Percutaneous Endovascular Stenting of an Acute Complicated Iatrogenic Type B Aortic Dissection in an Infant.

Thoracic endovascular aortic repair has emerged as a viable alternative for managing Sanford type B aortic dissection in adults. We report the first case of managing an acute and evolving communicating type B aortic dissection in an infant with endovascular aortic stenting.

Mid-Term Outcomes Following TEVAR for Chronic Type B Aortic Dissection.

Objective: To evaluate the mid-term outcomes following thoracic endovascular aortic repair (TEVAR) for chronic type B aortic dissection (TBD), especially to know which re-entry closure affects the thoracic false lumen remodeling in the late chronic TBD. Methods: From April 2017 to April 2022, 25 patients with chronic TBD underwent TEVAR. The late chronic TBD received the re-entry closure including stent-graft deployment in the renal artery, infrarenal aorta, and unilateral or bilateral iliac artery. Results: Complete shrinkage of the thoracic false lumen was accomplished in 67% of the early chronic cases but only 13% of the late chronic cases. The thoracic false lumen shrinkage over 5 mm in diameter was obtained in 78% of the early chronic cases and 69% of the late chronic cases. Univariate and multiple logistic regression analyses revealed the re-entry closure of common or external iliac artery affects the thoracic false lumen remodeling. Conclusion: The re-entry closure in the common or external iliac artery could affect the thoracic false lumen remodeling following TEVAR for the late chronic TBD. (This is a translation of Jpn J Vasc Surg 2023; 32: 351-356).

Evaluation of Thoracic Endovascular Repair for the Treatment of Type B Aortic Dissection Complicated by Malperfusion.

Objectives: This study aims to investigate the efficacy of thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD) complicated by malperfusion. Methods: This retrospective study included patients who underwent TEVAR for the treatment of TBAD complicated by malperfusion from June 1998 to June 2022 in four institutions. In addition to the common outcomes, including short- and medium-term mortality and morbidity, the preservation of each organ was investigated. Results: A total of 23 patients were included in this analysis. The 30-day mortality was 4% (1/23) of the patients. The overall survival rate was 87% at 1 year. The preservation rate of each organ was 33% (4/12) for the visceral organs, 85% (17/20) for the kidneys, and 100% (18/18) for the legs. Fisher's exact test showed a significant difference in the preservation rate between the viscera and the other organs (P = 0.018 vs. kidneys, P = 0.0025 vs. legs). It was shown that the survival rate of patients with visceral malperfusion was significantly lower than that of patients with non-visceral malperfusion (P = 0.006). Conclusion: In terms of mortality, TEVAR showed satisfactory results. The preservation of visceral organs was still challenging even with TEVAR and adjunctive measures.

Effectiveness of the 5As Model-Based Transitional Care Program among Chinese Patients with Type B Aortic Dissection Post-TEVAR: A Randomized Controlled Trial.

Background: Thoracic aortic endovascular repair (TEVAR) is the primary treatment for Stanford type B aortic dissection (type B AD). However, patients often encounter significant difficulties post-TEVAR that endanger their safety when transitioning from hospital- to home-based care. Moreover, information on the ideal transitional care for patients with type B AD post-TEVAR is scarce in China. This single-masked randomized clinical trial aimed to assess the effectiveness of the Assess, Advise, Agree, Assist, and Arrange (5As) model-based transitional care in improving discharge preparation level and transitional care quality post-TEVAR among patients with type B AD in China. Methods: This study was conducted at a hospital in China between January 2021 and October 2021. Patients with type B AD were randomly divided into intervention and control groups. Participants in the intervention group received the 5As model-based transitional nursing care. The 5As model is an evidence-based intervention strategy comprising: (1) Assess: assessing the preoperative cardiovascular risk behavior of patients with AD. (2) Advise: making suggestions according to the risk behaviors of the patients. (3) Agree: reaching a consensus on goals and action plans by making decisions with the patients and their families. (4) Assist: assisting patients in solving obstacles to implementing health plans. (5) Arrange: arranging follow-up visits according to the actual situation of the patients and guiding them in adhering to a schedule. The control group received the usual nursing care for the same duration and number of follow-up visits. A trained research nurse collected all the baseline data of the patients on admission, assessed discharge readiness level (using the Readiness for Hospital Discharge Scale) on the day of discharge, and collected transitional quality of care (by the Care Transition Measure-15) data on day 30 after discharge. Results: Overall, 72 patients with type B AD were recruited. Discharge readiness level and transitional care quality in the intervention group were significantly superior to those in the control group. Conclusions: This study showed that the 5As model-based transitional care program can effectively promote discharge readiness and transitional care quality of patients with type B AD post-TEVAR. Clinical Trial Registration: The Chinese Clinical Trial Registry Center: ChiCTR2200060797 (https://www.chictr.org.cn/showproj.html?proj=167403).

Physician-modified funnel-shaped covered stent for selective false lumen exclusion in chronic type B aortic dissection.

PURPOSE: To describe the technique of off-centering a balloon-expandable covered stent for selective occlusion of a distal entry tear (ET) in a patient, conservatively treated for chronic type B aortic dissection (cTBAD), presenting FL expansion. TECHNIQUE: A 63-year-old male, with conservatively managed cTBAD, presented at follow-up with FL partial thrombosis and expansion (thoracic aorta FL from 21 mm to 27 mm and abdominal aorta FL from 11 mm to 15 mm in 6 months). No proximal ET was identifiable. Distal FL perfusion was caused by an ET in the abdominal aorta feeding a 2 mm accessory renal artery (ARA). As the aortic diameter was below the threshold for endovascular repair, a selective occlusion of the distal ET and ARA was planned. A balloon-expandable covered stent was modified by off-centering the covered stent proximally and resulting in a funnel-shape occluder after deployment across the ET into the ARA. To prevent type Ic endoleak due to possible FL expansion caused by an intra-operatively detected phrenic artery (PA), coils were deployed into the lumen of the modified stent and the ARA. The pre-discharge computed tomography angiography showed exclusion of both the ARA and ET and a type 2 endoleak from the PA. CONCLUSION: A balloon-expandable covered stent can be modified by off-centering the covered stent resulting in a funnel shape to adapt to different diameter requirements.

Long-term outcomes of primary surgical repair for communicating DeBakey IIIb chronic dissecting aortic aneurysm.

Objective: This study aimed to evaluate the long-term outcomes of surgical strategies for communicating DeBakey IIIb chronic dissecting aortic aneurysm, considering the optimal primary surgical repair to prevent aortic events. Methods: From 2002 to 2021, 101 patients with communicating DeBakey IIIb chronic dissecting aortic aneurysm who underwent surgical repair were categorized based on the primary surgical repair: 1-stage repair of thoracoabdominal aortic aneurysm (TAAAR) (n = 22) or staged repair, such as descending thoracic aneurysm repair (DTAR) (n = 43) or total arch replacement with elephant trunk implantation (TARET) (n = 25), and thoracic endovascular aortic repair (TEVAR) (n = 11). Early and late postoperative outcomes were compared among the groups. Results: Early outcomes for TAAAR, DTAR, TARET, and TEVAR were associated with the incidence of stroke (9.1% vs 0% vs 4.0% vs 9.1%, respectively), spinal cord injury (13.6% vs 4.7% vs 8.0% vs 0%, respectively), and in-hospital mortality (9.1% vs 2.3% vs 0% vs 9.1%, respectively). During follow-up, the 10-year overall survival and 7-year aortic event-free rates for TAAAR, DTAR, TARET, and TEVAR were 61.8%, 71.6%, 21.5%, and 26.5% and 93.8%, 84.3%, 74.4%, and 51.4%, respectively. TAAAR had significantly higher overall survival (P = .05) and aortic event-free rates (P = .03) than TEVAR. TARET (hazard ratio, 2.27; P < .01) and TEVAR (hazard ratio, 3.40; P < .01) were independently associated with the incidence of aortic events during follow-up. Conclusions: Considering the optimal primary surgical repair based on long-term outcomes, TEVAR was not a durable treatment option. Patient-specific TAAAR or DTAR should be considered rather than defaulting to minimally invasive primary repairs for all patients with communicating DeBakey IIIb chronic dissecting aortic aneurysm.

Adult Epiglottitis as an Often Overlooked, Life-threatening Condition Requiring Special Airway Consideration; a Case Report.

After the implementation of vaccination against Haemophilus Influenza Type B (Hib), adult patients comprise the majority of patients with acute epiglottitis. Its presentation with stridor mandates swift recognition and intervention to prevent airway compromise and mortality. Here, we present a case of a 44-year-old male with diabetes mellitus who presented with acute onset of shortness of breath and stridor following days of throat soreness and fever. Initial treatment for suspected anaphylaxis provided partial relief, and emergency department evaluation revealed characteristic signs of acute epiglottitis on lateral soft tissue neck x-ray and nasopharyngoscopy. Treatment was initiated with intravenous ampicillin/sulbactam and dexamethasone, and the patient was discharged home on day 4. This case underscores the critical importance of maintaining a high index of suspicion for acute epiglottitis in adults presenting with stridor and respiratory distress. Prompt recognition, airway management, and appropriate antibiotic therapy are paramount in mitigating the potentially devastating outcomes associated with this condition. As demographics shift and vaccination impacts epidemiology, heightened vigilance in emergency settings is essential to improve outcomes in adult patients with acute epiglottitis.

Elective Root Replacement Increases the Risk of Type B Dissection in Patients with Marfan Syndrome.

OBJECTIVE: Marfan syndrome (MFS) is a genetic disorder with increased risk of aortic dissection. Currently, type A aortic dissection risk is mitigated by aortic root replacement with Dacron. It is unclear if root replacement increases the risk of distal aortic disease given the non-compliant nature of Dacron. METHODS: All adult patients with a diagnosis of MFS at a single academic center, excluding those with history of dissection or concomitant arch repair, were studied (n=322). Student's t-test or Wilcoxon-Mann-Whitney test were used for continuous variables; Chi-squared or Fisher's exact test for categorical variables. Propensity matching used age, sex, hypertension, race, BMI, family history of MFS, and genetic mutational class. Differences in freedom from type B aortic dissection (TBAD) were determined using the log-rank test. RESULTS: 124 patients underwent root replacement (RR) compared to 198 patients with no prior aortic surgery (NRR). Median follow-up time was 9.90 years. Male sex, weight, and hypertension prevalence was higher in the RR group (p<0.05). Distribution of fibrillin-1 mutations was homogenous (p>0.9). TBAD frequency in the RR group was higher (21% (n=20) vs 4.2% (n=4), p<0.001). Aortic-related mortality was higher in the RR group (11% (n=14) vs. 3.5% (n=7), p<0.01). Distal aortic intervention frequency was higher in the RR group (p=0.009). CONCLUSIONS: Marfan syndrome patients who undergo elective aortic root replacement appear to have a higher incidence of subsequent type B aortic dissection, independent of other risk factors. Careful consideration must be made to the management of the distal aorta in MFS patients who undergo root replacement.

VEPTP inhibition with an extracellular domain targeting antibody did not restore albuminuria in a mouse model of diabetic kidney disease.

Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease. DKD is a heterogeneous disease with complex pathophysiology where early endothelial dysfunction is associated with disease progression. The Tie2 receptor and Angiopoietin 1 and 2 ligands are critical for maintaining endothelial cell permeability and integrity. Tie2 signaling is negatively regulated by the endothelial specific transmembrane receptor Vascular Endothelial Protein Tyrosine Phosphatase (VEPTP). Genetic deletion of VEPTP protects from hypertension and diabetes induced renal injury in a mouse model of DKD. Here, we show that VEPTP inhibition with an extracellular domain targeting VEPTP antibody induced Tie2 phosphorylation and improved VEGF-A induced vascular permeability both in vitro and in vivo. Treatment with the VEPTP blocking antibody decreased the renal expression of endothelial activation markers (Angpt2, Edn1, and Icam1) but failed to improve kidney function in db/db uninephrectomized ReninAAV DKD mice.

Early three-dimensional growth in uncomplicated type B aortic dissection is associated with long-term outcomes.

OBJECTIVE: Late adverse events (LAEs) are common among initially uncomplicated type B aortic dissection (uTBAD); however, identifying those patients at highest risk of LAEs remains a significant challenge. Early false lumen (FL) growth has been suggested to increase risk, but confident determination of growth is often hampered by error in two-dimensional clinical measurements. Semi-automated three-dimensional (3D) mapping of aortic growth, such as by vascular deformation mapping (VDM), can potentially overcome this limitation using computed tomography angiograms (CTA). We hypothesized that FL growth in the early pre-dissection phase by VDM can accurately predict LAEs. METHODS: We performed a two-center retrospective study of patients with uTBAD, with paired CTAs in the acute (1-14 days) and subacute/early chronic (1-6 months) periods. VDM analysis was used to map 3D growth. Standard clinical CT measures (ie, aortic diameters, tear characteristics) were also collected. Multivariate analysis was conducted using a decision tree and Cox proportional hazards model. LAEs were defined as aneurysmal FL (>55 mm); rapid growth (>5 mm within 6 months); aorta-specific mortality, rupture, or re-dissection. RESULTS: A total of 107 (69% male) patients with uTBAD initially met inclusion criteria with a median follow-up of 7.3 years (interquartile range [IQR], 4.7-9.9 years). LAEs occurred in 72 patients (67%) at 2.5 years (IQR, 0.7-4.8 years) after the initial event. A multivariate decision tree model identified VDM growth (>2.1 mm) and baseline diameter (>42.7 mm) as optimal predictors of LAEs (area under the receiver operating characteristic curve = 0.94), achieving an 87% accuracy (sensitivity of 93%, specificity of 76%) after leave-one-out validation. Guideline reported high-risk features were not significantly different between groups. CONCLUSIONS: Early growth of the FL in uTBAD was the best tested indicator for LAEs and improves upon the current gold-standard of baseline diameter in selecting patients for early prophylactic thoracic endovascular aortic repair.

Left Atrial Compression by an Intramural Hematoma: A Rare Case of Obstructive Shock.

A 3.5 cm diameter descending aorta focal aneurysm was incidentally found when a computed tomography (CT) was conducted due to persistent pyrexia in an 85-year-old woman hospitalized for a non-obstructive urinary tract infection. Ten days later, whilst fever subsided and inflammation markers decreased, she became hypoxic. CT revealed an aortic intramural hematoma (Stanford type B) increasing the diameter of the thoracic aorta aneurysm to 6.5 cm. A thoracic endovascular aortic repair (TEVAR) surgery was performed. Seven days after the operation she developed respiratory and hemodynamic compromise. CT depicted further enlargement of the aortic intramural hematoma, increasing the aortic diameter to 8 cm. Transthoracic echocardiography provided valuable information showing extrinsic compression of the left atrium and left ventricle inflow obstruction provoking obstructive shock.

Comparison of the novel Ankura Plus stent and Castor stent for the treatment of Stanford type B aortic dissection with an insufficient proximal anchoring area.

OBJECTIVE: To compare the efficacy and safety of the Ankura Plus and Castor stents in Stanford type B aortic dissection (TBAD) with an insufficient proximal anchoring area. METHODS: Between January 2020 and October 2022, 54 patients with TBAD were enrolled, including 16 patients with Ankura Plus stents and 38 patients with Castor stents. Data from the two stents were retrospectively analyzed. RESULTS: The surgical success rate for both stents was 100%, and no endoleaks or deaths occurred during hospitalization. The Ankura Plus stent group had a longer surgery time than the Castor stent group (122.6±5.1 vs. 103.7±10.0, P ＜0.001). After an average follow-up of 12 months, the patency rates of the main and branch stents were 100% in both groups. The diameter of the true lumen (TL) was significantly increased, the diameter of the false lumen (FL) was reduced, and there was no statistically significant difference in the probability of complete thrombosis of the FL (68.8% vs. 67.6%, P=0.993). There were no significant differences in the incidences of renal failure (6.3% vs. 8.1%, P = 0.814), stroke (6.3% vs. 2.7%, P = 0.520), or endoleaks (6.3% vs. 10.5%, P = 0.621) between the Ankura Plus and Castor stent groups. One patient in the Castor stent group underwent reintervention because of a type I endoleak three months after surgery. One patient in the Ankura Plus stent group had an additional covered stent placed after one month due to distal TL stenosis of the main stent. One patient in the Castor stent group died of renal failure four months after surgery. CONCLUSION: Both the Ankura Plus and Castor stents are feasible, safe, and effective in the treatment of TBAD with an insufficient proximal anchoring area. Additional long-term studies are required to evaluate the robustness and applicability of Ankura Plus stents.

Radiomics-Based Risk Assessment Correlates With Outcomes in Patients With Acute Type B Aortic Dissection Undergoing Thoracic Endovascular Repair.

OBJECTIVES: Our study aimed to investigate the correlations between radiomics-based assessment and outcomes, including positive aortic remodeling (PAR), reintervention for dissection at 1 year, and overall survival, in patients with Type B aortic dissection (TBAD) who underwent thoracic endovascular aortic repair (TEVAR). METHODS: This was a single-center, retrospective, cohort study. The cohort comprised 104 patients who had undergone TEVAR of TBAD in our institution between January 2010 and October 2022. We segmented preoperative computed tomography (CT) images of the patients' descending aorta regions, then extracted a comprehensive set of radiomic features, including first-order features, shape features (2D and 3D), gray-level co-occurrence matrix (GLCM), gray-level size zone matrix, gray-level run length matrix, gray-level dependence matrix, neighborhood gray-tone difference matrix, from the regions of interest. Next, we selected radiomics features associated with total descending aorta positive aortic remodeling (TDA-PAR) and reintervention by least absolute shrinkage and selection operator (LASSO) regression and features associated with survival by LASSO-Cox regression. This enabled us to calculate radiomics-based risk scores for each patient. We then allocated the patients to high and low radiomics-based risk groups, the cutoff being the median score. We used 3 different models to validate the radiomics-based risk scores. RESULTS: The patients' baseline characteristics did not differ between those who achieved TDA-PAR and those who did not. The radiomics-based risk scores were significantly and independently associated with all 3 outcomes. As to the impact of specific radiomics features, we found that GLSZM_SmallAreaLowGrayLevelEmphasis and shape_Maximum2DDiameterColumn had positive impacts on both reintervention and survival outcomes, whereas GLCM_Idmn positively affected survival but negatively affected reintervention. We found that radiomics-based risk for TDA-PAR correlated most significantly with zone 6 PAR. CONCLUSIONS: Radiomics-based risk scores were significantly associated with the outcomes of TDA-PAR, reintervention, and overall survival. Radiomics has the potential to make significant contributions to prediction of outcomes in patients with TBAD undergoing TEVAR. CLINICAL IMPACT: In this study of 104 patients with Type B aortic dissection, we demonstrated associations between radiomics-based risk and postoperative outcomes, including total descending aorta positive aortic remodeling, reintervention and survival. These findings highlight radiomics' potential as a tool for risk stratification and prognostication in acute Type B aortic dissection management.

The TATA-box binding protein-associated factor TAF12b facilitates the degradation of type-B response regulators to negatively regulate cytokinin signaling.

Cytokinins (CKs) are one of important classes of plant hormones essential for plant growth and development. The TATA-box binding protein-associated factor 12b (TAF12b) is involved in cytokinin (CK) signaling, but its molecular and biochemical mechanisms remain unclear. In this study, TAF12b of Nicotiana benthamiana (NbTAF12b) was found to mediate CK response by directly interacting with type-B response regulators (B-RRs), which are positive regulators of CK signaling, and inhibiting their transcriptional activities. The co-factor specifically facilitated the proteasomal degradation of non-phosphorylated B-RRs by recruiting the KMD family of F-box proteins. Such interactions between TAF12b and B-RRs also occur in other plant species. Genetic transformation experiments further showed that overexpression of NbTAF12b attenuates the CK-hypersensitive phenotype conferred by NbRR1 overexpression. Taken together, these results suggest a conserved mechanism that TAF12b negatively regulates CK responses through promoting 26S proteasome-mediated degradation of B-RRs degradation in multiple plant species, which provides novel insights into the regulatory network of CK signaling in plants.

Hidden in Plain Sight: Deciphering Chest Pain, Hypertension, and Elevated Creatinine to Unveil Aortic Dissection.

Chest pain is a common yet complex presentation in the emergency department, often requiring the exclusion of life-threatening conditions such as aortic dissection. Stanford type B aortic dissection, which affects the descending aorta, poses significant diagnostic and therapeutic challenges but can often be managed medically without immediate surgery. This case underscores the necessity of having a vigilant mindset, performing a detailed clinical examination, and including aortic dissection in the differential diagnosis, especially when typical symptoms are observed. The challenging part of this case was the investigation, as computed tomography angiography couldn't be performed, necessitating the use of magnetic resonance imaging for diagnosis. It highlights the importance of individualized patient care, vigilant monitoring, and comprehensive management strategies in the treatment of aortic dissection.

In situ fenestration (ISF) versus single-branched stent graft (SBSG) implantation in the management of acute Stanford type B aortic dissection involving the left subclavian artery.

Background: With the advances in medical technology and materials, thoracic endovascular aortic repair has become the mainstay of treatment for aortic dissection. In situ fenestration (ISF) and single-branch stent graft (SBSG) implantation are commonly used methods, with each having its own advantages and disadvantages. The study aimed to compare the perioperative outcomes and one-year follow-up results of patients who underwent ISF or SBSG in the treatment of acute Stanford type B aortic dissection involving the left subclavian artery (LSA). Methods: From January 2018 to December 2022, consecutive patients with Stanford type B aortic dissection were retrospectively recruited and divided into ISF group and SBSG group according to the type of surgery. The patient's aortic physiology was evaluated by computed tomography angiography at 1, 3, 6, and 12 months after discharge. Results: This study included 67 patients in the SBSG group and 21 patients in the ISF group. The baseline and preoperative indices were similar between the groups. The success rate of perioperative treatment was 100%, and no adverse consequences occurred in either group. No spinal cord ischemia, stroke, or paraplegia occurred in either group during the one-year follow-up. The rate of endoleak in the SBSG group was significantly lower (3%, all type I endoleaks) than that in the ISF group (9.5% type I and 14.3% type II endoleaks) (P=0.005). Type II endoleak mainly occurred in the LSA. In addition, complete thrombosis of the false lumen was achieved in 95.5% of the SBSG group versus 81.0% of the ISF group, but this was not a significant difference (P=0.091). The maximum diameter of the true lumen increased significantly in the ISF (P<0.001) and SBSG (P<0.001) groups. Meanwhile, the maximum diameter of the false lumen was significantly reduced in the ISF (P<0.001) and SBSG (P<0.001) groups, but the difference in the maximum diameter change of the true or false lumen between the two groups was not statistically significant (P>0.05). Conclusions: SBSG was associated with a significantly lower incidence of endoleak than was ISF. However, there were no differences observed in complete thrombosis of the false lumen. Further studies with larger sample sizes are needed to definitively establish which treatment is superior in terms of complete thrombosis of the false lumen.

Efficacy of thoracic endovascular aortic repair versus medical therapy for treatment of type B aortic dissection.

BACKGROUND: Techniques in endovascular therapy have evolved to offer a promising alternative to medical therapy alone for Type B aortic dissections (TBADs). AIM: The aim of this meta-analysis was to compare mortality and overall complications between thoracic endovascular aortic repair (TEVAR) and best medical therapy (BMT) in patients with TBADs. METHODS: We included randomized control trials and prospective or retrospective cohort studies that compared TEVAR and BMT for the treatment of type B aortic dissection. Multiple electronic databases were searched. RESULTS: Thirty-two cohort studies including 150,836 patients were included. TEVAR was associated with a significantly lower 30-day mortality rate than BMT (RR = 0.79, CI = 0.63, 0.99, P = 0.04), notably in patients ≥ 65 years of age (RR = 0.78, CI = 0.64, 0.95, P = 0.01). The TEVAR group had a significantly prolonged hospital stay (MD = 3.42, CI = 1.69, 5.13, P = 0.0001) and ICU stay (MD = 3.18, CI = 1.48, 4.89, P = 0.0003) compared to the BMT. BMT was associated with increased stroke risk (RR = 1.52, CI = 1.29, 1.79, P < 0.00001). No statistically significant differences in late mortality (1, 3, and 5 years) or intervention-related factors (acute renal failure, spinal cord ischemia, myocardial infarction, respiratory failure, and sepsis) were noted between the groups. CONCLUSION: Our meta-analysis revealed a significant association between the TEVAR group and a decreased mortality rate of TBAD compared to the medical treatment group, especially in patients aged 65 years or older. Further randomized controlled trials are needed to confirm our findings.

Patient-specific compliant simulation framework informed by 4DMRI-extracted pulse wave Velocity: Application post-TEVAR.

We introduce a new computational framework that utilises Pulse Wave Velocity (PWV) extracted directly from 4D flow MRI (4DMRI) to inform patient-specific compliant computational fluid dynamics (CFD) simulations of a Type-B aortic dissection (TBAD), post-thoracic endovascular aortic repair (TEVAR). The thoracic aortic geometry, a 3D inlet velocity profile (IVP) and dynamic outlet boundary conditions are derived from 4DMRI and brachial pressure patient data. A moving boundary method (MBM) is applied to simulate aortic wall displacement. The aortic wall stiffness is estimated through two methods: one relying on area-based distensibility and the other utilising regional pulse wave velocity (RPWV) distensibility, further fine-tuned to align with in vivo values. Predicted pressures and outlet flow rates were within 2.3 % of target values. RPWV-based simulations were more accurate in replicating in vivo hemodynamics than the area-based ones. RPWVs were closely predicted in most regions, except the endograft. Systolic flow reversal ratios (SFRR) were accurately captured, while differences above 60 % in in-plane rotational flow (IRF) between the simulations were observed. Significant disparities in predicted wall shear stress (WSS)-based indices were observed between the two approaches, especially the endothelial cell activation potential (ECAP). At the isthmus, the RPWV-driven simulation indicated a mean ECAP>1.4 Pa-1 (critical threshold), indicating areas potentially prone to thrombosis, not captured by the area-based simulation. RPWV-driven simulation results agree well with 4DMRI measurements, validating the proposed pipeline and facilitating a comprehensive assessment of surgical decision-making scenarios and potential complications, such as thrombosis and aortic growth.

Immunohistochemistry for YAP1 N-terminus and C-terminus highlights metaplastic thymoma and high-grade thymic epithelial tumors by different staining patterns.

Metaplastic thymoma (MT), a rare subtype of thymic epithelial tumors (TETs), harbors YAP1::MAML2 fusions. Poroma, a skin tumor, also carries these fusions and exhibits a unique staining pattern for YAP1 immunohistochemistry (IHC), namely, a YAP1 N-terminus (YAP1[N])-positive but YAP1 C-terminus (YAP1[C])-negative pattern. In this context, MT was recently reported to lack YAP1(C) expression exclusively among TET subtypes. However, a lack of information about YAP1(N) expression in that study and another report that wild-type YAP1 expression was diminished in type B3 thymoma and thymic carcinoma warrants further studies for YAP1 expression in TETs. Thus, we immunohistochemically examined YAP1(N) and YAP1(C) staining patterns in our TET samples, including 14 cases of MT. In addition, 11 of the 14 MT cases were genetically analyzed with the formalin-fixed paraffin-embedded tissues if they harbored YAP1::MAML2 fusions. MT consistently exhibited YAP1(N)-positive and YAP(C)-negative staining, whereas type B3 thymoma and thymic carcinoma showed relatively heterogeneous staining patterns for YAP1(N) and YAP1(C) and were sometimes negative for both antibodies. Furthermore, a lower expression of YAP1 was found in type B3 compared to B2 thymomas. Among genetically analyzed 11 MT cases, 6 cases showed YAP1::MAML2 fusions, whereas the analysis failed in 5 very old cases due to poor RNA quality. These results indicate that IHC of both YAP1(N) and YAP1(C) is recommended to obtain staining patterns almost unique to MT. The biological significance of YAP1 in high-grade TETs warrants further investigation.

Emerging Trends in the Care of Type B Aortic Dissections.

Aortic dissection is the most common of the acute aortic syndromes. Acute aortic dissection remains a highly morbid and potentially lethal condition despite contemporary advances in medical and surgical care. Type B aortic dissection (TBAD) is classified as uncomplicated, uncomplicated with high-risk features, and complicated. The role of thoracic endovascular aortic repair (TEVAR) in uncomplicated TBAD remains uncertain and is the topic of ongoing clinical trials. In most complicated cases, TEVAR is effective at restoring visceral and extremity blood flow. TEVAR has also been shown to arrest hemorrhage in the setting of thoracic aortic rupture. TEVAR has been demonstrated to induce satisfactory remodeling in the covered segment of the thoracic aorta, but progressive enlargement of the visceral aorta has led to a variety of techniques designed to promote remodeling in the uncovered aortic segment. There is a need to better define high-risk features so that treatment can be tailored to specific clinical conditions.