Current strategies of spinal cord protection during thoracoabdominal aortic surgery

Rehabilitation report of 2 cases of spinal cord ischemic injury after intra-aortic repair

RATIONALE

Spinal cord ischemia injury is a serious complication after intra-aortic surgery, with a low incidence but high disability rate. However, patients often do not receive comprehensive treatment in the early stages of the disease. Therefore, active neurological intervention is needed to protect and prevent spinal cord ischemia during and after surgery. In this paper, rehabilitation program and imaging data of 2 cases with spinal cord ischemic injury are presented and discussed regarding causes, prevention and acute treatment with this disease, which could be referred by clinicians.

PATIENT CONCERNS

Case report 1: A 69-year-old male patient underwent aortic arch aneurysm and thoracic endovascular aortic repair (coated stent) was performed under general anesthesia. Complete paralysis of both lower limbs, constipation, and urinary retention occurred after surgery and was subsequently referred to our rehabilitation department. Case report 2: A man aged 41 years experienced sudden chest pain with no dizziness or headache. Weakness of both lower limbs gradually appeared over 30 minutes with subsequent loss of consciousness. He was diagnosed with aortic dissection and underwent aortic stent implantation. Inpatient rehabilitation began systematically 3 months after discharge.

DIAGNOSES

The 2 patients were diagnosed with paraplegia and spinal cord ischemic injury.

INTERVENTIONS

The patients received strength and transfer training, sensory input, health mission, and activities of daily living.

OUTCOMES

Patient 1 returned home without assistive devices and patient 2 returned home with wheelchair.

LESSONS

Perioperative spinal cord protection is directly related to postoperative quality of life. Once the symptoms of spinal cord ischemic injury occur, cerebrospinal fluid drainage should be performed as soon as possible to increase mean arterial pressure. At the same time, methylprednisolone, ganglioside, anticoagulation, vasodilator drugs, and symptomatic supportive treatments are required. Intercostal artery and subclavian artery are reconstructed if necessary. Symptom stability flags referral to commence rehabilitation. Repetitive functional training is necessary to help patients return to the family and society as soon as possible.

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.

Highlights and Perioperative Implications from the 2022 American College of Cardiology and American Heart Association Guidelines for Diagnosis and Management of Aortic Disease

As the understanding of aortic diseases and their complications grow, increasing importance of uniformity in diagnosis and management is crucial for optimal care of this patient population. The 2022 American College of Cardiology and American Heart Association Guidelines for Diagnosis and Management of Aortic Disease discusses these considerations in detail. The purpose of this review is to highlight essential recommendations that are of relevance to the perioperative physician who manages these patients. A few notable points include, shared decision-making with patients, creation of multidisciplinary aortic teams, lower diameter thresholds for surgery in certain situations, and increased testing for patients with heritable aortic diseases. In addition to briefly reviewing basics of aortic diseases, the authors discuss changes to guidelines that are especially relevant to perioperative care.

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.

Distal Perfusion With Modified Centrifugal Pump Circuit in Thoracic and Thoracoabdominal Aortic Aneurysm Repair

OBJECTIVE

The left heart bypass is currently the most frequent adjunct to provide distal aortic perfusion during aortic clamping. However, closed-circuits cannot respond to sudden hemodynamic fluctuations during aortic clamping which may lead to complications. In this report, we aim to give the technical aspects of reservoir-added centrifugal pump circuit system, its implementation and the clinical outcomes.

METHODS

Between 2002 and 2020, the data of 35 patients underwent aortic aneurysm repair with the use of modified pump circuit were analyzed. The mean age was 53.4 years (range 24-73) and 91.4% of all was male. Preoperative demographics, intraoperative pump data and postoperative clinical outcomes were reported.

RESULTS

Thoracoabdominal incision was used in 22 patients (62.9%) and cerebrospinal fluid (CSF) drainage catheter was placed in 15 patients (42.9%). The left inferior pulmonary vein for outflow and the left femoral artery for inflow cannulation were used preferably. Median duration of pump support was 50 mins (13-121) in the cohort. The median transfusion of red packed cells was 2 units. Renal failure was observed in two patients and permanent paraplegia in one patient. Only one patient died in the elective group (1/34) and one patient in the emergent.

CONCLUSIONS

The reservoir-added centrifugal pump is an effective, practical, and flexible perfusion system which should be in the armamentarium of surgeons in order to solve difficult problems during open repair of descending and thoracoabdominal aortic aneurysms.

Recovery of neurological function following type B aortic dissection complicated by paraplegia

A woman in her 50s presented with uncontrolled hypertension, chest/back pain, paraplegia, right lower limb ischaemia and acute kidney injury. A CT angiogram demonstrated a type B aortic dissection originating distal to the left subclavian artery to bilateral common iliac arteries complicated by occlusion of the right renal artery and right common iliac artery. She was started on intravenous antihypertensive therapy and transferred to our institution for emergent thoracic endovascular aortic repair. Due to bleeding risk from coagulopathy, a spinal drain was not placed immediately post-operatively but instead was inserted after 24 hours while maintaining a mean arterial pressure of 80-100 mm Hg. Postoperatively, her right lower extremity perfusion was re-established, and her renal function recovered following temporary dialysis. At discharge on postoperative day 13, she regained full neurological function.

Perioperative management of patients undergoing thoracic endovascular repair

Thoracic endovascular aortic repair (TEVAR) is a less invasive method for treating thoracic and some thoracoabdominal aortic aneurysms, dissections of the thoracic aorta and blunt traumatic aortic injury, compared with conventional open surgery. Maximizing the likelihood of a successful outcome requires diligent multidisciplinary (surgical, critical care, nursing, pharmacy, nutrition and physical therapy) perioperative care. In this article, we discuss fundamentals for managing patients after endovascular aortic aneurysm repair. These principles focus on the transition between the operating room and the intensive care unit, prevention and management of spinal cord deficits (SCD), and vital neurological, respiratory, cardiovascular, renal, gastrointestinal and hematological concerns. The better the care team understands the expected postoperative course, the earlier that deviations can be recognized and the more likely that successful rescue can be achieved to reduce the incidence and severity of adverse outcomes. Achieving optimal results after TEVAR requires attention to detail across the preoperative, intraoperative and postoperative phases of care.

Critical care management after open thoracoabdominal aortic aneurysm repair

Thoracoabdominal aortic aneurysm repair is technically demanding for the surgeon and physiologically demanding on the patient. As such, it requires diligent multidisciplinary perioperative care to maximize the likelihood of a successful outcome. In this article, we discuss key principles for managing patients after open thoracoabdominal aortic aneurysm repair, which we have learned over the course of performing more than 3500 of such procedures. These principles address patient handoff between the operating room and Intensive Care Unit, resuscitation, prevention and management of spinal cord deficits, and important neurological, respiratory, cardiovascular, renal, gastrointestinal, and hematological considerations. Understanding the expected postoperative course allows for earlier recognition of deviations from that course and increases the likelihood of successful rescue of patients from adverse outcomes. Achieving positive outcomes after thoracoabdominal aortic aneurysm repair requires attention to detail across the perioperative, intraoperative, and postoperative phases of care.

Remote Ischemic Preconditioning in Spinal Cord Protection: A Surviving Porcine Study

Surgical repair of thoracic aorta can compromise blood flow of the spinal cord. To mitigate spinal cord ischemia (SCI) additional protection methods are needed. In experimental studies remote ischemic preconditioning (RIPC) has proven to be an effective method of protecting organs from ischemia. The aim of the study was to assess efficacy of RIPC in spinal cord protection in a chronic porcine model. Sixteen piglets were assigned into the RIPC group (8) and the control group (8). RIPC was performed using blood pressure cuff in a 5-minute ischemia followed by a 5-minute reperfusion repeating cycles 4 times. The left subclavian artery and all segmental arteries above diaphragm were ligated at 5-minute intervals to accomplish SCI. The follow-up comprised a 4-hour intensive monitoring and a 7-day recovery phase. Blood samples were obtained, motor-evoked potentials and near-infrared spectroscopy (NIRS) of longitudinal back muscles were measured. Paraplegia was assessed every day postoperatively. Histopathological analysis of the spinal cord was performed after 7 days. NIRS values 4 hours after SCI were higher in the RIPC group, 45.5 (44.5-47.0), than in the control group, 41.5 (40.5-44.0) (P = 0.042). Nadir value of NIRS was 43.4 (39.3-46.0) in the RIPC group and 38.9 (38.-40.0) in the control group (P = 0.014). On the first postoperative day the RIPC group reached modified Tarlov score of 3 (2-3) vs 2 (1-2) in the control group (P = 0.024). RIPC hastens the recovery from SCI during the first postoperative day.

Spinal cord deficit after 1114 extent II open thoracoabdominal aortic aneurysm repairs

OBJECTIVE

Crawford extent II repairs are the most extensive thoracoabdominal aortic aneurysm operations and pose the greatest risk of postoperative spinal cord deficit. We sought to examine spinal cord deficit after open extent II thoracoabdominal aortic aneurysm repair to identify predictors of the most serious type: persistent paraplegia or paraparesis.

METHODS

We included 1114 extent II thoracoabdominal aortic aneurysm repairs performed from 1991 to 2017. Intercostal/lumbar artery reattachment (n = 959, 86.1%) and cerebrospinal fluid drainage (n = 698, 62.7%) were used to mitigate the risk of postoperative spinal cord deficit. We used univariate and multivariable analyses to examine spinal cord deficit and identify predictors of persistent paraplegia or paraparesis, defined as paraplegia or paraparesis present at the time of early death or hospital discharge.

RESULTS

Spinal cord deficit developed after 151 (13.6%) repairs: 86 (7.7%) cases of persistent paraplegia or paraparesis (51 paraplegia; 35 paraparesis) and 65 (6.1%) cases of transient paraplegia or paraparesis. Patients with spinal cord deficit were older (median 68 vs 65 years, P < .001) and had more rupture (6.6% vs 2.2%, P = .002) and urgent/emergency repair (25.2% vs 16.9%, P = .01) than those without. Persistent paraplegia or paraparesis developed immediately in 47 patients (4.2%) and was delayed in 39 patients (3.5%). Urgent/emergency repair (relative risk ratio, 2.31; P = .002), coronary artery disease (relative risk ratio, 1.80, P = .01), and chronic symptoms (relative risk ratio, 1.76, P = .02) independently predicted persistent paraplegia or paraparesis. Reattaching intercostal/lumbar arteries (relative risk ratio, 0.38, P < .001) and heritable disease (relative risk ratio, 0.36, P = .01) were protective. Early and late survival were poorer in those with persistent paraplegia or paraparesis than in those without.

CONCLUSIONS

Spinal cord deficit after extent II thoracoabdominal aortic aneurysm repairs remains concerning; survival is worse in patients with persistent paraplegia or paraparesis. The complexity of spinal cord deficit and persistent paraplegia or paraparesis warrant further study.

Two-stage repair of DeBakey type IIIb aneurysm, using total arch replacement

Background

Open repair for chronic DeBakey type IIIb dissecting aortic aneurysm is an invasive procedure involving open proximal anastomosis under hypothermic cardiac arrest, with significant morbidity in high-risk patients. We adopted a two-stage repair strategy using total arch replacement with the elephant trunk technique, which enables aortic crossclamping and avoids open proximal anastomosis at the second-stage graft replacement through a left thoracotomy.

Methods

From January 2008 to October 2018, we performed DeBakey type IIIb dissecting aortic aneurysm repair in 76 cases, and compared the results of two-stage repair (group 1, 25 cases) and single-stage repair using graft replacement with open proximal anastomosis through a left thoracotomy (group 2, 31 cases).

Results

In group 1, the elephant trunk technique was successful in all cases. The second intervention included endovascular repair (13 cases) and graft replacement through a left thoracotomy (7 cases). Five cases were followed up conservatively because the false lumen was thrombosed after the elephant trunk technique. Aorta-related adverse events were seen in 5 cases in group 1 (1 re-dissection, 1 rupture, 2 stent-graft-induced new entries, 1 stent-graft migration) and 6 in group 2 (1 additional thoracic endovascular aortic repair, 1 rupture, 4 acute type A aortic dissections). There were no statistical differences between the two groups regarding aorta-related adverse events and death. The postoperative course was acceptable in both groups.

Conclusions

Single-stage repair with open proximal anastomosis is an option in patients not at high risk for invasive surgery, while two-stage repair is recommended for high-risk patients.

A practical guide for anesthetic management during intraoperative motor evoked potential monitoring

Postoperative motor dysfunction can develop after spinal surgery, neurosurgery and aortic surgery, in which there is a risk of injury of motor pathway. In order to prevent such devastating complication, intraoperative monitoring of motor evoked potentials (MEP) has been conducted. However, to prevent postoperative motor dysfunction, proper understanding of MEP monitoring and proper anesthetic managements are required. Especially, a variety of anesthetics and neuromuscular blocking agent are known to attenuate MEP responses. In addition to the selection of anesthetic regime to record the baseline and control MEP, the measures to keep the level of hypnosis and muscular relaxation at constant are crucial to detect the changes of MEP responses after the surgical manipulation. Once the changes of MEP are observed based on the institutional alarm criteria, multidisciplinary team members should share the results of MEP monitoring and respond to check the status of monitoring and recover the possible motor nerve injury. Prevention of MEP-related adverse effects is also important to be considered. The Working Group of Japanese Society of Anesthesiologists (JSA) developed this practical guide aimed to help ensure safe and successful surgery through appropriate anesthetic management during intraoperative MEP monitoring.

Postoperative paraplegia after transapical transcatheter aortic valve implantation

An 84-year-old man with severe aortic valve stenosis underwent transcatheter aortic valve implantation (TAVI). We selected a transapical approach TAVI because he had a 48-mm abdominal aortic aneurysm and his descending aorta was covered with severe atherosclerosis, a so-called "shaggy aorta". A 26-mm Sapien XT prosthesis (Edwards Lifesciences, Irvine, CA, USA) was successfully implanted, and TAVI was performed using cardiopulmonary bypass. His postoperative clinical course was unremarkable on the first day. On postoperative day 3, however, his systemic circulation suddenly collapsed due to cardiac tamponade. We performed an emergency re-thoracotomy. This operation improved his systemic circulation, but he had no movement in either leg. Magnetic resonance imaging showed spinal cord ischemia around the T10 level and acute multifocal micro cerebral infarctions. The cause of his neurological symptoms was thought to be spinal cord ischemia brought about by the shaggy aorta and low blood pressure due to cardiac tamponade after TAVI. <Learning objective: Postoperative spinal cord injury is caused by hypotension embolisms, and aortic dissection particularly in patients with severe aortic arteriosclerosis. Spinal cord ischemia is a rare complication after transcatheter aortic valve implantation because the descending aorta is not operated upon. However, it is necessary to keep in mind that postoperative hemodynamic instability can cause spinal cord ischemia in patients with a shaggy aorta.>.