Central nervous injury risk factors after endovascular repair of a thoracic aortic aneurysm with type B aortic dissection

BACKGROUND

Aortic dissection is the deadliest disease of the cardiovascular system. Type B aortic dissection accounts for 30%-60% of aortic dissections and is mainly treated by endovascular repair of thoracic endovascular aneurysm repair (TEVAR). However, patients are prone to various complications after surgery, with central nervous system injury being the most common, which seriously affects their prognosis and increases the risk of disability and death. Therefore, exploring the risk factors of central nervous system injury after TEVAR can provide a basis for its prevention and control.

AIM

To investigate the risk factors for central nervous system injury after the repair of a thoracic endovascular aneurysm with type B aortic dissection.

METHODS

We enrolled 306 patients with type B aortic dissection who underwent TEVAR at our hospital between December 2019 and October 2022. The patients were categorized into injury (n = 159) and non-injury (n = 147) groups based on central nervous system injury following surgery. The risk factors for central nervous system injury after TEVAR for type B aortic dissection were screened by comparing the two groups. Multivariate logistic regression analysis was performed.

RESULTS

The Association between age, history of hypertension, blood pH value, surgery, mechanical ventilation, intensive care unit stay, postoperative recovery times on the first day after surgery, and arterial partial pressure of oxygen on the first day after surgery differed substantially (P < 0.05). Multivariate logistic regression analysis indicated that age, surgery time, history of hypertension, duration of mechanical ventilation, and intensive care unit stay were independent risk factors for central nervous system injury after TEVAR of type B aortic dissection (P < 0.05).

CONCLUSION

For high-risk patients with central nervous system injury after TEVAR of type B aortic dissection, early intervention measures should be implemented to lower the risk of neurological discomfort following surgery in high-risk patients with central nervous system injury after TEVAR for type B aortic dissection.

Temporal trends in mortality of aortic dissection and rupture in the UK, Japan, the USA and Canada

OBJECTIVE

Aortic dissection and aortic aneurysm rupture are aortic emergencies and their clinical outcomes have improved over the past two decades; however, whether this has translated into lower mortality across countries remains an open question. The purpose of this study was to compare mortality trends from aortic dissection and rupture between the UK, Japan, the USA and Canada.

METHODS

We analysed the WHO mortality database to determine trends in mortality from aortic dissection and rupture in four countries from 2000 to 2019. Age-standardised mortality rates per 100 000 persons were calculated, and annual percentage change was estimated using joinpoint regression.

RESULTS

Age-standardised mortality rates per 100 000 persons from aortic dissection and rupture in 2019 were 1.04 and 1.80 in the UK, 2.66 and 1.16 in Japan, 0.76 and 0.52 in the USA, and 0.67 and 0.81 in Canada, respectively. There was significantly decreasing trends in age-standardised mortality from aortic rupture in all four countries and decreasing trends in age-standardised mortality from aortic dissection in the UK over the study period. There was significantly increasing trends in mortality from aortic dissection in Japan over the study period. Joinpoint regression identified significant changes in the aortic dissection trends from decreasing to increasing in the USA from 2010 and Canada from 2012. In sensitivity analyses stratified by sex, similar trends were observed.

CONCLUSIONS

Trends in mortality from aortic rupture are decreasing; however, mortality from aortic dissection is increasing in Japan, the USA and Canada. Further study to explain these trends is warranted.

Acute Type B Aortic Dissection Complicated With Spinal Cord Ischemia and Paraplegia Treated With Endovascular Scissor Technique

Spinal cord ischemia leading to paraplegia is a rare, life-limiting complication of acute type B aortic dissection. We report a case of spinal cord ischemia occurred in a young woman treated with endovascular scissor technique in urgent setting. The patient had an uneventful post-procedural course. After 4 months, computed tomography angiography confirmed false lumen reperfusion and major symptoms were regressed. In selected cases, this procedure is a tool to improve false lumen perfusion in type B dissections, and demonstrated to be helpful in our case of spinal cord ischaemia.

Hemodynamic Evaluation of Type B Aortic Dissection Using Compressed Sensing Accelerated 4D Flow MRI

BACKGROUND

4D Flow MRI is a quantitative imaging technique to evaluate blood flow patterns; however, it is unclear how compressed sensing (CS) acceleration would impact aortic hemodynamic quantification in type B aortic dissection (TBAD).

PURPOSE

To investigate CS-accelerated 4D Flow MRI performance compared to GRAPP-accelerated 4D Flow MRI (GRAPPA) to evaluate aortic hemodynamics in TBAD.

STUDY TYPE

Prospective.

POPULATION

Twelve TBAD patients, two volunteers.

FIELD STRENGTH/SEQUENCE

1.5T, 3D time-resolved cine phase-contrast gradient echo sequence.

ASSESSMENT

GRAPPA (acceleration factor [R] = 2) and two CS-accelerated (R = 7.7 [CS7.7] and 10.2 [CS10.2]) 4D Flow MRI scans were acquired twice for interscan reproducibility assessment. Voxelwise kinetic energy (KE), peak velocity (PV), forward flow (FF), reverse flow (RF), and stasis were calculated. Plane-based mid-lumen flows were quantified. Imaging times were recorded.

TESTS

Repeated measures analysis of variance, Pearson correlation coefficients (r), intraclass correlation coefficients (ICC). P < 0.05 indicated statistical significance.

RESULTS

The KE and FF in true lumen (TL) and PV in false lumen (FL) did not show difference among three acquisition types (P = 0.818, 0.065, 0.284 respectively). The PV and stasis in TL were higher, KE, FF, and RF in FL were lower, and stasis was higher in GRAPPA compared to CS7.7 and CS10.2. The RF was lower in GRAPPA compared to CS10.2. The correlation coefficients were strong in TL (r = [0.781-0.986]), and low to strong in FL (r = [0.347-0.948]). The ICC levels demonstrated moderate to excellent interscan reproducibility (0.732-0.989). The FF and net flow in mid-descending aorta TL were significantly different between CS7.7 and CS10.2.

CONCLUSION

CS-accelerated 4D Flow MRI has potential for clinical utilization with shorter scan times in TBAD. Our results suggest similar hemodynamic trends between acceleration types, but CS-acceleration impacts KE, FF, RF, and stasis more in FL.

EVIDENCE LEVEL

1 Technical Efficacy: Stage 2.

How to TEVAR swine for scientific research: Technical, anatomic, and device considerations to translate human TEVAR techniques into the large animal laboratory

OBJECTIVE

Thoracic Endovascular Aortic Repair (TEVAR) is well established in humans. Despite widespread use, additional research questions related to thoracic aortic stenting and endovascular innovation require large animal models. Translating human TEVAR devices and techniques into animal models, however, is a challenge even for experienced endovascular surgeons looking to develop a large animal TEVAR model.This article describes swine-specific strategies to deploy human TEVAR stent grafts, delineate how to select, size, prepare, and re-use human stents and deployment systems in swine, and how to translate human imaging modalities to large animal TEVAR.

METHODS

We describe a selection of related TEVAR models and techniques in Yorkshire swine to support scientific inquiry. This includes an animal husbandry and pre-operative preparation and planning program. All imaged specimens in this paper are castrated male Yorkshire swine in the 60-80 kg range and underwent TEVAR with the Medtronic Navion stent and deployment system.

RESULTS

To study human aortic stent grafts in swine, the animals generally must be at least 50 kgs to guarantee a 2 cm internal aortic diameter at the left subclavian, and for the iliac arteries to accommodate the human deployment system. Swine will have longer torsos and shorter iliofemoral segments than a human of the same weight which can make human deployment systems too short to reach the left subclavian from the femoral arteries in larger animals. We provide techniques to overcome this, including open iliac access or upside-down carotid TEVAR, which may be particularly useful if the scientific data would be confounded by iliofemoral access.Unlike humans that present clinically with axial imaging, swine will generally not have preoperative imaging, and many translational research laboratories do not have access to inexpensive preoperative CT, or any intraoperative CT scanning, which we are fortunate to have. We describe, therefore, several strategies for imaging in this setting including TEVAR via C-arm fluoroscopy and with or without in-laboratory CT scanning. Due to the low-resource setting of most large animal laboratories, as compared to a human hybrid room, we also describe several techniques to reduce cost and reuse materials, including the stent grafts, which at the end of non-survival experiments can be recovered during necropsy, cleaned, reinserted into the deployment device and reused on additional animals.

CONCLUSIONS

This article describes a collection of related techniques and tips to translate human TEVAR imaging, sizing/selection, deployment, and anatomy to swine research. Using this framework alone, an experienced human vascular or endovascular surgeon may develop a complete aortic stenting animal model with strategies for scientific data acquisition.

Acute Kidney Injury in Patients with Acute Type B Aortic Dissection

OBJECTIVE

Acute kidney injury (AKI) is common in patients with aortic diseases; however, it has not been extensively studied in acute type B aortic dissection (TBAD). AKI is known to be associated with adverse kidney outcomes and premature death. This study investigated the incidence and impact of AKI in patients with acute TBAD.

METHODS

This was a retrospective study including data from two tertiary vascular centres in the UK. Case notes and electronic records were reviewed for consecutive patients presenting with acute symptomatic TBAD. Patients were managed according to a uniform clinical protocol; both patients who underwent surgery and those managed conservatively were included in this analysis. Serum creatinine values were used to calculate the number of patients who developed AKI, based on validated Kidney Disease Improving Global Outcomes definitions. Associations between incidence of AKI, death, and Major Adverse Kidney Events (MAKE; defined as death, dialysis and/or drop in estimated glomerular filtration rate > 25%) were explored.

RESULTS

Overall, 66 (42.6%) of 155 patients developed AKI within one week of presenting with TBAD. Of these, 23 patients (34.8%) had stage 1, 26 patients (39.4%) stage 2, and 17 patients (25.8%) stage 3 AKI. MAKE at 30 and 90 days occurred in 17 (11.0%) and 12 patients (7.7%), respectively. AKI was associated with significantly worse outcomes, with a 24.2% mortality rate in the AKI group compared with 7.8% among those with no AKI (p <.001); this association was also significant in adjusted analyses, both in patients who did and did not undergo surgery.

CONCLUSION

AKI is very common among patients presenting with acute TBAD, even in clinically uncomplicated disease. There was a significant association with mortality and MAKE, whether patients underwent surgery or not. This warrants further investigation to better understand the underlying causes of the AKI and investigate management strategies which may improve outcomes.

Coronary artery involvement in type A aortic dissection: Fate of the coronaries

BACKGROUND

Type A aortic dissection (TAAD) involves a tear in the intimal layer of the thoracic aorta proximal to the left subclavian artery, and hence, carries a high risk of mortality and morbidity and requires urgent intervention. This dissection can extend into the main coronary arteries. Coronary artery involvement in TAAD can either be due to retrograde extension of the dissection flap into the coronaries or compression and/or blockage of these vessels by the dissection flap, possibly causing myocardial ischemia. Due to the emergent nature of TAAD, coronary involvement is often missed during diagnosis, thereby delaying the required intervention.

AIMS

The main scope of this review is to summarize the literature on the incidence, mechanism, diagnosis, and treatment of coronary artery involvement in TAAD.

METHODS

A comprehensive literature search was performed using multiple electronic databases, including PubMed, Ovid, Scopus and Embase, to identify and extract relevant studies.

RESULTS

Incidence of coronary artery involvement in TAAD was seldom reported in the literature, however, some studies have described patients diagnosed either preoperatively, intraoperatively following aortic clamping, or even during autopsy. Among the few studies that reported on this matter, the treatment choice for coronary involvement in TAAD was varied, with the majority revascularizing the coronary arteries using coronary artery bypass grafting or direct local repair of the vessels. It is well-established that coronary artery involvement in TAAD adds to the already high mortality and morbidity associated with this disease. Lastly, the right main coronary artery was often more implicated than the left.

CONCLUSION

This review reiterates the significance of an accurate diagnosis and timely and effective interventions to improve prognosis. Finally, further large cohort studies and longer trials are needed to reach a definitive consensus on the best approach for coronary involvement in TAAD.

Endovascular Repair of the Thoracic Aorta Combined with Drug Therapy in Acute Uncomplicated Type B Aortic Dissection

Objective

This study was to evaluate the clinical efficacy of thoracic endovascular aortic repair (TEVAR) combined with Best Medical Therapy (BMT) in acute uncomplicated type B aortic dissection (TBAD).

Methods

Using the random method, 90 patients admitted to our hospital between January 2018 and January 2020 with acute uncomplicated TBAD were randomly divided into a control group and a study group, with 45 cases in each of the groups. The effectiveness of BMT combined with TEVAR treatment was compared.

Results

The incidence of recent adverse reactions did not differ significantly between the two groups. Compared to the control group, the 1-year survival rate and 2-year survival rate of patients in the study group were considerably higher. In order to examine the relationship between survival and time, the Kaplan-Meier curve was used. Both groups reached the median survival time after 24 months of follow-up. The expected survival time of the study group was longer than that of the control group. False lumen thrombosis or absence of thrombus was significantly more prevalent in the study group than in the control group.

Conclusion

For patients with acute uncomplicated TBAD, BMT combined with TEVAR can significantly improve the long-term survival rate and increase the expected survival time.

What is the optimal timing for thoracic endovascular aortic repair in uncomplicated Type B aortic dissection?

BACKGROUND

Uncomplicated Stanford Type B aortic dissection (un-TBAD) is characterized by a tear in the aorta distal to the left subclavian artery without ascending aorta and arch involvement. Optimized cardiovascular control (blood pressure and heart rate) is the current gold standard treatment according to current international guidelines. However, emerging evidence indicates that thoracic endovascular aortic repair (TEVAR) is both safe and effective in the treatment of un-TBAD with improved long-term survival outcomes in combination with optimal medical therapy (OMT) relative to OMT alone. However, the optimal timeframe for intervention is not entirely clarified.

AIMS

This review critically addresses current state-of-the-art comparing TEVAR with OMT and corresponding clinical outcomes for un-TBAD based on timing of intervention.

METHODS

We carried out a comprehensive literature search on multiple electronic databases including PUBMED and Scopus to collate all research evidence on timing of TEVAR in uncomplicated Type B aortic dissection.

RESULTS

TEVAR has proven to be a safe and effective treatment for un-TBAD in combination with OMT through comparable survival outcomes, improved aortic remodeling, and relatively low periprocedural added risks. Though the timing of intervention remains controversial, it is becoming clear that performing TEVAR during the subacute phase of un-TBAD yields better outcomes compared to earlier and delayed (>90 days) intervention.

CONCLUSIONS

Further research is required into both short- and long-term outcomes of TEVAR in addition to its optimal therapeutic window for un-TBAD. With stronger evidence, TEVAR is likely to be adopted as the gold-standard intervention for un-TBAD with definitive timeframe guidelines.

Secondary Interventions After TEVAR for Aortic Dissection

The goal of thoracic endograft placement in type B aortic dissection is to prevent aneurysmal degeneration and other complications. Although TEVAR is a highly effective tool for managing type B aortic dissection, many patients will require additional interventions. In this article, we present a case-based review of techniques for the management of persistent false lumen perfusion and stent-graft induced new entry tears after TEVAR for aortic dissection.