Perioperative cerebrospinal fluid drainage for the prevention of spinal ischemia after endovascular aortic repair

Endovascular treatment of thoracic and thoracoabdominal aortic diseases is accompanied by a risk of spinal ischemia in 1-19% of patients, depending on the entity and extent of the disease. The use of perioperative drainage of cerebrospinal fluid is one of the invasive measures to reduce the occurrence of this severe complication. This article reviews the incidence of spinal ischemia, its risk factors, the evidence for carrying out cerebrospinal fluid drainage and its modern use by means of an automated, pressure controlled system (LiquoGuard®7).

Neurologic complications of polytrauma

Neurologic complications in polytrauma can be classified by etiology and clinical manifestations: neurovascular, delirium, and spinal or neuromuscular problems. Neurovascular complications include ischemic strokes, intracranial hemorrhage, or the development of traumatic arteriovenous fistulae. Delirium and encephalopathy have a reported incidence of 67-92% in mechanically ventilated polytrauma patients. Causes include sedation, analgesia/pain, medications, sleep deprivation, postoperative state, toxic ingestions, withdrawal syndromes, organ system dysfunction, electrolyte/metabolic abnormalities, and infections. Rapid identification and treatment of the underlying cause are imperative. Benzodiazepines increase the risk of delirium, and alternative agents are preferred sedatives. Pharmacologic treatment of agitated delirium can be achieved with antipsychotics. Nonconvulsive seizures and status epilepticus are not uncommon in surgical/trauma intensive care unit (ICU) patients, require electroencephalography for diagnosis, and need timely management. Spinal cord ischemia is a known complication in patients with traumatic aortic dissections or blunt aortic injury requiring surgery. Thoracic endovascular aortic repair has reduced the paralysis rate. Neuromuscular complications include nerve and plexus injuries, and ICU-acquired weakness. In polytrauma, the neurologic examination is often confounded by pain, sedation, mechanical ventilation, and distracting injuries. Regular sedation pauses for examination and maintaining a high index of suspicion for neurologic complications are warranted, particularly because early diagnosis and management can improve outcomes.

Nicotinamide Adenine Dinucleotide Protects against Spinal Cord Ischemia Reperfusion Injury-Induced Apoptosis by Blocking Autophagy

The role of autophagy, neuroprotective mechanisms of nicotinamide adenine dinucleotide (NAD⁺), and their relationship in spinal cord ischemic reperfusion injury (SCIR) was assessed. Forty-eight Sprague-Dawley rats were divided into four groups: sham, ischemia reperfusion (I/R), 10 mg/kg NAD⁺, and 75 mg/kg NAD⁺. Western blotting, immunofluorescence, and immunohistochemistry were used to assess autophagy and apoptosis. Basso, Beattie, and Bresnahan (BBB) scores were used to assess neurological function. Expression levels of Beclin-1, Atg12-Atg5, LC3B-II, cleaved caspase 3, and Bax were upregulated in the I/R group and downregulated in the 75 mg/kg NAD⁺ group; p-mTOR, p-AKT, p62, and Bcl-2 were downregulated in the I/R group and upregulated in the 75 mg/kg NAD⁺ group. Numbers of LC3B-positive, caspase 3-positive, Bax-positive, and TUNEL-positive cells were significantly increased in the I/R group and decreased in the 75 mg/kg NAD⁺ group. The mean integrated option density of Bax increased and that of Nissl decreased in the I/R group, and it decreased and increased, respectively, in the 75 mg/kg NAD⁺ group. BBB scores significantly increased in the 75 mg/kg NAD⁺ group relative to the I/R group. No difference was observed between I/R and 10 mg/kg NAD⁺ groups for these indicators. Therefore, excessive and sustained autophagy aggravates SCIR; administration of NAD⁺ alleviates injury.

Endovascular repair of residual intimal tear or distal new entry after frozen elephant trunk for type A aortic dissection

BACKGROUND

In patients with type A dissection, residual dissection and new distal entry tears following the frozen elephant trunk (FET) procedure adversely affect long-term prognosis. Management include open and endovascular repair, while clinical experience is limited. We evaluate the efficacy of thoracic endovascular aortic repair (TEVAR) in management of residual intimal tear or distal new entry tear following FET in patients with type A aortic dissection (TAAD).

METHODS

Between May 2003 and April 2013, we performed FET and total arch replacement for 1,003 patients with TAAD. Among these, 23 patients (2.3%) required TEVAR for distal new entry (n=2) or residual intimal tear (n=21) at a mean of 2.0±1.6 years after FET. Mean age was 50.1±11.5 years. Marfan syndrome was seen in 2 patients (8.7%).

RESULTS

Procedural success was 100%. The distal landing zone was above the 11th thoracic vertebra (T11) in 86.9% (20/23). Neither death nor any paraplegia or stroke occurred early after TEVAR. Follow-up was complete in 100% averaging 2.8±1.7 years (0.3-6.4). One non-Marfan patient died of distal aortic rupture at 4 months after TEVAR. No late stroke or paraplegia occurred. Survival was 95.7% (95% CI, 72.9-99.4%) at 3 and 5 years, respectively. CTA detected false lumen obliteration by thrombus around the endograft in the descending aorta in 91.3% (21/23) of patients.

CONCLUSIONS

These early and midterm outcomes show the efficacy of TEVAR in obliterating the residual intimal tear or distal new entry after FET in patients with TAAD. TEVAR may be an alternative approach to distal new entry or residual intimal tear following FET for patients with TAAD.

A two-stage hybrid approach for complex aortic coarctation combined with ascending-descending aorta dilatation and concomitant aortic valve regurgitation

We present a case of aortic coarctation combined with ascending-descending aorta dilatation and concomitant aortic valve regurgitation. The technique involved using endovascular stenting, a two-stage balloon dilation procedure post-stent implantation and a Bentall procedure.

Measurements After Image Post-processing Are More Precise in the Morphometric Assessment of Thoracic Aortic Aneurysms: An Intermodal and Intra-observer Evaluation

OBJECTIVES

Precise pre-procedural anatomical analysis of aneurysmal anatomy is essential for successful thoracic endovascular aortic repair (TEVAR). Since surgeons and radiologists have to perform multiple measurements in the same patient, high intra-observer reliability of any imaging method is mandatory. Commercially available three dimensional (3D) post-processing techniques are expected to be superior to conventional two dimensional multiplanar reconstructions (MPRs) derived from computed tomography angiograms (CTAs). However, few data exist to support this view. This study aims to evaluate the intermodal and intra-observer differences using 3D software (3surgery) in descending thoracic aortic aneurysms (dTAAs).

METHODS

Pre-operative CTAs (performed between 2004 and 2010) of 30 dTAAs (mean maximum diameter 61.4 ± 13 mm) were assessed by three independent investigators with different experience in the measurement of aortic pathologies. Intra-observer reliability and intermodal differences (3D vs. 2D) were investigated using pre-specified measurement points (distances of total length, maximum diameter, proximal and distal landing zones). Statistical analyses were performed using the Bland-Altman method and a mixed regression model.

RESULTS

Intermodal comparison showed that 2D measurements significantly underestimate the measured distances (maximum diameter 3.7 mm [95% CI -5.3 to -2.1] and landing zone maximum 1.4 mm [95% CI -2.0 to -0.2] shorter with 2D, p < .05). In almost all 3D measurements, all investigators showed lower variability comparing the intra-observer differences, most notably in the measuring point total length (reduction of the SD up to 7.9 mm).

CONCLUSIONS

These data show that both techniques led to significant measurement disparity. This occurs especially at the point of indication (maximum diameter) and the total length of the aneurysm (important for correct stent graft selection). But overall the variability is reduced with the 3D technique, which also tends to measure greater distances. The use of post-processing software therefore leads to more precise device selection for TEVAR in TAA.

Hybrid two-stage repair of thoracoabdominal aortic aneurysm

Thoracoabdominal aortic aneurysm is a challenging disease that often requires an invasive surgical repair. Recently, a less invasive hybrid approach has been proposed to improve postoperative outcomes in high-risk patients. It consists of an open first stage where arterial visceral rerouting is obtained, using a vascular graft followed by a second stage where the remaining thoracoabdominal aorta is covered with a stent graft. Initial results using this approach seem promising. Here, we sought to describe the hybrid two-stage technique that is most frequently used in this extensive aortic pathology.

The use of lumbar drains in preventing spinal cord injury following thoracoabdominal aortic aneurysm repair: an updated systematic review and meta-analysis

OBJECTIVE Paraplegia and paraparesis following aortic aneurysm repair occur at a substantially high rate and are often catastrophic to patients, their families, and the overall health care system. Spinal cord injury (SCI) following open thoracoabdominal aortic aneurysm (TAAA) repair is reported to be as high as 20% in historical controls. The goal of this study was to determine the impact of CSF drainage (CSFD) on SCI following TAAA repair. METHODS In August 2015 a systematic literature search was performed using clinicaltrials.gov , the Cochrane Library, PubMed/MEDLINE, and Scopus that identified 3478 articles. Of these articles, 10 met inclusion criteria. Random and fixed-effect meta-analyses were performed using both pooled and subset analyses based on study type. RESULTS The meta-analysis demonstrated that CSFD decreased SCI by nearly half (relative risk 0.42, 95% confidence interval 0.25-0.70; p = 0.0009) in the pooled analysis. This effect remained in the subgroup analysis of early SCI but did not remain significant in late SCI. CONCLUSIONS This meta-analysis showed that CSFD could be an effective strategy in preventing SCI following aortic aneurysm repair. Care should be taken to prevent complications related to overdrainage. No firm conclusions can be drawn about the newer endovascular procedures at the current time.

Malperfusion syndromes in aortic dissections

Aortic dissection remains a challenging clinical scenario, especially when complicated by peripheral malperfusion. Improvements in medical imaging have furthered understanding of the pathophysiology of malperfusion events in association with aortic dissection, including the elucidation of different mechanisms of branch vessel obstruction. Despite these advances, malperfusion syndrome remains a deadly entity with significant mortality. This review presents the latest knowledge regarding the pathogenesis of aortic dissection complicated by malperfusion syndrome, and discusses the diagnostic and therapeutic guidelines for management of this vicious entity.

Neuromonitoring, Cerebrospinal Fluid Drainage, and Selective Use of Iliofemoral Conduits to Minimize Risk of Spinal Cord Injury During Complex Endovascular Aortic Repair

Purpose: To review outcomes of continuous motor/somatosensory-evoked potential (MEP/SSEP) monitoring, cerebrospinal fluid drainage, and selective use of iliofemoral conduits in patients undergoing endovascular repair of descending thoracic aneurysm (DTA) and thoracoabdominal aortic aneurysms (TAAAs). Methods: The clinical data of 49 patients (mean age 75±8 years; 38 men) who underwent endovascular repair of DTA and TAAAs (2011–2014) were reviewed. All patients had cerebrospinal fluid drainage, permissive hypertension (mean arterial pressure ≥80 mm Hg), and MEP/SSEP monitoring. There were 44 (90%) patients with TAAAs and 5 (10%) with DTA. Types I and II TAAAs were repaired in staged procedures. Iliofemoral conduits were used for small iliac arteries and to minimize time of lower extremity ischemia in patients with difficult anatomy. In patients with changes in MEP/SSEPs, a standardized protocol was employed to optimize spinal cord perfusion and restore lower extremity blood flow. Endpoints were mortality, spinal cord injury (SCI), and lower extremity ischemic complications. Results: Sixteen (33%) patients had staged TAAA repair. A total of 163 visceral arteries were targeted by fenestrations and branches (mean 3.7±1.0 vessels/patient). Temporary iliofemoral conduits were used in 16 limbs/14 patients. A stable MEP/SSEP was achieved in all patients. Thirty-one (63%) patients had a ≥75% decrease in MEP/SSEP amplitude in 50 limbs starting on average 75±28 minutes after obtaining vascular access. MEP/SSEP amplitude improved with maneuvers in 12 (39%) patients and returned to baseline with restoration of lower extremity flow in all except 1 patient who developed immediate SCI. Thirty-day mortality was 4%. Three (6%) patients had SCI, 2 permanent and 1 temporary at 14 days. There were no lower extremity ischemic complications. Conclusion: Neuromonitoring predicted immediate SCI and allowed use of a protocol to optimize spinal cord and lower extremity perfusion during complex endovascular aortic repair. Larger clinical experience is needed to evaluate the efficacy of neuromonitoring to prevent SCI.