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Objective: This study aimed to create a morphology grading system, solely based on 2D images from computed tomography angiography, to predict negative aortic remodelling (NAR) for patients with high risk uncomplicated type B aortic dissection (TBAD) after thoracic endovascular aortic repair (TEVAR)., Methods: This single centre retrospective cohort study extracted and analysed consecutive patients diagnosed with high risk uncomplicated TBAD. Negative aortic remodelling was defined as an increase in the false lumen or total aortic diameter, or decrease in the true lumen diameter. The multivariable Cox regression model identified risk factors and a prediction model was created for two year freedom from NAR. A three category grading system, in which patients were classified into low, medium, and high risk groups, was further developed and internally validated., Results: Of 351 patients included, 99 (28%) developed NAR. The median age was 52 years (interquartile range 45, 62 years) and 56 (16%) were female. The rate of two year freedom from NAR was 71% (95% CI 65 - 77%). After the multivariable Cox regression analysis, Patent false lumen, Aberrant right subclavian artery, Taper ratio, abdominal circumferential Extent, coeliac artery or reNal artery involved, and four channel dissection (Three false lumens) remained independent predictors and were included in the PATENT grading system. The risk score was statistically significantly associated with NAR (HR 1.21; 95% CI 1.14 - 1.29; p < .001). The medium and high risk groups demonstrated a higher rate of NAR (medium risk, HR 2.82; 95% CI 1.57 - 5.01; p = .001; high risk, HR 4.39; 95% CI 2.58 - 7.48; p < .001). The grading system was characterised by robust discrimination with Harrell's C index of 0.68 (95% CI 0.63 - 0.75)., Conclusion: The PATENT grading system was characterised by good discrimination and calibration, which may serve as a clinician friendly tool to aid risk stratification for TBAD patients after TEVAR., (Copyright © 2024 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.)

Objectives: This study aimed to derive a novel classification of blood flow pattern in abdominal aortic aneurysms (AAA) based on computational fluid dynamics (CFDs), and to determine the predictive value of flow patterns in AAA rupture., Methods: This was an age and sex matched case control study. Cases were identified as patients who underwent emergency endovascular or open repair due to ruptured or AAA at risk of impending rupture. Controls were age and sex matched with patients with an AAA who were asymptomatic and had a confirmed unruptured AAA from computed tomography angiography images from the same period. Classification of blood flow pattern (type I: non-helical main flow channel with multiple vortices; type II: non-helical main flow channel with single vortices; and type III, helical main flow channel with helical vortices) and haemodynamic parameters (areas of low wall shear stress [A lowWSS ], aneurysm pressure drop [Δ pressure], etc) were derived from CFD analyses. Multivariable regression was used to determine independent AAA rupture risk factors. The incremental discriminant and reclassification abilities for AAA rupture were compared among different models., Results: Fifty-three ruptured and 53 intact AAA patients were included. Ruptured AAA showed a higher prevalence of type III flow pattern than intact AAA (60.4% vs. 15.1%; p < .001). Type III flow pattern was associated with a significantly increased risk of aneurysm rupture (odds ratio 10.22, 95% confidence interval 3.43 - 30.49). Among all predicting models, the combination of AAA diameter, haemodynamic parameters (A lowWSS or Δ pressure), and flow pattern showed highest discriminant abilities in both the overall population (c-index = 0.862) and subgroup patients with AAAs < 55 mm (c-index = 0.972). Compared with AAA diameter, adding the flow pattern could significantly improve the reclassification abilities in both the overall population (net reclassification index [NRI] = 0.321; p < .001) and the subgroup of AAAs < 55 mm (NRI = 0.732; p < .001)., Conclusion: Type III flow pattern was associated with a significantly increased risk of AAA rupture. The integration of blood flow pattern may improve the identification of high risk aneurysms in both overall population and in those with AAAs < 55 mm., (Copyright © 2022 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.)

Objective: The aim was to compare mid term outcomes between crossed limb (CL) and standard limb (SL) configuration in patients who underwent endovascular aortic aneurysm repair (EVAR)., Methods: This was a comparative cohort study. Eligible patients who underwent EVAR between September 2011 and March 2019 in a tertiary academic centre were included. Inverse probability of treatment weighting (IPTW) was used to balance the demographic, anatomical and operative baseline characteristics between the two groups. The primary outcome was adverse limb events including type IB endoleak (T1BEL), type III endoleak, and limb occlusion. Cox proportional hazards regression and marginal structural model were performed to compare time to event outcomes., Results: The study included 729 patients (194 CL and 535 SL) with a median follow up of 34 months (interquartile range 16 - 62 months). The weighted analyses revealed no significant difference between CL and SL EVAR in terms of adverse limb events, type IA endoleak (T1AEL), type II endoleak (T2EL), re-intervention, and overall survival. In the subgroup analysis of large aneurysm sac, the CL configuration was associated with a significantly decreased risk of T1BEL (hazard ratio [HR] 0.31, 95% confidence interval [CI] 0.12 - 0.78, p = .014). Similar results were also observed in the subgroup of tortuous iliac arteries (HR 0.30, 95% CI 0.11 - 0.81, p = .017). After stratification by severe neck angulation, no significant difference was found between CL and SL EVAR for T1AEL, but the CL configuration was associated with a significantly increased risk of re-intervention (HR 2.69, 95% CI 1.31 - 5.51, p = .007). In addition, a trend towards a higher risk of adverse limb events in the CL group with severely angulated proximal neck was observed., Conclusion: CL configuration in EVAR is safe and may be associated with a lower risk of T1BEL in patients with a large aneurysm sac or tortuous iliac arteries. However, it should be applied cautiously to aneurysms with a severely angulated neck due to the potentially higher risk of re-intervention., (Copyright © 2021 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.)

Objective: For thoraco-abdominal aortic aneurysms (TAAA), it is unclear whether it is better to perform hybrid repair in one (single) or two stages (staged). This study aimed to compare the clinical outcomes of single vs. staged hybrid repair of TAAA., Methods: The Medline, Embase, and Cochrane Databases (1 January 1994 to 11 May 2020) were searched for studies on hybrid repair of TAAA. Cohort studies and case series reporting outcomes of single and staged hybrid repair of TAAA were eligible for inclusion. The Newcastle-Ottawa scale and an 18 item tool were used to assess the risk of bias. The primary outcome was 30 day mortality, and the secondary outcomes included post-operative complications, overall survival, and other mid term events. A random effects model was used to calculate pooled estimates., Results: A total of 37 studies was included in the meta-analysis. The quality assessment of the included studies suggested low or moderate risk of bias. The pooled estimates for aneurysm rupture and death during stage interval were 2% (95% CI 0%-4%, I 2  = 0%) and 4% (95% CI 2%-7%, I 2  = 0%), respectively. Single repair was associated with a significantly higher 30 day risk of death when compared with patients who completed staged procedures successfully (OR 2.64, 95% CI 1.36-5.12, I 2  = 0%). Staged repair also had lower incidence of major adverse cardiac events (MACE) (single: 10%, 95% CI 5%-16%; staged: 2%, 95% CI 0%-5%) and intestinal complications (single: 15%, 95% CI 8%-25%; staged: 3%, 95% CI 1%-6%). For mid term outcomes, single and staged repair had comparable 12 month overall survival, aneurysm related mortality, rate of re-intervention, and graft patency., Conclusion: Two stage hybrid repair may represent a better choice for patients with controlled risk of aneurysm rupture, because it can provide lower 30 day mortality risks, MACE, and intestinal complications, as well as comparable mid term outcomes. Randomised controlled trials are needed to ascertain the effect of repair staging in patients for elective TAAA., (Copyright © 2020 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.)