Rate Of Thrombus Formation Research Articles

How I do It: High flow EC-IC bypass for complex middle cerebral artery aneurysms using the lateral circumflex femoral artery as interposition graft.

High-flow bypasses with parent vessel occlusion are required for complex aneurysms originating from the ICA or MCA. Traditional graft options are the saphenous vein however, it has a higher rate of thrombus formation than an arterial graft. The radial artery is commonly used, however, tapers in its distal course and is contraindicated in some patients while the lateral circumflex femoral artery is an excellent graft vessel and easy to harvest. We present our technique and experience harvesting the lateral circumflex femoral artery as an alternative graft vessel for high-flow bypasses. The lateral circumflex femoral artery is easy to harvest and is a reliable graft vessel for high-flow bypasses for complex aneurysms.

Peculiarities of Hemostasis and Proteomics in Patients With Acute Myocardial Infarction and Healthy Volunteers After SARS-CоV-2 Infection.

To identify the features of plasma, platelet hemostasis, and proteomic composition of the blood plasma in patients with acute myocardial infarction (AMI) and healthy volunteers after COVID-19. The study included patients with AMI who have recently had COVID-19 (AMI-post-COVID, n=56) and patients with AMI who have not recently had COVID-19 (AMI-control, n=141). Healthy volunteers constituted the control groups and were also divided into control-post-COVID (n=32) and control-control (n=71) groups. Previous SARS-CoV-2 infection was determined by anti-N IgG in the blood serum, the level of which persists for 6-10 months after the disease. Hemostasis was evaluated by thromboelastometry (on whole blood), thrombodynamics (on platelet-poor plasma), fibrinolysis, impedance aggregometry, and proteomic analysis. The AMI-post-COVID and AMI-control groups had higher values of thrombus growth rate, size and density based on the data of thromboelastometry and thrombodynamics, as well as increased concentrations of the complement system components, proteins regulating the state of the endothelium, and a number of acute-phase and procoagulant proteins compared to the control groups. Furthermore, in the AMI-post-COVID group, compared to the AMI-control group, the thrombus density was lower, and its lysis rates were higher when measured by the thrombodynamics method on platelet-poor plasma, while the platelet aggregation induced by ADP and thrombin was higher. Also, in the control-post-COVID group, compared to the control-control group, the thrombus formation rate was lower, whereas, in contrast, the thrombus size as measured by the thrombodynamics method and the platelet aggregation induced by arachidonic acid and thrombin were higher. In addition, in the AMI-post-COVID group, compared to the AMI-control group, the concentrations of proteins involved in inflammation and hemostasis were lower. Patients with AMI who have recently had COVID-19 are characterized by a less pronounced activation of the immune response compared to patients with AMI who have not had COVID-19. This may be due to long-term chronic inflammation and depletion of components of the immune activation system after SARS-CoV-2 infection. Long-term activation of the hemostasis system in both patients with AMI and healthy volunteers after COVID-19 is primarily due to the platelet component of hemostasis.

Covered Stent Treatment for Direct Carotid-Cavernous Fistulas: A Meta-Analysis of Efficacy and Safety Outcomes

BackgroundDirect carotid-cavernous fistulas (dCCFs) involve the abnormal shunting of blood between the internal carotid artery and the cavernous sinus. The use of covered stents (CSs) has been reported for the treatment of complex carotid artery lesions. However, the efficacy and safety of CS treatment for dCCFs remain controversial. Thus, we performed a systematic review and meta-analysis to evaluate these efficacy and safety endpoints. MethodsA systematic literature review was performed by comprehensively searching the Medline, Embase, and Web of Science databases to identify studies that were related to CS treatment for dCCFs. Then, a meta-analysis was conducted to pool the efficacy and safety outcomes from these studies based on perioperative and follow-up data. ResultsFourteen non-comparative studies enrolling 156 patients with 160 dCCFs met the inclusion criteria. When analyzing perioperative outcomes, the technical success rate was 98.5% [95% confidence interval (CI), 0.948, 1.000], and the immediate complete occlusion rate was 90.9% (95% CI, 0.862, 0.959). Vasospasm and dissection occurred in 32.2% (95% CI, 0.238, 0.463) and 0.1% (95% CI, 0.000, 0.012) of patients, respectively. The in-stent acute thrombus formation rate was 0.1% (95% CI, 0.000; 0.013). Postoperatively, the mortality rate was 0.1% (95% CI, 0.000, 0.013). Based on available follow-up data, the final complete occlusion and parent artery stenosis rates were 99.3% (95% CI, 0.959, 1.000) and 18.6% (95% CI, 0.125, 0.277), respectively. ConclusionsCS placement can be used to safely and effectively treat dCCFs. These results provide a reference for future clinical trials.

Efficacy and safety of tranexamic acid in the treatment of gastric cancer complicated with upper gastrointestinal bleeding.

To investigate the efficacy and safety of tranexamic acid (TXA) in preventing upper gastrointestinal (GI) bleeding in patients with gastric cancer. The clinical data of patients with gastric cancer complicated with acute non-operative GI bleeding treated in the Fourth Hospital of Hebei Medical University from 2020 to 2022 were collected and retrospectively analyzed. The survival status of the patients was followed up by telephone. The dataset of 168 patients was divided into a control group (n=85) and a TXA group (n=83), at a 1:1 ratio. The patients in the control group were treated with esomeprazole, and the patients in the TXA group received additional TXA. The hemostatic effect, rebleeding rate, and mortality of patients were compared between the two groups. The Cox proportional hazard model was used to evaluate the overall survival of patients as well as the related risk factors. The success rate of hemostasis and the normal blood coagulation rate in the TXA group were significantly higher than those in the control group (P=0.003 and P=0.016). The secondary bleeding rate, thrombus formation rate and digestive tract perforation rate in the TXA group were significantly lower than those in the control group (P=0.002, P=0.003 and P=0.035). The improvement of all indicators in the TXA group was better than that in the control group (all P<0.05). For patients with gastric cancer complicated with acute GI bleeding treated with TXA, the Cox proportional hazard model identified III~IV stage, time of TXA treatment, surgical treatment after hemorrhage, and an increase of D-dimer as independent risk factors for upper GI bleeding (all P<0.05). TXA can be an effective treatment for patients with gastric cancer complicated by GI bleeding.

Predictive value of echocardiography combined with CT angiography for left atrial appendage thrombosis in patients with non-valvular atrial fibrillation.

The aim of this study was to investigate the detection rate of left atrial appendage thrombus (LAAT) formation in non-valvular atrial fibrillation (NVAF) patients using three methods and the efficacy of combined electrocardiogram (ECG) and Computed Tomography Angiography (CTA) in the diagnosis of LAAT. A total of 80 NVAF patients who underwent Transesophageal echocardiography (TEE) at our hospital from August 2018 to August 2022 were included in the study. The baseline data of patients were observed, and the positive rates of LAAT formation by ECG, CTA, and TEE were compared. The efficacy of combined ECG and CTA in the diagnosis of LAAT was also evaluated. Among the 80 NVAF patients, 23 were LAAT positive and 57 were LAAT negative. There were statistically significant differences between the two groups in terms of age, body mass index (BMI), N-terminal prohormone of brain natriuretic peptide NT-probNP, fibrinogen, CHA2DS2-VASC [congestive Heart Failure, Hypertension, Age (75 or older), diabetes mellitus, stroke, vascular disease, age (65-74), sex category] score, paroxysmal atrial fibrillation, renal insufficiency, D-dimer, heart failure, and serum uric acid (p<0.05). The positive rate of LAAT detected by ECG combined with CTA was closest to the gold standard TEE, but the difference was not statistically significant (p>0.05). Statistically significant differences were found between LAAT positive and negative patients in various parameters related to left atrial and left ventricular dimensions and function (p<0.05), while some parameters showed no significant differences (p>0.05). ECG combined with CTA has a high diagnostic value for LAAT formation in NVAF patients, with a high degree of confidence and reduced patient intolerance. The sensitivity, accuracy, and negative predictive value of ECG combined with CTA for the diagnosis of LAAT formation in NVAF patients are high and have good predictive value.

Nutritional value and dietary significance of natural canned Japanese mackerel

The aim: evaluate natural canned Japanese mackerel as specialized products for dietary nutrition based on indicators of nutritional and biological value, as well as lipid health indices. The methods: The nutritional (chemical composition) and biological value of canned Japanese mackerel, the composition of lipids and fatty acids were studied, on the basis of which lipid indices of atherogenicity, thrombogenicity and hypocholesterolemic coefficient were calculated, characterizing the dietary properties of canned Japanese mackerel. The results: It has been established that the process of high-temperature preservation of Japanese mackerel does not cause significant changes in the nutrient composition of the product. Canned Japanese mackerel is characterized by a high content of phospholipids (7.80 ± 1.1 of the total lipids or 1.41 ± 0.3 g per 100 g of the product) and PUFAs of the omega-3 family (32.26 % of the number of fatty acids). The index of atherogenicity of the lipid profile of canned food was 0.57, thrombogenicity — 0.16, and hypocholesterolemic coefficient — 2.80. Conclusions: Canned Japanese mackerel are characterized by high nutritional and biological value and are a rich source of essential lipids. The lipid indices of canned Japanese mackerel characterize the potential for the product to normalize lipid metabolism in humans and reduce the risk of developing diseases of the cardiovascular system. The newness: Based on a new methodological approach to assessing the lipid profile of canned Japanese mackerel, a possible positive effect of the product on cholesterol metabolism and the rate of thrombus formation in human blood vessels was shown. The practical significance: Natural canned food from Japanese mackerel can be recommended for inclusion in the diet of certain population groups as specialized products for dietary preventive nutrition.

BIO22: Effects of Leakage Flows around TAVI models on Thrombus Formation by Optical Visualization Method with Various Geometries in Vitro

Background: There is a possibility of leakage (PVL; Paravalvular leak) flow around TAVI (Transcatheter Aortic Valve Implantation) and a high risk of thrombus formation. To find out the mechanism of thrombus formation by this leakage flow is important issue. In our previous studies, effects of the high shear rate on the thrombus formation rate at wall on orifice flow were examined by observation of thrombus formation using laser sheet, and it was found that the thrombus formation rates increase with the high shear rates. In this study, observation of thrombus formation around TAVI models including leakage flows by laser sheet in vitro with various geometries. Method: Experimental objects are orifice pipe flow and the leakage models with (Fig.1) for observation of thrombus formation. Each leakage size h is 0mm, 0.5mm, 1mm respectively with 20 mm diameter with stenosis to simulate valve part. The target flow filed with fresh blood plasma of pigs is observed with high speed CCD camera by laser sheet. Once the thrombus formation starts, the scattering wave can be detected by this system. The movies for three kinds of geometries and two flow rates (3 and 5l/min). Results & Conclusions: As for visualization results, typical distribution of thrombus formation area at h= 0, 0.5, 1 mm is shown in Fig.2. Due to the increasing of leakage size, the thrombus formation area at the outer wall decreases. In case of leakage size h=0.5 and 1 mm, these areas correspond to wake size at the back side of the stenosis. Figure 3 shows the thrombus formation rate by evaluation of the thrombus area with changing the leakage size and geometries. It was found that the thrombus formation rate increases with the leakage size, and there are differences between the two geometries. These findings related thrombus formation area were also evaluated from the leakage flow rates in the CFD (Computational Fluid Dynamics) results. And it was also found that this formation rates increase with leakage flow rate obtained by CFD. In conclusion, there is a high possibility to generate thrombus formation with larger leakage flow for TAVI. In future, the effects of valve motion should be investigated.

11,12-EET suppressed LPS induced TF expression and thrombus formation by accelerating mRNA degradation rate via strengthening PI3K-Akt signaling pathway and inhibiting p38-TTP pathway

Epoxyeicosatrienoic acids (EETs), which are synthesized from arachidonic acid by cytochrome P450 epoxygenases, function primarily as autocrine and paracrine effectors in the cardiovascular system. So far, most research has focused on the vasodilatory, anti-inflammatory, anti-apoptotic and mitogenic properties of EETs in the systemic circulation. However, whether EETs could suppress tissue factor (TF) expression and prevent thrombus formation remains unknown. Here we utilized in vivo and in vitro models to investigate the effects and underlying mechanisms of exogenously EETs on LPS induced TF expression and inferior vein cava ligation induced thrombosis. We observed that the thrombus formation rate and the size of the thrombus were greatly reduced in 11,12-EET treated mice，accompanied by decreased TF and inflammatory cytokines expression. Further in vitro studies showed that by enhancing p38 MAPK activation and subsequent tristetraprolin (TTP) phosphorylation, LPS strengthened the stability of TF mRNA and induced increased TF expression. However, by strengthening PI3K-dependent Akt phosphorylation, which acted as a negative regulator of p38-TTP signaling pathway，11,12-EET reduced LPS-induced TF expression in monocytes. In addition, 11,12-EET inhibited LPS-induced NF-κB nuclear translocation by activating the PI3K/Akt pathway. Further study indicated that the inhibitory effect of 11,12-EET on TF expression was mediated by antagonizing LPS-induced activation of thromboxane prostanoid receptor. In conclusion, our study demonstrated that 11,12-EET prevented thrombosis by reducing TF expression and targeting the CYP2J2 epoxygenase pathway may represent a novel approach to mitigate thrombosis related diseases.

Incidence of intra-procedural complications according to the timing of endovascular treatment in ruptured intracranial aneurysms.

Although endovascular treatment of ruptured intracranial aneurysms is well-established, some critical issues have not yet been clarified, such as the effects of timing on safety and effectiveness of the procedure. The aim of our study was to analyze the incidence of intra-procedural complications according to the timing of treatment, as they can affect morbidity and mortality. We retrospectively analyzed all patients who underwent endovascular treatment for ruptured intracranial aneurysms at three high flow center. For all patients, imaging and clinical data, aneurysm's type, mean dimension and different treatment techniques were analyzed. Intra-procedural complications were defined as thrombus formation at the aneurysm's neck, thromboembolic events, and rupture of the aneurysm. Patients were divided into three groups according to time between subarachnoid hemorrhage and treatment (<12 h hyper-early, 12-36 h early, and >36 h delayed). The final study population included 215 patients. In total, 84 patients (39%) underwent hyper-early, 104 (48%) early, and 27 (13%) delayed endovascular treatment. Overall, 69% of the patients were treated with simple coiling, 23% with balloon-assisted coiling, 1% with stent-assisted coiling, 3% with a flow-diverter stent, 3% with an intrasaccular flow disruptor device, and 0.5% with parent vessel occlusion. Delayed endovascular treatment was associated with an increased risk of total intra-procedural complications compared to both hyper-early (p = 0.009) and early (p = 0.004) treatments with a rate of complications of 56% (vs. 29% in hyper-early and 26% in early treated group-p = 0.011 and p = 0.008). The delayed treatment group showed a higher rate of thrombus formation and thromboembolic events. The increased risk of total intra-procedural complications in delayed treatment was confirmed, also considering only the patients treated with simple coiling and balloon-assisted coiling (p = 0.005 and p = 0.003, respectively, compared to hyper-early and early group) with a rate of complications of 62% (vs. 28% in hyper-early and 26% in early treatments-p = 0.007 and p = 0.003). Also in this subpopulation, delayed treated patients showed a higher incidence of thrombus formation and thromboembolic events. Endovascular treatment of ruptured intracranial aneurysms more than 36 h after SAH seems to be associated with a higher risk of intra-procedural complications, especially thrombotic and thromboembolic events.

Evaluation of factors associated with limb thrombus formation after endovascular aortic aneurysm repair

BackgroundLimb thrombus formation is a complication that can occur after endovascular aortic repair (EVAR), and its clinical significance has continued to be debated. Our objective was to report the incidence of limb thrombus after EVAR and determine the association of specific demographic, anatomic, and/or graft variables. MethodsA retrospective analysis of EVAR patients at a single tertiary center between January 2010 and December 2018 was performed to determine the limb thrombus rate. Demographic, graft, and anatomic variables were analyzed for an association with limb thrombus. ResultsA total of 301 patients were included. The average follow-up was 27.6 ± 4.9 months. The mean age was 76.5 ± 0.5 years, and 85% were men. Limb thrombus occurred in 22 patients (7.3%). Of these 22 patients, 11 (50.0%) had had occlusive limb thrombus, 14 (63.6%) were symptomatic, and 17 (77.3%) had required intervention. The patients with limb thrombus were younger (69.8 ± 1.3 years vs 77.1 ± 0.5 years; P < .0001) and more likely to be smokers (10.2% vs 5.2%; P = .10). The incidence of limb thrombus with the Alpha graft (10.7%; Cook Medical Inc, Bloomington, IN) was compared with that with non-Cook grafts (4.0%; P = .07). The average common iliac artery diameter for patients with and without limb thrombus was 14.1 mm and 16.1 mm, respectively (P < .01). Right-sided limb thrombus was more likely in smaller right iliac arteries (14.7 ± 0.9 cm vs 17.0 ± 0.6 cm; P < .05), with a similar finding on the left (13.6 ± 0.9 cm vs 15.2 ± 0.4 cm; P = .13). Unilateral limb thrombus was almost twice as likely on the main body side than on the contralateral side (11 vs 6). Limb thrombus was not associated with aortoiliac disease (odds ratio [OR], 1.31; 95% confidence interval [CI], 0.37-4.62), limb extension (OR, 0.47; 95% CI, 0.06-3.62), or nonmatching limb heights (OR, 1.36; 95% CI, 0.54-3.43). Limb thrombus was also not associated with increased 30-day mortality (P > .05). ConclusionsLimb thrombus formation is a complication that can occur after EVAR (7.3%). In our study, limb thrombus was seen more frequently in younger patients and those who smoked. Cook Alpha grafts had a thrombus formation rate of 10.7%, which was not significantly higher than that with other brands. Limb thrombus was more likely in smaller iliac arteries and on the main body side.

Comparing Velocity and Mean Arterial Pressure to Assess Pulsatility in Patients with Continuous Flow Left Ventricular Assist Devices

<h3>Purpose</h3> An increasing number of end-stage heart failure patients are supported by continuous-flow Left Ventricular Assist Devices (cfLVADs). In these patients, accurate assessment of arterial pulsatility remains a challenge because of diminished pulse pressure. Limited pulsatility in modern cfLVADs itself can be associated with adverse events such as stroke. Our study investigates the value of simultaneous arterial pressure and arterial blood velocity assessment in cfLVAD patients. <h3>Methods</h3> Both velocity (cm/s) and pressure (mmHg) data were collected during routine follow up. Pressure was measured using a brachial cuff oscillometry system (Sphygmocor XCel) providing a systolic and diastolic readings, while velocity was measured using a digital doppler (Huntleigh) from the brachial artery. Velocity measurements obtained included peak, minimum, average velocity and pulsatility index. Pressure measurements obtained were systolic and diastolic which allowed us to derive a mean arterial pressure (MAP) from the brachial artery. <h3>Results</h3> From a total of 24 patients (88% males), there were 44 velocity and pressure measurements. Mean device support duration was 240 days (SD 116). Mean derived brachial MAP was 85 mmHg (SD 9), whereas mean peak brachial artery velocity was 14 cm/s (SD 9). Mean pulsatility index was 2 (SD 2). Correlation analysis using Spearman's rho demonstrated a significant inverse relationship between Brachial derived MAP and Peak velocity (Rho=-0.41, p=0.007). <h3>Conclusion</h3> Arterial doppler measurements may provide incremental value over purely pressure-based measurements. The inverse relationship between derived MAP and peak velocity in this study may be partially explained by the degree of arterial compliance. In turn, this provides significant information on the relationship between higher MAP and lower blood velocity to subsequently explain increased thrombus formation and stroke rate due to longer transit time of blood.

Lysine-Histone Triggers Thrombotic Thrombocytopenic Purpura in Zebrafish and Mice

Background: Thrombotic thrombocytopenic purpura (TTP) is a potentially fatal syndrome, primarily resulting from a severe deficiency of plasma ADAMTS13 activity due to mutations in ADAMTS13 gene or autoantibodies against ADAMTS13. However, severe deficiency of plasma ADAMTS13 activity alone is often not sufficient to cause an acute episode; additional environmental and/or genetic factors may be required to trigger acute TTP.Objectives: To address the potential triggers and identify novel therapeutic targets for TTP, we established and characterized a novel Adamts13-/- zebrafish line and determined the pathogenic role of lysine-histone in triggering TTP in both zebrafish and mice.Methods and Results:CRISPR/Cas9 was employed to create an 8-nt deletion mutation in the signal peptide region of zebrafish Adamts13, resulting in complete deficiency of Adamts13 protein. Adamts13-/- zebrafish on the double transgenic (fli1-eGFP/gata1-dsRed) background showed normal size, morphology, and fertility except for the consistent appearance of a branching interseptal vessel. Adamts13-/- zebrafish larvae exhibited a significantly increased response to oxidative stress with an increased mortality rate and an accelerated rate of thrombus formation in microvasculature and caudal vessels after oxidative injury. Additionally, Adamts13-/- zebrafish demonstrated a significantly reduced number of circulating mature thrombocytes (thrombocytopenia) and an increased number of fragmented red blood cells (schistocytosis), consistent with the clinical phenotype of a spontaneous TTP. Moreover, plasma levels of histone/DNA complexes were found to be highly elevated in patients with acute TTP, but their pathogenic role is not known. Wild-Type and Adamts13-/- zebrafish and mice were challenged with a lysine rich-histone (H5505) intraperitoneally (200 μg/g body weight) and intravenously (20, 60, and 120 μg/g body weight), respectively. Complete blood counts were determined over a period of 14 and 3 days, respectively. We showed a more severe and persistent thrombocytopenia, increased fragmentation of red blood cells, as well as increased mortality rate in Adamts13-/- compared to Wild-Type zebrafish (Figure). Similar dose-dependent and profound thrombocytopenia was observed in Adamts13-/- but not in Wild-Type mice. Histological analysis of the organ tissues from Adamts13-/- zebrafish that died after histone challenge revealed the presence of microvascular thrombosis, supporting the diagnosis of TTP in these zebrafish.Conclusions: These results demonstrate for the first time the success in establishing a zebrafish model of Adamts13-/- and TTP. Such a novel animal model enables us to rapidly evaluate the role of lysine-histone and many other potential environmental or genetic factors in the onset, progression, and outcome of TTP. This model may also help to identify novel therapeutic targets for both hereditary and acquired TTP in at an unprecedented pace. [Display omitted] DisclosuresZheng:Alexion: Speakers Bureau; Ablynx: Consultancy.

Plasma Levels of Big Endothelin-1 Are Associated with Renal Insufficiency and In-Hospital Mortality of Immune Thrombotic Thrombocytopenic Purpura.

Immune thrombotic thrombocytopenic purpura (iTTP) is caused by severe deficiency of plasma ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity. Despite advances in early diagnosis and management, the mortality rate of acute iTTP remains high in a large part of world where access to some of the most novel therapies is limited. To determine the role of plasma big endothelin-1 (bigET-1) or its bioactive product ET-1 as a biomarker and/or a pathogenic factor in acute iTTP, plasma levels of bigET-1 were determined using an immunoassay in patients with iTTP on admission and during remission, as well as in healthy controls; moreover, the biological effect of ET-1 in thrombus formation was determined by a microfluidic assay. We show that plasma levels of bigET-1 were dramatically increased in patients with acute iTTP on admission, which was significantly decreased during clinical response/remission; elevated admission levels of plasma bigET-1 were associated with low estimated glomerular filtration rate, the need for intensive care unit admission or intubation, and in-hospital mortality. Moreover, an addition of a bioactive product ET-1 to cultured endothelial cells in a microfluidic channel significantly accelerated the rate of thrombus formation under arterial flow. Our results demonstrate for the first time a potential role of measuring plasma bigET-1 in patients with acute iTTP in assessing the disease severity and risk of in-hospital mortality, which may help stratify patients for a more aggressive monitoring and therapeutic strategy; also, the bioactive ET-1, derived from bigET-1, may result in acute renal injury in TTP patient, likely through its vasoconstriction and prothrombotic properties.

Role of anticoagulation in the management of tumor thrombus: A 10-year single-center experience.

Children with cancer diagnosis are overall at a higher risk of thrombosis. For a newly diagnosed blood clot, patients are commonly started on anticoagulants to prevent further extension and embolization of the clot. In the rare instance that a pediatric patient has a tumor thrombus, role of anticoagulation is less clear. Patients under 21years of age with a finding of tumor thrombus on imaging from 2010 to 2020 at Texas Children's Hospital were identified and their medical records were reviewed. A total of 50 patients were identified. Most thrombi were incidental findings at diagnosis; however, two patients presented with pulmonary embolism (PE). Inferior vena cava extension was noted in 36% of the patients, and 24% patients had an intracardiac tumor thrombus. Anticoagulation was initiated in 10 patients (20%). There was no difference in the rate of bland thrombus formation and/or embolization in patients who did or did not receive anticoagulation. However, three of the six patients with asymptomatic tumor thrombus who were started on anticoagulation had bleeding complications compared to only two patients in the no anticoagulation cohort (p<.05). Children with intravascular extension of solid tumors were not commonly started on anticoagulation at the time of diagnosis, irrespective of the extent of tumor thrombus. Furthermore, we observed a significant trend toward higher incidence of bleeding complications after initiation of anticoagulation for asymptomatic tumor thrombus. There is inadequate evidence at this time to support routine initiation of anticoagulation in pediatric patients with intravascular extension of solid tumors.

Delayed Occlusion of the Anterior Choroidal Artery Following Flow Diverter Stent Deployment for Unruptured Aneurysm: A Case Report and Literature Review

Flow diverter stent has been a promising device for intracranial aneurysm treatment. For treating aneurysms located in the anterior circulation, critical branches may be covered by flow diverter stent. The occlusion incidence of these branches has been reported, and even if branch vessel occlusions occur, associated neurological deficits are extremely rare. We present a 55-year-old woman who had a large saccular aneurysm at the right internal carotid artery (ICA). A developed fetal-type posterior communicating artery (PCOM) originated from the sac. We administered flow diverter stent deployment with coil insertion following surgical anastomosis of the superficial temporal artery to the posterior cerebral artery (STA-PCA) with ligation of the origin of the PCOM. On the seventh morning following the intervention, ischemic complication developed due to anterior choroidal artery occlusion jailed by the flow diverter stent. The occlusion of anterior choroidal artery covered by flow diverter stent is extremely rare. However, if the branch arises from the aneurysm sac, occlusion can transpire and induce serious complication. The most probable cause of occlusion in this case was that the orifice was jailed apart from the stent strut because the branch originated from the sac rather than the neck. Furthermore, the progression rate of intra-aneurysm thrombus formation is also an important factor affecting the side branch occlusion.

Female Gender Is Associated with Increased Thrombus Burden within Stent Graft Following Thoracic Endovascular Aortic Repair

Mural thrombus within stent grafts develops at an unclear incidence following thoracic endovascular aortic repair (TEVAR). The significance of this phenomenon has not been determined, nor have the risk factors for development of intragraft thrombus. Small graft diameter is hypothesized to be a risk factor for thrombus development. A retrospective analysis was performed of a multicenter health-care system including all patients who underwent TEVAR between July 2011 and July 2019 with at least one year of subsequently available surveillance contrast-enhanced commuted tomography imaging. Standard demographic, preoperative, intraoperative, and postoperative variables were collected. Measurements were obtained via direct off-line images from computed tomography scans. Patent intragraft diameters were compared with baseline and interval change values were normalized to time to follow-up. The primary outcome measure was annual rate of intragraft thrombus formation. There were 208 patients who met the inclusion criteria (94 women, 114 men) with a median follow-up of 822 days. The mean (standard deviation) annual rate of percent intragraft diameter reduction was 10.5% (7.7%) for women and 7.6% (5.6%) for men (P = .0026). Multivariate analysis demonstrated female sex (P = .0283), preoperative diagnosis of hypertension (P = .0449), and need for coverage of the left subclavian artery (P = .0328) were all significant predictors of intragraft thrombus formation. Small aortic diameters were not independently found to be associated with development of thrombus, nor was concomitant use of antiplatelet or anticoagulation medications. High rates of thrombus formation, defined as >20% intragraft diameter reduction, were associated with increased need for any reintervention, including for malperfusion, endoleak, and symptomatic aneurysm (P = .0249). Kaplan-Meier estimate demonstrated a significant sex-associated difference in high rates of intragraft thrombus formation (P = .00189) (Fig). In this analysis, female sex is shown to be the most significant nonmodifiable risk factor for intragraft thrombus formation following TEVAR. Development of thrombus is not benign as such findings were associated with increased need for reintervention. This finding may be attribuTable to differences in aortic compliance or sex-associated differences in coagulation pathways and merits further investigation. Surveillance following thoracic stent grafting must account for patient-specific variations in complication risk.

Comparison of intra-wound drainage tubes after cardiac surgery: Blake drains versus Multichannel drains.

Blake and Multichannel drains have been used in our department. Although both are made up of silicone, they differ in structure. We investigated the drainage effects of these two types of drains and the factors related to their occlusion. We enrolled 100 consecutive cases (50 using Blake drains and 50 using Multichannel drains) of cardiovascular surgery performed in our department from July 2017 to April 2018. The formation of thrombi in the groove and tube of the drains was evaluated in each case. The tube portion was checked for the presence of occlusion, and the groove portion was examined for the number and ratio of thrombi formed in the grooves. The clot formation rate in the groove part was slightly higher in the Multichannel cases than in the Blake cases. In addition, analysis within the Multichannel cases revealed that the thrombus formation rate between the catheter lumen and the three grooves (without the catheter lumen) was significantly different, with the highest groove clot formation rate occurring in the catheter lumen. Out of 34 cases of occlusions, there were 26 cases (52%) of Multichannel drains, and only 8 cases (16%) of Blake drains (p < 0.01). A multiple logistic regression analysis revealed that the most important contributory factor in tube obstruction was the drain type. The catheter lumen of the Multichannel drain was more susceptible to thrombus formation than the groove. The tube part of the Multichannel drain was more prone to occlusion than that of the Blake drain.

Histone-induced thrombotic thrombocytopenic purpura in adamts13 -/- zebrafish depends on von Willebrand factor.

Thrombotic thrombocytopenic purpura (TTP) is caused by severe deficiency of ADAMTS13 (A13), a plasma metalloprotease that cleaves endothelium-derived von Willebrand factor (VWF). However, severe A13 deficiency alone is often not sufficient to cause an acute TTP; additional factors may be required to trigger the disease. Using CRISPR/Cas9, we created and characterized several novel zebrafish lines carrying a null mutation in a13−/−, vwf, and both. We further used these zebrafish lines to test the hypothesis that inflammation that results in neutrophil activation and release of histone/DNA complexes may trigger TTP. As shown, a13−/− zebrafish exhibit increased levels of plasma VWF antigen, multimer size, and ability of thrombocytes to adhere to a fibrillar collagen-coated surface under flow. The a13−/−zebrafish also show an increased rate of occlusive thrombus formation in the caudal venules after FeCl3 injury. More interestingly, a13−/− zebrafish exhibit ~30% reduction in the number of total, immature, and mature thrombocytes with increased fragmentation of erythrocytes. Administration of a lysine-rich histone results in more severe and persistent thrombocytopenia and a significantly increased mortality rate in a13−/−zebrafish than in wildtype (wt) ones. However, both spontaneous and histone-induced TTP in a13−/− zebrafish are rescued by the deletion of vwf. These results demonstrate a potentially mechanistic link between inflammation and the onset of TTP in light of severe A13 deficiency; the novel zebrafish models of TTP may help accelerate our understanding of pathogenic mechanisms and the discoveries of novel therapeutics for TTP and perhaps other arterial thrombotic disorders.

Mechanical antithrombogenic properties by vibrational excitation of the impeller in a magnetically levitated centrifugal blood pump.

Mechanical circulatory support devices have been used clinically for patients with heart failure for over 10years. However, thrombus formation inside blood pumps remains a risk to patient life, causing pump failure and contributing to neurological damage through embolization. In this article, we propose a method for preventing thrombus formation by applying vibrational excitation to the impeller. We evaluate the ability of this method to enhance the antithrombogenic properties of a magnetically levitated centrifugal blood pump and ensure that the impeller vibration does not cause undue hemolysis. First, 3 vibrational conditions were compared using an isolated pump without a mock circulation loop; the vibrational excitation frequencies and amplitudes for the impeller were set to (a) 0Hz-0μm, (b) 70Hz-10μm, and (c) 300Hz-2.5μm. The motor torque was measured to detect thrombus formation and obtain blood coagulation time by calculating the derivative of the torque. Upon thrombus detection, the pump was stopped and thrombi size were evaluated. The results showed an increase in the blood coagulation time and a decrease in the rate of thrombus formation in pumps with the impeller vibration. Second, an in vitro hemolysis test was performed for each vibrational condition to determine the effect of impeller vibration on hemolysis. The results revealed that there was no significant difference in hemolysis levels between each condition. Finally, the selected vibration based on the above test results and the non-vibration as control were compared to investigate antithrombogenic properties under the continuous flow condition. The blood coagulation time and thrombi size were investigated. As a result, vibrational excitation of the impeller at a frequency of 300Hz and amplitude of 2.5μm was found to significantly lengthen clotting time, decreasing the rate of pump thrombus compared to the non-vibration condition. We indicate the potential of impeller vibration as a novel mechanical antithrombogenic mechanism for rotary blood pumps.

Current concepts in portal vein thrombosis: etiology, clinical presentation and management.

The aim of this article is to focus on etiology, risk factors, clinical presentation and classification systems of acute and chronic PVT as well as focusing on current diagnostic and therapeutic options for the management of acute and chronic PVT. PVT represents a serious clinical concern in cirrhotic patients and in those with specific local or systemic risk factors. The rate and extent of thrombus formation can significantly impact patient presentation and the resulting clinical outcomes. The presentation of acute PVT can range from abdominal pain to intestinal ischemia/infarction and even death, while chronic PVT can remain clinically silent. A number of imaging modalities including US, CT and MRI can be used to confirm the diagnosis. In addition to addressing underlying risk factors, AC therapy forms a cornerstone of treatment and has demonstrated efficacy in both acute and chronic settings. Proper caution should be used when initiating AC therapy in cirrhotic patients given their underlying coagulopathic status with attention now being paid to NOACs and LMWH. For patients with bowel ischemia, extensive thrombosis, contraindications or poor response to AC, or for those with co-morbidities that preclude AC, minimally invasive endovascular techniques offer alternative treatment options. Familiarity with the etiology, clinical presentation and classification of PVT optimize early detection and incorporate effective therapeutic options, the management of these complex patients should be undertaken by a multidisciplinary team. Minimally invasive catheter-based therapies and endovascular portosystemic shunt creation demonstrated efficacy in the treatment of AC-resistant patients and for patients with extensive or complicated disease.