Thrombin Generation in a patient with Triple Positive Antiphospholipid Syndrome Treated with Three Different Anticoagulants

IntroductionVenous and arterial thrombosis is one of the hallmarks of Antiphospholipid Antibody Syndrome (APS). The traditional treatment for individuals with APS and venous thrombosis has been vitamin K antagonists. However, with the widespread use of direct oral anticoagulants (DOACs) there has been conflicting evidence regarding their safety and failure rate as alternatives to warfarin. Reasons for this failure remain elusive. We utilized the thrombin generation assay (TGA) to investigate the anticoagulation efficacy of three different agents in a patient with triple-positive APS to acquire a better understanding of the pathophysiology of APS.MethodsBlood samples were obtained from a single patient with APS at five distinct time points while on three different anticoagulants: rivaroxaban, warfarin, and enoxaparin. The effects of these anticoagulants on TG potential were evaluated using the TGA.ResultsIn the presence of thrombomodulin, rivaroxaban had the highest endogenous thrombin potential, thrombin peak, velocity index, and thrombin inactivation velocity (821.9 nMmin, 121.5 nM, 36.44 nM/min, 7.19 nM/min) when compared to warfarin (121-367 nMmin, 13.85-121.5 nM, 3.02-3.85 nM/min, 0.64-4.55 nM/min) and enoxaparin (242-378.8 nM min, 21.33-23.78 nM, 2.87-3.85 nM/min, 0.747-0.784 nM/min). This trend was also observed in the absence of thrombomodulin.ConclusionsThese results suggest that patients with APS treated with rivaroxaban may be at greater risk for thrombosis compared to warfarin or enoxaparin. The findings may provide insight into the recent studies in patients with triple positive APS randomized to different anticoagulants demonstrating high rates of thrombosis with rivaroxaban. Further studies are necessary to elucidate the clinical significance.     

The difficult balance between thrombosis and bleeding after transcatheter aortic valve replacement: A translational review

The difficult balance between thrombosis and bleeding after transcatheter aortic valve replacement. TAVR: transcatheter aortic valve replacement.

     

Clinico-radiological profile of CVT patients and its correlation with D-dimer

Cerebral Venous Thrombosis (CVT) is a well-known disease with diverse clinical presentation and causes. With advances in neuroimaging and changing lifestyles, the clinical profile and causes of CVT are changing. D-dimer has been studied in early diagnosis of CVT with variable results. This prospective study was carried out to assess the clinical profile of CVT and role of D-dimer in early diagnosis of CVT. The study period was from September 2017 to July 2019 and included 32 imaging proven patients of CVT. We also included 32 patients of migraine for assessing D-dimer. Data was collected according to a preformed format. D-dimer was assessed by a rapid semi-quantitative latex agglutination assay. Out of 32 CVT patients, 16(50%) were females. The mean age of the patients was 31.56 ± 14.31 years. Most common clinical features were headache (96.25%), papilloedema (37.5%) and seizures 10 (31.25%). Puerperium was the most common cause of CVT in females. Superior sagittal and transverse sinuses were the most common sinuses to be affected. The sensitivity of D-dimer assay was 81.25% and specificity 62.5%. Cerebral venous thrombosis is a disease with equal predilection among both genders affecting mostly young individuals. Most of the patients present with headache. Puerperium still contributes to majority of the cases. Iron deficiency anaemia needs to be evaluated as an association for CVT. Positive D-dimer should strengthen the suspicion of CVT in patients with acute headache.     

Thromboses et thrombopathies dans les syndromes myéloprolifératifs

Myeloproliferative neoplasms are acquired hematological malignancies, mainly affecting the adult and whose morbidity and mortality stems from haemostasis disorders. The most frequently encountered complications include thrombosis, affecting preferentially the arterial territory, but also atypical locations such as splanchnic vein thrombosis. The pathophysiology of these thromboses is complex and involves different actors: blood cells, endothelium and flow conditions. Numerous studies have been conducted to identify risk factors for thrombosis. To date, only two risk factors have been validated through prospective studies (age over 60 years old, history of thrombotic events) and allow classification of patients as “low risk” and “high risk” as the basis for current treatment recommendations. Haemorrhagic manifestations, less frequent than thrombosis, are mainly related to an alteration of primary haemostasis and are therefore manifested by mucocutaneous bleeding. In these patients, platelet dysfunctions and/or acquired Willebrand syndromes can be found. The pathophysiology of thrombosis and platelet dysfunction during myeloproliferative neoplasms remains to date partially unknown. In this review, we offer to focus on physiopathological mechanisms as well as the latest advances in their understanding.     

The effect of ChAdOx1 nCov-19 vaccine on arterial thrombosis development and platelet aggregation in female rats

ChAdOx1 nCoV-19 adenoviral vector vaccine (ChAd) against coronavirus disease 2019 has been associated with vaccine-induced thrombosis and thrombocytopenia (VITT), especially in young women who have presented with unusual localized thrombosis after receiving the vaccine. The pathogenesis of VITT remains incompletely understood. We tried to provide new insights into mechanisms underlying this phenomenon in the model of arterial thrombosis electrically induced in the carotid artery of female rats. At 28 days post-vaccination, ChAd induced SARS-CoV-2-specific neutralizing antibody responses in all animals. The analysis of the blood vessel/thrombus area showed slight luminal narrowing of the carotid artery with extravasation of blood in vaccinated rats. These small changes were not accompanied by differences in thrombus weight and composition. The vaccinated animals presented a slight increase (by around 14–24%) in platelet aggregation. ChAd did not significantly affect blood coagulation, platelet counts, and their activation markers. Unaffected thrombus formation, the lack of thrombocytopenia and all the measured blood and hemostasis parameters that predominantly stayed unchanged, indicate that the ChAd does not increase the risk of arterial thrombosis development in female rats.     

The incidence of deep vein thrombosis and pulmonary embolism with the elective use of external fixators

Little evidence exists about the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) with the use of external fixators. We investigated this in a cohort of 207 consecutive patients undergoing 258 elective frame applications by case note review. Case notes were obtained for 84 % of the sample population. The type of surgery, demographic data, thromboembolic risk factors and the incidence of DVT/PE were recorded. One patient experienced DVT (0.39 %) and one a PE (0.39 %). Both were of high risk and had received mechanical and chemical thromboprophylaxis during their inpatient stay. These complications were identified at least 3 months post-operatively. These findings help to more accurately counsel patients undergoing elective frame surgery on the risks of DVT/PE and also contribute to the discussion between surgeons about whether or not extended course chemical thromboprophylaxis would be of overall benefit.     

Acute celiac trunk thrombosis revealed by biliary peritonitis

Acute thrombosis of the celiac trunk is a very uncommon condition, which is a life-threatening emergency. The clinical presentation is highly variable depending on the extent of the ischemic territory. We report a case of biliary peritonitis related to an acute thrombosis of the celiac trunk. This case highlights the role of abdominal computed tomography in the diagnosis of acute upper abdominal pain.     

Frequency of and factors associated with vascular complications after pediatric liver transplantation

Objectiveto evaluate the frequency and factors associated with vascular complications after pediatric liver transplantation.Methodrisk factors were evaluated in 99 patients under 18 years of age with chronic liver disease who underwent deceased donor liver transplantation (DDLT) between March of 1995 and November of 2009 at the Hospital de Clínicas de Porto Alegre, Brazil. The variables analyzed included donor and recipient age, gender, and weight; indication for transplant; PELD/MELD scores; technical aspects; postoperative vascular complications; and survival.Resultsvascular complications occurred in 19 patients (19%). Arterial events were most common, occurred earlier in the postoperative period, and were associated with high graft loss and mortality rates. In the multivariate analysis, the following factors were identified: portal vein diameter ≤ 3 mm, donor‐to‐recipient body weight ratio (DRWR), prolonged ischemic time, and use of arterial grafts.Conclusionthe choice of treatment depends on the timing of diagnosis; however, in this study, surgical revision or correction produced worse outcomes than percutaneous angioplasty. The reduction of risk factors and early detection of vascular complications are key elements to a successful transplantation.