), previous descending thoracic aortic surgery (n = 6), previous TEVAR (n = 6), unavailability of optimal preoperative computed tomography data (n = 17), double-barreled dissection (n = 40), and other reasons. The mean ± standard deviation age of the remaining 212 patients was 75.8 ± 6.4 years, and 42 (19.8%) were women. Of the 212 patients, 14 (6.6%) developed SCI after TEVAR. The low mean density of the mural thrombus, total thrombus volume, low-density (≥-100 HU but <30 HU) thrombus volume, intermediate-density (≥30 HU but <150 HU) thrombus volume, treatment length, urgent surgery, and baseline dialysis differed significantly between patients with and without SCI. Although subsequent multivariate analysis could not be performed owing to the small number of SCI events, vulnerable low-density thrombus/plaque was a stronger predictor among the aneurysm-related factors of SCI after TEVAR on univariate analysis. Well-known risk factors, such as distal coverage between T8 and L1, left subclavian artery coverage, previous abdominal aortic surgery, and prophylactic spinal drainage, did not show significant differences.

CONCLUSIONS

The results from the present study have demonstrated that among aneurysm-related factors, a lower density mural thrombus/plaque in the descending thoracic aorta is a predictor of SCI development after TEVAR. These results suggest that microembolism is one of the important mechanisms of SCI after TEVAR, which might change the prophylactic strategy.

Use of Fenestrated Stent-Grafts for Preservation of Spinal Artery Flow During Endovascular Repair of Thoracoabdominal Aortic Disease

We illustrate the safety and feasibility of the application of fenestrated stent-grafts for the preservation of spinal artery flow during endovascular repair of thoracoabdominal aortic aneurysms (TAAA) in 2 patients deemed high-risk for spinal cord ischemia (SCI). In one case, an unstented fenestration was used in a 78-year-old male treated for distal stent-graft induced new entry tear. In the other case, a fenestration with a bridging stent-graft was used to revascularize a spinal artery in a 66-year-old female with Marfan disease and island patch aneurysm following open TAAA reconstruction. Both procedures were successful without any postoperative neurologic complication. The unstented fenestration led to a type III endoleak that required the relining of the aortic stent-graft 2 years later. The stented spinal fenestration was patent at a 5-year imaging follow-up.

Thoracic aortic remodeling with endografting after a decade of thoracic endovascular aortic repair experience

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) results have been studied in short-term time frames. This study aimed to evaluate midterm and long-term outcomes of TEVAR, emphasizing postoperative aortic remodeling and need for reintervention.

METHODS

This is an institutional retrospective review of TEVAR for isolated descending thoracic aortic aneurysms. Data were collected from 2004 to 2018. Primary outcomes studied included aneurysm sac remodeling, freedom from reintervention, and all-cause mortality. Other outcomes studied include endoleak rates, neurologic complication rates, and any overall postoperative complication rates.

RESULTS

During the study period, 219 patients underwent TEVAR for descending thoracic aortic aneurysms. The median effect of TEVAR on sac diameter was a 0.7-cm decrease in size (interquartile range, -1.4 to 0.0 cm). During the study period, 80% (n = 147) of patients experienced aneurysm sac regression or stability. Perioperative neurologic complications occurred in 16% (n = 34) of patients. Significant predictors of sac growth were endoleak (odds ratio [OR], 65; P < .001), preoperative carotid-subclavian bypass (OR, 8; P = .003), and graft oversizing <20% (OR, 15; P = .046). Every 1-mm increase in aortic diameter at the proximal TEVAR landing zone led to an increased odds of endoleak (OR, 2; P = .049). Access complications (OR, 8) and subclavian artery coverage (OR, 6) significantly increased the odds of reintervention, whereas every percentage of graft oversizing protected against reintervention (OR, 0.005). Life-table analysis revealed an overall survival of 78% (71%-83%) at median follow-up. At 3 years, survival was 88% (80%-93%) for those with aneurysm sac stability or regression, whereas it was 70% (49%-84%) for those with aneurysm sac growth (P = .0402). Cox proportional hazards model showed that the only protective factor for mortality was percentage oversizing, with every 1% of oversizing having a hazard ratio (HR) of <.001 (P = .032). This was counterbalanced by the fact that patients with graft oversizing >30% had an increased odds of mortality with HR >10 (P = .049). Other significant factors that increased the odds of mortality included endoleak (HR, 3.6; P = .033), diabetes (HR, 4.1; P = .048), age (every 1-year increase in age; HR, 1.2; P = .002), year of surgery (every year subsequent to 2004; HR, 1.3; P = .012), and peripheral artery disease (HR, 5.2; P = .041).

CONCLUSIONS

The majority of patients (80%) experience sac stability or regression after TEVAR, which offers a clear survival advantage. Endoleaks are predictive of sac growth, conferring increased mortality. Rigorous surveillance is necessary to prevent future aortic events through reintervention.