Spinal Cord Protection in Elective Thoracoabdominal Aortic Procedures

The frozen elephant trunk: seeking a more definitive treatment for acute type A aortic dissection

OBJECTIVES

Conventional treatment for type A aortic dissection includes replacement of the ascending aorta with an open distal anastomosis in the hemiarch position. The frozen elephant trunk (FET) is a hybrid technique that extends the repair to the descending thoracic aorta. The goal is to improve resolution of malperfusion syndrome and to induce positive aortic remodelling and reduce the need for reintervention on the downstream aorta. We aim to summarize the data on the short and long-term outcomes of this technique.

METHODS

A thorough search of the literature was conducted isolating all articles dealing with aortic remodelling after the use of FET in case of type A acute aortic dissection. Keywords 'aortic dissection', 'frozen elephant trunk', 'aortic remodelling' and 'false lumen thrombosis' were used. Data for type B and chronic aortic dissections were excluded.

RESULTS

FET use favourably influences aortic remodelling. The main advantages lie in the exclusion of distal entry tears in either the aortic arch or descending aorta thus restoring antegrade blood flow in the true lumen and inducing false lumen thrombosis. False lumen thrombosis is not only induced at the level of the stent deployment but also lower in the distal descending aorta. Moreover, it offers an adequate landing zone in the mid-descending aorta for second-stage endovascular or open surgical aortic repair, if needed.

CONCLUSIONS

FET can be advantageous in the treatment of acute type A aortic dissection dealing with extended aortic pathology.

Risk factors of 30-day and long-term mortality and outcomes in open repair of thoracoabdominal aortic aneurysm

BACKGROUND

Open repair of thoracoabdominal aortic aneurysm (TAAA) was characterized by significant risk of postoperative mortality and morbidity. The aim of this study was to determine the perioperative predictors of early and long-term mortality in patients undergoing open repair of TAAA. Besides, the postoperative outcomes in patients with open repair of TAAA were described.

METHODS

This is a single-center retrospective study, and 146 patients with open repair of TAAA from January 4, 2011, to November 22, 2018 was involved. Categorical variables were analyzed by the Chi-square test or Fisher's exact test, and continuous variables were analyzed by the independent sample t-test and the WilCoxon rank-sum test. Multivariate Logistic regression and Cox regression were applied to identify the predictors of 30-day and long-term mortality, respectively. The Kaplan Meier curves were used to illustrate survival with the Log-rank test.

RESULTS

The 30-day mortality was 9.59% (n = 14). Older than 50 years, the intraoperative volume of red blood cell (RBC) and epinephrine use were independently associated with postoperative 30-day mortality in open repair of TAAA. Long-term mortality was 17.12% (n = 25) (median of 3.5 years (IQR = 2-5 years) of follow-up). Prior open thoracoabdominal aortic aneurysm (TAAA) repair, aortic cross-clamping (ACC) time, intraoperative volume of RBC and use of epinephrine were independently correlated with long-term mortality.

CONCLUSIONS

Identifying perioperative risk factors of early and long-term mortaliy is crucial for surgeons. Intraoperative volume of RBC and use of epinephrine were predictors of both early and long-term mortality. In addition, patients of advanced age, prior open repair of TAAA and prolonged ACC time should be paid more attention.

Systematic Review and Meta-analysis of Short-term and Mid-term Outcomes After Use of t-Branch Off-the-shelf Multibranched Endograft for Elective and Urgent Treatment of Thoracoabdominal Aortic Aneurysms

OBJECTIVE

To conduct a meta-analysis to assess the safety and efficacy of t-Branch off-the-shelf multibranched endograft for the treatment of thoracoabdominal aortic aneurysm (TAAA).

DATA SOURCES

PubMed, Embase, and Web of Science.

REVIEW METHODS

Online databases were searched from June 2012 to March 2023. The data were pooled together using a random-effects model of proportions. The outcomes overall included technical success, spinal cord ischemia, target vessel occlusion, type I or III endoleak, reintervention, early mortality (30-day), and mid-term outcomes. Subgroup meta-analyses and meta-regression were performed to explore variation among studies.

RESULTS

A total of 15 studies containing 1238 patients were included in the meta-analysis. The overall study quality assessment was found to be moderate to good. The pooled technical success was 97.0% (95% confidence interval [CI]=95.5-98.6, I2=53.01%, 1185/1238 cases, 15 studies). Overall, early mortality was 7.3% (95% CI=4.4-10.1, I2=74.48%, 124/1238 cases, 15 studies). Early spinal cord ischemia was 13.4% (95% CI=9.6-17.2, I2=67.24%, 160/1238 cases, 15 studies), and early type I or III endoleak was 6.0% (95% CI=3.4-8.5, I2=53.71%, 68/1032 cases, 9 studies). Mid-term outcomes showed target vessel occlusion was 4% (95% CI=1.4-6.5, I2=65.18%, 28/528 cases, 10 studies, 5-21.2 months), type I or III endoleak was 4.7% (95% CI=2-7.5, I2=49.74%, 38/512 cases, 10 studies, 5-21.2 months), reintervention was 11.2% (95% CI=8.1-14.3, I2=31.06%, 85/650 cases, 10 studies, 5-21.2 months), and pooled mortality was 13.9% (95% CI=7.2-20.7, I2=76.32%, 84/550 cases, 11 studies, 5-21.2 months). Meta-regression found a significant linear association between higher technical success and earlier publication year (p=0.014) and studies with anatomic inclusion criteria (p=0.037). Urgent patients (p=0.021) and later publication year (p=0.048) were significantly associated with higher early mortality.

CONCLUSION

The use of the off-the-shelf t-Branch multibranched endograft for elective or urgent endovascular TAAA repair is associated with high technical success rates and proved to be safe and effective at early and mid-term follow-up. However, the heterogeneity between the included studies is high, and prospective, randomized studies along with future larger studies with long-term follow-up are needed.

CLINICAL IMPACT

The Zenith t-Branch (Cook Medical, Bloomington, Ind) was approved as a commercially available device in Europe in June 2012. Although a decade has past, the outcomes of t-Branch have rarely been synthesized at the global level. This meta-analysis included 15 studies containing 1238 patients. The meta-analyses included technical success, major adverse events, reintervention, early mortality, and mid-term outcomes. The outcome was very meaningful and representative for the use of t-Branch. It is helpful for endovascular surgeons to make decisions on the treatment of TAAA patients.

Risk Factors for Spinal Cord Injury during Endovascular Repair of Thoracoabdominal Aneurysm: Review of the Literature and Proposal of a Prognostic Score

Despite recent improvements, spinal cord ischemia remains the most feared and dramatic complication following extensive aortic repair. Although endovascular procedures are associated with a lower risk compared with open procedures, this risk is still significant and must be considered. A combined medical and surgical approach may help to optimize the tolerance of the spinal cord to ischemia. The aim of this review is to describe the underlying mechanism involved in spinal cord injury during extensive endovascular aortic repair, to describe the different techniques used to improve spinal cord tolerance to ischemia-including the prophylactic or curative use of spinal drainage-and to propose our algorithm for spinal cord protection and the rational use of spinal drainage.

Protective effect of valproic acid on ischemia-reperfusion induced spinal cord injury in a rat model

PURPOSE

This study aims to determine the anti-inflammatory, antioxidant, and anti-apoptotic effects of valproic acid (VPA) on rat spinal cord tissue in ischemia-reperfusion (IR) injury model created by abdominal aorta occlusion.

MATERIALS AND METHODS

Sprague Dawley rat (male sex) weighing 190-260 g divided into four experimental groups: control only underwent laparotomy, sham group, pre-IR injury (200 mg/kg dose), and post-IR injury (300 mg/kg) VPA. We measured serum levels of TNF-α, IL-6, IL-1β, IL-18, Total Oxidant Status (TOS) and Total Antioxidant Status (TAS), and serum Oxidative Stress Index (OSI) ratio, and tissue expression of Bax and Bcl2, Caspase3, and Bax/Bcl2 ratio.

RESULTS

Serum IL-18 was higher in the sham than the control group(P = 0.001), and there were declines in the pre-IR treatment (P = 0.002) and the post-IR treatment when compared to sham (P = 0.001). Despite these reductions, IL-18 expression levels in both the pre- and post-IR treatment groups were higher than in the control group (P = 0.001 & P = 0.003). The favorable effects of pre-IR VPA administration on immunohistochemical biomarkers were superior to post-IR VPA administration.

CONCLUSIONS

Comparative analyses between prophylactic VPA administration and post-IR interventions revealed congruence in their anti-inflammatory and anti-apoptotic ramifications. VPA can reduce spinal cord IR injury in an aortic occlusion model of rats.

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.

A multidisciplinary multistage complete mega aorta replacement and utilization of extracorporeal membrane oxygenation in thoracoabdominal aneurysm repair

A 49-year-old woman underwent a 11-month multistage complete replacement of a mega aorta. Replacement stages included ascending aorta and arch replacement in conjunction with a frozen elephant trunk thoracic endovascular aortic repair, extension of thoracic endovascular aortic repair to zone 5, and open repair of the thoracoabdominal aneurysm with the use of venoarterial extracorporeal membrane oxygenation for circulatory support. This case illustrates the complexity of repairing a mega aorta, the multidisciplinary care and staging needed for repair, and the use of peripheral venoarterial extracorporeal membrane oxygenation for circulatory perfusion during thoracoabdominal aneurysm repair.

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.