Fluctuations in Spinal Cord Perfusion Pressure: A Harbinger of Delayed Paraplegia After Thoracoabdominal Aortic Repair

2022 ACC/AHA guideline for the diagnosis and management of aortic disease: A report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

Effect of cerebrospinal fluid drainage pressure in descending and thoracoabdominal aortic repair: a prospective multicenter observational study

PURPOSE

Cerebrospinal fluid drainage (CSFD) is recommended during open or endovascular thoracic aortic repair. However, the incidence of CSFD complications is still high. Recently, CSF pressure has been kept high to avoid complications, but the efficacy of CSFD at higher pressures has not been confirmed. We hypothesize that CSFD at higher pressures is effective for preventing motor deficits.

METHODS

This prospective observational study included 14 hospitals that are members of the Japanese Society of Cardiovascular Anesthesiologists. Patients who underwent thoracic and thoracoabdominal aortic repair were divided into four groups: Group 1, CSF pressure around 10 mmHg; Group 2, CSF pressure around 15 mmHg; Group 3, CSFD initiated when motor evoked potential amplitudes decreased; and Group 4, no CSFD. We assessed the association between the CSFD group and motor deficits using mixed-effects logistic regression with a random intercept for the institution.

RESULTS

Of 1072 patients in the study, 84 patients (open surgery, 51; thoracic endovascular aortic repair, 33) had motor deficits at discharge. Groups 1 and 2 were not associated with motor deficits (Group 1, odds ratio (OR): 1.53, 95% confidence interval (95% CI): 0.71-3.29, p = 0.276; Group 2, OR: 1.73, 95% CI: 0.62-4.82) when compared with Group 4. Group 3 was significantly more prone to motor deficits than Group 4 (OR: 2.56, 95% CI: 1.27-5.17, p = 0.009).

CONCLUSION

CSFD is not associated with motor deficits in thoracic and thoracoabdominal aortic repair with CSF pressure around 10 or 15 mmHg.

Reappraisal of the role of motor and somatosensory evoked potentials during open distal aortic repair

OBJECTIVE

Intraoperative motor and somatosensory evoked potentials have been applied to monitor spinal cord ischemia during repair. However, their predictive values remain controversial. The purpose of this study was to evaluate the impact of motor evoked potentials and somatosensory evoked potentials on spinal cord ischemia during open distal aortic repair.

METHODS

Our group began routine use of both somatosensory evoked potentials and motor evoked potentials at the end of 2004. This study used a historical cohort design, using risk factor and outcome data from our department's prospective registry. Univariate and multivariable statistics for risk-adjusted effects of motor evoked potentials and somatosensory evoked potentials on neurologic outcome and model discrimination were assessed with receiver operating characteristic curves.

RESULTS

Both somatosensory evoked potentials and motor evoked potentials were measured in 822 patients undergoing open distal aortic repair between December 2004 and December 2019. Both motor evoked potentials and somatosensory evoked potentials were intact for the duration of surgery in 348 patients (42%). Isolated motor evoked potential loss was observed in 283 patients (34%), isolated somatosensory evoked potential loss was observed in 18 patients (3%), and both motor evoked potential and somatosensory evoked potential loss were observed in 173 patients (21%). No spinal cord ischemia occurred in the 18 cases with isolated somatosensory evoked potential loss. When both signals were lost, signal loss happened in the order of motor evoked potentials and then somatosensory evoked potentials. Immediate spinal cord ischemia occurred in none of those without signal loss, 4 of 283 (1%) with isolated motor evoked potential loss, and 15 of 173 (9%) with motor evoked potential plus somatosensory evoked potential loss. Delayed spinal cord ischemia occurred in 12 of 348 patients (3%) with intact evoked potentials, 24 of 283 patients (8%) with isolated motor evoked potentials loss, and 27 of 173 patients (15%) with motor evoked potentials + somatosensory evoked potentials loss (P < .001). Motor evoked potentials and somatosensory evoked potentials loss were each independently associated with spinal cord ischemia. For immediate spinal cord ischemia, no return of motor evoked potential signals at the conclusion of the surgery had the highest odds ratio of 15.87, with a receiver operating characteristic area under the curve of 0.936, whereas motor evoked potential loss had the highest odds ratio of 3.72 with an area under the curve of 0.638 for delayed spinal cord ischemia.

CONCLUSIONS

Somatosensory evoked potentials and motor evoked potentials are both important monitoring measures to predict and prevent spinal cord ischemia during and after open distal aortic repairs. Intraoperative motor evoked potential loss is a risk for immediate and delayed spinal cord ischemia after open distal aortic repair, and somatosensory evoked potential loss further adds predictive value to the motor evoked potential.

Open Treatments for Thoracoabdominal Aortic Aneurysm Repair

Thoracoabdominal aortic aneurysms (TAAA) represent a unique pathology that is associated with considerable mortality if untreated. While the advent of endovascular technologies has introduced new modalities for consideration, the mainstay of TAAA treatment remains open surgical repair. However, the optimal conduct of open TAAA repair requires careful consideration of patient risk factors and a collaborative team effort to mitigate the risk of perioperative complications. In this chapter, we briefly outline the history of treating TAAA, preoperative preparation and postoperative care, and our operative techniques for treatment.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate. Structure: Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

Postoperative management in patients with complex aortic aneurysms

Patients with complex aortic aneurysms (CAA) are often high risk due to advanced age and widespread atherosclerosis affecting numerous vascular territories. Therefore, a thorough perioperative evaluation is needed prior to performing in any type of aortic repair, regardless of whether an endovascular or open surgical approach is selected. Because these operations are technically demanding and often result in end organ ischemia, it is not surprising that complex aortic repair carries significant risk of morbidity and mortality. Disabling complications such as dialysis, major stroke and paraplegia constitute the main limitation of complex aortic repair. The aim of this article was to review postoperative management to mitigate complications after CAA repair.

Non-Coding RNAs: Emerging Therapeutic Targets in Spinal Cord Ischemia-Reperfusion Injury

Paralysis or paraplegia caused by transient or permanent spinal cord ischemia–reperfusion injury (SCIRI) remains one of the most devastating post-operative complications after thoracoabdominal aortic surgery, even though perioperative strategies and surgical techniques continue to improve. Uncovering the molecular and cellular pathophysiological processes in SCIRI has become a top priority. Recently, the expression, function, and mechanism of non-coding RNAs (ncRNAs) in various diseases have drawn wide attention. Non-coding RNAs contain a variety of biological functions but do not code for proteins. Previous studies have shown that ncRNAs play a critical role in SCIRI. However, the character of ncRNAs in attenuating SCIRI has not been systematically summarized. This review article will be the first time to assemble the knowledge of ncRNAs regulating apoptosis, inflammation, autophagy, and oxidative stress to attenuate SCIRI. A better understanding of the functional significance of ncRNAs following SCIRI could help us to identify novel therapeutic targets and develop potential therapeutic strategies. All the current research about the function of nRNAs in SCIRI will be summarized one by one in this review.

Spinal Cord Protection for Thoracoabdominal Aortic Surgery

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

The Evolution and Future of Spinal Drain for Thoracic Aortic Aneurysm Repair: A Review

For decades, spinal drains for cerebrospinal fluid (CSF) pressure monitoring and drainage have been used as adjuncts to protect against spinal cord injury resulting from thoracic aortic aneurysm repair. There are many different approaches to placement and management of CSF drains, with no true consensus on best practice. Furthermore, the incidence of complications resulting from spinal drains largely has been stagnant. This review describes the history and rationale behind placement of CSF drains, explore various considerations, techniques, and equipment, and discuss potential considerations for developing more comprehensive protocols.

Current practices and goals for mean arterial pressure and spinal cord perfusion pressure in acute traumatic spinal cord injury: Defining the gaps in knowledge

Context: The mainstay of treatment for acute traumatic spinal cord injury (SCI) is to artificially elevate the patient's mean arterial pressure (MAP) to >85 mmHg to increase blood flow to the injured spinal cord for 7 days. However, the literature supporting these recommendations are only Class III evidence. In fact, the critical time window in which to elevate MAP after SCI and the optimal vasopressor to use are largely unknown, as is whether cerebrospinal fluid diversion has a role, and this leads to variability among practitioners. Also undefined is whether manipulating these parameters improves neurological outcome.Objective: Our goal is to better delineate current clinical practice and identify gaps in knowledge surrounding the care of patients with traumatic SCI.Methods: We undertook a systematic review of the current literature identified from PubMed on MAP elevation and spinal cord parenchymal pressure in acute SCI.Results: The 8 articles (6 human; 2 porcine) that met our inclusion criteria were all published within the last 6 years. Four were prospective, 1 was retrospective, and 3 were review articles. Only one study was randomized. All of these studies involved small sample sizes and varying lengths of MAP elevation. Choice of vasopressor was variable as well.Conclusions: From our literature review, we posit that norepinephrine may be the vasopressor of choice, that spinal parenchymal pressure monitors can be safely placed at the injury site, and that the combination of MAP elevation and cerebrospinal fluid drainage may improve neurologic outcome more than either intervention alone.

Open thoracoabdominal aortic aneurysm surgery technique: how we do it

More than four decades have passed since the modern principals to treat thoracoabdominal aortic aneurysm (TAAA) have been established. The historical challenges in repair of TAAA are represented by - and continue to be - multiorgan protection. Among all organs, the spinal cord remains one of the most vital and vulnerable. We described our current techniques of open extent II TAAA repair, including the following topics: anesthesia, intraoperative monitoring, skin incision, exposure of the TAAA, left heart bypass, graft replacement technique, intercostal artery reattachment, visceral/renal artery reconstructions, and postoperative care. We use cerebrospinal fluid drainage, distal aortic perfusion, mild passive hypothermia, sequential clamping, and visceral and renal perfusion using roller pump in all the cases for multiorgan protection. Both motor-evoked potentials and somatosensory-evoked potentials ere used to guide the conduct of intercostal artery reattachment. Our group demonstrated that the use of adjuncts has reduced the overall spinal cord ischemia rate after Extent I TAAA from 15% to less than 2% and after Extent II TAAA from 33% (50% with clamp time exceeding 40 minutes in "clamp and go" era) to less than 4%. The current standard practice of TAAA repair with adjuncts has improved outcomes, especially regarding spinal cord ischemia.

Outcomes of open repairs of chronic distal aortic dissection anatomically amenable to endovascular repairs

OBJECTIVE

To review short-term outcomes and long-term survival and durability after open surgical repairs for chronic distal aortic dissections in patients whose anatomy was amenable to thoracic endovascular aortic repair (TEVAR).

METHODS

Between February 1991 and August 2017, we repaired chronic distal dissections in 697 patients. Of those patients, we enrolled 427 with anatomy amenable to TEVAR, which included 314 descending thoracic aortic aneurysms (DTAAs) and 105 extent I thoracoabdominal aortic aneurysms (TAAAs). One hundred eighty-five patients (44%) had a history of type A dissection, and 33 (7.9%) had a previous DTAA/TAAA repair. Variables were assessed with logistic regression for 30-day mortality and Cox regression for long-term mortality. Time-to-event analysis was performed using Kaplan-Meier methods.

RESULTS

Thirty-day mortality was 8.4% (n = 36). In all, 22 patients (5.2%) developed motor deficit (paraplegia/paraparesis), and 17 (4.0%) experienced stroke. Multivariable analysis identified low estimated glomerular filtration rate (eGFR; <60 mL/min/1.73 m²), previous DTAA/TAAA repair, and chronic obstructive pulmonary disease (COPD) as associated with 30-day mortality. Patients without all 3 risk factors had a 30-day mortality rate of 2.6%. During a median follow-up of 6.5 years, 160 patients died. The survival rate was 81% at 1 year and 61% at 10 years. Cox regression analysis identified preoperative aortic rupture, eGFR <60 mL/min/1.73 m², previous DTAA/TAAA repair, COPD, and age >60 years as predictive of long-term mortality. Forty-five patients required subsequent aortic procedures, including 8 reinterventions to the treated segment. Freedom from any aortic procedures was 85% at 10 years, and aortic procedure-free survival was 45% at 10 years. Hereditary aortic disease was the sole predictor for any aortic interventions (hazard ratio, 3.2; P = .004).

CONCLUSIONS

Open surgical repair provided satisfactory low neurologic complication rates and durable repairs in chronic distal aortic dissection. Patients without low eGFR, redo, and COPD are the low-risk surgical candidates and may benefit from open surgical repair at centers with similar experience to ours. Patients with hereditary aortic disease warrant close surveillance.

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.

Permissive Hypertension and Collateral Revascularization May Allow Avoidance of Cerebrospinal Fluid Drainage in Thoracic Endovascular Aortic Repair

BACKGROUND

The utility of cerebrospinal fluid drainage (CSFD) for prevention of spinal cord ischemia (SCI) after thoracic endovascular aortic repair (TEVAR) remains unclear. We previously published our institutional algorithm restricting preoperative CSFD to patients deemed high risk for SCI. Since that publication, our algorithm has evolved with preoperative CSFD avoided in all patients undergoing isolated descending TEVAR with or without arch involvement (+/- arch TEVAR). This study evaluated the updated algorithm in a contemporary cohort.

METHODS

Patients who underwent TEVAR for descending aortic +/-arch pathology between February 2012 and September 2018 at a single center were identified from an institutional aortic surgery database. The algorithm includes left subclavian artery (LSA) revascularization in cases of coverage with no preservation of antegrade flow, permissive hypertension, and use of evoked potential monitoring. The primary end points were SCI or postoperative CSFD.

RESULTS

During the study interval, 225 patients underwent descending +/- arch TEVAR. CSFD was used before TEVAR in 2 patients (0.9%) in violation of the algorithm, and they were excluded from the study cohort. Endograft coverage below T6 occurred in 81%. The LSA was fully covered in 100 patients (47%), all of whom underwent LSA revascularization. Following the updated algorithm, the incidence of temporary or permanent SCI was 0%. No patient required postoperative CSFD.

CONCLUSIONS

A restrictive lumbar CSFD algorithm, including permissive hypertension and LSA revascularization in the setting of descending +/- arch TEVAR, appears safe, with a 0% incidence of SCI in 223 consecutive patients treated during a 6.5-year interval. We recommend consideration of further prospective study to evaluate this algorithm.