Spinal Cord Perfusion and Protection During Descending Thoracic and Thoracoabdominal Aortic Surgery: The Collateral Network Concept

Patterns of collateral arteries to the spinal cord after thoraco-abdominal aortic aneurysm repair

OBJECTIVES

Our goal was to evaluate postoperative patterns of collateral arteries to the spinal cord during occlusion of the segmental arteries supplying the artery of Adamkiewicz (AKA).

METHODS

Between April 2011 and December 2022, a total of 179 patients underwent thoraco-abdominal aortic aneurysm repair; 141 had an identifiable AKA on preoperative multidetector computed tomography scans, 40 underwent thoraco-abdominal aortic aneurysm replacement (TAAR) and 101 underwent thoracic endovascular aortic repair (TEVAR). New postoperative collateral blood pathways invisible on preoperative contrast-enhanced computed tomography scans were identified in 42 patients (10 patients who had TAAR vs 32 patients who had TEVAR) who underwent preoperative and postoperative multidetector computed tomography scanning for AKA identification.

RESULTS

The thoracodorsal and segmental arteries were the main collateral pathways in both groups. Th9-initiated collaterals were the most common. Collaterals from the internal thoracic artery were observed in the TEVAR group but not in the TAAR group. One patient in the TEVAR group experienced postoperative paraparesis, which was not observed in the TAAR group. Postoperative paraplegia was more common in the non-Th9-origin group, but this difference was not significant.

CONCLUSIONS

Thoracodorsal and segmental arteries may be important collateral pathways after TEVAR and TAAR. For thoracodorsal arteries, preserving the thoracodorsal muscle during the approach would be crucial; for segmental arteries, minimizing the area to be replaced or covered would be paramount. An AKA not initiated at the Th9 level poses a high risk of postoperative paraplegia.

A direct aorta to segmental artery bypass for prevention of spinal cord ischemia after endovascular aortic repair

Spinal cord ischemia remains a persistent challenge after endovascular aortic aneurysm repair. We present a novel direct aorta to segmental artery bypass before aneurysm repair in a 64-year-old woman presenting with an enlarging aneurysm following dissection. Through an eighth intercostal incision, a polyester graft was sewn into the aorta using pledgeted sutures. An entry needle was used to directly access the previously treated aortic segment, and the opening was stented and angioplasty was performed to create inflow. Anastomoses were performed to a prominent left T10 segmental artery with a harvested saphenous vein. The patient remained neurologically intact postoperatively and the 1-month follow-up angiography demonstrated bypass patency.

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.

Trends in hospitalization of patients undergoing endovascular treatment of thoracoabdominal aortic aneurysms based on cerebrospinal fluid drainage strategy

OBJECTIVE

The aim of this study was to identify trends in hospital length of stay (HLOS) and intensive care unit length of stay (ICULOS), and the relationship with cerebrospinal fluid drainage (CSFD) protocols in patients undergoing fenestrated-branched endovascular aortic repair (FB-EVAR) of thoracoabdominal aortic aneurysms (TAAAs).

METHODS

A retrospective review of patients who underwent elective FB-EVAR for extent I to IV TAAAs between 2008 and 2023 at a single aortic center of excellence was conducted. Patient demographics, cardiovascular comorbidities, surgical risk, technical details, CSFD strategy (prophylactic or therapeutic), procedural success, and perioperative outcomes were collected. Patients were divided into two groups based on CSFD protocol. Group 1 included patients treated before 2020 when prophylactic CSFD was performed widely, and Group 2 consisted of patients treated since 2020 with therapeutic CSFD. Primary end points were HLOS, ICULOS, major adverse events, and perioperative mortality.

RESULTS

FB-EVAR was performed in 702 patients; 412 underwent elective TAAA repair and were included in the analysis. Mean age was 73 ± 8 years and 68% were male. Patient-specific manufactured devices were used in 252 patients (61%), physician-modified endografts in 110 (27%), and 50 patients (12%) were treated with off-the-shelf devices. Demographics, aneurysm extent, major adverse events (including spinal cord ischemia [SCI]), and mortality were similar in both groups. A significant reduction in mean HLOS between the groups (9 ± 9 vs 6 ± 5 days; P = .02) coincided with decreased use of prophylactic CSFD (70% vs 1.2%; P < .001), with similar rates of SCI (7.6% vs 4.9%; P = .627) and ICULOS (3 ± 3 vs 2.5 ± 3; P = .19). Patients in the therapeutic drainage cohort (group 2) had a higher incidence of congestive heart failure (24% vs 11%; P = .003), hypercholesterolemia (91% vs 80%; P = .015), chronic obstructive pulmonary disease (55% vs 37%; P = .004), and peripheral artery disease (39% vs 19%; P < .001) compared with group 1, suggesting treatment of a more complex patient cohort. On adjusted multivariable analysis accounting for American Society of Anesthesiologists score, comorbidities, and device type, the difference in HLOS remained statistically significant (P = .01).

CONCLUSIONS

HLOS decreased over time in patients undergoing FB-EVAR for TAAA after transition from a prophylactic to a therapeutic CSFD protocol. This transition was the only modifiable, independent risk factor for a shorter HLOS, without an increase in SCI, albeit with similar ICULOS.

Perioperative and Anesthetic Considerations in Shone's Complex

Shone's complex is a congenital cardiac disease consisting of the following four lesions: parachute mitral valve, supravalvar mitral ring, subaortic stenosis, and aortic coarctation. Though not all components are required for a diagnosis, the end result is both left ventricular inflow and outflow obstruction, which typically present in patients as congestive heart failure. The complex pathology requires careful management and surgical decision-making to ensure an optimal outcome. This review will focus on the anatomy, physiology, and perioperative anesthetic management of patients with Shone's complex.

Covering the intercostal artery branching of the Adamkiewicz artery during endovascular aortic repair increases the risk of spinal cord ischemia

Objectives

This study aimed to determine the relationship between covering the intercostal artery branching of the Adamkiewicz artery (ICA-AKA) and spinal cord ischemia (SCI) during thoracic endovascular aortic repair (TEVAR).

Methods

Patients who underwent TEVAR from 2008 to 2022 were enrolled. Stent grafts covered the ICA-AKA in 108 patients (covered AKA group) and stent grafts didn't cover the ICA-AKA in 114 patients (uncovered AKA group). The characteristics of 58 patients from each group were matched based on propensity scores.

Results

No significant differences in SCI rates were detected between the covered AKA (10%; 11/108) and uncovered AKA (3.5%; 4/114) groups (P = .061). Shaggy aorta (odds ratio [OR], 5.16; 95% confidence interval [CI], 1.74-15.3, P = .003), iliac artery access (OR, 6.81; 95% CI, 2.22-20.9, P = .001), and procedural time (OR, 1.01; 95% CI, 1.00-1.02, P = .003) were risk factors for SCI in the entire cohort. Although covering the ICA-AKA (OR, 2.60; 95% CI, 0.86-7.88, P = .058) was not a significant risk factor, shaggy aorta (OR, 8.15; 95% CI, 2.07-32.1, P = .003), iliac artery access (OR, 9.09; 95% CI, 2.22-37.2, P = .002), and procedural time (OR, 1.01; 95% CI, 1.01-1.02, P = .008) were risk factors for SCI in the covered AKA group. No significant risk factors were detected in the uncovered AKA group.

Conclusions

Covering the ICA-AKA was not an independent risk for SCI in TEVAR. However, covering the ICA-AKA was indirectly associated with the risk of SCI in patients with shaggy aorta, iliac access, and procedural time.

Impact of Intercostal Artery Reinsertion on Neurological Outcome after Thoracoabdominal Aortic Replacement: A 25-Year Single-Center Experience

BACKGROUND

Intercostal artery reinsertion (ICAR) during thoracoabdominal aortic replacement remains controversial. While some groups recommend the reinsertion of as many arteries as possible, others consider the sacrifice of multiple intercostals practicable. This study investigates the impact of intercostal artery reinsertion or sacrifice on neurological outcomes and long-term survival after thoracoabdominal aortic repair.

METHODS

A total of 349 consecutive patients undergoing thoracoabdominal aortic replacement at our institution between 1996 and 2021 were analyzed in a retrospective single-center study. ICAR was performed in 213 patients, while all intercostal arteries were ligated and sacrificed in the remaining cases. The neurological outcome was analyzed regarding temporary and permanent paraplegia or paraparesis.

RESULTS

No statistically significant differences were observed between the ICAR and non ICAR groups regarding the cumulative endpoint of transient and permanent spinal cord-related complications (12.2% vs. 11.8%, p = 0.9). Operation, bypass, and cross-clamp times were significantly longer in the ICAR group. Likewise, prolonged mechanical ventilation was more often necessary in the ICAR group (26.4% vs. 16.9%, p = 0.03). Overall long-term survival was similar in both groups in the Kaplan-Meier analysis.

CONCLUSION

Omitting ICAR during thoracoabdominal aortic replacement may reduce operation and cross-clamp times and thus minimize the duration of intraoperative spinal cord hypoperfusion.

Recognition of Significantly Delayed Spinal Cord Ischemia Following Thoracic Endovascular Aortic Repair: A Case Report and Review of the Literature

Spinal cord ischemia (SCI) is an uncommon but serious complication of thoracic endovascular aortic repair (TEVAR). SCI after TEVAR is thought to result from decreased segmental blood supply to an important network of collateral blood flow in the spinal cord. Little is known about the prevalence and optimal treatment of SCI that occurs beyond the periprocedural period. We report a case of delayed SCI in a 67-year-old patient who underwent TEVAR. The patient presented almost two years after TEVAR with acute paraplegia preceded by pre-syncope. The delayed SCI was likely triggered by pre-syncope, a thrombosed endoleak shown on imaging, and the patient's vascular risk factors. Treatments included cerebrospinal fluid (CSF) drainage, mean arterial pressure (MAP) augmentation, and a naloxone infusion, which resulted in moderate recovery in lower extremity motor function. This case highlights the tenuous nature of spinal cord perfusion after TEVAR and that prompt recognition and early treatment of SCI are critical in preventing the progression from ischemia to infarction.

Multifocal disease progression and subsequent intervention in patients with actin alpha-2 variants: A single-center experience

OBJECTIVES

To describe patient characteristics and indications for surgical intervention, reoperation, and outcomes in patients with actin alpha-2 (ACTA2) variants.

METHODS

A single-center retrospective cohort study with prospective follow-up was performed for 38 patients with an ACTA2 variant.

RESULTS

From 1999 to 2020, 26 (70%) patients underwent surgery; 11 remain under surveillance (mean follow-up, 7.5 ± 5 years). Median age at index operation was 42 (range, 10-69) years, with 4 pediatric cases. Thoracic aortic aneurysm was present in 19 (73%) patients (mean adult max diameter, 5.2 ± 0.8 cm; pediatric z score, 10.7 ± 5.4). Aortic dissection was present in 13 (50%) patients, with 4 (15%) having type A dissection. Operations included replacement of the aortic root in 16 (17%), ascending aorta in 20 (77%), and aortic arch in 14 (54%) patients. Four (15%) patients had coronary artery disease, and 2 (7.7%) underwent concomitant coronary artery bypass grafting. There was no operative mortality, stroke, reoperation for bleeding, or dialysis-dependent renal failure; One (3.8%) patient developed acute on chronic kidney injury. Three patients (12%) required prolonged ventilation. Eleven (42%) patients underwent 26 reoperations, median time 45 (range, 4-147) months, including 5 open thoracoabdominal aneurysm repairs.

CONCLUSIONS

Patients with ACTA2 variants frequently develop aortic aneurysm and are at risk of aortic dissection and coronary artery disease. However, age at diagnosis and symptoms at presentation are highly variable. Multiple operations are often required for disease management, particularly after dissection. Close monitoring and timely intervention are important in mitigating disease progression and improving outcomes.

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.

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.

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

Objectives

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

Methods

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

Results

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

Conclusions

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

Comparison of slow-infusion magnetic resonance angiography with sequential k-space filling and computed tomography angiography to detect the Adamkiewicz artery

OBJECTIVE

Radiographic detection of the Adamkiewicz artery (AKA) before aortic surgery helps to avoid spinal cord ischemia (SCI). We applied magnetic resonance angiography (MRA) using gadolinium enhancement (Gd-MRA) by means of the slow-infusion method with sequential k-space filling and compared AKA detectability with that of computed tomography angiography (CTA).

METHODS

A total of 63 patients with thoracic or thoracoabdominal aortic disease (30 with aortic dissection [AD] and 33 with aortic aneurysm) who underwent both CTA and Gd-MRA to detect AKA were evaluated. The detectability of the AKA using Gd-MRA and CTA were compared among all patients and subgroups based on anatomical features.

RESULTS

The detection rates of the AKAs using Gd-MRA and CTA were higher in all 63 patients (92.1% vs. 71.4%, p = 0.003). In AD cases, the detection rates using Gd-MRA and CTA were higher in all 30 patients (93.3% vs. 66.7%, p = 0.01) as well as in seven patients whose AKA originated from false lumens (100% vs. 0%). In aneurysm cases, the detection rates using Gd-MRA and CTA were higher in 22 patients whose AKA originated from the non-aneurysmal parts (100% vs. 81.8%, p = 0.03). In clinical, SCI was observed in 1.8% of cases after open or endovascular repair.

CONCLUSION

Despite the longer examination time and more complicated imaging techniques compared to those of CTA, the high spatial resolution of slow-infusion MRA may be preferable for detecting AKA before performing various thoracic and thoracoabdominal aortic surgeries.

Comparison of single- and multistage strategies during fenestrated-branched endovascular aortic repair of thoracoabdominal aortic aneurysms

OBJECTIVE

The aim of this study was to compare outcomes of single or multistage approach during fenestrated-branched endovascular aortic repair (FB-EVAR) of extensive thoracoabdominal aortic aneurysms (TAAAs).

METHODS

We reviewed the clinical data of consecutive patients treated by FB-EVAR for extent I to III TAAAs in 24 centers (2006-2021). All patients received a single brand manufactured patient-specific or off-the-shelf fenestrated-branched stent grafts. Staging strategies included proximal thoracic aortic repair, minimally invasive segmental artery coil embolization, temporary aneurysm sac perfusion and combinations of these techniques. Endpoints were analyzed for elective repair in patients who had a single- or multistage approach before and after propensity score adjustment for baseline differences, including the composite 30-day/in-hospital mortality and/or permanent paraplegia, major adverse event, patient survival, and freedom from aortic-related mortality.

RESULTS

A total of 1947 patients (65% male; mean age, 71 ± 8 years) underwent FB-EVAR of 155 extent I (10%), 729 extent II (46%), and 713 extent III TAAAs (44%). A single-stage approach was used in 939 patients (48%) and a multistage approach in 1008 patients (52%). A multistage approach was more frequently used in patients undergoing elective compared with non-elective repair (55% vs 35%; P < .001). Staging strategies were proximal thoracic aortic repair in 743 patients (74%), temporary aneurysm sac perfusion in 128 (13%), minimally invasive segmental artery coil embolization in 10 (1%), and combinations in 127 (12%). Among patients undergoing elective repair (n = 1597), the composite endpoint of 30-day/in-hospital mortality and/or permanent paraplegia rate occurred in 14% of single-stage and 6% of multistage approach patients (P < .001). After adjustment with a propensity score, multistage approach was associated with lower rates of 30-day/in-hospital mortality and/or permanent paraplegia (odds ratio, 0.466; 95% confidence interval, 0.271-0.801; P = .006) and higher patient survival at 1 year (86.9±1.3% vs 79.6±1.7%) and 3 years (72.7±2.1% vs 64.2±2.3%; adjusted hazard ratio, 0.714; 95% confidence interval, 0.528-0.966; P = .029), compared with a single stage approach.

CONCLUSION

Staging elective FB-EVAR of extent I to III TAAAs was associated with decreased risk of mortality and/or permanent paraplegia at 30 days or within hospital stay, and with higher patient survival at 1 and 3 years.

Spinal Cord Ischemia in Open and Endovascular Aortic Repair

Despite the improvements, spinal cord ischemia is still one of the major and most dramatic potential complications after thoracic and thoracoabdominal aortic treatments, for both open and endovascular procedures. A multimodal approach, which includes several intraoperative and postoperative maneuvers, may contribute to optimizing the spinal cord tolerance to ischemia. The aim of this article is to report the different techniques employed to improve spinal cord perfusion, directly and indirectly through collateral circulation.

Comprehensive review of hybrid aortic arch repair with focus on zone 0 TEVAR and our institutional experience

Even with increasing operator experience and a better understanding of the disease and the operation, intervention for aortic arch pathologies continues to struggle with relatively higher mortality, reintervention, and neurologic complications. The hybrid aortic arch repair was introduced to simplify the procedure and improve the outcome. With recent industry-driven advances, hybrid repairs are not only offered to poor surgical candidates but have become mainstream. This review discusses the evolution of hybrid repair, terminology pertinent to this technique, and results. In addition, we aim to provide a pervasive review of hybrid aortic arch repairs with reference to relevant literature for a detailed understanding. We have also discussed our institutional experience with hybrid repairs.

Priming protects the spinal cord in an experimental aortic occlusion model

OBJECTIVES

Paraplegia is a devastating complication in aortic aneurysm surgery. Modifying the spinal cord vasculature is a promising method in spinal cord protection. The aim of this study was to assess whether the spinal cord can be primed by occluding thoracic segmental arteries before simulated aneurysm repair in a porcine model.

METHODS

Twelve piglets were randomly assigned to the priming group (6) and the control group (6). Eight uppermost thoracic segmental arteries were occluded at 5-minute intervals in the priming group before a 25-minute aortic crossclamp. In the control group, the aorta was crossclamped for 25 minutes. During the first 5 minutes, 8 segmental arteries were occluded. After the aortic crossclamping, piglets were observed under anesthesia for 5 hours and followed up 5 days postoperatively. Near-infrared spectroscopy, motor-evoked potentials, blood samples, neurology with the modified Tarlov score, and histopathology of the spinal cord were assessed.

RESULTS

The median Tarlov score during the first postoperative day was higher in the priming group than in the control group (P = .001). At the end, 50% of the control animals had paraplegia compared with 0% of paraplegia in the priming group. The mean regional histopathologic score differed between the priming group and the control group (P = .02). The priming group had higher motor-evoked potentials during the operation at separate time points. The lactate levels were lower in the priming group compared with the control group (Pg = .001, Pg×t = .18).

CONCLUSIONS

Acute priming protects the spinal cord from ischemic injury in an experimental aortic crossclamp model.

Effects of fluids vs. vasopressors on spinal cord microperfusion in hemorrhagic shock induced ischemia/reperfusion

OBJECTIVE

Spinal cord injury induced by ischemia/reperfusion is a devastating complication of aortic repair. Despite developments for prevention and treatment of spinal cord injury, incidence is still considerably high majorly impacting patient outcome. Microcirculation is paramount for tissue perfusion and oxygen supply and often dissociated from macrohemodynamic parameters used to guide resuscitation. Effects of fluids vs. vasopressors in the setting of hemodynamic resuscitation on spinal cord microperfusion are unknown. Aim of this study was to compare the effects of vasopressor and fluid resuscitation on spinal cord microperfusion in a translational acute pig model of hemorrhagic shock induced ischemia/reperfusion injury.

METHODS

We designed this study as prospective randomized explorative large animal study. We induced hemorrhagic shock in 20 pigs as a model of global ischemia/reperfusion injury. We randomized animals to receive either fluid or vasopressor resuscitation. We measured spinal cord microperfusion using fluorescent microspheres as well as laser-Doppler probes. We monitored and analyzed macrohemodynamic parameters and cerebrospinal fluid pressure.

RESULTS

Spinal cord microperfusion decreased following hemorrhagic shock induced ischemia/reperfusion injury. Both fluids and vasopressors sufficiently restored spinal cord microperfusion. There were no important changes between groups (percentage changes compared to baseline: fluids 14.0 (0.31-27.6) vs. vasopressors 24.3 (8.12-40.4), p = .340). However, cerebrospinal fluid pressure was higher in animals receiving fluid resuscitation (percentage changes compared to baseline: fluids 27.7 (12.6-42.8) vs. vasopressors -5.56 ((-19.8)-8.72), p = .003). Microcirculatory resuscitation was in line with improvements of macrohemodynamic parameters.

CONCLUSIONS

Both, fluids and vasopressors, equally restored spinal cord microperfusion in a porcine acute model of hemorrhagic shock induced ischemia/reperfusion injury. However, significant differences in cerebrospinal fluid pressure following resuscitation were present. Future studies should evaluate these effects in perfusion disruption induced ischemia/reperfusion conditions of microcirculatory deterioration.

Thoracoabdominal Aortic Disease and Repair: JACC Focus Seminar, Part 3

Thoracoabdominal aortic disease is a rare but life-threatening condition that requires expert multidisciplinary collaborative management. Intervention is indicated in patients with symptomatic aneurysms or when an aneurysm reaches a certain threshold of diameter or rate of expansion. The strategies for spinal cord and end-organ protection have evolved over several decades, resulting in improved outcomes after repair. Open repair, although invasive, provides definitive and durable repair. Endovascular approaches are rapidly evolving, and the results with fenestrated and branched endografts are promising. Both open repair and endovascular repair require highly specialized expertise, and outcomes are best when repair is undertaken in an elective setting by a dedicated team. Patients with degenerative thoracoabdominal aortic aneurysms and chronic dissections should be followed up closely and referred for elective repair when indicated.

Iliac branch device to treat type IB endoleak with a brachial access or an "up-and-over" transfemoral technique

PURPOSE

This study aimed to review the results of secondary IBD (iliac branch device) implantation in patients with type IB endoleak after prior fenestrated and/or branched or infrarenal endovascular aortic repair (F/B-EVAR or EVAR), using either brachial access or an "up-and-over" transfemoral technique.

METHODS

A retrospective single centre analysis was conducted between Jan 2016 and Oct 2021 including consecutive patients that underwent IBD to correct a type IB endoleak after prior EVAR or F/B-EVAR. Groups were defined by arterial access which was either brachial (group 1) or transfemoral (group 2). All IBD implanted were manufactured by Cook Medical (INC, Bloomington, IN, USA). Demographics, anatomical features, technical success, and 30-day major adverse events (MAE) were recorded according to the current SVS standards. Survival curves according to Kaplan-Meier were calculated. Branch instability was a composite endpoint of any IIA branch-related complication or reintervention indicated to treat endoleak, kink, disconnection, stenosis, occlusion or rupture.

RESULTS

Overall, 28 patients (93% male, median age 74 years) receiving 32 IBDs were included, with 14 patients in each group. Prior endovascular aortic repairs were 23 EVAR and 5 F/B-EVAR, with time from initial repair being 58 months [48, 70]. Median pre-IBD maximal aneurysm diameter was 63.5 mm [59.0, 78.0]. Patients' baseline characteristics were similar in both groups except for pulmonary status. All procedures were performed in a hybrid operative room. Median total operating time, fluoroscopy time and dose area product were 120 min [86, 167], 23 min [15, 32] and 54 Gy.cm2 [40, 62], respectively. Total operating time was shorter in group 2 (p=0.006). Technical success rate was 100% and no early death reported. One 30-day MAE occurred including a medically treated colonic ischemia (group 2). Aortic-related secondary interventions were required in 7 patients (5 in group 1 and 2 in group 2) including 3 surgical explantations. Median follow-up was 31 months [24, 42] and 6 months [3, 10] in group 1 and 2, respectively. In group 1, 2-year freedom from aortic-related secondary intervention and IIA branch instability were 84.6% [67.1-100] and 92.3% [78.9-100], respectively. In group 2, 6-month freedom from aortic-related secondary intervention and IIA branch instability were 87.5% [67.3-100] and 91.7% [77.3-100], respectively.

CONCLUSION

The secondary implantation of IBD to correct distal type I endoleak of previous aortic stent-graft is safe with a high technical success rate. The "up-and-over" technique could be considered as an alternative to the brachial access in patients with suitable anatomy.

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.

Intraoperative Optical Monitoring of Spinal Cord Hemodynamics Using Multiwavelength Imaging System

The spinal cord is a major structure of the central nervous system allowing, among other things, the transmission of afferent sensory and efferent motor information. During spinal surgery, such as scoliosis correction, this structure can be damaged, resulting in major neurological damage to the patient. To date, there is no direct way to monitor the oxygenation of the spinal cord intraoperatively to reflect its vitality. This is essential information that would allow surgeons to adapt their procedure in case of ischemic suffering of the spinal cord. We report the development of a specific device to monitor the functional status of biological tissues with high resolution. The device, operating with multiple wavelengths, uses Near-InfraRed Spectroscopy (NIRS) in combination with other additional sensors, including ElectroNeuroGraphy (ENG). In this paper, we focused primarily on aspects of the PhotoPlethysmoGram (PPG), emanating from four different light sources to show in real time and record biological signals from the spinal cord in transmission and reflection modes. This multispectral system was successfully tested in in vivo experiments on the spinal cord of a pig for specific medical applications.

A Novel Clinically Based Classification System for the Profunda Femoris Artery and the Circumflex Femoral Arteries

OBJECTIVE

The profunda femoris artery (PFA) supplies important collateral branches to both the ipsilateral internal iliac and the distal superficial femoral artery (SFA). The size and patency of these collateral pathways can determine the risk of pelvic malperfusion, spinal cord ischemia, and lower extremity limb loss following vascular interventions. Despite its importance, the anatomy of the PFA is rarely characterized in clinical studies involving the pelvic or lower extremity circulation. This discussion may be limited by the lack of a comprehensive classification system. Our objective was to describe the most common PFA anatomic variants and present a classification system based on its branching patterns.

METHODS

We dissected 155 fixed and non-fixed femoral artery systems from 88 cadavers. Seventy-seven female and 78 male femoral exposures were performed. Vessel diameters, branch configurations and relative distances between the inguinal ligament, PFA, lateral circumflex femoral artery (LCFA), and medial circumflex femoral artery (MCFA) were recorded.

RESULTS

The mean diameters of the common femoral artery, SFA and PFA in males were 10.3mm, 8.0mm and 6.9mm, and 8.9mm, 6.9mm and 6.1 in females, respectively (p < 0.05). The mean distances from the inguinal ligament for PFA, MCFA and LCFA were 41mm, 41.7mm and 52.5mm respectively. No significant differences were noted relative to laterality or fixation. We developed a clinically applicable classification system based on the orientation of the PFA, LCFA, and MCFA. Six PFA, 5 LCFA and 5 MCFA variations were identified and ranked by frequency. The five most common combinations accounted for 56.1% of our cadaver series.

CONCLUSION

The anatomic orientation of the PFA and its branches is highly variable. We propose a novel classification system of this rich collateral system to facilitate consistent communication in academic and clinical vascular surgery.

Complete Transfemoral Endovascular Repair with Homemade Steerable Sheath of Intercostal Artery Patch Aneurysm after Open Repair of Thoracoabdominal Aortic Aneurysm

The aim of this paper is to describe a case of complete transfemoral approach for endovascular treatment of a large intercostal patch aneurysm with custom-made stent-graft in a patient with Loeys-Dietz syndrome and previous multiple aortic operations. Three aortic components were used to exclude a 65-mm intercostal patch aneurysm. Because of the reimplantation site of supra-aortic trunks in a previous open arch repair, we used a complete transfemoral approach with a homemade steerable sheath to deliver all the renovisceral bridging stents through the downward side-branches. No major complications were registered. A 6-month follow-up resulted uneventfully, and an initial shrinkage of the aneurysmal lesion was found. The use of a homemade steerable sheath was safe and effective for catheterization and stenting of all the target vessels through the downward side branches.

Elevated intraspinal pressure in traumatic spinal cord injury is a promising therapeutic target

The currently recommended management for acute traumatic spinal cord injury aims to reduce the incidence of secondary injury and promote functional recovery. Elevated intraspinal pressure (ISP) likely plays an important role in the processes involved in secondary spinal cord injury, and should not be overlooked. However, the factors and detailed time course contributing to elevated ISP and its impact on pathophysiology after traumatic spinal cord injury have not been reviewed in the literature. Here, we review the etiology and progression of elevated ISP, as well as potential therapeutic measures that target elevated ISP. Elevated ISP is a time-dependent process that is mainly caused by hemorrhage, edema, and blood-spinal cord barrier destruction and peaks at 3 days after traumatic spinal cord injury. Duraplasty and hypertonic saline may be promising treatments for reducing ISP within this time window. Other potential treatments such as decompression, spinal cord incision, hemostasis, and methylprednisolone treatment require further validation.

Neuromonitoring during descending aorta procedures

Thoraco-abdominal aneurysm (TAA) repair carries a significant risk of spinal cord infarction. The latter results from irreversible changes in the spinal cord arterial network, e.g., sacrifice of the segmental arteries. Intra-operative neurophysiology with somatosensory and especially motor evoked potential (SEP and MEP respectively) monitoring, has emerged as an effective tool to assess the efficiency of the collateral blood flow, detect reversible spinal cord ischemia and guide the peri-operative multidisciplinary management to prevent postoperative paraplegia. The main roles of such monitoring include diagnosis of spinal cord vs peripheral limb ischemia, titration of mean arterial pressure during aortic clamping, the guidance of selective re-implantation of critical segmental arteries, and management of hemodynamics in the immediate postoperative period. In addition, manipulation of the aortic arch and proximal descending aorta, adds the risk of cerebral infarction from both low flow state and/or thromboembolic events. As such, EEG monitoring may be a useful add-on for either assessment of the efficiency of cerebral cooling as a neuroprotective method and/or for detection and treatment of reversible cerebral ischemia. This chapter presents the multimodality approach to open TAA monitoring as a versatile tool for the prevention of devastating postoperative neurologic deficits.

Risk factors for spinal cord ischemia in frozen elephant trunk–induced upper spinal cord ischemia in patients with combination of degenerative arch aneurysms and peripheral artery diseases: a possible mechanism

Background

Degenerative aortic arch aneurysms are known to develop through a pathological process of arterial atherosclerosis, which could be accompanied by peripheral artery diseases and resultant development of intrapelvic collateral arteries to the ischemic lower limbs. The aim of this study was to investigate the relationship between peripheral collateral circulation and postoperative paraplegia after total arch repair with a frozen elephant trunk in patients with degenerative aortic arch aneurysms and peripheral artery diseases.

Methods

Between October 2014 and March 2020, 27 patients (20 men; 69.8 ± 7.7 years old) underwent total arch repair with a frozen elephant trunk. Two of the 27 patients developed paraplegia postoperatively. The patients were divided into two groups, spinal cord ischemia (SCI) group (2 patients) and no-SCI group (25 patients). The aortic shagginess score, arterial calcification (subclavian artery; hypogastric artery) score, and the number of hypogastric artery branches, assessed using preoperative contrast-enhanced computed tomography images, were compared between the two groups.

Results

The ankle brachial artery pressure index (i.e., lower side value each patient) was lower in the SCI group than that in the no-SCI group (0.64, 0.71, and 1.09±0.07, respectively). There was no difference between the two groups in the arterial calcification scores or the aortic shagginess score. The number of hypogastric artery branches was greater in the SCI group than in the no-SCI group (66, 66, and 30.7±7.5, respectively).

Conclusions

Enhanced collateral circulation to the ischemic lower limbs in patients with combination of degenerative aortic arch aneurysms and peripheral artery diseases may be involved in paraplegia the upper thoracic spinal cord injury after total arch repair with a frozen elephant trunk.

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.

A Systematic Review of Spinal Cord Ischemia Prevention and Management After Open and Endovascular Aortic Repair

OBJECTIVE

Spinal cord ischemia (SCI) is one of the most devastating complications after descending thoracic aortic (DTA) and thoracoabdominal aortic (TAA) repairs. Patients who develop SCI have a poor prognosis with mortality rates reaching 75% within the first year after surgery. Many factors have been shown to increase the risk of this complication, including extent of TAA repair, length of aortic and collateral network coverage, embolization, and reduced spinal cord perfusion pressure. As a result, a variety of treatment strategies have evolved. We aimed to provide an up-to-date review of SCI rates with associated treatment algorithms from open and endovascular DTA and TAA repairs.

METHODS

Using PRISMA guidelines, a literature review with the Medical Subject Headings (MeSH) terms "spinal cord ischemia; spinal cord ischemia prevention and mitigation strategies; spinal cord ischemia rates; spinal cord infarction" was performed in the Cochrane and PubMed databases to seek all peer-reviewed studies of DTA and TAA repairs with SCI complications, limited to 2012-2021 and the English language. MeSH subheadings including diagnosis, complications, physiopathology, surgery, mortality, and therapy were used to further restrict the articles. Studies were excluded if they were not in humans, not pertaining to SCI in DTA/TAA operative repairs, and if the study primarily discussed neuromonitoring techniques. Additionally, studies with <40 patients or limited information regarding SCI protection strategies were excluded. Each study was individually reviewed by two researchers to assess for type and extent of aortic pathology, operative technique, SCI protection or mitigation strategies, rates of overall and permanent SCI symptoms, associations with SCI on multivariate analysis, and mortality.

RESULTS

Of 450 studies returned by the MeSH search strategy, 41 met inclusion criteria and were included in the final analysis. For endovascular DTA repair patients, overall SCI rates ranged from 0-10.6% with permanent SCI symptoms ranging from 0-5.1%. Endovascular and open TAA repairs had rates of overall SCI of 0-35%. Permanent SCI symptom rate was reported by only one open study at 1.1% while endovascular TAA repairs had between 2-20.5%.

CONCLUSION

This review provides an up-to-date review of current rates of SCI as well as prevention and mitigation strategies for DTA and TAA repairs. We find that a multimodal approach, including a bundled institutional protocol, staging of multiple repairs, preservation of collateral blood flow network, augmented spinal cord perfusion, selective cerebrospinal fluid drainage, and distal aortic perfusion in open TAA repairs, appears to be important in reducing the risk of SCI.

Spinal cord ischemia following open surgery of a ruptured isolated internal iliac artery aneurysm: A case report

INTRODUCTION

Isolated internal iliac artery (IIA) aneurysms (IIIAAs) rarely occur. However, they may enlarge asymptomatically and rupture, causing fatality. Even after successful surgery of ruptured IIIAAs, there might be a potential risk of postoperative spinal cord ischemia (SCI)-related paraplegia, which is extremely rare. However, this paraplegia significantly impacts patients' activities of daily living.

PATIENT CONCERNS

A 71-year-old man who had no remarkable medical history was referred to our hospital with sudden lower abdominal pain.

DIAGNOSIS

Computed tomography (CT) revealed right IIIAA with small volumes of contrast medium extravasation and hematoma. He presented with cyanosis in the bilateral lower limbs. Moreover, blood gas analysis showed lactic acidosis. Therefore, he was diagnosed with ruptured IIIAA complicated by peripheral circulatory failure.

INTERVENTIONS

Considering his pre-shock status, an emergency operation comprising ligation of the proximal neck and suture closure of the distal IIA orifice was successfully performed.

OUTCOMES

Immediately after surgery, motor and sensory dysfunction in the bilateral lower limbs occurred. Magnetic resonance imaging confirmed the presence of SCI. The patient could not stand independently and had neurogenic bladder and rectal disorder.

CONCLUSION

Postoperative SCI is a serious complication with no definitive predictors, preventive methods, or highly efficacious treatments. Therefore, vascular surgeons should preempt its occurrence and focus on preventing hemodynamic instability and maintain collateral extra-segmental arterial blood flow, especially in ruptured cases.

Feasibility and Preliminary Patency of Prophylactic Hypogastric Artery Stenting for Prevention of Spinal Cord Ischemia in Complex Endovascular Aortic Repair

BACKGROUND

To report early results of feasibility and patency of prophylactic hypogastric artery (HA) stenting during complex endovascular aortic repair.

METHODS

This is a single centre retrospective non comparative cohort study of all consecutive patients undergoing prophylactic HA stenting during fenestrated and/or branched EVAR (F/B EVAR) in order to prevent spinal cord ischemia (SCI). Endpoints included technical success and early outcomes in terms of morbidity, mortality and patency of the implanted stents.

RESULTS

Between May 2014 and June 2019 prophylactic HA stenting was performed in 36 consecutive patients with significant HA stenosis during F/B EVAR to prevent SCI. 69.4% of patients presented with asymptomatic, 25% with symptomatic and 5.6% with ruptured aortic aneurysms. 55.6% were treated for thoracoabdominal aortic aneurysms, 44.4% for pararenal abdominal aortic aneurysms. In 13.9% aortic coverage was limited to the abdominal aorta. In 86.1% the aortic coverage was in the thoracoabdominal aortic segment. Unilateral HA stenting was performed in 91.7%, whereas 8.3% underwent bilateral stenting. Technical success was 100%. The primary patency of the implanted stents after a median follow-up time of 9.5 months was 97.5%. One intraprocedural bleeding from an HA branch occurred and was successfully treated by coil embolization. No further procedure-related complications occurred. 11.1% of the patients developed SCI.

CONCLUSIONS

HA stenting is feasible and safe with high rates of technical success and short-term patency.

Clinical feasibility and safety of transoesophageal motor-evoked potential monitoring

OBJECTIVES

Canine experiments have shown that transoesophageal motor-evoked potential monitoring is feasible, safe and stable, with a quicker response to ischaemia and a better prognostic value than transcranial motor-evoked potentials. We aimed to elucidate whether or not these findings were clinically reproducible.

METHODS

A bipolar oesophageal electrode mounted on a large-diameter silicon tube and a train of 5 biphasic wave stimuli were used for transoesophageal stimulation. Results of 18 patients (median age 74.5 years, 13 males) were analysed.

RESULTS

There were no mortalities, spinal cord injuries or complications related with transoesophageal stimulation. Transcranial motor-evoked potential could not be monitored up to the end of surgery in 3 patients for unknown reasons, 2 of whom from the beginning. Transoesophageal motor-evoked potential became non-evocable after manipulation of a transoesophageal echo probe in 2 patients. Strenuous movement of the upper limbs during transoesophageal stimulation was observed in 3 patients. In 14 patients who successfully completed both monitoring methods up to the end of surgery (11 thoraco-abdominal and 3 descending aortic repair), the final results were judged as false positives in 6 by transcranial stimulation and in 1 by transoesophageal stimulation. The stimulation intensity was significantly lower and the upper limb amplitude was significantly higher by transoesophageal stimulation, while the lower limb amplitude was comparable.

CONCLUSIONS

Transoesophageal motor-evoked potential monitoring is clinically feasible and safe with a low false positive rate. A better electrode design is required to avoid its migration by transoesophageal echo manipulation. Further studies may be warranted.

CLINICAL REGISTRATION NUMBER

UMIN000022320.

The intraspinal arterial collateral network: a new anatomical basis for understanding and preventing paraplegia during aortic repair

OBJECTIVES

The anatomical distribution pattern of epidural intraspinal arteries is not entirely understood but is likely to substantially impact maintaining perfusion during segmental artery sacrifice when treating acute and chronic thoraco-abdominal aortic diseases. We investigated the anatomical distribution pattern of intraspinal arteries.

METHODS

Twenty fresh, non-embalmed cadaveric human bodies were studied. Anatomical dissection and investigation of the epidural arterial network were performed according to a standardized protocol. We used a generalized mixed linear model to test whether the presence probability for certain vessels differed between vertebrae/segments.

RESULTS

There was craniocaudal continuity of all ipsilateral longitudinal connections from T1 to L5 by the anterior radicular artery. The mean [±standard deviation (SD)] number of transverse anastomoses was 9.7 ± 2.1. The presence probability of transverse anastomoses along the spine was different between vertebrae (P < 0.0001). There were 2 distribution peaks along the spine: 1 peak around T4-T6 and 1 around T11. The mean (±SD) number of thoracic and lumbar anterior radiculomedullary arteries (ARMAs) was 3.0 ± 1.1. The probability of the presence of ARMAs along the spine was different for each vertebral segment (P < 0.0001). Between ARMAs there were gaps of up to a maximum of 9 vertebrae. All Adamkiewicz arteries were located caudally to T7. The median segment of the Adamkiewicz presence was T10/11.

CONCLUSIONS

The epidural collateral network shows craniocaudal continuity. The number of transverse anastomoses is high. The number of ARMAs is low, and there is considerable variation in their distribution and offspring, which is highly likely to impact perfusion during segmental artery sacrifice when treating thoraco-abdominal aortic disease.

RETRACTED: Anesthesic and surgical guideline for the treatment of the thoraco-abdominal aorta. Consensus Document of the Spanish Societies of Anesthesia and Cardiovascular Surgery

Este artículo ha sido retirado por indicación del Editor Jefe de la revista, después de constatar que parte de su contenido había sido plagiado, sin mencionar la fuente original: European Heart Journal (2014) 35, 2873 926.: https://academic.oup.com/eurheartj/article/35/41/2873/407693#89325738 El autor de correspondencia ha sido informado de la decisión y está de acuerdo con la retirada del artículo. El Comité Editorial lamenta las molestias que esta decisión pueda ocasionar. Puede consultar la política de Elsevier sobre la retirada de artículos en https://www.elsevier.com/about/our-business/policies/article-withdrawal

Extrathoracic collaterals to critical segmental arteries after endovascular thoraco-abdominal aneurysm repair

OBJECTIVES

The risk of spinal cord injury after thoraco-abdominal aortic aneurysm repair increases when the segmental arteries (SAs) in the critical segment are sacrificed. Such critical SAs cannot be reconstructed when performing thoracic endovascular aortic repair (TEVAR). We aimed to elucidate extrathoracic collaterals to the critical SAs (T9-L1) that develop after TEVAR.

METHODS

Between 2006 and 2018, the critical SAs (T9-L1) of 38 patients were sacrificed during TEVAR. Nineteen of these patients who underwent multidetector row computed tomography 6 months after surgery were included (mean age 60 ± 13 years; 10 male; Crawford extent II:III, 14:5). We retrospectively assessed extrathoracic collaterals to the sacrificed critical SAs.

RESULTS

Ninety-four collaterals to the critical SAs were observed, originating from the subclavian (26/94), external iliac (50/94) and internal iliac (18/94) arteries. Twenty-five of the 26 (96%) collaterals from the subclavian artery were from its lateral descending branch, and 19 of the 26 (73%) collaterals fed into T9. Forty-three of the 50 (86%) collaterals from the external iliac artery were from its lateral ascending branch, and 25 of the 50 (50%) collaterals communicated with T11. Patients with a history of left thoracotomy (no collaterals in 6 patients) had fewer collaterals via the lateral descending branch of the left subclavian artery in comparison with the patients without (10 collaterals in 13 patients) (P = 0.009).

CONCLUSIONS

After critical SAs were sacrificed, extrathoracic collaterals developed with certain regularity. Previous left thoracotomy could influence the development of extrathoracic collaterals from the left subclavian artery.

Arch replacement with collared elephant trunks: The Siena approach

Objective

To illustrate our experience and results in patients with diffuse aneurysmal disease treated with arch replacement using the Siena collared graft, a device designed in 2002 to improve the elephant trunk technique. Results of the first step surgical implant and the subsequent treatment strategies, with extensive use of endovascular techniques, are reported.

Methods

All aortic arch–replacement procedures using the Siena graft between February 2002 and January 2020 were retrospectively analyzed for early and late clinical outcomes.

Results

Of 146 patients (54 women, 36.9%) with a median age of 69.1 years (interquartile range 58.4-75.0 years), 55 (37.6%) had acute/chronic dissection with false lumen aneurysmal dilatation, 91 (62.3%) had degenerative aneurysms, 45 (30.8%) were redo operations, and 14 (9.5%) had connective tissue disease. First-stage outcomes: 10.9% 30-day mortality (n = 16); 5.4% stroke (n = 8, 6 disabling, 2 nondisabling; 3 fatal); and 0.6% paraplegia. Outcomes for 113 second-stage procedures (77.3%, n = 97 endovascular [66.4%], n = 16 surgical [10.9%]) were 5.3% and 8.8% 30-day and 180-day mortality; no stroke; 10.6% paraplegia. Median follow-up was 5.7 years (range: 0-18.02 years) median survival was 16.65 years (95% lower confidence limit, 10.06 years) with no significant difference between aneurysm and dissection patients. Freedom from further treatment was 87.0% (95% confidence interval, 79.9%-94.7%) at 5 years and 71.4% (95% confidence interval, 71.4%-84.7%) at 10 years; median time to reintervention was 2.59 years (interquartile range, 0.52-5.20 years) with no difference (P = .22) between dissection and aneurysm groups.

Conclusions

Siena collared graft represents a reliable platform for the treatment of diffuse aneurysmal disease. This device offers the flexibility required in the treatment of extended aortic lesions and guarantees the choice of the most appropriate approach for treatment completion. In this context, the availability of hybrid grafts has not modified the role of this device in arch surgery.

Physician-Modified Branched Double-Trunk Stent-Graft (PBDS) for Thoracoabdominal Aortic Aneurysm

PURPOSE

To describe the preliminary experience of using physician-modified, branched, double-trunk stent-grafts (PBDS) for treating thoracoabdominal aortic aneurysms (TAAA).

MATERIALS AND METHODS

Ten (10) patients with TAAA were included in the study from June 2017 to March 2020. The technical success, perioperative complications, re-intervention, and patency of branch arteries were assessed.

RESULTS

The technical success rate was 100%. There were four type III endoleaks (40%) recorded in the perioperative period. The median follow-up was 13.4 months (range, 3-36 months). During follow-up, two renal stent-graft occlusions (2 of 37 visceral arteries reconstructed, 5.4%), one cerebral infarction (1 of 10, 10%) and one paraplegia (1 of 10, 10%) occurred. No aortic-related death was recorded.

CONCLUSION

PBDS is useful in sealing TAAA and preventing visceral branches, providing an option for patients unsuited for open surgical repair. A larger sample size of patients is required to confirm the safety and effectiveness of this technique.

Collateral Circulation in Spinal Cord Injury: A Comprehensive Review

Surgery is the most common cause of spinal cord ischemia; it is also caused by hemodynamic changes, which disrupt the blood flow. Direct ligation of the spinal arteries, especially the Adamkiewicz artery is involved as well. Other causes of spinal cord ischemia include arteriography procedures, thoracic surgery, epidural and rachianesthesia, foraminal infiltration, arterial dissection, systemic hypotension, emboligenic heart disease, thoracic disc herniation, and compression. Understanding the vascular anatomy of the spinal cord is essential to develop optimal strategies for preventing ischemic injuries to the spinal cord. During ischemia, a rich network of intra and paraspinal collaterals allow enough blood flow to compensate the intensity of spinal cord ischemia. In case of interruption of flow of a main artery, the collateral artery increases its flow to maintain perfusion to the tissues. Avoiding spinal cord ischemia by using collateral circulation is necessary to prevent the establishment of hypovolemia, hyperthermia and elevations in venous pressures. The objective of this narrative review is to present the current concepts of spinal collateral circulation and its role in the setting of ischemic events, affecting the vascular supply of the spinal cord.

Bipolar transesophageal thoracic spinal cord stimulation: A novel clinically relevant method for motor-evoked potentials

Objective

Although transesophageal motor-evoked potential elicited by monopolar cervical cord stimulation is more stable and rapid in response to ischemia than transcranial motor-evoked potential in canine experiments, direct cervical alpha motor neuron stimulation precludes clinical application. We evaluated a novel stimulation method using a bipolar esophageal electrode to enable thoracic cord stimulation.

Methods

Twenty dogs were anesthetized. For bipolar transesophageal stimulation, the interelectric pole distance was set at 4 cm. Changes in amplitude in response to incremental stimulation intensity (100-600 V) were measured to evaluate stability. Spinal cord ischemia was induced by aortic balloon occlusion at the T8 to T10 level for 10 minutes to evaluate response time or at the T3 to T5 level for 25 minutes to evaluate prognostic value. Neurological function was evaluated using the Tarlov score at 24 and 48 hours postoperatively.

Results

Bipolar transesophageal stimulation was successful in all animals and their forelimb waveforms were identical to those after transcranial stimulation. The minimum stimulation intensity to produce >90% of the maximum amplitude was significantly lower in both monopolar and bipolar transesophageal stimulation than in transcranial stimulation (n = 5). Time to disappearance and recovery (>75%) of the hindlimb potentials were significantly shorter by both monopolar and bipolar transesophageal stimulation than by transcranial stimulation (n = 5). Correlation with neurological outcomes was comparable among all stimulation methods (n = 10).

Conclusions

Motor-evoked potential can be elicited by bipolar transesophageal thoracic cord stimulation without direct cervical alpha motor neuron stimulation, and its stability and response time are comparable to those elicited by monopolar stimulation.