Thrombus Volume Research Articles

Resultados preliminares en el análisis de elementos finitos de aneurismas de aorta abdominal en rango no quirúrgico

IntroductionThe diagnosis and management of abdominal aortic aneurysms currently relies on the maximal aortic diameter, which grows in an unpredictable manner. The aim of this study was to compare the results of the biomechanical variables using finite elements analysis between the 2 groups of small aneurysms (group I 40-49mm, group II 50-54mm). MethodsA total of 23 patients with abdominal aortic aneurysm (group I N=14, group II N=9) who had undergone a thoraco-abdominal angio computed tomography in this hospital were prospectively identified. Abdominal aortic aneurysms diameter, peak wall rupture (PWR), PWR Index, Rupture Risk Equivalent Diameter (RRED) abdominal aortic aneurysms and thrombus volume were measured and calculated using finite element analysis software. The variability between maximum abdominal aortic aneurysms diameter and RRED was also determined. ResultsAn increased PWS, PWRR, and RRED, was observed in group II. Moreover, 5 (21.74%) patients had a positive variability (>0.5mm), and 2 of them (8.70%) had a PWRR >0.5, which is associated with a higher aneurysm rupture risk. ConclusionPWR and PWRR are elevated in group II, perhaps secondary to a larger abdominal aortic aneurysms diameter. Further studies are required before using this software in clinical decisions.

The clinical course of symptomatic deep vein thrombosis after 3 months of anticoagulant therapy using fondaparinux/edoxaban or fondaparinux/vitamin K antagonist.

BackgroundFor the management of venous thromboembolism (VTE), providing anticoagulant therapy within the therapeutic range has been a major challenge, as conventional therapy with unfractionated heparin (UFH) and vitamin K antagonist (VKA) requires frequent laboratory monitoring and dose adjustment. Recently, fondaparinux and edoxaban are being used as beneficial alternatives to UFH and VKA.MethodsWe evaluated the clinical course of symptomatic deep vein thrombosis (DVT) in patients who received the 3-month anticoagulation therapy with fondaparinux/edoxaban (Group A; n=40) in comparison with the findings from our previous experience of patients who received the fondaparinux/VKA combination (Group B; n=33).ResultsIn both Groups A and B, serum D-dimer was significantly improved after treatment (p<0.001). The thrombus volume assessed by quantitative ultrasound thrombosis (QUT) score was significantly reduced in both groups (p<0.001). There was no difference in the proportion of patients who were normalized (ie, disappearance of DVT) between the groups, although Group A had significantly more patients who were normalized or improved (ie, disappearance and reduction of DVT) (p<0.001). No bleeding event was observed in either group. However, in one patient in Group B, worsening of DVT and development of symptomatic PE were observed.ConclusionFondaparinux/edoxaban therapy is as effective as fondaparinux/VKA. This treatment has the possible advantage in thrombus regression. This would be a beneficial therapeutic option for both patients and physicians.

Abstract WMP21: Texture Analysis of Intracranial Thrombus Using CT and CTA Predicts Early Recanalization With Intravenous Alteplase

Objective: In acute ischemic stroke (AIS), thrombus lysis and early restoration of blood flow to ischemic brain is the goal of reperfusion therapy. We hypothesize that image texture analysis of thrombus using non-contrast CT (NCCT) and CTA can predict early recanalization with IV alteplase in AIS patients with ICA/M1 MCA thrombi. Methods: We used a case control design for the study using the whole cohort of the clinical trial of Identifying New approaches to optimize Thrombus characterization for predicting Early Recanalization and Reperfusion with iv tPA using Serial CT angiography (INTERRSeCT). Cases were 31 patients with ICA/M1 MCA thrombi treated with IV alteplase, who achieved early recanalization (as assessed on first angio run in patients undergoing additional IA therapy or on repeat CTA at 4 hrs). Cases were matched with controls (37 patients with ICA/M1 MCA thrombi treated with IV alteplase who did not achieve recanalization). All patients had thin slice NCCT (slice thickness &lt; 2.5 mm) and CTA (≤ 0.625mm). Thrombi in ICA/M1 MCA region were manually contoured from NCCT guided by co-registered CTA. We extracted 378 features (including thrombus length and volume, first order statistics, and image texture features) from each thrombus in both NCCT and CTA images. This was followed by feature selection using linear discriminative analysis. The top 5 features from NCCT and CTA images along with the clot texture difference between NCCT and CTA were used to train a linear support vector machine classifier. Five times 6-fold cross validation was used to evaluate the trained classifier. Results: Receiver operator curves show that thrombus texture from NCCT and CTA are predictive of early recanalization with IV alteplase. Combined NCCT &amp; CTA features and texture difference is the best predictor (AUC: 0.82). Conclusions: Thrombus texture features from NCCT and CTA are strongly predictive of early recanalization with IV alteplase in AIS patients with proximal occlusions.

Anti-thrombotic efficacy of S007-867: Pre-clinical evaluation in experimental models of thrombosis in vivo and in vitro

Pharmacological inhibition of platelet collagen interaction is a promising therapeutic strategy to treat intra-vascular thrombosis. S007-867 is a novel synthetic inhibitor of collagen-induced platelet aggregation. It has shown better antithrombotic protection than aspirin and clopidogrel with minimal bleeding tendency in mice. The present study is aimed to systematically investigate the antithrombotic efficacy of S007-867 in comparison to aspirin and clopidogrel in vivo and to delineate its mechanism of action in vitro. Aspirin, clopidogrel, and S007-867 significantly reduced thrombus weight in arterio-venous (AV) shunt model in rats. In mice, following ferric chloride induced thrombosis in either carotid or mesenteric artery; S007-867 significantly prolonged the vessel occlusion time (1.2-fold) and maintained a sustained blood flow velocity for >30 min. Comparatively, clopidogrel showed significant prolongation in TTO (1.3-fold) while aspirin remained ineffective. Both S007-867 and aspirin did not alter bleeding time in either kidney or spleen injury models, and thus maintained hemostasis, while clopidogrel showed significant increase in spleen bleeding time (1.7-fold). The coagulation parameters namely thrombin time, prothrombin time or activated partial thromboplastin time remained unaffected even at high concentration of S007-867 (300 µM), thus implying its antithrombotic effect to be primarily platelet mediated. S007-867 significantly inhibited collagen-mediated platelet adhesion and aggregation in mice ex-vivo. Moreover, when blood was perfused over a highly thrombogenic combination of collagen mimicking peptides like CRP-GFOGER-VWF-III, S007-867 significantly reduced total thrombus volume or ZV50 (53.4 ± 5.7%). Mechanistically, S007-867 (10–300 μM) inhibited collagen-induced ATP release, thromboxane A2 (TxA2) generation, intra-platelet [Ca+2] flux and global tyrosine phosphorylation including PLCγ2. Collectively the present study highlights that S007-867 is a novel synthetic inhibitor of collagen induced platelet activation, that effectively maintains blood flow velocity and delays vascular occlusion. It inhibits thrombogenesis without compromising hemostasis. Therefore, S007-867 may be further developed for the treatment of thrombotic disorders in clinical settings.

Effects of epidermal growth factor on reduction of the formation of thrombus and vessel wall healing in an experimental rat model.

The aim of the current study was to investigate the synergistic effects of epidermal growth factor (EGF) and Enoxaparin in thrombus resolution. Forty rats were divided into five groups (n = 8/group). Thrombosis was induced in all groups except the Sham group. Group 1: Sham; Group 2: Phosphate buffered saline; Group 3: Enoxaparin; Group 4: EGF; Group 5: EGF+Enoxaparin. The treatments were applied 2 hours preoperatively, then postoperatively at 48 hours. Rats were sacrificed 7 days after the 2nd injection. Tissue samples were examined with hematoxylin-eosin, trichrome, vascular endothelial growth factors (VEGF), von Villebrand factor (VWF), CD34 and CD68 for histopathological and immunohistochemical analyses. Neovascularisation, recanalization and macrophage accumulation were statistically significantly higher in the EGF+Enoxaparin group than the other groups (p < 0.05), and the volume of thrombus was determined to be significantly lower. Recanalization was found to be higher in the Enoxaparin group than in the other groups. As for the thrombus resolution, statistically significant regress in the EGF+Enoxaparin group (p < 0.05) compared to the other groups was found. Immunohistochemical antibodies were statistically higher in the EGF+Enoxaparin group than in the other groups (p < 0.05). The results of this study demonstrate that concomitant use of EGF and Enoxparin has a synergistic effect and contributes significantly to thrombus resolution (Fig. 10, Ref. 35).

Effect of model thrombus volume and elastic modulus on magnetomotive ultrasound signal under pulsatile flow

Effect of model thrombus volume and elastic modulus on magnetomotive ultrasound signal under pulsatile flow

Neutrophil Elastase-Derived Fibrin Degradation Products Indicate Presence of Abdominal Aortic Aneurysms and Correlate with Intraluminal Thrombus Volume.

The intraluminal thrombi (ILT) of abdominal aortic aneurysms (AAA) contain neutrophils, which can secrete elastase. We evaluated whether plasma neutrophil elastase-derived cross-linked fibrin degradation products (E-XDP) could reveal the presence, size and mechanical stress of AAAs and its ILTs. E-XDP and D-dimer were measured in plasma from 37 male patients with AAA and 42 male controls. The ILT volumes of the AAAs and any coexisting aneurysms could be measured in 29 patients and finite element analysis was performed to estimate mechanical stress of the ILT. E-XDP, neutrophil elastase and neutrophil marker CD66acd were evaluated in aortic tissue with immunohistochemistry (IHC). The association between ILT volume and E-XDP was validated in a separate cohort (n = 51). E-XDP levels were elevated in patients with AAA compared with controls (p = 5.8e-13), indicated AAA with 98% sensitivity, 86% specificity and increased with presence of coexisting aneurysms. The association between AAA and increased E-XDP was independent of smoking, comorbidities and medication. E-XDP correlated with volume of all ILTs (r = 0.76, p = 4.5e-06), mean ILT stress (r = 0.46, p = 0.013) and the volume of the AAA-associated ILT (r = 0.64, p = 0.00017). E-XDP correlated stronger with ILT volume compared with D-dimer (r = 0.76 vs. r = 0.64, p = 0.018). The correlation between E-XDP and ILT volume was validated in the separate cohort (r = 0.53, p = 7.6e-05). IHC revealed E-XDP expression in the ILT, spatially related to neutrophil elastase and neutrophils. E-XDP is a marker of the presence of AAA and coexisting aneurysms as well as the volume and mechanical stress of the ILT.

Stenosis of the Inferior Vena Cava: A Murine Model of Deep Vein Thrombosis

Deep vein thrombosis (DVT) and its devastating complication, pulmonary embolism, are a severe health problem with high mortality. Mechanisms of thrombus formation in veins remain obscure. Lack of mobility (e.g., after surgery or long-haul flights) is one of the main factors leading to DVT. The pathophysiological consequence of the lack of mobility is blood flow stagnation in venous valves. Here, a model is described that mimics such flow disturbance as a thrombosis-driving factor. In this model, partial flow restriction (stenosis) in the inferior vena cava (IVC) is created. Closure of about 90% of the IVC lumen for 48 h results in development of thrombi structurally similar to those in humans. The similarities are: i) most of the thrombus volume is red, i.e., consists of red blood cells and fibrin, ii) presence of a white part (lines of Zahn), iii) non-denuded endothelial monolayer, iv) elevated plasma D-Dimer levels, and v) possibility to prevent thrombosis by low molecular weight heparin. Limitations include variable size of thrombi and the fact that a certain percentage of wild-type mice (0 - 35%) may not produce a thrombus. In addition to visual observation and measurement, thrombi may be visualized by non-invasive technologies, such as ultrasonography, which allows for monitoring the dynamics of thrombus development. At shorter time points (1 - 6 h), intravital microscopy may be applied to directly observe events (e.g., recruitment of cells to the vessel wall) preceding thrombus formation. Use of this method by several teams around the world has made it possible to uncover basic mechanisms of DVT initiation and identify potential targets that might be beneficial for its prevention.

Stenosis of the Inferior Vena Cava: A Murine Model of Deep Vein Thrombosis.

Deep vein thrombosis (DVT) and its devastating complication, pulmonary embolism, are a severe health problem with high mortality. Mechanisms of thrombus formation in veins remain obscure. Lack of mobility (e.g., after surgery or long-haul flights) is one of the main factors leading to DVT. The pathophysiological consequence of the lack of mobility is blood flow stagnation in venous valves. Here, a model is described that mimics such flow disturbance as a thrombosis-driving factor. In this model, partial flow restriction (stenosis) in the inferior vena cava (IVC) is created. Closure of about 90% of the IVC lumen for 48 h results in development of thrombi structurally similar to those in humans. The similarities are: i) most of the thrombus volume is red, i.e., consists of red blood cells and fibrin, ii) presence of a white part (lines of Zahn), iii) non-denuded endothelial monolayer, iv) elevated plasma D-Dimer levels, and v) possibility to prevent thrombosis by low molecular weight heparin. Limitations include variable size of thrombi and the fact that a certain percentage of wild-type mice (0 - 35%) may not produce a thrombus. In addition to visual observation and measurement, thrombi may be visualized by non-invasive technologies, such as ultrasonography, which allows for monitoring the dynamics of thrombus development. At shorter time points (1 - 6 h), intravital microscopy may be applied to directly observe events (e.g., recruitment of cells to the vessel wall) preceding thrombus formation. Use of this method by several teams around the world has made it possible to uncover basic mechanisms of DVT initiation and identify potential targets that might be beneficial for its prevention.

Common First-Pass CT Angiography Findings Associated With Rapid Growth Rate in Abdominal Aorta Aneurysms Between 3 and 5 cm in Largest Diameter.

The purpose of this study was to describe CT angiography (CTA) findings of lumen contrast heterogeneity and intraluminal thrombus volume and to evaluate their relationship with rapid aneurysm growth in patients with abdominal aortic aneurysms (AAA) between 3 and 5 cm. This institutional review board-approved and HIPAA-compliant single-center retrospective study included CTA studies obtained between January 2004 and December 2014 in 140 patients with AAA (101 men, 39 women; mean age ± SD, 70 ± 9 years old; age range, 22-87 years old). Standardized measurements for aneurysm intraluminal thrombus volume and a relatively new metric termed "lumen contrast heterogeneity" were obtained from the CTA images. AAA growth rate data were acquired from all subsequent cross-sectional studies. The association between the imaging findings and rapid aneurysm growth (> 0.4 cm/y) was evaluated using multivariate logistic regression. Patient comorbidities and medications were added to the regression model to assess for further associations with rapid growth rate. Using a baseline logistic regression model, lumen contrast heterogeneity (odds ratio [OR], 1.16; 95% CI, 1.05-1.32), intraluminal thrombus volume (OR, 2.15; 95% CI, 1.26-3.86), and maximum AAA diameter (OR, 1.69; 95% CI, 1.03-2.84) were independently associated with increased likelihood of rapid aneurysm growth. None of the patient comorbidities or medications were significantly associated with the outcome when added to the baseline model. Both intraluminal thrombus and lumen contrast heterogeneity are seen on AAA CTA studies and can be quantified; both of these metrics are independently associated with rapid growth rate and should be recognized by radiologists evaluating patients with AAA during surveillance.

Temporal Changes in Intraluminal Thrombus Volume Within Abdominal Aortic Aneurysms: Implications for Planning Endovascular Aneurysm Sealing

Purpose: To explore whether or not there are temporal changes in the abdominal aortic aneurysm (AAA) and intraluminal thrombus (ILT) volumes between planning and implantation of the endovascular aneurysm sealing (EVAS) device and how these changes influence lumen volume. Methods: A retrospective review was conducted of 51 AAA patients (mean age 76±7.1 years; 36 men) in whom 2 serial preoperative computed tomography angiograms (CTAs) had been performed within 1 to 18 months before fenestrated endovascular repair. The 2 preoperative CTAs were analyzed to identify changes in total sac, ILT, and lumen volumes. Results: Over a median 7.0 months (interquartile range 4, 10), 46 (90%) of 51 AAAs increased in volume between the 2 CTAs. ILT volume increased in 44 aneurysms. In contrast, lumen volume increased in 31 and decreased in 20 AAAs. There was a strong correlation between changes in AAA volume and ILT volume (rs=0.859, p<0.001), which remained significant after adjustment for initial volumes (rs=0.815; p<0.001). There was no correlation between the time interval separating the 2 CTAs and changes in AAA volume (rs=0.115; p=0.421), changes in ILT volume (rs=0.084; p=0.599), or changes in lumen volume (rs=0.060; p=0.676). The AAA growth rate (defined as the change in AAA size/days between CTAs) showed a weak correlation with ILT volume (rs=0.272, p=0.054), which disappeared after adjustment for initial AAA size (rs=−0.002, p=0.991). Between the 2 CTAs, 12 aneurysms crossed the new <1.4 Nellix maximum aorta/lumen diameter ratio. Conclusion: As AAAs grow, the increase in aortic volume is largely occupied by additional ILT formation, with minimal change in lumen volume. These changes may alter the suitability of the aneurysm for the Nellix device and could have implications for EVAS planning and device deployment.

The Impact of Distal Stent Graft–Induced New Entry on Aortic Remodeling of Chronic Type B Dissection

In chronic type B aortic dissection, late distal stent graft-induced new entry (SINE) has a possible negative role in long-term aortic remodeling. This study aimed to investigate the impact of SINE occurrence on survival by evaluating true and false lumen remodeling in thoracic and abdominal segments at midterm surveillance. This study enrolled 65 patients with chronic type B aortic dissection (DeBakey type IIIb), who had received hybrid thoracic endovascular aortic repair (TEVAR) and had completed surveillance for at least 3 years. The 3-year survival rate was 84.7%. The patients were classified into non-SINE (n= 47) and SINE (n= 18) groups. Serial computed tomography scans were used to analyze volumetric change, true and false lumens, and thrombus volume from arch to aortic bifurcation level. The SINE event occurred at a median of 22.5 months. In the SINE group, there was a significant interruption of the abdominal true lumen expansion in the second year (median 0.01 [interquartile range (IQR), -0.03 to 0.12] in the non-SINE group versus median -0.04 [IQR, -0.12 to 0.04] in the SINE group; p= 0.014). There was a significantly worse thoracic false lumen remodeling in the SINE group compared with the non-SINE group in the third year after the SINE event occurred (median 0 [IQR, -0.09 to 0.05] in the non-SINE group versus median 0.06 [IQR, 0 to 0.13] in the SINE group; p= 0.038). For chronic aortic dissection, late occurrence of distal SINE could influence abdominal true lumen expansion and thoracic false lumen shrinkage. Early reintervention for distal SINE could improve aortic remodeling in chronic aortic dissection.

EROSION Study (Effective Anti-Thrombotic Therapy Without Stenting: Intravascular Optical Coherence Tomography-Based Management in Plaque Erosion): A 1-Year Follow-Up Report.

The initial EROSION study (Effective Anti-Thrombotic Therapy Without Stenting: Intravascular Optical Coherence Tomography-Based Management in Plaque Erosion) demonstrated that patients with acute coronary syndrome caused by plaque erosion might be stabilized with aspirin and ticagrelor without stenting for ≤1 month. However, a long-term evaluation of outcomes is lacking. The aim of this study was to assess whether the initial benefit of noninterventional therapy for patients with acute coronary syndrome caused by plaque erosion is maintained for ≤1 year. Among 53 patients who completed clinical follow-up, 49 underwent repeat optical coherence tomography imaging at 1 year. Median residual thrombus volume decreased significantly from 1 month to 1 year (0.3 mm3 (0.0-2.0 mm3] versus 0.1 mm3 [0.0-2.0 mm3]; P=0.001). Almost half of the patients (46.9%) had no residual thrombus at 1 year. Minimal effective flow area remained unchanged (2.1 mm2 [1.5-3.8 mm2] versus 2.1 mm2 [1.6-4.0 mm2]; P=0.152). Among 53 patients, 49 (92.5%) remained free from major adverse cardiovascular event for ≤1 year: 3 (5.7%) patients required revascularization because of exertional angina and 1 (1.9%) patient had gastrointestinal bleeding. One-year follow-up optical coherence tomography demonstrated a further decrease in thrombus volume between 1-month and 1-year follow-up. A majority (92.5%) of patients with acute coronary syndrome caused by plaque erosion managed with aspirin and ticagrelor without stenting remained free of major adverse cardiovascular event for ≤1 year. URL: https://www.clinicaltrials.gov. Unique identifier: NCT02041650.

Predictive value of thrombus volume for recanalization in stent retriever thrombectomy

This retrospective study investigated whether the volume or density of the thrombus is predictive of recanalization in stent retriever (SR) treatment. Consecutive patients treated with SR thrombectomy as the first endovascular modality were enrolled. The thrombus volume and density were measured on thin-section noncontrast computed tomography using 3-dimensional software. The patients were grouped by recanalization status and the number of SR passes. Among 165 patients, recanalization was achieved with the first pass in 68 (50.0%), 2–3 passes in 43 (31.6%), and ≥4 passes in 25 (18.4%) patients. The thrombus volume was smaller in patients with (107.5 mm3) than without (173.7 mm3, p = 0.025) recanalization, and tended to be larger with increasing number of passes (p for trend = 0.001). The thrombus volume was an independent predictor of first-pass recanalization (odds ratio 0.93 per 10 mm3, 95% confidence interval 0.89–0.97). However, the thrombus density was not associated with recanalization success. Recanalization within 3 passes was associated with a favorable outcome. In conclusion, the thrombus volume was significantly related to recanalization in SR thrombectomy. Measuring the thrombus volume was particularly predictive of first-pass recanalization, which was associated with a higher likelihood of a favorable outcome.

CT imaging features of symptomatic and asymptomatic floating aortic thrombus

To present the computed tomography (CT) imaging features of floating aortic thrombus with emphasis on clinical and radiographic predictors for systemic shower emboli. A retrospective computerised search for patients with protruding thoracic aortic thrombus on CT was conducted. Clinical and demographic characteristics were retrieved from medical files. Patients were divided into two groups: symptomatic and asymptomatic, based on the presence or absence of documented systemic emboli at the time of diagnosis or during follow-up. CT imaging features were analysed: location and extent of systemic emboli, presence or absence of thrombus insertion calcification, percentage of thrombus circumference that is attached to the aortic wall and thrombus volume. Clinical and demographic variables and CT imaging features were analysed as potentially associated with symptomatic emboli. The symptomatic group included 6/15 (40%) patients and the asymptomatic group included 9/15 (60%) patients. Patients in the symptomatic group were significantly younger (symptomatic: 53.3±11.7 years, asymptomatic: 76.9±8.4 years, p=0.003). All the symptomatic patients were women (100%), while 2/9 (22.2%) of the asymptomatic patients were women, (p=0.007). A non-calcified insertion site was more frequent in the symptomatic group (symptomatic 4/6 [66.7%] versus asymptomatic group 1/9 [11.1%], p=0.011). The percentage of thrombus circumference attached to the aortic wall was significantly smaller in symptomatic patients (symptomatic: 31.8±8.4%, asymptomatic: 43.7±5%, p=0.003). The imaging features of symptomatic floating thrombus include a narrow base of attachment and lack of insertion calcification. Free-floating thrombus should be actively sought and diagnosed or excluded when performing CT andiography for emboli.

Rivaroxaban for the treatment of venous thromboembolism in patients with nephrotic syndrome and low AT-III: A pilot study.

The anticoagulation effect of heparin requires adequate serum antithrombin (AT)-III levels. Rivaroxaban, however, exhibits its anticoagulation effects independent of AT-III. The aim of the present study was to evaluate the efficacy and safety of rivaroxaban as a treatment for venous thromboembolism in patients with AT-III deficiency due to nephrotic syndrome. Patients with nephrotic syndrome and low serum concentration and functional activity of AT-III and venous thromboembolism were randomly assigned to the rivaroxaban group (n=8) and low weight molecular heparin group (n=8). The patients were treated for 4 weeks and evaluated at weeks 2 and 4. The primary endpoint was thrombus dissolution or a >90% decrease in thrombus volume in 4 weeks. Secondary endpoints included an increase in the volume of the pre-existing thrombosis and safety assessments. In each of the two groups, 7/8 patients achieved a primary endpoint. At week 2, 5 patients in the rivaroxaban group and 4 in the low weight molecular heparin group had achieved the primary endpoint. Notably, at week 2 the patients whose AT-III levels and functional activity remained low in the low weight molecular heparin group did not achieve the primary endpoint. The adverse effects were similar in both groups, with no severe hemorrhage observed. In conclusion, the results of this pilot study demonstrate that rivaroxaban may be an effective, safe, single-agent approach for treating vein thromboembolism in patients with nephrotic syndrome and low AT-III levels. The potential benefits of rivaroxaban over low weight molecular heparin treatment require further investigation with a larger sample size in order to validate the findings of the present study.

Biomechanical changes during abdominal aortic aneurysm growth.

The biomechanics-based Abdominal Aortic Aneurysm (AAA) rupture risk assessment has gained considerable scientific and clinical momentum. However, such studies have mainly focused on information at a single time point, and little is known about how AAA properties change over time. Consequently, the present study explored how geometry, wall stress-related and blood flow-related biomechanical properties change during AAA expansion. Four patients with a total of 23 Computed Tomography-Angiography (CT-A) scans at different time points were analyzed. At each time point, patient-specific properties were extracted from (i) the reconstructed geometry, (ii) the computed wall stress at Mean Arterial Pressure (MAP), and (iii) the computed blood flow velocity at standardized inflow and outflow conditions. Testing correlations between these parameters identified several nonintuitive dependencies. Most interestingly, the Peak Wall Rupture Index (PWRI) and the maximum Wall Shear Stress (WSS) independently predicted AAA volume growth. Similarly, Intra-luminal Thrombus (ILT) volume growth depended on both the maximum WSS and the ILT volume itself. In addition, ILT volume, ILT volume growth, and maximum ILT layer thickness correlated with PWRI as well as AAA volume growth. Consequently, a large ILT volume as well as fast increase of ILT volume over time may be a risk factor for AAA rupture. However, tailored clinical studies would be required to test this hypothesis and to clarify whether monitoring ILT development has any clinical benefit.

P2-5 - Increase Dose Rivaroxaban Is Effective for Chronic Thromboembolic Pulmonary Hypertension; 3 Cases Report

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare complication of acute pulmonary embolism (PE). However, up to 25% of CTEPH patients have no previous diagnosis of PE. These patients were administered no anti-coagulation agent. We report 3 cases of PE whose symptom sustained over 5 months and tricuspid regurgitation pressure gradient (TRPG) were over 50 mmHg. All patients had complete obstruction of distal brunch, and two patients had large mural thrombus in right main pulmonary artery brunch. We administered rivaroxaban (15 mg twice daily for 3 weeks followed by 15 mg once daily) to these patients. After 2 months, all patients had remarkable reduction of thrombus volume. 1 patient had 20 mmHg TRPG reduction. Despite of these favorable result, all 3 patients were still pulmonary hypertension. We diagnosed them as CTEPH, and administered another agent such as riociguat. Rivaroxaban maybe favorable anticoagulation for CTEPH caused by reduction of chronic thrombus. Of course, other agents were need for optimal treatment of CTEPH.

Impedance biosensor for real-time monitoring and prediction of thrombotic individual profile in flowing blood.

A new biosensor for the real-time analysis of thrombus formation is reported. The fast and accurate monitoring of the individual thrombotic risk represents a challenge in cardiovascular diagnostics and in treatment of hemostatic diseases. Thrombus volume, as representative index of the related thrombotic status, is usually estimated with confocal microscope at the end of each in vitro experiment, without providing a useful behavioral information of the biological sample such as platelets adhesion and aggregation in flowing blood. Our device has been developed to work either independently or integrated with the microscopy system; thus, images of the fluorescently labeled platelets are acquired in real-time during the whole blood perfusion, while the global electrical impedance of the blood sample is simultaneously monitored between a pair of specifically designed gold microelectrodes. Fusing optical and electrical data with a novel technique, the dynamic of thrombus formation events in flowing blood can be reconstructed in real-time, allowing an accurate extrapolation of the three-dimensional shape and the spatial distribution of platelet thrombi forming and growing within artificial capillaries. This biosensor is accurate and it has been used to discriminate different hemostatic conditions and to identify weakening and detaching platelet aggregates. The results obtained appear compatible with those quantified with the traditional optical method. With advantages in terms of small size, user-friendliness and promptness of response, it is a promising device for the fast and automatic individual health monitoring at the Point of Care (POC).

Evolution of Computed Tomography Imaging the First Year after Endovascular Sealing of Infrarenal Aortic Aneurysms Using the Nellix Device

The Nellix endovascular aneurysm sealing (EVAS) system is an alternative endovascular treatment option for infrarenal aortic aneurysms (AAAs), with a unique appearance on computed tomography angiography (CTA). Normal evolution of post-EVAS CTA appearance follow-up is still largely unknown and important to timely detect eventual complications. The objective is to assess the normal appearance of CTA images 30days and 1year after EVAS in 50 consecutive patients. Fifty patients treated with Nellix EVAS for an infrarenal AAA were included from 3 hospitals. Using dedicated software, a total of 150 CTA scans were analyzed by predetermined variables per anatomical segment. Thirty days post-EVAS, there was a slight, but not statistically significant, increase in AAA diameter that returned to the preoperative value after 1 year. A shift in total aortic volume distribution was observed without changing aortic diameter, including a trend toward a decreased thrombus volume (85.6±49.1mL and 78.8±35.5mL at 30days and 1 year, respectively, P<0.242) and a slight, but statistically significant, increase in polymer volume (68.2±34.1mL and 71.9±35.2mL at 30days and 1 year, respectively, P<0.001). The β-angle (P=0.06) and iliac artery angulation (P<0.001) decreased after implant. The latter returned to its original state after 1 year, whereas the neck straightening remained. Over time, there was a significant decrease in radiodensity in the middle of the polymer-filled endobags with an increase at its edges (P<0.05). Thrombus radiodensity significantly increased over the first year (P<0.05). Diameters of the infrarenal neck and common iliac arteries remained unchanged, no endoleaks were observed, and the position of the device was stable. Change of CT appearance after EVAS is unique, and as such, the judgment of these images requires experience. The appearance of the endobags in respect to volume and radiodensity differ from classic EVAR. Normal changes over time are observed in aortoiliac angulation, volumes, and radiodensities.