Establishment of an acute arterial mesenteric ischaemia model in canines with an endovascular approach.

Purpose: This study aimed to evaluate the feasibility of establishing an arterial acute mesenteric ischemia (AMI) model in canines using transcatheter autologous thrombus administration. Materials and methods: Ten canines were divided into the experimental group (Group A, n = 5) and the sham group (Group B, n = 5). The canines in Group A received thrombus administration to the superior mesenteric artery (SMA) through a guiding catheter, while the canines in Group B received normal saline administration. Blood samples were collected and tested at baseline and 2 h after modelling. Canines in Group A underwent manual thromboaspiration after blood and intestine samples were collected. Ischaemic grades of intestinal mucosa were evaluated under light microscopes. Results: The AMI models were successfully conducted in all canines without procedure-related vessel injury or death. At the 2-h follow-up, the high-sensitivity C-reactive protein and D-dimer in Group A were significantly higher than in Group B (5.72 ± 1.8 mg/L vs. 2.82 ± 1.5 mg/L, p = 0.024; 2.25 ± 0.8 µg/mL vs. 0.27 ± 0.10 µg/mL, p = 0.005; respectively). The mean histopathologic intestinal ischaemic grade in Group A was significantly higher than in Group B (2.4 ± 0.5 vs. 0.8 ± 0.4, p < 0.001). After a median of 2 times of thromboaspiration, 80% (4/5) of the canines achieved complete SMA revascularisation. Conclusion: This experimental study demonstrated that establishing an arterial model in canines using endovascular approaches was feasible. The present model may play an important role in the investigation of endovascular techniques in the treatment of arterial AMI.

Thrombogenic Risk Assessment of Transcatheter Prosthetic Heart Valves Using a Fluid-Structure Interaction Approach.

Background and Objective: Prosthetic heart valve interventions such as TAVR have surged over the past decade, but the associated complication of long-term, life-threatening thrombotic events continues to undermine patient outcomes. Thus, improving thrombogenic risk analysis of TAVR devices is crucial. In vitro studies for thrombogenicity are typically difficult to perform. However, revised ISO testing standards include computational testing for thrombogenic risk assessment of cardiovascular implants. We present a fluid-structure interaction (FSI) approach for assessing thrombogenic risk of prosthetic heart valves. Methods: An FSI framework was implemented via the incompressible computational fluid dynamics multi-physics solver of the Ansys LS-DYNA software. The numerical modeling approach for flow analysis was validated by comparing the derived flow rate of the 29-mm CoreValve device from benchtop testing and orifice areas of commercial TAVR valves in the literature to in silico results. Thrombogenic risk was analyzed by computing stress accumulation (SA) on virtual platelets seeded in the flow fields via Ansys EnSight. The integrated FSI-thrombogenicity methodology was subsequently employed to examine hemodynamics and thrombogenic risk of TAVR devices with two approaches: 1) engineering optimization and 2) clinical assessment. Results: The simulated effective orifice areas of the commercial devices were in the range reported in the literature. The flow rates from the in vitro flow testing matched well with the in silico results. The approach was used to analyze the effect of various TAVR leaflet designs on hemodynamics. Platelets experienced different magnitudes of SA along their trajectories as they flowed past each design. Post-TAVR deployment hemodynamics in patient-specific bicuspid aortic valve anatomies revealed varying degrees of thrombogenic risk for these patients, despite being clinically defined as "mild" paravalvular leak. Conclusions: Our methodology can be used to improve the thromboresistance of prosthetic valves from the initial design stage to the clinic. It allows for unparalleled optimization of devices, uncovering key TAVR leaflet design parameters that can be used to mitigate thrombogenic risk, in addition to patient-specific modeling to evaluate device performance. This work demonstrates the utility of advanced in silico analysis of TAVR devices that can be utilized for thrombogenic risk assessment of other blood recirculating devices.

A Rare Case of Right Atrial Thrombus in a Patient With Recurrent Classical Hodgkin Lymphoma.

Patients with cancer are at risk for thrombotic complications due to a hypercoagulable state. However, the benefit of prophylactic anticoagulation is unclear in many subsets of these patients. For the first episode of acute thromboembolic disease (VTE) in patients with active cancer, anticoagulant therapy is administered for at least three to six months. Herein, we present a 31-year-old female with active, recurrent stage IIIa classical Hodgkin lymphoma (CHL) (nodular sclerosis), previously treated for proximal upper extremity deep vein thrombosis (DVT), presenting for evaluation of shortness of breath and eventually diagnosed with bilateral pulmonary embolism (PE) secondary to a right atrial thrombus. The patient was successfully treated with surgical resection of the thrombus. With this case report, we hope to encourage physicians to use prophylactic indefinite anticoagulation in patients with active cancer and previous DVT, including patients with upper extremity DVT.

The bile acid receptor TGR5 inhibits platelet activation and thrombus formation.

Liver failure and cirrhosis are characterized by abnormal hemostasis with aberrant platelet activation. In particular, the consequences of cholestatic liver disease and molecular mechanisms, including the role of bile acids leading to impaired platelet responses, are not well understood. Here, we demonstrate that bile acids inhibit human and murine platelet activation, adhesion and spreading, leading to reduced thrombus formation under flow conditions. We identified the G-protein coupled receptor TGR5 in platelets and provide support for its role as mediator of bile acid-induced impairment of platelet activation. In the liver, TGR5 couples to Gαs proteins, activates the adenylate cyclase to induce a transient cAMP rise and stimulates the MAPK signaling pathway to regulate cholangiocyte proliferation, hepatocyte survival and inflammation. In this report, we demonstrate that the genetic deficiency of TGR5 in mice led to enhanced platelet activation and thrombus formation, suggesting that TGR5 plays an important role in hemostasis. Mechanistically, platelet inhibition is achieved by TGR5 mediated PKA activation and modulation of AKT and ERK1/2 phosphorylation. Thus, this report provides evidence for the ability of TGR5 ligands to reduce platelet activation and identifies TGR5 agonism as a new target for the prevention of cardiovascular diseases.

What is the context? Liver failure or cirrhosis are related to impaired hemostasis and a role of bile acids in impaired platelet responses is known but only less understood.Platelets express the bile acid receptor FXR. Ligand binding to the FXR on platelets causes a shift in platelet reactivity and is atheroprotective suggesting that the FXR is a potential target for the prevention of atherothrombotic diseases.What is new? Treatment of murine and human blood with bile acids in low molecular quantity led to reduced platelet activation, adhesion and thrombus formation.The bile acid receptor TGR5 was identified on human and murine platelets.TGR5 plays an important role in hemostasis because TGR5 deficient mice showed elevated platelet reactivity and enhanced thrombus formation.Loss of TGR5 led to enhanced PKA activation and modulated the phosphorylation of MAPK such as AKT and ERK1/2.What is the impact? Impairment of platelet activation by bile acids is mediated by TGR5 via the protein kinase A signaling pathway.Our findings provide evidence for the modulation of TGR5 activation as a potential new target of both, anti-platelet therapy in cardiovascular diseases and the restoration of hemostasis upon liver injury.

Right Atrial Thrombus Masquerading as Myxoma.

Introduction: In-situ right atrial (RA) thrombus is a rare occurrence typically associated with heightened inflammatory or hypercoagulable states. Here, we present a case of in-situ RA thrombus mimicking atrial myxoma in a patient with sepsis and bacteraemia. Case description: A 41-year-old man presented with septic arthritis and bacteraemia caused by methicillin-resistant Staphylococcus aureus (MRSA). A transoesophageal echocardiogram revealed a large pediculated mass resembling atrial myxoma, which was not visible on transthoracic echocardiography performed four days earlier. Cardiac magnetic resonance (CMR) imaging strongly suggested a thrombus, leading to the patient undergoing transcatheter aspiration. Subsequent pathology confirmed an organised fibrin thrombus without evidence of infection. Discussion: The patient's in-situ RA thrombus likely developed in response to a heightened inflammatory state associated with sepsis. Limited data exist on in-situ RA thrombi in the absence of atrial fibrillation, though some reports suggest a correlation between heightened inflammation and a hypercoagulable state. Conclusion: CMR imaging is invaluable for characterising such masses and can aid in distinguishing a thrombus from a myxoma. LEARNING POINTS: Differentiating right atrial (RA) thrombus from myxoma: cardiac magnetic resonance imaging is essential for distinguishing RA thrombus from myxoma, preventing unnecessary surgeries.Hypercoagulable and inflammatory states: spontaneous in-situ RA thrombi can occur without deep vein thrombosis (DVT) or atrial fibrillation, especially in hypercoagulable and inflammatory conditions.Transcatheter aspiration: this less invasive alternative to surgery is effective for large, mobile RA thrombi, reducing embolisation risk.

Endocarditis, Intra-cardiac Thrombus, and Pulmonary Artery Aneurysm in a Patient with Behcet's Syndrome.

Behçet's Syndrome (BS) is a chronic vasculitis of unknown etiology. Arterial involvement occurring in the pulmonary artery is associated with poor prognosis. It may cause pulmonary thrombus (PTE) and aneurysm (PAA) which may also lead to a rare complication, intracardiac thrombus. PAA and PTE can be complications of BS and are associated with high morbidity and mortality. A 30-year-old male patient had a fever of 38.4°C, recurrent oral-genital ulcers, shortness of breath, cough, and sputum. In this case report, medical history, clinical and laboratory examinations, radiography, echocardiography, and computer tomography imaging examinations were performed. PAA, PTE, intracardiac and left popliteal vein thrombosis, and infective endocarditis were present. The patient was diagnosed with BS according to the International Study Group criteria. Surgery was performed for intracardiac thrombus. Vegetation within the thrombus was demonstrated histopathologically. The patient's clinical condition and laboratory tests improved with intervention and medical treatments. The patient with BS, PAA, PTE, intracardiac thrombus, and infective endocarditis was successfully treated with pulmonary embolization, antibiotics, and systemic immunosuppression, despite its rarity, poor prognosis, and high morbidity and mortality rates.

Left main coronary artery disease treated with beating heart surgery: 10-year single center results.

Introduction: Left main (LM) coronary disease is believed to represent a complex, advanced, and potentially life-threatening atherosclerotic syndrome that can be treated by either percutaneous or surgical interventions. Despite its satisfactory results, the declined number of off-pump coronary artery bypass grafting (OPCAB) is observed. Aim: To compare 10-year survival and point out possible mortality risk factors in patients referred for left main and multivessel OPCAB surgery followed by transit time bypass measurements. Material and methods: There were 159 patients (128 (81%) men and 31 (19%) women) in a median age of 66 (60-70) years enrolled in retrospective analysis who were referred to surgical intervention due to left main (51, 32%) and multivessel (108, 68%) disease. The regression analysis for long-term mortality risk and the Kaplan-Meyer survival curve were analyzed. Results: Multivariable analysis pointed female sex (HR = 1.08, 95% CI: 1.03-1.14, p = 0.001) and diabetes mellitus (HR = 6.33, 95% CI: 1.86-21.52, p = 0.003) as possible risk factors for 10-year mortality risk. There was no significant difference in Kaplan-Meyer 10-year mortality comparison between left main and multivessel disease patients treated by off-pump surgical revascularization (HR = 0.93, 95% CI: 0.40-2.13, p = 0.86). Conclusions: Off-pump surgery in the left main disease, compared to multivessel disease, represents a safe surgical technique with satisfactory long-term results. The female sex and diabetes mellitus were found as possible risk factors for 10-year mortality risk in multivariable analysis.

Incidence and predictors of device-related thrombus after left atrial appendage closure with Watchman device.

Introduction: Left atrial appendage closure (LAAC) with Watchman device prevents thromboembolism in patients with atrial fibrillation (AF). However, thrombus may develop on the atrial surface of the device. Aim: To investigate the incidence and predictors of device-related thrombus (DRT) in patients with AF who were treated with LAAC. Material and methods: Ninety-one consecutive patients with AF underwent LAAC procedure using first-generation Watchman 2.5 device followed by antiplatelet therapy. In our analysis we have included all patients (n = 78) who had clinical follow-up visits with transesophageal echocardiography (TEE) after the procedure. Results: The median (IQR) CHA2DS2-VASc score was 4 (4.0-6.0) and HAS-BLED score was 3 (3.0-4.0). DRTs were observed in 5 (6.4%) patients. When compared with patients without DRT, those with DRT presented more often with lower median ejection fraction (40% (23.5-45.5) versus 55% (48.0-60.0); p = 0.005), lower emptying velocity of LAA (25 cm/s (17.5-27.0) versus 53 cm/s (26.5-78.0); p = 0.009), and with greater depth of implantation (18 mm (14.0-20.5) versus 8 mm (5.0-11.0); p < 0.001). Furthermore, patients with DRT had greater depth of LAA (35 mm (29.5-41.0) versus 29 mm (25.5-31.0); p = 0.003), greater mean (SD) dimension in 900 (22.4 mm (3.2) versus 19 mm (2.7); p = 0.02). Patients with DRT were also younger than those without DRT (67.4 years (7) versus 75 years (8.3), p = 0.045). Conclusions: The DRT after Watchman device implantation remains a rare complication. Its formation was related to several patient and procedural characteristics, which need to be confirmed in larger studies.

Renal Infarction in SARS-CoV-2 Infection: A Case Report.

The novel coronavirus disease 2019 (COVID-19) is an infectious disease caused by SARS-CoV-2 and associated with a wide spectrum of clinical manifestations ranging from asymptomatic carrier states to fulminant respiratory distress and multiple organ dysfunction. The intravascular arterial and venous thrombotic phenomena are one of the most prevalent and devastating consequences and tend to occur in patients with a severe disease state. Here we present a 45-year-old male with a medical history of essential hypertension (HTN) who presented with severe left flank pain accompanied by dry cough and fever for five days. He was found to have acute kidney injury (AKI) with concomitant renal infarction in computed tomography angiography (CTA) in the setting of a COVID-19 infection. He was eventually managed with novel oral anticoagulation (NOAC) and was discharged after a short hospital stay. Follow-up thereafter showed stable baseline renal function with no relevant symptoms.

"The Failing Watchman": Recurrent Left Atrial Appendage Occlusion Device (LAAOD) Thrombus After Successful Initial Implantation.

A 79-year-old female with chronic atrial fibrillation was being treated with dabigatran (Pradaxa). Pradaxa was discontinued after a significant bleeding episode. A WATCHMAN device was successfully implanted and Pradaxa was started. A transesophageal echocardiogram (TEE) 49 days later showed a 3.6×2.2 cm clot overlying the device. Pradaxa was switched to Coumadin. Subsequent TEEs showed the complete resolution of the thrombus after five months on Coumadin. Coumadin was discontinued. Six months later, TEE showed a large mobile thrombus attached to the left atrial appendage occlusion device (LAAOD). The patient's hypercoagulable workup was negative. Due to recurrent thrombotic events, she was started on apixaban (Eliquis) due to a prior history of bleeding on Coumadin. She is currently on Eliquis with no further episodes of bleeding or device thrombus.

Challenges and advances in device-related thrombus in left atrial appendage occlusion.

Oral anticoagulation therapy (OAC) is a mainstay for mitigating stroke and other embolic events in patients with atrial fibrillation (AF). Despite the demonstrated efficacy of OAC in reducing events, many patients are unable to tolerate OAC due to bleeding risks. Left atrial appendage occlusion (LAAO) devices were developed as implantable technologies to moderate stroke risk in patients with intolerance to OAC. Despite clinical data supporting near-comparable protection against thromboembolic events with OAC, device-related thrombus formation has emerged as a critical complication following LAAO that remains a potential limitation to the safety and efficacy of LAAO. Improved biocompatibility of LAAO devices with fluoropolymers, a well-established stent-coating technology used to reduce thrombus formation and promote endothelialization, may optimize outcomes after LAAO.

[Box: see text].

Role of leukocyte parameters in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention with high thrombus burden.

Objective: Leukocyte parameters are associated with cardiovascular diseases. The aim of the present study was to investigate the role of leukocyte parameters in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI) with high thrombus burden (HTB). Methods: A total of 102 consecutive STEMI patients with HTB who underwent PPCI within 12 h from the onset of symptoms between June 2020 and September 2021 were enrolled in this study. In addition, 101 age- and sex-matched STEMI patients with low thrombus burden (LTB) who underwent PPCI within 12 h from the onset of symptoms were enrolled as controls. Leukocyte parameters, such as neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and monocyte to lymphocyte ratio (MLR), were calculated at the time of admission. Results: The value of NLR and MLR were significantly higher in the HTB group than in the LTB group (6.24 ± 4.87 vs. 4.65 ± 3.47, p = 0.008; 0.40 ± 0.27 vs. 0.33 ± 0.20, p = 0.038). A cutoff value of >5.38 for NLR had a sensitivity and specificity of 53.9% and 74.3%, respectively, and MLR >0.29 had a sensitivity and specificity of 60.8% and 55.4%, respectively, for determining the STEMI patients with HTB [area under the receiver operating characteristic curve (AUC): 0.603, 95% confidence interval (CI): 0.524-0.681, p = 0.012; AUC: 0.578, 95% CI: 0.499-0.656, p = 0.046]. There was no significant difference of all-cause mortality rate and major adverse cardiac events (MACEs) between the STEMI patients with HTB or with LTB (3.92% in HTB group vs. 2.97% in LTB group, p = 0.712; 10.78% in HTB group vs. 8.91% in LTB group, p = 0.215). Compared with the HTB patients in the low NLR group, C-reactive protein, baseline troponin I, baseline brain natriuretic peptide, and leukocyte parameters, such as white blood cell, neutrophil, lymphocyte, NLR, PLR, and MLR, were also significantly higher in the high NLR group in STEMI patients who underwent PPCI with HTB (18.94 ± 19.06 vs. 35.23 ± 52.83, p = 0.037; 10.99 ± 18.07 vs. 21.37 ± 19.64, p = 0.007; 199.39 ± 323.67 vs. 430.72 ± 683.59, p = 0.028; 11.55 ± 3.56 vs. 9.31 ± 2.54, p = 0.001; 9.77 ± 3.17 vs. 5.79 ± 1.97, p = 0.000; 1.16 ± 0.44 vs. 2.69 ± 1.23, p = 0.000; 9.37 ± 4.60 vs 1.31 ± 2.58, p = 0.000; 200.88 ± 89.90 vs. 97.47 ± 50.99, p = 0.000; 0.52 ± 0.29 vs. 0.26 ± 0.14, p = 0.000, respectively). MACEs and heart failure in the high NLR group were significantly higher than that in the low NLR group of STEMI patients who underwent PPCI with HTB (20.45% vs. 4.25%, p = 0.041; 10.91% vs. 2.13%, p = 0.038). Conclusion: The value of NLR and MLR were higher in STEMI patients who underwent PPCI with HTB. In STEMI patients who underwent PPCI with HTB, a raised NLR could effectively predict the occurrence of MACEs and heart failure.

Reduced platelet activation and thrombus formation in male transgenic model mice of Alzheimer's disease suggests early sex-specific differences in platelet pathophysiology.

Alzheimer's disease (AD) is the most common form of dementia and characterized by extracellular amyloid-ß (Aß) plaques, intracellular neurofibrillary tau tangles and neurodegeneration. Over 80 % of AD patients also exhibit cerebral amyloid angiopathy (CAA). CAA is a cerebrovascular disease caused by deposition of Aß in the walls of cerebral blood vessels leading to vessel damage and impairment of normal blood flow. To date, different studies suggest that platelet function, including activation, adhesion and aggregation, is altered in AD due to vascular Aß deposition. For example, the transgenic AD model mice APP23 mice that exhibit CAA and parenchymal Aß plaques, show pre-activated platelets in the blood circulation and increased platelet integrin activation leading to a pro-thrombotic phenotype in these mice late stages of AD. However, it is still an open question whether or not platelets exhibit changes in their activation profile before they are exposed to vascular Aß deposits. Therefore, the present study examined platelets from middle-aged transgenic APP23 mice at the age of 8-10 months. At this age, APP23 mice show amyloid plaques in the brain parenchyma but not in the vasculature. Our analyses show that these APP23 mice have unaltered platelet numbers and size, and unaltered surface expression of glycoproteins. However, the number of dense granules in transgenic platelets was increased while the release was unaltered. Male, but not female APP23 mice, exhibited reduced platelet activation after stimulation of the thrombin receptor PAR4 and decreased thrombus stability on collagen under flow conditions ex vivo compared to control mice. In an arterial thrombosis model in vivo, male APP23 mice showed attenuated occlusion of the injured artery compared to controls. These findings provide clear evidence for early changes in platelet activation and thrombus formation in male mice before development of overt CAA. Furthermore, reduced platelet activation and thrombus formation suggest sex-specific differences in platelet physiology in AD that has to be considered in future studies of platelets and their role in AD.

Predictors of left atrial appendage thrombus in atrial fibrillation patients undergoing cardioversion.

BACKGROUND: Atrial fibrillation and atrial flutter represent the most prevalent clinically significant cardiac arrhythmias. While the CHA2DS2-VASc score is commonly used to inform anticoagulation therapy decisions for patients with these conditions, its predictive power is limited. Therefore, we sought to improve risk prediction for left atrial appendage thrombus (LAAT), a known risk factor for stroke in these patients. METHODS: We developed and validated an explainable machine learning model using the eXtreme Gradient Boosting algorithm with 5 × 5 nested cross-validation. The primary outcome was to predict the probability of LAAT in patients with atrial fibrillation and atrial flutter who underwent transesophageal echocardiogram prior to cardioversion. Our algorithm used 37 demographic, comorbid, and transthoracic echocardiographic variables. RESULTS: A total of 795 patients were included in our analysis. LAAT was present in 11.3% of the patients. The average age of patients was 63.3 years and 34.7% were women. Patients with LAAT had significantly lower left ventricular ejection fraction (29.9% vs 43.5%; p < 0.001), lower E' lateral velocity (5.7 cm vs. 7.9 cm; p < 0.001) and higher E/A ratio (2.6 vs 1.8; p = 0.002). Our machine learning model achieved a high AUC of 0.79, with a high specificity of 0.82, and modest sensitivity of 0.57. Left ventricular ejection fraction was the most important variable in predicting LAAT. Patients were split into 10 buckets based on the percentile of their predicted probability of having thrombus. The lower the percentile (e.g., 10%), the lower the probability of having thrombus. Using a cutoff point of 0.16 which includes 10.0% of the patients, we can rule out thrombus with 100% confidence. CONCLUSION: Using machine learning, we refined the predictive power of predicting LAAT and explained the model. These results show promise in providing better guidance for anticoagulation therapy and cardioversion in AF and AFL patients.

Impact of 12-Month Angioscopic Thrombi and Yellow Plaque After Drug-Eluting Stent Implantation.

BACKGROUND: Coronary angioscopy (CAS) has 2 unique abilities: direct visualization of thrombi and plaque color. However, in the recent drug-eluting stent (DES) era, serial CAS findings after DES implantation have not been fully elucidated. We investigated the impact of CAS findings after implantation of a polymer-free biolimus A9-coated stent (PF-BCS) or durable polymer everolimus-eluting stent (DP-EES).Methods and Results: We investigated serial CAS and optical coherence tomography (OCT) findings at 1 and 12 months in 99 patients who underwent PF-BCS or DP-EES implantation. We evaluated factors correlated with angioscopic thrombi and yellow plaque, and the clinical impact of both thrombi and yellow plaque at 12 months (BTY). The BTY group included 17 (22%) patients. The incidence and grade of thrombi and yellow plaque decreased from 1 to 12 months. Although no patients had newly appearing thrombi at 12 months, 2 DP-EES patients had newly appearing yellow plaque at 12 months. Multivariable analysis revealed HbA1c, minimum stent area, and adequate strut coverage were significant factors correlated with 12-month angioscopic thrombi, and DP-EESs were significantly correlated with 12-month yellow plaque. However, BTY was not correlated with clinical events. CONCLUSIONS: The management of diabetes, stent area, and adequate stent coverage are important for intrastent thrombogenicity and polymer-free stents are useful for stabilizing plaque vulnerability.

Warfarin Therapy and Percutaneous Left Atrial Appendage Closure for a Patient with Atrial Fibrillation and Antithrombin-III Deficiency.

Some patients develop ischemic stroke despite taking direct oral anticoagulants because of the presence of other risk factors such as coagulopathies. A 65-year-old male patient with non-valvular atrial fibrillation (NVAF) taking rivaroxaban was diagnosed as having embolic stroke and antithrombin-III (AT-III) deficiency. Echocardiography revealed a thrombus in the left atrial appendage (LAA). He was prescribed warfarin, and after resolution of the thrombus, we successfully performed percutaneous LAA closure (LAAC), with no subsequent recurrence or device-related thrombosis. Warfarin and LAAC may be feasible for NVAF patients with AT-III deficiency.

The Role of Platelets and Aneurysm Thrombus in the EVAR Post Implantation Syndrome.

OBJECTIVE: Post implantation syndrome (PIS) is a well-defined entity with unclear etiology, complicating a number of patients with AAAs treated with EVAR. The aim of this study was to assess the platelets' role and the influence of aneurysmal sac thrombus volumes in the development of PIS. DESIGN: A retrospective analysis of prospectively collected data was performed and 76 patients that were treated by EVAR (2011-2013) were studied. Aneurysms with endoleak were not included in the study. Based on the criteria for SIRS (Systemic Inflammatory Response Syndrome), 17 patients (22%) developed PIS (which is considered a SIRS analogue), while 59 (78%) did not. METHODS: The two groups were compared in relation to the following parameters: baseline platelet count (PLT), decrease of platelet count (PLT drop), volume of the arterial flow before the procedure (V Flow), volume of thrombus of the aneurysm (V thromb), ratio of thrombus volume to aneurysm sac volume (V ratio) and the volume of new formed thrombus (V new). Volume flow measurements were calculated by Osirix ™ software preoperatively and in the 1st month postoperatively. Parametric and non-parametric techniques (unpaired t-test, Mann-Whitney U test) were used accordingly. RESULTS: Baseline platelets absolute count was greater in the PIS group (239000 ± 17000) vs. the non-PIS group (194000 ± 6900, p=0.004), and the PLT drop was larger in the PIS group (74000 ± 15600 vs. 45000 ± 5300, p=0.019). No difference was found regarding the aneurysm volumes (Vflow, Vthromb, Vratio, Vnew) between the two groups. CONCLUSION: Platelets, in terms of their absolute baseline count and their decrease after the procedure, seem to be an important factor in developing PIS after EVAR. Further, more tailored studies are needed to elucidate the role of platelets and flow/thrombus volumes in the development of PIS.

A Rare Presentation of Ascites Secondary to Inferior Vena Cava Thrombosis in a Patient With Factor V Leiden Mutation.

We present the case of a 36-year-old female with Factor V Leiden mutation taking warfarin, who presented to the emergency department with swelling in the abdominal and bilateral lower extremities. Initial assessment revealed an international normalized ratio (INR) of 5.0. Abdomen/pelvis computed tomography (CT) and computed tomographic angiography (CTA) scans indicated chronic thrombosis of the inferior vena cava (IVC), leading to the development of ascites and swelling. Extensive investigations were conducted to explore potential contributing factors for the ascites and edema, all of which yielded negative results. Warfarin was discontinued, and unfractionated heparin was initiated once the INR decreased to 2.0. The patient underwent IVC angioplasty with stent placement, resulting in significant improvement of ascites and lower extremity swelling. Subsequently, heparin was transitioned to oral warfarin, and therapeutic INR levels were achieved before discharge. At the follow-up outpatient visit, the patient's ascites and lower extremity edema had completely resolved. This case highlights a rare instance of IVC involvement associated with Factor V Leiden mutation. Furthermore, the patient's history of noncompliance with medication, initial supratherapeutic INR, and chronic IVC thrombosis emphasize the importance of medication adherence and the crucial role of primary care in ensuring regular follow-up and monitoring.

The Management of Intracardiac Thrombus in a COVID-19 Patient Using IV Thrombolytics: A Case Report.

The coronavirus disease 2019 (COVID-19) pandemic has unveiled numerous clinical challenges, particularly its association with thrombotic events, which significantly contribute to morbidity and mortality. While thrombotic complications such as arterial and venous thromboembolism (VTE) are well-documented, instances of intracardiac thrombus are notably rare. This case report discusses a 60-year-old male with COVID-19 who came to the hospital due to respiratory distress. Despite treatment with remdesivir, the patient's condition worsened prompting further workup. His nuclear medicine (NM) ventilation-perfusion scan was inconclusive, but a 2D echocardiogram showed an intracardiac thrombus in the right atrium (RA) and right ventricle (RV). As the patient's condition worsened, necessitating a transition from nasal cannula to high-flow nasal cannula, a decision was made to treat him with intravenous (IV) thrombolytic therapy. The patient received 100 mg IV alteplase and IV heparin, resulting in significant respiratory improvement and symptomatic relief. A repeat echocardiogram after 48 hours showed normal ejection fraction and complete thrombus resolution. In conclusion, this case highlights the complex link between COVID-19 infection and prothrombotic states, leading to severe complications such as intracardiac thrombus in transit. The successful treatment of this patient through a multidisciplinary approach and thrombolytic therapy underscores the importance of prompt recognition and intervention in high-risk cases.