Prevention of Paraplegia during Thoracoabdominal Aortic Aneurysm Repair

Structural reconstruction of mouse acute aortic dissection by intravenously administered human Muse cells without immunosuppression

BACKGROUND

Stanford type B-acute aortic dissection (type B-AAD) is often life-threatening without invasive surgery. Multilineage-differentiating stress enduring cell (Muse cells), which comprise several percent of mesenchymal stem cells (MSCs), are endogenous pluripotent-like stem cells that selectively home to damaged tissue and replace damaged/apoptotic cells by in-vivo differentiation.

METHODS

Mortality, aortic diameter expansion, cell localization, cell differentiation, and inflammation of the dissected aorta were evaluated in type B-AAD model mice intravenously injected with human-Muse cells, -elastin-knockdown (KD)-Muse cells, -human leukocyte antigen-G (HLA-G)-KD-Muse cells, or MSCs, all without immunosuppressant.

RESULTS

Here, we show the Muse (50,000 cells) group has a lower incidence of aortic rupture and mortality of AAD compared with the MSC-50K (50,000 human-MSCs) and vehicle groups. Spectrum computed tomography in-vivo dynamics and 3-dimensional histologic analyses demonstrate that Muse cells more effectively home to the AAD tissue and survive for 8 weeks in the Muse group than in the MSC-750K (750,000 human-MSCs containing 50,000 Muse cells) group. Homing of Muse cells is impeded in the HLA-G-KD-Muse (50,000 cells) group. Differentiation of homed Muse cells into CD31(+) and alpha-smooth muscle actin (+) cells, production and reorganization of elastic fibers in the AAD tissue, and suppression of diameter expansion are greater in the Muse group than in the MSC-750K and elastin-KD-Muse (50,000 cells) groups.

CONCLUSIONS

Intravenously administered Muse cells reconstruct the dissected aorta and improve mortality and diameter enlargement rates. Moreover, small doses of purified Muse cells are more effective than large doses of MSCs. HLA-G is suggested to contribute to the successful survival and homing of Muse cells.

Mildronate Has Ameliorative Effects on the Experimental Ischemia/Reperfusion Injury Model in the Rabbit Spinal Cord

BACKGROUND

Mildronate is a useful anti-ischemic agent and has antiinflammatory, antioxidant, and neuroprotective activities. The aim of this study is to investigate the potential neuroprotective effects of mildronate in the experimental rabbit spinal cord ischemia/reperfusion injury (SCIRI) model.

METHODS

Rabbits were randomized into 5 groups of 8 animals as groups 1 (control), 2 (ischemia), 3 (vehicle), 4 (30 mg/kg methylprednisolone [MP]), and 5 (100 mg/kg mildronate). The control group underwent only laparotomy. The other groups have the spinal cord ischemia model by a 20-minute aortic occlusion just caudal to the renal artery. The malondialdehyde and catalase levels and caspase-3, myeloperoxidase, and xanthine oxidase activities were investigated. Neurologic, histopathologic, and ultrastructural evaluations were also performed.

RESULTS

The serum and tissue myeloperoxidase, malondialdehyde, and caspase-3 values of the ischemia and vehicle groups were statistically significantly higher than those of the MP and mildronate groups (P < 0.001). Serum and tissue catalase values of the ischemia and vehicle groups were statistically significantly lower than those of the control, MP, and mildronate groups (P < 0.001). The histopathologic evaluation showed a statistically significantly lower score in the mildronate and MP groups than in the ischemia and vehicle groups (P < 0.001). The modified Tarlov scores of the ischemia and vehicle groups were statistically significantly lower than those of the control, MP, and mildronate groups (P < 0.001).

CONCLUSIONS

This study presented the antiinflammatory, antioxidant, antiapoptotic, and neuroprotective effects of mildronate on SCIRI. Future studies will elucidate its possible use in clinical settings in SCIRI.

Paraplegia After Open Surgical Repair Versus Thoracic Endovascular Aortic Repair for Thoracic Aortic Disease: A Retrospective Analysis of Japanese Administrative Data

OBJECTIVES

To comparatively examine the risk of postoperative paraplegia between open surgical descending aortic repair and thoracic endovascular aortic repair (TEVAR) among patients with thoracic aortic disease.

DESIGN

Retrospective cohort study.

SETTING

Acute-care hospitals in Japan.

PARTICIPANTS

A total of 6,202 patients diagnosed with thoracic aortic disease.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The main outcome of this study was the incidence of postoperative paraplegia. Multiple logistic regression models, using inverse probability of treatment weighting and an instrumental variable (ratio of TEVAR use to open surgical repair and TEVAR uses), showed that the odds ratios of paraplegia for TEVAR (relative to open surgical descending aortic repair) were 0.81 (95% confidence interval: 0.42-1.59; p = 0.55) in the inverse probability of treatment-weighted model and 0.88 (0.42-1.86; p = 0.75) in the instrumental-variable model.

CONCLUSIONS

There were no statistical differences in the risk of paraplegia between open surgical repair and TEVAR in patients with thoracic aortic disease. Improved perioperative management for open surgical repair may have contributed to the similarly low incidence of paraplegia in these two surgery types.

Ventriculoperitoneal Shunt Malfunction, a Rare Cause of Paraplegia after Kyphosis Correction: A Case Report and Literature Review

Ventriculoperitoneal shunt (VPS) malfunction after kyphosis surgery in 12-year boy caused a sudden hydrocephalus which increased cerebrospinal fluid pressure within the spinal cord and decreased cord perfusion. Spinal cord at apex of deformity was vulnerable to ischemia which caused paraplegia. The ischemic event was reversible after re-insertion of the VPS.

Study Design.

Case report and literature review.

Objective.

The aim of this study was to report a rare case of hydrocephalus due to ventriculoperitoneal shunt (VPS) malfunction following kyphosis correction that resulted in paraplegia in the postoperative period. The available English literature to explain the possible cause of paraplegia is reviewed.

Summary of Background Data.

Twelve-year male child presented with a severe dorsal kyphoscoliosis deformity with spastic paraparesis since 4 months. The lower extremities had grade-2 power and spasticity. The sensation was reduced below D9. The deep tendon reflexes were exaggerated with ankle clonus. Bowel-bladder had urgency and frequency. The radiographs and CT showed D6-7 hemi-vertebra with complex kyphoscoliosis deformity. magnetic resonance imaging showed a stretching cord at D6-7 due to 92° angular kyphosis. The somatosensory evoked potential showed posterior column involvement. The VPS was placed for hydrocephalus at 4 months of age. The shunt remained functioned throughout childhood.

Methods.

He underwent posterior vertebral column resection and kyphosis correction surgery. Postoperative CNS function was normal. Neurology was status quo. After 20 hours, the boy appeared irritable, confused with a headache and repetitive vomiting (Glasgow coma scale: 7-8/15). Computed tomography brain showed dilated both ventricles with left shunt in situ. Immediate re-shunting was done from right side. The CNS status improved dramatically and regained consciousness. Neurology deteriorated to grade-0 with increased spasticity and further decreased sensation below D9. The spinal causes (hematoma, implant malposition, syrinx) were ruled out.

Results.

Delayed neurological recovery was seen at 6th week after shunt surgery. The Rapid motor march was observed and became independent ambulatory at 12th week. At 6 months, he improved up-to grade4 power with grade 2 spasticity which maintained at 2 years.

Conclusion.

VPS blockage caused a sudden hydrocephalus which increased CSF pressure within the spinal cord and decreased cord perfusion. Spinal cord at apex of deformity was vulnerable to ischemia which caused paraplegia.

Level of Evidence: 5

Staged hybrid repair of type II thoracoabdominal aneurysms

BACKGROUND

Open repair of type II thoracoabdominal aortic aneurysms (TAAAs) remains a challenging procedure. Staged procedures could decrease the incidence and severity of complications after complex aortic repair. In the present report, we have described a strategy using thoracic endovascular aortic repair (TEVAR) for proximal repair, followed by distal open repair.

METHODS

From 2014 to 2018, 14 patients had undergone TEVAR, followed by distal open repair, for type II TAAAs. All patients should have a suitable proximal landing zone according to the current guidelines. In cases of chronic dissection, false lumen embolization was performed to achieve total exclusion.

RESULTS

The mean patient age was 48 ± 15 years. Of the 14 patients, 5 had had Marfan syndrome (36%) and 6 had undergone previous aortic arch repair (43%). Ten patients had had a chronic dissection. The maximal aortic diameter was 73 ± 12 mm. The TEVAR technical success rate was 100%. The aortic length coverage was 211 ± 63 mm. The number of covered segmental arteries was 6 (range, 4-13). Two endoleaks were observed, one type Ib and one type II. The delay between TEVAR and open repair was 12 ± 8 weeks. Cerebrospinal fluid drainage was used in 13 patients. Six patients had undergone segmental artery reattachment during surgery. No spinal cord ischemic event was observed. One patient had died 5 weeks after open repair of multiple organ failure. During the 32 months of follow-up, no aortic-related deaths had occurred. No new aortic procedure was needed. The type Ib endoleak had resolved during open repair, and the type II TAAA had resolved spontaneously. The mean maximal thoracic aortic diameter had significantly decreased to 49 ± 8 mm (P < .0001). Aneurysmal shrinkage of ≥5 mm was observed in 13 patients (93%).

CONCLUSIONS

Staged hybrid repair of type II TAAAs appears to be efficient, with low morbidity and mortality rates. This technique could improve postoperative outcomes after open repair, and TEVAR might have a role in ischemic preconditioning to protect against spinal cord ischemia.

Epidural Corticosteroids, Lumbar Spinal Drainage, and Selective Hemodynamic Control for the Prevention of Spinal Cord Ischemia in Thoracoabdominal Endovascular Aortic Repair: A New Clinical Protocol

INTRODUCTION

In patients undergoing thoracoabdominal aorta repair, spinal cord ischemia (SCI) remains one of the most common and important complications resulting in transient paraparesis through to permanent flaccid paraplegia. In this manuscript, after a brief introduction to spinal cord ischemia complication and its prevention in thoracoabdominal endovascular aortic repair (TEVAR), we propose a new clinical protocol potentially able to prevent such complication.

METHODS

The proposed protocol suggests the use of high dosages of corticosteroids by epidural route, along with drainage of cerebrospinal fluid and controlled vascular hypertension, to reduce the incidence of SCI in TEVAR. Moreover, we paid particular attention to the control of the hemodynamic parameters to obtain adequate peripheral tissue perfusion (oxygen delivery), including in the spinal cord.

RESULTS

We applied this new protocol in 50 consecutive patients treated with TEVAR for thoracoabdominal aortic aneurysms (TAAs); 47 patients completed the procedure: 27 patients Crawford type I and 20 Crawford type II. Three patients died during surgery because of untreatable aneurysm rupture. The results show that in all patients there were no cases of SCI, after 5 days from TEVAR.

DISCUSSION

To the best of our knowledge, there are no clinical studies on the use of epidural corticosteroids in patients undergoing treatment of aortic syndrome (both in "open surgery" and endovascular aortic repair). This initial study on 50 consecutive patients has shown that the clinical protocol used could be of great interest to prevent one of the worse complications of TEVAR. Its limitations are the low number of patients studied till now, and the non-randomized protocol adopted. Further studies would be necessary.

CONCLUSION

Our experience and the results obtained with this new perioperative protocol with epidural corticosteroid and accurate hemodynamic control have been encouraging and it seems a valid proposal to be explored in future by well-structured prospective, randomized protocols.

CNB-001 reduces paraplegia in rabbits following spinal cord ischemia

Spinal cord ischemia associated with trauma and surgical procedures including thoraco-abdominal aortic aneurysm repair and thoracic endovascular aortic repair results in devastating clinical deficits in patients. Because spinal cord ischemia is inadequately treated, we studied the effects of [4-((1E)-2-(5-(4-hydroxy-3-methoxystyryl-)-1-phenyl-1H-pyrazoyl-3-yl) vinyl)-2-methoxy-phenol)] (CNB-001), a novel curcumin-based compound, in a rabbit SCI model. CNB-001 is known to inhibit human 5-lipoxygenase and 15-lipoxygenase and reduce the ischemia-induced inflammatory response. Moreover, CNB-001 can reduce the level of oxidative stress markers and potentiate brain-derived neurotrophic factor and brain-derived neurotrophic factor receptor signaling. The Tarlov scale and quantal analysis technique results revealed that CNB-001 administered as an intravenous dose (bolus) 30 minutes prior to spinal cord ischemia improved the behaviors of female New Zealand White rabbits. The improvements were similar to those produced by the uncompetitive N-methyl-D-aspartate receptor antagonist memantine. At 48 hours after aortic occlusion, there was a 42.7% increase (P < 0.05) in tolerated ischemia duration (n = 14) for rabbits treated with CNB-001 (n = 16), and a 72.3% increase for rabbits treated with the positive control memantine (P < 0.05) (n = 23) compared to vehicle-treated ischemic rabbits (n = 22). CNB-001 is a potential important novel treatment for spinal cord ischemia induced by aortic occlusion. All experiments were approved by the CSMC Institutional Animal Care and Use Committee (IACUC #4311) on November 1, 2012.

The attenuation of neurological injury from the use of simvastatin after spinal cord ischemia-reperfusion injury in rats

Background

Spinal cord ischemic injury remains a serious complication of open surgical and endovascular aortic procedures. Simvastatin has been reported to be associated with neuroprotective effect after spinal cord ischemia-reperfusion (IR) injury. The aim of this study was to determine the therapeutic efficacy of starting simvastatin after spinal cord IR injury in a rat model.

Methods

In adult Sprague-Dawley rats, spinal cord ischemia was induced using a balloon-tipped catheter placed in the descending thoracic aorta. The animals were then randomly divided into 4 groups: group A (control); group B (0.5 mg/kg simvastatin); group C (1 mg/kg simvastatin); and group D (10 mg/kg simvastatin). Simvastatin was administered orally upon reperfusion for 5 days. Neurological function of the hind limbs was evaluated for 7 days after reperfusion and recorded using a motor deficit score (MDS) (0: normal, 5: complete paraplegia). The number of normal motor neurons within the anterior horns of the spinal cord was counted after final MDS evaluation. Then, the spinal cord was harvested for histopathological examination.

Results

Group D showed a significantly lower MDS than the other groups at post-reperfusion day 1 and this trend was sustained throughout the study period. Additionally, a greater number of normal motor neurons was observed in group D than in other groups (group D 21.2 [3.2] vs. group A: 15.8 [4.2]; group B 15.4 [3.4]; and group C 15.5 [3.7]; P = 0.002).

Conclusions

The results of the current study suggest that 10 mg/kg can significantly improve neurologic outcome by attenuating neurologic injury and restoring normal motor neurons after spinal cord IR injury.

Protection from spinal cord ischemia-reperfusion damage with alpha-lipoic acid preconditioning in an animal model

Background

This study aims to investigate whether preconditioning with alpha-lipoic acid has any protective effect in neuronal damage in an experimental spinal cord ischemia-reperfusion injury model.

Methods

Eighteen adult male New Zealand rabbits (2.4-3.5 kg) were equally divided into sham, control and treatment groups. The abdominal aorta was occluded for 30 min proximally 1 cm below the renal artery and distally 1 cm above the bifurcation using aneurysm clips in control and treatment groups. Treatment group received intraperitoneal 100 mg/kg lipoic acid 20 min before aortic cross-clamping. The animals were sacrificed 48 hours after the operation and spinal cord segments between L2 and L5 were removed for biochemical and histopathological analysis. Levels of glutathione, malondialdehyde, total nitrate/nitrite, advanced oxidation protein products, catalase, superoxide dismutase, and glutathione peroxidase were examined in spinal cord.

Results

Preconditioning with alpha-lipoic acid demonstrated significantly favorable effects in all measured parameters of oxidative stress. Histopathological evaluation of the tissues also demonstrated significantly decreased neuronal degeneration, axonal damage, and microglial and astrocytic infiltration in the treatment group compared to the control group.

Conclusion

The results of this study indicate that alpha-lipoic acid administration before aortic cross-clamping has significant neuroprotective effect on spinal cord injury in rabbits.

Thoracic Endovascular Aneurysm Sealing of a Complex Thoracoabdominal Aneurysm

PURPOSE

To report bailout treatment of a thoracoabdominal aortic aneurysm using a single Nellix stent and parallel stents.

CASE REPORT

A 74-year-old man with multiple comorbidities and a previous fenestrated Anaconda stent-graft for a 60-mm juxtarenal aneurysm was diagnosed with a type IV thoracoabdominal aneurysm on the 2-year computed tomography angiography (CTA) scans. The imaging showed >10-mm downward migration of the proximal Anaconda stent with a massive type Ia endoleak and aneurysmal evolution of the distal descending thoracic aorta; the superior mesenteric artery (SMA) and renal artery covered stents were patent and intact. Open conversion or a second custom-made endograft was not feasible. A plan was devised to use off-the-shelf materials, including the deployment of a single Nellix stent extending from the descending thoracic aorta into the stented area of the fenestrated endograft, with parallel chimney stent-grafts into the SMA and right renal artery; the left renal artery was treated with a bare stent in a periscope configuration. Transient paraparesis was resolved with cerebrospinal fluid drainage. At 6-month CTA, ongoing aneurysm exclusion with patent SMA and renal arteries was confirmed.

CONCLUSION

Thoracic endovascular aneurysm sealing with visceral and renal stenting seems to be a feasible bailout alternative treatment for urgent, complex cases without reconstruction options.

Simultaneous Endovascular Repair for Thoracic and Abdominal Aortic Pathologies: Early and Midterm Results

BACKGROUND

To analyze information from a single clinical center, evaluating early and midterm results of simultaneous thoracic endovascular aortic repair (TEVAR) and endovascular aneurysm repair (EVAR) for coexisting thoracic and abdominal aortic pathologies.

METHODS

From January 2005 to December 2014, 13 patients (8 men, 5 women; mean age, 75.3 years; range, 69-82 years) with concomitant thoracic and abdominal aortic disease (aneurysms, type B dissection, penetrating aortic ulcers) were treated with simultaneous TEVAR and EVAR. All patients had significant comorbidities. No preoperative cerebrospinal fluid drainage was performed. The follow-up rate was 100% during a period of 36 months (range, 1-60 months).

RESULTS

Technical success was achieved in all 13 patients, including deliberate partial or total coverage of the left subclavian artery in 3 patients, coverage of both internal iliac arteries in 1 patient, and coverage of left subclavian artery and unilateral internal iliac artery in 1 patient. The average procedural time was 160 min (range, 120-200 min). Mean blood loss was 140 mL (range, 100-250 mL). Four types of commercially available stent grafts (SGs) were used. The lengths of the thoracic SGs were 150-200 cm. Overall survival was 92.3% at 1- and 3-year follow-ups. None of the patients developed stroke or paralysis. The average hospital stay was 9 days (range, 7-12 days). No patients developed endoleak or SG migration.

CONCLUSIONS

Combined TEVAR and EVAR can be performed successfully with minimal morbidity and mortality. When anatomically feasible, simultaneous TEVAR and EVAR is a viable alternative to staged or hybrid repair.

Inflammogenesis of Secondary Spinal Cord Injury

Spinal cord injury (SCI) and spinal infarction lead to neurological complications and eventually to paraplegia or quadriplegia. These extremely debilitating conditions are major contributors to morbidity. Our understanding of SCI has certainly increased during the last decade, but remains far from clear. SCI consists of two defined phases: the initial impact causes primary injury, which is followed by a prolonged secondary injury consisting of evolving sub-phases that may last for years. The underlying pathophysiological mechanisms driving this condition are complex. Derangement of the vasculature is a notable feature of the pathology of SCI. In particular, an important component of SCI is the ischemia-reperfusion injury (IRI) that leads to endothelial dysfunction and changes in vascular permeability. Indeed, together with endothelial cell damage and failure in homeostasis, ischemia reperfusion injury triggers full-blown inflammatory cascades arising from activation of residential innate immune cells (microglia and astrocytes) and infiltrating leukocytes (neutrophils and macrophages). These inflammatory cells release neurotoxins (proinflammatory cytokines and chemokines, free radicals, excitotoxic amino acids, nitric oxide (NO)), all of which partake in axonal and neuronal deficit. Therefore, our review considers the recent advances in SCI mechanisms, whereby it becomes clear that SCI is a heterogeneous condition. Hence, this leads towards evidence of a restorative approach based on monotherapy with multiple targets or combinatorial treatment. Moreover, from evaluation of the existing literature, it appears that there is an urgent requirement for multi-centered, randomized trials for a large patient population. These clinical studies would offer an opportunity in stratifying SCI patients at high risk and selecting appropriate, optimal therapeutic regimens for personalized medicine.

Extended Motor Evoked Potentials Monitoring Helps Prevent Delayed Paraplegia After Aortic Surgery

OBJECTIVE

Motor evoked potentials (MEPs) monitoring can promptly detect spinal cord ischemia (SCI) from aortic clamping during open thoracoabdominal aneurysm repair (OTAAR) with distal aortic perfusion (DAP) and thus help decrease the risk of immediate postoperative SCI (IP-SCI). However, neither stable MEPs during aortic clamp interval (ACI) nor absence of IP-SCI eliminate the possibility of delayed postoperative SCI (DP-SCI). We hypothesized that extension of MEPs monitoring beyond ACI can also help decrease the risk of DP-SCI.

METHODS

We identified 150 consecutive patients at our institution between April 2005 and October 2014 who underwent OTAAR with DAP and MEPs monitoring and had no IP-SCI. Using logistic regression analysis, we studied the independent effect of extended MEPs monitoring on the risk of developing DP-SCI. We used a propensity score analysis to adjust for potential confounders, such as poorly controlled hypertension, previous aneurysm surgery, splenectomy, acute aortic dissection, aneurysm type, older age, and history of diabetes and smoking.

RESULTS

From the 150 patients, 129 (86%) remained neurologically intact whereas 21 (14%) developed DP-SCI. Nineteen of these twenty-one patients (90%) had no extended monitoring. Fifty-seven of fifty-nine (97%) patients who benefited from extended monitoring had no DP-SCI (p = 0.003). Extended MEPs monitoring was independently associated with decreased risk of DP-SCI (odds ratio = 0.14; 95% confidence interval: 0.03, 0.65; p = 0.01).

INTERPRETATION

MEPs detect the lowest systemic blood pressure that ensures appropriate spinal cord perfusion in the postoperative period. Thus, they inform the hemodynamic management of patients post-OTAAR, particularly in the absence of a reliable neurological exam.

Stent graft types for endovascular repair of thoracic aortic aneurysms

BACKGROUND

The UK prevalence of thoracic aneurysm is estimated at 10.4 per 100,000 person-years. Progressive and unpredictable enlargement can lead to rupture. Endovascular repair of thoracic aortic aneurysms involves a stent graft system being introduced via the femoral artery and manipulated within the aorta under radiological guidance. Following endograft deployment, a seal is formed at the proximal and distal landing zones to exclude the aneurysm sac from the circulation. With the increasing popularity of endovascular repair there has been an increase in the number of commercially available stent graft designs on the market. This is an update of the review first published in 2013.

OBJECTIVES

This review aimed to assess the different stent graft types for endovascular repair of thoracic aortic aneurysms.

SEARCH METHODS

The Cochrane Vascular Group Trials Search Co-ordinator (TSC) searched the Specialised Register (last searched February 2015) and the Cochrane Register of Studies CENTRAL (2015, Issue 1). Trial databases were searched by the TSC for details of ongoing and unpublished studies.

SELECTION CRITERIA

All published and unpublished randomised controlled trials (RCTs) of stent graft types in the repair of thoracic aortic aneurysms were sought without language restriction.

DATA COLLECTION AND ANALYSIS

Data collection and analysis was conducted in accordance with the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

No studies were identified that met the inclusion criteria. It was not possible to assess the quality of the evidence in the absence of studies eligible for inclusion in the review.

AUTHORS' CONCLUSIONS

Unfortunately, no data exist regarding direct comparisons of the performance of different stent graft types. High quality RCTs evaluating stent graft types in thoracic endovascular aneurysm repair are required.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[Successful endovascular treatment of thoracic aortic aneurysm secondary to infection of the umbilical artery catheter in preterm infants]

Aortic aneurysms (AA) in the paediatric population are uncommon. The use of umbilical catheters in neonates has been associated with infections and, on some occasions, the formation of aortic aneurysms. The surgical repair of these aneurysms is one type of treatment; however, percutaneous intervention with stents could provide an alternative treatment route, with fewer complications. The aim of this report is to present the therapeutic scope of a hybrid procedure, in which the combined surgical and percutaneous technique offers a less invasive alternative to open surgery for the repair of aortic aneurysms or their main branches.

CLINICAL CASE

The case concerns a pre-term newborn of 30 weeks weighing 1,335 g. An umbilical catheter was introduced, which was withdrawn at 14 days due to an infection. It developed as Staphylococcus aureus with sepsis. The echocardiogram and Angio-CT confirmed AA, which were managed using a hybrid procedure of surgery and the endovascular implantation of 2 coated stents (Atrium V12 XR Medical Corp, Hudson, NH). The post-procedure clinical follow-ups, including abdominal echo-tomography, confirmed the success of the treatment.

CONCLUSION

The endovascular aortic aneurysm repair procedure in premature newborns may be considered when deciding treatment of this disease, and could avoid the risks associated with open surgery. However, follow-up and monitoring is required while the patient grows up, due to the possibility that the implanted stents require re-dilating. The outcomes of neonatal endovascular procedures in the future are unknown.

Neuroprotective effect of atorvastatin in spinal cord ischemia-reperfusion injury

OBJECTIVES

Prevention of the development of paraplegia during the repair of the damage caused by descending thoracic and thoracoabdominal aneurysms remains an important issue. Therefore, we investigated the protective effect of atorvastatin on ischemia-induced spinal cord injury in a rabbit model.

METHOD

Thirty-two rabbits were divided into the following four equally sized groups: group I (control), group II (ischemia-reperfusion), group III (atorvastatin treatment) and group IV (atorvastatin withdrawal). Spinal cord ischemia was induced by clamping the aorta both below the left renal artery and above the iliac bifurcation. Seventy-two hours postoperatively, the motor function of the lower limbs of each animal was evaluated according to the Tarlov score. Spinal cord and blood samples were obtained for histopathological and biochemical analyses.

RESULTS

All of the rabbits in group II exhibited severe neurological deficits. Atorvastatin treatment (groups III and IV) significantly reduced the level of motor dysfunction. No significant differences were observed between the motor function scores of groups III and IV at the evaluated time points. Light microscopic examination of spinal cord tissue samples obtained at the 72nd hour of reperfusion indicated greater tissue preservation in groups III and IV than in group II.

CONCLUSION

This study demonstrates the considerable neuroprotective effect of atorvastatin on the neurological, biochemical and histopathological status of rabbits with ischemia-induced spinal cord injury. Moreover, the acute withdrawal of atorvastatin therapy following the induction of spinal cord ischemia did not increase the neuronal damage in this rabbit model.

Predictors of paraplegia with current thoracoabdominal aortic aneurysm repair

Background

Although the results of surgical repair of thoracoabdominal aortic aneurysm continue to improve, the incidence of paraplegia remains within a wide range depending on each institution. The purpose of this study was to find predictors of paraplegia following thoracoabdominal aortic aneurysm repair in our institute, using the current spinal cord protection strategies.

Methods

From January 2007 to December 2011, 200 consecutive patients underwent thoracoabdominal aortic aneurysm repair. Of these, 24 (12%) had Crawford extent I repair, 82 (41%) had extent II, 51 (25.5%) had extent III, 10 (5%) had extent IV, and 33 (16.5%) had extent V (modified by Safi). Aortic dissection was present in 101 (50.5%) patients. Adjuncts used during the procedures included left heart bypass in all patients, cerebrospinal fluid drainage in 164 (82%), and intercostal artery reimplantation in 76 (38%).

Results

There were 20 (10%) hospital deaths including 6 (3%) within 30 days; hospital mortality was 8.8% in elective operations. Postoperative complications included paraplegia in 17 (8.5%) patients, stroke in 5 (2.5%), and acute renal failure requiring dialysis in 5 (2.5%). Logistic regression analysis revealed that significant factors for the development of paraplegia were preoperative hypotension ( p = 0.005, odds ratio 18.5), intraoperative hypotension ( p = 0.001, odds ratio 77.6), and an open distal anastomosis technique ( p = 0.012, odds ratio 4.6).

Conclusions

The predictors of postoperative paraplegia in our institution were perioperative hypotension and an open distal anastomosis technique. Avoidance of these risk factors might diminish the incidence of postoperative paraplegia.

How to prevent spinal cord injury during endovascular repair of thoracic aortic disease

The incidence of spinal cord injury in thoracic endovascular aortic repair (TEVAR) has been 3-5 % from recent major papers where sacrifice of the critical intercostal arteries is inevitable by a stent graft. Hemodynamic stability, which depends on a network of blood vessels around the cord is most important not only during but also after stent-graft deployment. High risk factors of spinal cord injury during endovascular aortic repair are (1) coverage of the left subclavian artery, (2) extensive coverage of long segments of the thoracic aorta, (3) prior downstream aortic repair, (4) compromising important intercostal (T8-L1), vertebral, pelvic and hypogastric collaterals, and (5) shaggy aorta. Preoperative, intraoperative, and postoperative managements have been required to prevent spinal cord injury with TEVAR. For imaging assessment of blood supply to spinal cord including Adamkiewicz artery, prophylactic cerebrospinal fluid drainage is mandatory, and monitoring motor-evoked potential is recommended for high risk factors of spinal cord injury. Mean arterial pressure should be maintained over 90 mmHg after stent-graft placement for a while to prevent delayed spinal cord ischemia in high-risk patients of spinal cord ischemia. Finally, because spinal cord injury during TEVAR is not rare and negligible, perioperative care during TEVAR should be strictly performed according to the protocol proposed by each cardiovascular team.

Cholesterol crystal embolism and delayed-onset paraplegia after thoracoabdominal aneurysm repair

Postoperative paraplegia caused by ischemic injury of the spinal cord is the most disabling complication of thoracoabdominal surgery. We described the case of a 75-year-old patient who underwent a thoracoabdominal aneurysm repair (type IV aneurysm according to Crawford classification). The aorta clamping was done at the T11 level without specific medullary protection. The first postoperative week was uneventful. On the postoperative day 8, renal failure and livedo of the left lower limb occurred together with complete hypotonic paraplegia and severe sepsis. Exploratory laparotomy revealed a gangrenous cholecystitis, and skin biopsies showed cholesterol crystals embolisms in the hypodermis small arteries. The patient died on the postoperative day 28 from a multiorgan failure. In this case, paraplegia was due to cholesterol crystal embolism, which migrated secondarily after aortic clamping.

Tat-DJ-1 protects neurons from ischemic damage in the ventral horn of rabbit spinal cord via increasing antioxidant levels

The DJ-1 gene is highly conserved in diverse species and DJ-1 is known as an anti-oxidative stress factor. In this study, we investigated the neuroprotective effects of DJ-1 against ischemic damage in the rabbit spinal cord. Tat-DJ-1 fusion proteins were constructed to facilitate the penetration of DJ-1 protein into the neurons. Tat-1-DJ-1 fusion protein was administered to the rabbit 30 min after ischemia/reperfusion, and transient spinal cord ischemia was induced by occlusion of the aorta at the subrenal region for 15 min. The administration of Tat-DJ-1 significantly improved the Tarlov score compared to that in the Tat (vehicle)-treated group at 24, 48 and 72 h after ischemia/reperfusion. At 72 h after ischemia/reperfusion, the number of cresyl violet-positive neurons was significantly increased in the Tat-DJ-1-treated group compared to that in the vehicle-treated group. Lipid peroxidation as judged from the malondialdehyde levels was significantly decreased in the Tat-DJ-1-treated group compared to that in the vehicle-treated group. In contrast, superoxide dismutase and catalase levels were significantly increased in the Tat-DJ-1-treated group compared to that in the vehicle-treated group. This result suggests that DJ-1 protects neurons from ischemic damage in the ventral horn of the spinal cord via its antioxidant effects.

Stent graft types for endovascular repair of thoracic aortic aneurysms

BACKGROUND

The UK prevalence of thoracic aneurysm is estimated at 10.4 per 100,000 person-years. Progressive and unpredictable enlargement can lead to rupture. Endovascular repair of thoracic aortic aneurysms involves a stent graft system being introduced via the femoral artery and manipulated within the aorta under radiological guidance. Following endograft deployment, a seal is formed at the proximal and distal landing zones to exclude the aneurysm sac from the circulation. With the increasing popularity of endovascular repair there has been an increase in the number of commercially available stent graft designs on the market.

OBJECTIVES

This review aimed to assess the different stent graft types for endovascular repair of thoracic aortic aneurysms.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator (TSC) searched the Specialised Register (last searched November 2012) and CENTRAL (2012, Issue 11). Trial databases were searched by the TSC for details of ongoing and unpublished studies.

SELECTION CRITERIA

All published and unpublished randomised controlled trials (RCTs) of stent graft types in the repair of thoracic aortic aneurysms were sought without language restriction.

DATA COLLECTION AND ANALYSIS

Data collection and analysis was conducted in accordance with the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

No studies were identified that met the inclusion criteria.

AUTHORS' CONCLUSIONS

Unfortunately, no data exist regarding direct comparisons of the performance of different stent graft types. Therefore, this review cannot recommend guidance to clinicians in their selection of stent graft types. High quality RCTs evaluating stent graft types in thoracic endovascular aneurysm repair are required.

The pressure distribution of cerebrospinal fluid responds to residual compression and decompression in an animal model of acute spinal cord injury

STUDY DESIGN

In vivo large animal (pig) model study of cerebrospinal fluid (CSF) pressures after acute experimental spinal cord injury (SCI).

OBJECTIVE

To determine how the CSF pressure (CSFP) and CSF pulse pressure amplitude (CSFPPA) cranial and caudal to the injury site change after an acute SCI with subsequent thecal occlusion and decompression.

SUMMARY OF BACKGROUND DATA

Lowering intrathecal pressure via CSF drainage is currently instituted to prevent ischemia-induced SCI during thoracoabdominal aortic aneurysm surgery and was recently investigated as a potential intervention for acute traumatic SCI. However, in SCI patients, persistent extradural compression commonly occludes the subarachnoid space. This may generate a CSFP differential across the injury site, which cannot be appreciated with lumbar catheter pressure measurements.

METHODS

Anesthetized pigs were subjected to an acute contusive SCI at T11 and 8 hours of sustained compression (n = 12), or sham surgery (n = 2). CSFP was measured cranial and caudal to the injury site, using miniature pressure transducers, during compression and for 6 hours after decompression.

RESULTS

The cranial-caudal CSFP differential increased (mean, 0.39 mm Hg/h), predominantly due to increased cranial pressure. On decompression, cranial CSFP decreased (mean, -1.16 mm Hg) and caudal CSFP increased (mean, 0.65 mm Hg). The CSFP differential did not change significantly after decompression. Cranial CSFPPA was greater than caudal CSFPPA, but this differential did not change during compression. On decompression, the caudal CSFPPA increased in some but not all animals.

CONCLUSION

Although extradural compression exists at the site of injury, lumbar CSFP may not accurately indicate CSFP cranial to the injury. Decompression may provide immediate, though perhaps partial, resolution of the pressure differential. CSFPPA was not a consistent indicator of decompression in this animal model. These findings may have implications for the design of future clinical protocols in which CSFP is monitored after acute SCI.

Subacute anterior spinal cord ischemia with lower limb monoplegia: a clinical dilemma and challenging scenario

A 70-year-old woman presented with crescendo right lower limb monoplegia. Magnetic resonance imaging depicted anterior spinal artery syndrome with an 8.5 cm Crawford type II thoracoabdominal aortic aneurysm (TAAA). A staged hybrid procedure was performed, following which she had total exclusion of her TAAA and full resolution of her monoplegia. Clinical presentations of TAAAs can be diverse and require detailed clinical knowledge and lateral thinking to unearth unorthodox presentations. This erratic presentation of a TAAA with anterior spinal artery syndrome outlines particular challenges with management and portrays the need for tailored utilization of contemporary techniques to deal with the growing complexity of TAAAs.

Neuroprotective effects of allicin on spinal cord ischemia-reperfusion injury via improvement of mitochondrial function in rabbits

Allicin, the active substance of garlic, exerts a broad spectrum of pharmacological activities and is considered to have potential therapeutic applications. The present study was designed to investigate the beneficial effects of allicin against spinal cord ischemia-reperfusion (I/R) injury and its associated mechanisms. Male New Zealand white rabbits were pretreated with allicin (1, 10 and 50 mg/kg) for two weeks, and exposed to infrarenal aortic occlusion-induced spinal cord I/R injury. We found that allicin significantly reduced the volume of the spinal cord infarctions, improved the histopathologic features and increased the number of motor neurons in a dose-dependent manner. This protection was associated with an improvement in neurological function, which was measured by the hind-limb motor function scores. Furthermore, allicin also significantly suppressed the accumulations of protein and lipid peroxidation products, and increased the activities of endogenous antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX) and glutathione S-transferase (GST). In addition, allicin treatment preserved the function of mitochondria respiratory chain complexes and inhibited the production of ROS and the release of mitochondrial cytochrome c in the spinal cord of this model. Collectively, these findings demonstrated that allicin exerts neuroprotection against spinal cord I/R injury in rabbits, which may be associated with the improvement of mitochondrial function.

Distal aortic perfusion during thoracoabdominal aneurysm repair for prevention of paraplegia

BACKGROUND

During thoracoabdominal aortic aneurysm (TAAA) surgery, decreased spinal cord perfusion can result in neurological deficits such as paraplegia and paraparesis. Distal aortic perfusion, alone or in combination with other adjuncts, may counter the decrease in spinal cord perfusion and hence reduce the risk of spinal cord injury.

OBJECTIVES

To determine the effectiveness of distal aortic perfusion with or without other adjuncts against other adjuncts without use of distal perfusion during TAAA surgery in reducing the risk of developing paraplegia and paraparesis.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Specialised Register (last searched 5 January 2012) and CENTRAL (Issue 4, 2011) were searched for publications describing randomised controlled trials of distal aortic perfusion during thoracoabdominal aortic aneurysm surgery. Reference lists of relevant studies were checked.

SELECTION CRITERIA

Randomised or quasi-randomised controlled clinical trials of distal aortic perfusion during TAAA repair.

DATA COLLECTION AND ANALYSIS

Studies identified for potential inclusion were independently assessed for inclusion by at least two authors, with excluded trials arbitrated by the third author.

MAIN RESULTS

There were no randomised controlled trials identified.

AUTHORS' CONCLUSIONS

Currently, there are no randomised controlled trials to support the role of distal aortic perfusion in TAAA surgery for prevention of neurological injury. However, randomised controlled trials are not always feasible based on ethical grounds. Observational studies suggest that distal aortic perfusion alone or in combination with other adjuncts, that is cerebrospinal fluid (CSF) drainage, reduces the rate of neurologic deficit across all types of TAAA; in particular making a striking difference in the rate of neurologic deficit following type II TAAA repair. In the absence of randomised controlled trials, we recommend a standardised approach to reporting through registry studies to strengthen the evidence base for distal aortic perfusion.

Hybrid procedure in a patient with symptomatic thoraco-abdominal aneurysm and prior abdominal aortic reconstruction - case report

Open repair of thoracoabdominal aortic aneurysm is connected with high mortality and morbidity. On the other hand, endovascular treatment of thoraco-abdominal aneurysms, which started 10 years ago, reduced perioperative mortality and morbidity. However, it results in a high level of late complications. It seems that an interesting solution to the problem is a hybrid procedure, which allows late complications to be reduced with acceptable levels of operative mortality and morbidity. This case report presents the use of a hybrid procedure in treatment of symptomatic thoraco-abdominal aneurysm in a patient with prior abdominal aortic reconstruction. In the first stage the patient underwent open revascularization of visceral vessels of the aorta. One week later a thoraco-abdominal stent-graft was implanted. The perioperative and postoperative period was uncomplicated. Two months after the second intervention the patient returned to work. Control imaging conducted 30 and 90 days after the procedure confirmed patency of all revascularized vessels and did not reveal any graft-related complications. The hybrid procedure seems to be an interesting alternative for open and endovascular repair of thoraco-abdominal aneurysms because it combines the advantages of open and endovascular repair. It also gives an opportunity to perform the procedure within a reasonable period of time from diagnosis of symptomatic thoraco-abdominal aneurysm.

New method for absolute spinal cord ischemia protection in rabbits

OBJECTIVE

This study aims to establish a superior procedure to prevent spinal cord damage after severe spinal cord ischemia during aortic surgery. We examined the synergistic effect of topical hypothermia of the spinal cord combined with radical scavenger infusion into the clamped segment of the aorta to prevent spinal cord damage in an animal model.

METHODS

Spinal cord ischemia was induced in rabbits by clamping the aorta between the renal artery and aortic bifurcation for 30 minutes. Rabbits were divided into four groups of 16 each: group I, sham-operated; group II, edaravone (6 mL, 4°C, 1 mg/kg); group III, saline (6 mL, 4°C) with transvertebral cooling pads; group IV, edaravone (6 mL, 4°C, 1 mg/kg) and transvertebral cooling pads. Solutions were injected into the clamped segment of the aorta. Postoperative assessments included the Tarlov score, spinal cord histopathology, and measurement of malondialdehyde levels in the spinal cord tissue.

RESULTS

At 48 hours after reperfusion, the mean Tarlov scores in groups I, II, III, and IV were 4.0, 1.5, 1.9, and 4.0, respectively. The mean number of normal motor neurons was significantly higher in groups I (54.1) and IV (53.7) than in groups II (32.8) and III (36.3; P < .001). The mean malondialdehyde level in groups I (19.8 nmol/mL) and IV (22.6 nmol/mL) was significantly lower than in groups II (64.8 nmol/mL) and III (60.9 nmol/mL; P < .001). At 168 hours after reperfusion, the mean Tarlov scores in groups I, II, III, and IV were 4.0, 1.1, 1.3, and 4.0, respectively. The mean number of normal motor neurons was significantly higher in groups I (52.9) and IV (50.8) than in groups II (22.4) and III (25.9; P < .001). The mean malondialdehyde level in groups I (20.7 nmol/mL) and IV (23.4 nmol/mL) was significantly lower than in groups II (68.9 nmol/mL) and III (61.6 nmol/mL; P < .001).

CONCLUSION

In a rabbit model with aortic clamping up to 30 minutes, which consistently produces complete paraplegia in rabbits, spinal cord damage was partially reduced by topical cooling with transvertebral cooling pads or the injection of edaravone into the clamped segment of aorta, but was more effectively protected by a combined use of these two strategies.