Aortic Arch Debranching and Thoracic Endovascular Aortic Repair (TEVAR) for Type B Aortic Dissection.

BACKGROUND: Since its introduction, thoracic endovascular aortic repair (TEVAR) has revolutionized the treatment of type B aortic dissections (TBADs). However, the proximal aspect of the aortic pathology treated may infringe on the origin of the left subclavian artery or even more proximally. Hence, to ensure durable outcomes, the origin of these vessels needs to be covered, but an extra-anatomical bypass is required to perfuse vital branches, known as aortic arch debranching. This series aims to describe and delineate the disparities of aortic arch debranching during TEVAR for TBAD. METHODS: A retrospective review and analysis of a multicenter international database was conducted to identify patients with TBAD treated with TEVAR between 2005 and 2021. Data analyzed included patient demographics, disease characteristics, operative characteristics, and postoperative outcomes with follow-up on mortality and reintervention. All statistical analyses were carried out using IBM SPSS 26. Patient survival was calculated using a Kaplan-Meier survival analysis, and a P value of less than 0.05 was considered statistically significant. RESULTS: A total of 58 patients were included in the analysis, of which 27 (46.6%) presented with complicated disease and 31 were uncomplicated, of which 10 (17.2%) were classed as high risk and 21 (36.2%) low risk. Zone 2 was the most common proximal landing zone for the stent graft. Left subclavian artery bypass was performed selectively (26%), with 1 stroke occurring, likely due to embolic reasons. A further 6 underwent more proximal aortic debranching before TEVAR (10%) and was a significant risk factor for mortality and the number of stents deployed. The overall rates of reintervention and mortality were 17.2% (n = 10) and 29.3% (n = 17). CONCLUSIONS: Aortic arch debranching and TEVAR for TBAD is associated with significant mortality. Future developments to treat aortic arch pathology could incorporate branched graft devices, eliminating the need for debranching, improving stroke rates, and reducing future reinterventions.

Personal protective equipment-induced systemic hypercapnic hypoxaemia: translational implications for impaired cognitive-clinical functional performance.

BACKGROUND: Personal protective equipment (PPE) adversely affects pulmonary gas exchange and may result in systemic hypercapnic hypoxaemia and headache. This study aimed to determine what extent PPE affects cerebral symptoms, global cerebral blood flow, and cognitive functional performance. METHODS: Higher surgical trainees participated in a randomized, repeated-measures, crossover study, completing 60 min of laparoscopic surgical simulation in both standard operating attire and type 3 PPE. Measurements were collected at baseline and after 60 min of simulation. The primary outcome measure was headache. Headache was examined using the validated visual analogue scale (VAS) and Environmental Symptoms Questionnaire C (ESQ-C), global cerebral blood flow with duplex ultrasonography, and visuospatial and executive gross/fine motor function with grooved peg board (GPB) and laparoscopic bead (LSB) board tasks. RESULTS: Thirty-one higher surgical trainees (20 men, 11 women) completed the study. Compared with standard operating attire, PPE increased headache assessment scores (mean(s.d.) VAS score 3.5(5.6) versus 13.0(3.7), P < 0.001; ESQ-C score 1.3(2.0) versus 5.9(5.1), P < 0.001) and was associated with poorer completion times for GPB-D (61.4(12.0) versus 71.1(12.4) s; P = 0.034) and LSB (192.5(66.9) versus 270.7(135.3) s; P = 0.025) tasks. Wearing PPE increased heart rate (82.5(13.6) versus 93.5(13.0) beats/min; P = 0.022) and skin temperature (36.6(0.4) versus 37.1(0.5)°C; P < 0.001), but decreased peripheral oxygen saturation (97.9(0.8) versus 96.8(1.0) per cent; P < 0.001). Female higher surgical trainees exhibited higher peripheral oxygen saturation across all conditions. No differences were observed in global cerebral blood flow as a function of attire, time or sex. CONCLUSION: Despite no marked changes in global cerebral blood flow, type 3 PPE was associated with increased headache scores and cerebral symptoms (VAS and ESQ-C) alongside impaired executive motor function highlighting the clinical implications of PPE-induced impairment for cognitive-clinical performance.

Myths and methodologies: Cardiopulmonary exercise testing for surgical risk stratification in patients with an abdominal aortic aneurysm; balancing risk over benefit.

The extent to which patients with an abdominal aortic aneurysm (AAA) should exercise remains unclear, given theoretical concerns over the perceived risk of blood pressure-induced rupture, which is often catastrophic. This is especially pertinent during cardiopulmonary exercise testing, when patients are required to perform incremental exercise to symptom-limited exhaustion for the determination of cardiorespiratory fitness. This multimodal metric is being used increasingly as a complementary diagnostic tool to inform risk stratification and subsequent management of patients undergoing AAA surgery. In this review, we bring together a multidisciplinary group of physiologists, exercise scientists, anaesthetists, radiologists and surgeons to challenge the enduring 'myth' that AAA patients should be fearful of and avoid rigorous exercise. On the contrary, by appraising fundamental vascular mechanobiological forces associated with exercise, in conjunction with 'methodological' recommendations for risk mitigation specific to this patient population, we highlight that the benefits conferred by cardiopulmonary exercise testing and exercise training across the continuum of intensity far outweigh the short-term risks posed by potential AAA rupture.

Dynamic and Static Vessel Malperfusion as a Consequence of Acute Type B Aortic Dissection.

BACKGROUND: Acute type B aortic dissection (TBAD) is relatively uncommon with an estimated incidence of up to 8 cases per 100,000 individuals annually. It can be classified based on presenting clinical and radiological features into complicated and uncomplicated. Following the initial tear, the direction and extent of the dissection flap is unpredictable, possibly propagating proximally or distally. One consequence of a dissection flap is the occurrence of organ malperfusion by occlusion of the origin of the branch vessel. The 2 types of malperfusion in TBAD are static and dynamic, with the latter being the more common mechanism. Thoracic endovascular aortic repair (TEVAR) has demonstrated its high safety and efficacy when used for TBAD and subsequent malperfusion. AIMS: This original study specifically examines patients diagnosed with acute TBAD and treated with TEVAR at a single vascular unit, focusing on those presenting with organ malperfusion. METHODS: Over 16 years, 28 TBAD patients were admitted to a single center and treated using TEVAR. After clinical examination, all patients underwent computed tomography of the thorax and abdomen/pelvis to confirm the diagnosis and classify the extent of the dissection proximally and distally. Once diagnosed, patients were transferred to the high dependency unit and started on blood pressure medication. Subsequent computed tomography scans were performed to classify patients, after which TEVAR was performed. RESULTS: Twenty five patients underwent TEVAR for TBAD, of which 8 (32%) had symptoms of organ malperfusion. The majority of cases presented with hypertension (89%), describing a sudden onset of upper/midthoracic pain. The origin of the left subclavian artery was occluded in 14 (56%) patients with 9 (64%) needing an extra-anatomical bypass. There was only a single mortality due to a posterior circulation stroke 2 days after TEVAR. Median (range) length of coverage of thoracic aorta by the stent-graft was 33 (15-35) cm. The true lumen (TL) perfused the celiac artery in 6/8 malperfusion patients, superior mesenteric artery in 7/8, right renal artery in 6/8, and, conversely, left renal artery in only 2/8. CONCLUSIONS: Complicated TBADs behave in an unpredictable manner as it seems the propagating intimal flap invariably maintains vital organ perfusion via the TL. Maintenance of abdominal vessels perfusion from the TL following TEVAR is vital to ensuring optimal results.

Cost Analysis of Thoracic Endovascular Aortic Repair in Type B Aortic Dissection: How Much Does Quality Cost?

BACKGROUND: Aortic dissection (AD) is a life-threatening medical emergency that affects an estimated 3-4 people per 100,000 annually, with 40% of cases classified as type B AD (TBAD). TBAD can be further classified as being complicated (co-TBAD) or uncomplicated (un-TBAD) based on the presence or absence of certain features such as malperfusion and rupture. TBAD can be managed conservatively with optimal medical therapy (OMT), or invasively with open surgical repair (OSR) or thoracic endovascular aortic repair (TEVAR), depending on several factors such as type of TBAD and its clinical acuity. The cost-effectiveness, or cost-benefit profile, of these strategies must be given equal consideration. However, TBAD studies featuring cost analyses are limited within the literature. This narrative review aims to address the gap in the literature on cost-effectiveness of TBAD treatments by providing an overview of cost analyses comparing OMT with TEVAR in un-TBAD and TEVAR with OSR in co-TBAD. Another aim is to provide a market analysis of the commercially available TEVAR devices. METHODS: A comprehensive literature search was performed using several search engines including PubMed, Ovid, Google Scholar, Scopus, and Embase to identify and extract relevant studies. RESULTS: Several TEVAR devices are available commercially on the global market costing $12,000-19,495. Nevertheless, the Terumo Aortic RELAY® stent graft seems to be the most cost-effective, yielding highly favourable clinical outcomes. Despite the higher initial cost of TEVAR, evidence in the literature strongly suggest that it is superior to OMT for un-TBAD on the long-term. In addition, TEVAR is well established in the literature as being gold-standard repair technique for co-TBAD, replacing OSR by offering a more optimal cost-benefit profile through lower costs and improved results. CONCLUSIONS: The introduction of TEVAR has revolutionized the field of aortovascular surgery by offering a highly efficacious and long-term cost-effective treatment for TBAD.

Fate and Consequences of the False Lumen After Thoracic Endovascular Aortic Repair in Type B Aortic Dissection.

BACKGROUND: Type B aortic dissection (TBAD) occurs due to an entry tear in the intimal layer of the aorta distal to the origin of the left subclavian artery where blood enters the newly formed false lumen (FL) and extends distally or proximally to form a dissection over an indeterminate length of the aorta which, over time, may eventually rupture. Thoracic endovascular aortic repair (TEVAR) aims to seal off the entry tear proximally with the stent-graft, occluding the origin of the dissection and excluding the FL. Nevertheless, in some cases, the perfusion to the FL is maintained, hindering the aortic remodelling process and increasing the risk of aneurysmal degeneration and rupture, particularly in the abdominal aorta where evidence suggest that remodelling is slower. This review examines the long-term effects of a patent or partially thrombosed FL on clinical outcomes following TEVAR in TBAD, also highlighting the pathological processes behind negative aortic remodelling. Another aim of this review is to provide an overview and appraisal of the currently available techniques for managing a patent or partially thrombosed FL to prevent long-term morbidity occurring. METHODS: A comprehensive literature search was performed using several search engines including PubMed, Ovid, Google Scholar, Scopus, and Embase to identify and extract relevant studies. RESULTS: Evidence in the literature show that a partially thrombosed FL is more dangerous than a patent FL due to the occlusion of the distal re-entry tears, impeding outflow and increasing mean arterial and diastolic pressures, whereas the latter is decompressed via distal re-entry sites. FL thrombosis and satisfactory remodelling is sometimes achieved in as few as 40% of patients after TEVAR due to the maintained perfusion of the FL either at the level of the thoracic or abdominal aorta. However, although the thoracic aorta is predominantly covered by the TEVAR stent-graft, poorer remodelling and more dilation is seen in the abdominal aorta. Several techniques are available to embolize the FL, including the Provisional Extension to Induce Complete Attachment, Stent Assisted Balloon Induced Intimal Disruption and Relamination in Aortic Dissection Repair, candy-plug, and Knickerbocker techniques. CONCLUSIONS: The management of TBAD is invariably TEVAR to seal off the proximal entry tear while extending the repair distally to completely exclude the FL. A risk of aortic wall dilatation distal to TEVAR stent-graft remains; hence, regular monitoring and accurate imaging are essential. At present, a patent FL can be treated using a range of different endovascular techniques.

Ethnic & Sex Disparities in Type B Aortic Dissection Patients Undergoing Thoracic Endovascular Aortic Repair: An International Perspective.

BACKGROUND: There has been a revolution in the management of type B aortic dissection (TBAD) over the last 2 decades due to the increasing development of endovascular techniques, with the prime example being thoracic endovascular aortic repair (TEVAR). However, many controversies concerning the use of TEVAR in TBAD exist. For instance, there is little available evidence suggesting any differences in demographics, disease characteristics, intervention technicalities, and clinical outcomes between males and females as well as different ethnicities when undergoing TEVAR for TBAD, both in the short and long term. Also, there is no risk prediction model/tool available. The objective of this international study is to describe and delineate the disparities between male and female patients of different ethnicities in terms of demographics, disease and interventional characteristics, and clinical outcomes. METHODS: Over 17 years a total of 58 TBAD patients were admitted to 2 tertiary vascular centres and treated using TEVAR. Mortality, postoperative complications and reintervention data were recorded for the first 30 days after the procedure as well as during follow-up. Follow-up for all patients lasted until the study endpoint or until a patient's death. Data were analysed retrospectively using IBM SPSS statistical package 26 for Windows. RESULTS: The mean age was similar between the 2 groups, with the majority of patients in both being Caucasian. More than half of the males had complicated TBAD, while the majority of females were classed as having uncomplicated disease. The most commonly utilized proximal and distal landing zone for the TEVAR stent graft was zone 2 and zone 4, respectively. The mean proximal stent diameter was significantly larger in males compared to females (P = 0.004). The difference in mean distal diameter between the 2 groups was insignificant (P = 0.721). The mean total stent coverage of the thoracic aorta was 251.3 mm in male patients compared to 291.2 mm in females (P = 0.203). A total of 32 patients underwent adjunctive procedures. Seven (17%) of the males had one or more postoperative complications compared to 2 (12%) females. Nine (22%) males underwent a reintervention procedure post TEVAR compared to only 1 (6%) female (P = 0.136). Overall, males had a mortality rate of 24% (n = 10) compared to 41% of females (n = 7) (P = 0.201). Estimated survival of males and females post TEVAR was 80.4 ± 9.6 months and 69.7 ± 14.4 months (P = 0.428). For the total population, the number of stent grafts was inversely correlated with mortality. CONCLUSIONS: Despite the favourable clinical outcomes achieved by TEVAR in TBAD, there remains a grey area concerning its management. Thus, it is important to perform risk stratification of individual patients using their demographics and comorbidities, particularly scrutinizing patient sex and ethnic origin, when considering intervention for TBAD to achieve optimum results.

'Fit for surgery': the relationship between cardiorespiratory fitness and postoperative outcomes.

NEW FINDINGS: What is the topic of this review? The relationships and physiological mechanisms underlying the clinical benefits of cardiorespiratory fitness (CRF) in patients undergoing major intra-abdominal surgery. What advances does it highlight? Elevated CRF reduces postoperative morbidity/mortality, thus highlighting the importance of CRF as an independent risk factor. The vascular protection afforded by exercise prehabilitation can further improve surgical risk stratification and postoperative outcomes. ABSTRACT: Surgery accounts for 7.7% of all deaths globally and the number of procedures is increasing annually. A patient's 'fitness for surgery' describes the ability to tolerate a physiological insult, fundamental to risk assessment and care planning. We have evolved as obligate aerobes that rely on oxygen (O2 ). Systemic O2 consumption can be measured via cardiopulmonary exercise testing (CPET) providing objective metrics of cardiorespiratory fitness (CRF). Impaired CRF is an independent risk factor for mortality and morbidity. The perioperative period is associated with increased O2 demand, which if not met leads to O2 deficit, the magnitude and duration of which dictates organ failure and ultimately death. CRF is by far the greatest modifiable risk factor, and optimal exercise interventions are currently under investigation in patient prehabilitation programmes. However, current practice demonstrates potential for up to 60% of patients, who undergo preoperative CPET, to have their fitness incorrectly stratified. To optimise this work we must improve the detection of CRF and reduce potential for interpretive error that may misinform risk classification and subsequent patient care, better quantify risk by expressing the power of CRF to predict mortality and morbidity compared to traditional cardiovascular risk factors, and improve patient interventions with the capacity to further enhance vascular adaptation. Thus, a better understanding of CRF, used to determine fitness for surgery, will enable both clinicians and exercise physiologists to further refine patient care and management to improve survival.

Malperfusion syndrome in acute type A aortic dissection: It's not what you know, it's what you can prove!

Organ malperfusion after type A aortic dissection represents a high-risk group for open surgical repair. This is particularly the case when mesenteric ischemia occurs. Central aortic repair should be considered for all presenting with malperfusion as many are due to dynamic obstruction. However, depending on imaging and clinical appearance many should be considered for adjunctive techniques including catheter-based endovascular and even open surgical revascularisation may be appropriate. This is due to as many as 20% with a static component to the malperfusion syndrome. Improving methods of ascertaining the type of malperfusion being treated and presenting symptoms requires a multidisciplinary team with access to a hybrid theater where all techniques can be accessed 24/7. This would only be achieved by centralization of vascular units whereby sufficient funding and organization are in place to deal with the consequences of this unpredictable and invariably deadly aortic pathology.

Modified Warden procedure using aortic homograft for superior vena caval translocation: Where is the evidence?

BACKGROUND: Partial anomalous pulmonary venous connection (PAPVC) occurs when at least one pulmonary vein drains into the right atrium or its tributaries rather than the left atrium, most commonly connecting with the superior vena cava (SVC). The Warden procedure involves transecting the SVC proximal to the uppermost connection of the pulmonary vein followed by proximal SVC reattachment to the right atrial appendage. However, descending thoracic aortic homograft replacement for SVC translocation has recently been introduced as a modified technique. AIMS: This commentary aims to discuss the recent study by Said et al. who reported their experiences with six PAPVC cases undergoing a modified Warden procedure using thoracic aortic homograft SVC translocation. METHODS: A comprehensive literature search was performed using multiple electronic databases to collate the relevant research evidence. RESULTS: The Warden procedure is associated with a 10% incidence of SVC obstruction with many requiring reintervention. Meanwhile, using the aortic homograft for SVC translocation, Said et al. observed no SVC obstructions. In addition, this modified technique does not require anticoagulation and has demonstrated an improvement in long-term SVC patency. Nevertheless, it can be considered an expensive procedure. Moreover, since the thoracic aortic homograft utilized is biological tissue, only long-term follow-up will determine whether calcification and graft degeneration is an issue. CONCLUSION: It can be concluded that the modified Warden procedure is a safe and effective method to reconstruct the systemic venous drainage into the right atrium when a direct anastomosis under tension might be prone to re-stenosis.

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.

Favorable neurological outcomes in thoracic endovascular aortic repair with RELAY™ branched-An international perspective.

BACKGROUND: While open surgical repair continues to be the mainstay option for aortic arch reconstruction, the associated mortality, morbidity, and high turn-down rates have led to a need for the development of minimally invasive options for aortic arch repair. Though RELAY™ Branched (Terumo Aortic, Inchinnan, UK) represents a promising option for complex endovascular aortic arch repair, neurological complications remain a pertinent risk. Herein we seek to present multicenter data from Europe documenting the neurological outcomes associated with RELAY™ Branched. METHODS: Prospective data collected between January 2019 and January 2022 associated with patients treated with RELAY™ single-, double-, and triple-branched endoprostheses from centers across Europe was retrospectively analyzed with descriptive and distributive analysis. Follow-up data from 30 days and 6, 12, and 24 months postoperatively were included. Patient follow-up was evaluated for the onset of disabling stroke (DS) and non-disabling stroke (NDS). RESULTS: Technical success was achieved in 147 (99.3%) cases. Over 24 months period, in total, six (4.1%) patients suffered DS, and eight (5.4%) patients suffered NDS after undergoing aortic arch repair with RELAY™. All patients that developed postoperative DS had been treated with the double-branched RELAY™ endoprosthesis. DISCUSSION: The data presented herein demonstrates that RELAY™ Branched is associated with favorable neurological outcomes and excellent technical success rates. Key design features of the endoprosthesis and good perioperative management can contribute greatly to mitigating neurological complications following endovascular aortic arch repair.

Subjective assessment underestimates surgical risk: On the potential benefits of cardiopulmonary exercise testing for open thoracoabdominal repair.

BACKGROUND: Initial clinical evaluation (ICE) is traditionally considered a useful screening tool to identify frail patients during the preoperative assessment. However, emerging evidence supports the more objective assessment of cardiorespiratory fitness (CRF) via cardiopulmonary exercise testing (CPET) to improve surgical risk stratification. Herein, we compared both subjective and objective assessment approaches to highlight the interpretive idiosyncrasies. METHODS: As part of routine preoperative patient contact, patients scheduled for major surgery were prospectively "eyeballed" (ICE) by two experienced clinicians before more detailed history taking that also included the American Society of Anesthesiologists score classification. Each patient was subjectively judged to be either "frail" or "not frail" by ICE and "fit" or "unfit" from a thorough review of the medical notes. Subjective data were compared against the more objective validated assessment of postoperative outcomes using established CPET "cut-off" metrics incorporating peak pulmonary oxygen uptake, V̇O2PEAK at the anaerobic threshold (V̇O2 -AT), and ventilatory equivalent for carbon dioxide that collectively informed risk stratification. These data were retrospectively extracted from a single-center prospective National Health Service database. Data were analyzed using the Chi-square automatic interaction detection decision tree method. RESULTS: A total of 127 patients were examined that comprised 58% male and 42% female patients aged 69 ± 10 years with a body mass index of 29 ± 7 kg/m2 . Patients were poorly conditioned with a V̇O2PEAK almost 20% lower than predicted for age, sex-matched healthy controls with 35% exhibiting a V̇O2 -AT < 11 ml/kg/min. Disagreement existed between the subjective assessments of risk with ∼34% of patients classified as not frail on ICE were considered unfit by notes review (p < .0001). Furthermore, ∼35% of patients considered not frail on ICE and ∼31% of patients considered fit by notes review exhibited a V̇O2 -AT < 11 ml/kg/min, and of these, ∼28% and ∼19% were classified as intermediate to high risk. CONCLUSIONS: These findings highlight the interpretive limitations associated with the subjective assessment of patient frailty with surgical risk classification underestimated in up to a third of patients compared to the validated assessment of CRF. They reinforce the benefits of a more objective and integrated approach offered by CPET that may help us to improve perioperative risk assessment and better direct critical care provision in patients scheduled for "high-stakes" surgery including open thoracoabdominal aortic aneurysm repair.

Cardiothoracic surgery leadership and learning are indispensable to each other.

Cardiothoracic surgery is facing a multitude of challenges in leadership and training on the global scale, these being a complex and aging patient population, shortage of cardiac surgeons, diminishing student interest and trainee enthusiasm, increasingly challenging training obstacles and work-life imbalances, suboptimal job prospects, reports of discrimination and bullying and lack of diversity as well as gap between innovation and technology, clinical application, and training of future surgeons. The survival of cardiac surgery hinges on the leadership attracting and retaining young surgeons into the specialty. Mentoring, leading through example, recognizing the work-life imbalances, adapting to diverse and modern training models and embracing diversity with respect to gender and race, will ultimately be required to create and cultivate a nurturing environment of training and preparing future leaders. The vision for training future generations of cardiothoracic surgeons must rely heavily on strengthening the unity of the heart team. In doing so we can provide the best possible care for our patients and a most fulfilling career for the future generation of cardiac surgeons.

Criteria for endovascular intervention in type B aortic dissection.

BACKGROUND: The use of thoracic endovascular aortic repair (TEVAR) for the management of uncomplicated type B aortic dissection (un-TBAD) remains controversial. There is a lack of consensus over whether pre-emptive TEVAR should be carried out in patients with un-TBAD at risk of progression to complicated TBAD. We present a review of current evidence and seek to suggest criteria where endovascular intervention in un-TBAD may prove beneficial relative to pharmacotherapy alone. METHODS AND MATERIALS: PubMed and Cochrane databases were searched using terms including: type B aortic dissection, risk factors, medical therapy, TEVAR, false lumen (FL) expansion, and mortality. Papers were selected based on title and abstract. RESULTS: Optimal medical therapy remains the mainstay treatment for patients with un-TBAD, however, patients with un-TBAD present with varying degrees of disease progression risk. Factors such as age, aortic morphology, history of connective tissue disorders, FL thrombosis, and aortic branch involvement may potentiate progression from un-TBAD to complicated TBAD. Short- and long-term outcomes associated with TEVAR for TBAD remain promising. CONCLUSION: Pre-emptive TEVAR may be beneficial in patients with un-TBAD presenting with the above factors, however, further prospective research into the optimal timing for TEVAR in un-TBAD is required.

Single-Cell RNA Sequencing Unveils Unique Transcriptomic Signatures of Organ-Specific Endothelial Cells.

BACKGROUND: Endothelial cells (ECs) display considerable functional heterogeneity depending on the vessel and tissue in which they are located. Whereas these functional differences are presumably imprinted in the transcriptome, the pathways and networks that sustain EC heterogeneity have not been fully delineated. METHODS: To investigate the transcriptomic basis of EC specificity, we analyzed single-cell RNA sequencing data from tissue-specific mouse ECs generated by the Tabula Muris consortium. We used a number of bioinformatics tools to uncover markers and sources of EC heterogeneity from single-cell RNA sequencing data. RESULTS: We found a strong correlation between tissue-specific EC transcriptomic measurements generated by either single-cell RNA sequencing or bulk RNA sequencing, thus validating the approach. Using a graph-based clustering algorithm, we found that certain tissue-specific ECs cluster strongly by tissue (eg, liver, brain), whereas others (ie, adipose, heart) have considerable transcriptomic overlap with ECs from other tissues. We identified novel markers of tissue-specific ECs and signaling pathways that may be involved in maintaining their identity. Sex was a considerable source of heterogeneity in the endothelial transcriptome and we discovered Lars2 to be a gene that is highly enriched in ECs from male mice. We found that markers of heart and lung ECs in mice were conserved in human fetal heart and lung ECs. We identified potential angiocrine interactions between tissue-specific ECs and other cell types by analyzing ligand and receptor expression patterns. CONCLUSIONS: We used single-cell RNA sequencing data generated by the Tabula Muris consortium to uncover transcriptional networks that maintain tissue-specific EC identity and to identify novel angiocrine and functional relationships between tissue-specific ECs.

Sensitivity analysis of the primary endpoint from the N-MOmentum study of inebilizumab in NMOSD.

BACKGROUND: In the N-MOmentum trial, the risk of an adjudicated neuromyelitis optica spectrum disorder (NMOSD) attack was significantly reduced with inebilizumab compared with placebo. OBJECTIVE: To demonstrate the robustness of this finding, using pre-specified sensitivity and subgroup analyses. METHODS: N-MOmentum is a prospective, randomized, placebo-controlled, double-masked trial of inebilizumab, an anti-CD19 monoclonal B-cell-depleting antibody, in patients with NMOSD. Pre-planned and post hoc analyses were performed to evaluate the primary endpoint across a range of attack definitions and demographic groups, as well as key secondary endpoints. RESULTS: In the N-MOmentum trial (ClinicalTrials.gov: NCT02200770), 174 participants received inebilizumab and 56 received placebo. Attack risk for inebilizumab versus placebo was consistently and significantly reduced, regardless of attack definition, type of attack, baseline disability, ethnicity, treatment history, or disease course (all with hazard ratios < 0.4 favoring inebilizumab, p < 0.05). Analyses of secondary endpoints showed similar trends. CONCLUSION: N-MOmentum demonstrated that inebilizumab provides a robust reduction in the risk of NMOSD attacks regardless of attack evaluation method, attack type, patient demographics, or previous therapy.The N-MOmentum study is registered at ClinicalTrials.gov: NCT2200770.

Renal Arteries Revisited: Anatomy, Pathologic Entities, and Implications for Endovascular Management.

The renal arteries (RAs) are important vessels that usually arise from the abdominal aorta and supply the kidneys; thus, these arteries play a vital role in physiologic functions such as hemofiltration and blood pressure regulation. An understanding of the basis for embryologic development and the frequently variable anatomy of the RAs is necessary to fully appreciate the range of diseases and the implications for procedural planning. Hemorrhage from an RA is relatively common and is typically traumatic or spontaneous, with the latter form often seen in association with underlying tumors or arteriopathy. Accurate diagnostic evaluation of RA disease due to conditions such as atherosclerosis, fibromuscular dysplasia, vasculitis, aneurysm, arteriovenous shunt, embolic disease, and dissection is dependent on the use of multimodality imaging and is essential for selecting appropriate clinical management, with endovascular therapy having a key role in treatment. Surgical considerations include extra-anatomic renal bypass, which remains an important treatment option even in this era of endovascular therapy, and RA embolization as an adjunct to tumor surgery. A novel area of research interest is the potential role of RA denervation in the management of refractory hypertension. ©RSNA, 2021.

The fate of the left subclavian artery in TEVAR for aortic arch pathology.

BACKGROUND AND AIM OF STUDY: The origin of the vertebral artery (VA) from the left subclavian (LSA) is variable and must be considered when proximal ligation or embolization is performed post thoracic endovascular aortic repair (TEVAR) and extra-anatomical bypass (EAB). A retrospective study was conducted to understand the patency of the LSA and VAs after TEVAR and the relationship of the EAB to the LSA. METHODS: Fifty-six patients underwent TEVAR where the LSA origin was occluded. A comparison was performed between the length of the proximal LSA from the arch of the aorta to the origin of the VA. Patient outcomes included posterior or anterior circulation cerebrovascular accident, spinal cord ischemia (SCI), and symptoms and signs of left arm ischemia (LAI). Thirty one underwent EAB with 8 undergoing occlusion of the LSA proximal to the origin of the left VA. A further 25 underwent TEVAR with no EAB performed. The mean (standard deviation) of origin of the VA from the origin at the arch was 37.0 (12.9) mm compared to 34.0 (13.7) mm in those where no bypass was performed (p 0.45). Four patients underwent intraluminal plug occlusion and four had external ligation of the proximal LSA in those undergoing EAB. CONCLUSIONS: Careful evaluation of the LSA is needed when planning TEVAR as occlusion techniques may be dependent on a minimum length of the VA from the aortic arch. The mean length of the VA from the aorta has high heterogeneity which may dictate the optimum occlusion method for LSA.

Generation of Endothelial Cells From Human Pluripotent Stem Cells.

Endothelial cells (ECs) are critical for several aspects of cardiovascular disease therapy, including vascular regeneration, personalized drug development, and tissue engineering. Human pluripotent stem cells (hPSCs) afford us with an unprecedented opportunity to produce virtually unlimited quantities of human ECs. In this review, we highlight key developments and outstanding challenges in our ability to derive ECs de novo from hPSCs. Furthermore, we consider strategies for recapitulating the vessel- and tissue-specific functional heterogeneity of ECs in vitro. Finally, we discuss ongoing attempts to utilize hPSC-derived ECs and their progenitors for various therapeutic applications. Continued progress in generating hPSC-derived ECs will profoundly enhance our ability to discover novel drug targets, revascularize ischemic tissues, and engineer clinically relevant tissue constructs. Visual Overview- An online visual overview is available for this article.