Thrombosis Tendency After Splenectomy in a Danish Family With Hemoglobin Volga, and a Literature Review

Hemoglobin (Hb) Volga is a rare, unstable β-chain hemoglobin variant (β27 Ala→Asp), causing chronic hemolytic anemia. This study presents two members of a Danish family, splenectomized due to Hb Volga at and with multiple thrombotic events. The proband was diagnosed with Hb Volga 9 years old and splenectomy was performed as a part of treatment. Throughout his life, he experienced multiple superficial thrombophlebitis, two episodes of distal deep venous thrombosis (DVT) on lower extremities (age 32 and 33) and a transient ischemic attack (TIA) presented as amaurosis fugax (age 51). Thrombophilia investigation was normal. The proband's son was diagnosed with Hb Volga and underwent splenectomy at the age of 6. Despite anticoagulation therapy, he suffered from multiple venous thromboembolic events in his youth and died of chronic pulmonary embolism (PE)/pulmonary hypertension combined with infection. Given the observed propensity for multiple thromboses in these two patients, a literature review was conducted investigating reported occurrence of thrombotic events in individuals with Hb Volga.

Currently 25 cases of Hb Volga are reported worldwide. The clinical symptoms primarily described are related to hemolytic anemia. Splenectomy is reported in 15 patients. Thromboses have previously been reported in only three patients who were also splenectomized. These cases involved DVT and PE, myocardial infarction, and an unspecified thrombotic event. The proband represents the first reported Hb Volga case with both venous and arterial thrombotic disorders. The exact mechanism underlying thrombotic tendency in patients with Hb Volga remains unknown, but it is probably associated with splenectomy.

Impact of allele-selective silencing of von Willebrand factor in mice based on a single nucleotide allelic difference in von Willebrand factor

INTRODUCTION

Von Willebrand factor (VWF) plays a pathophysiological role in hemostatic disorders. Partial inhibition of the VWF gene through small interfering RNA (siRNA)-mediated allele-selective silencing could be a promising therapeutic strategy. For von Willebrand disease, allele-selectively inhibiting dominant-negative VWF-alleles might ameliorate the phenotype. For thrombotic disorders, partial VWF reduction can lower thrombotic risk, while avoiding bleeding. Previously, we demonstrated the feasibility of Vwf-silencing in homozygous C57BL/6J (B6) or 129S1/SvImJ (129S) mice. The present study investigated allele-selective Vwf-silencing in a complex heterozygous setting of crossed B6 and 129S mice and its subsequent hemostatic impact.

MATERIALS AND METHODS

Heterozygous B6.129S mice were treated with siRNAs targeting Vwf expressed from either B6- (siVwf.B6) or 129S-alleles (siVwf.129S). Plasma VWF and lung Vwf mRNA were determined. siVwf.B6-treated B6.129S mice were subjected to ferric chloride-induced mesenteric vessel thrombosis and tail-bleeding.

RESULTS

In B6.129S mice, siVwf.B6 reduced Vwf mRNA of the targeted B6-allele by 72% vs. only 12% of the non-targeted 129S-allele (41% total mRNA reduction), lowering plasma VWF by 46%. Oppositely, siVwf.129S reduced Vwf mRNA by 45%, now selectively inhibiting the 129S-allele over the B6-allele (58% vs. 9%), decreasing plasma VWF by 43%. The allele-selective VWF reduction by siVwf.B6 coincided with decreased thrombus formation in mesenteric arterioles, without prolonging tail-bleeding times.

CONCLUSIONS

This study demonstrates the feasibility of allele-selective Vwf-silencing in a heterozygous setting, achieving a controlled close to 50% reduction of plasma VWF. The observed thromboprotection and absence of prolonged bleeding times underline the potential of allele-selective Vwf-silencing as a therapeutic strategy in hemostatic disorders.

Risk factors for venous thrombosis after esophagectomy

BACKGROUND

Venous thrombosis (VT) after esophagectomy for esophageal cancer is an important complication, potentially leading to pulmonary embolism. However, there are few available information about the risk for the postsurgical VT.

METHODS

This study included 271 patients who underwent esophagectomy for esophageal cancer between 2006 and 2019. Contrast-enhanced computed tomography (CT) was performed for all patients on the seventh postoperative day to survey complications, including VT.

RESULTS

VT was radiologically visualized in 48 patients (17.7%), 8 of whom (16.7%) had pulmonary embolism. The thrombus disappeared in 42 patients, the thrombus size was unchanged in 5 patients, and 1 patient died. Multivariate analysis was performed on factors clinically considered to have a significant influence on thrombus formation. The analysis showed that CVC insertion via the femoral vein (odds ratio, 7.67; 95% CI, 2.64-22.27; P < 0.001), retrosternal reconstruction route (odds ratio, 3.94; 95% CI, 1.90-8.17; P < 0.001) and intraoperative fluid balance < 5 ml/kg/hr (odds ratio, 0.38; 95% CI, 0.17-0.85; P = 0.019) were independently related to VT.

CONCLUSIONS

Intraoperative fluid balance < 5 ml/kg/hr, along with CVC insertion via the femoral vein and retrosternal reconstruction may be potential risk factors for VT after esophagectomy.

Emerging artificial intelligence-aided diagnosis and management methods for ischemic strokes and vascular occlusions: A comprehensive review

Large-vessel occlusion (LVO) stroke is a promising field for the use of AI, especially machine learning (ML) because optimal results are highly dependent on timely diagnosis, communication, and treatment. In order to better understand the current state of artificial intelligence (AI) in relation to LVO strokes, its efficacy, and potential future applications, we searched relevant literature to perform a comprehensive evaluation of the topic. The databases PubMed, Embase, and Scopus were extensively searched for this review. Studies were then screened using title and abstract criteria and duplicate studies were excluded. By using pre-established inclusion and exclusion criteria, it was decided whether or not to include full-text papers in the final analysis. The studies were analyzed, and the relevant information was retrieved. In recognizing LVO on computed tomography, ML approaches were very accurate. There is a shortage of AI applications for thrombectomy patient selection, despite the fact that certain research accurately evaluates individual patient eligibility for endovascular therapy. Machine learning algorithms may reasonably predict clinical and angiographic outcomes as well as associated factors. AI has shown promise in the diagnosis and treatment of people who have just suffered a stroke. However, the usefulness of AI in management and forecasting remains restricted, necessitating more studies into machine learning applications that can guide decision making in the future.

Smaller nadroparin dose reductions required for patients with renal impairment: A multicenter cohort study

BACKGROUND

Guidelines advise 50 % and 25 % dose reduction of the therapeutic nadroparin dose (86 IU/kg) in patients with eGFR 15-29 and 30-60 ml/min respectively. For monitoring, peak anti-Xa levels are suggested. Data lack whether this results in therapeutic anti-Xa levels or in anti-Xa levels that are comparable to those of patients without renal impairment.

AIMS

To determine dose ranges in patients with renal impairment that result in therapeutic anti-Xa levels and to determine the percentage of the 86 IU/kg dose that results in anti-Xa levels normally occurring in patients without renal impairment.

METHODS

A retrospective cohort study was conducted in five hospitals. Patients ≥18 years of age, with an eGFR ≥ 15 ml/min were included. The first correctly sampled peak (i.e. 3-5 h after ≥ third administration, regardless of dose per patient) was included. Simulated prediction models were developed using multiple linear regression.

RESULTS

770 patients were included. eGFR and hospital affected the association between dose and anti-Xa level. The doses for peak anti-Xa levels of 0.75 IU/ml differed substantially between hospitals and ranged from 55 to 91, 65-359 and 68-168 IU/kg in eGFR 15-29, 30-60 and > 60 ml/min/1.73m2, respectively. In eGFR 15-29 and 30-60 ml/min/1.73m2, doses of 75 % and 91 % of 86 IU/kg respectively, were needed for anti-Xa levels normally occurring in patients with eGFR > 60 ml/min.

CONCLUSION

We advise against anti-Xa based dose-adjustments as long as anti-Xa assays between laboratories are not harmonized and an anti-Xa target range is not validated. A better approach might be to target levels similar to eGFR > 60 ml/min/1.73m2, which are achieved by smaller dose reductions.

Comparison of the safety and efficacy for different regimens of pharmaco-prophylaxis among severely burned patients: a randomized controlled trial

PURPOSE

Venous thromboembolism (VTE) is a common complication in critically ill patients, including severe burn cases. Burn patients respond differently to medications due to pharmacokinetic changes. This study aims to assess the feasibility and safety of different VTE pharmaco-prophylaxis in patients admitted to the ICU with severe burns.

METHODS

A pilot, open-label randomized controlled trial was conducted on ICU patients with severe burns (BSA ≥ 20%). By using block randomization, patients were allocated to receive high-dose enoxaparin 30 mg q12hours (E30q12), standard-dose enoxaparin 40 mg q24hours (E40q24), or unfractionated heparin (UFH) 5000 Units q8hours. In this study, the primary outcomes assessed were the recruitment and consent rates, as well as bleeding or hematoma at both the donor and graft site. Additionally, secondary measures were evaluated to provide further insights.

RESULTS

Twenty adult patients out of 114 screened were enrolled and received E30q12 (40%), E40q24 (30%), and UFH (30%). The recruitment rate was one patient per month with a 100% consent rate. Donor site bleeding occurred in one patient (16.7%) in the UFH group. On the other hand, graft site bleeding was only reported in one patient (12.5%) who received E30q12. Major bleeding happened in two patients, one in E30q12 and one in the UFH group. Five patients (25.0%) had minor bleeding; two patients (25.0%) received E30q12, two patients E40q24, and one patient UFH. RBC transfusion was needed in four patients, two on E30q12 and two on UFH. Only one patient had VTE, while four patients died in the hospital.

CONCLUSION

The study observed a low recruitment rate but a high consent rate. Furthermore, there were no major safety concerns identified with any of the three pharmacologic prophylaxis regimens that were evaluated.

TRIAL REGISTRATION NUMBER

NCT05237726.

Phenotypes in antiphospholipid syndrome: A hierarchical cluster analysis based on two independent databases

BACKGROUND

Antiphospholipid syndrome (APS) is a rare autoimmune disease characterized by thromboses at various sites and obstetric events associated with the persistent presence of antiphospholipid antibodies. The identification of clinical phenotypes in APS patients is a clinical need. In this study, we aimed to determine the clinical phenotypes of APS patients through an unsupervised analysis of two well-characterized cohorts of APS patients.

PATIENTS AND METHODS

APS phenotypes were defined by an ascending hierarchical cluster analysis to identify preferential associations between 18 types of organ involvement and clinical characteristics. This analysis was performed on an initial multi-center cohort of 1000 patients, with validation in a replication cohort of 435 patients.

RESULTS

The hierarchical analysis identified three APS phenotypes in both the initial and replication cohorts: an obstetric phenotype (n = 259 and n = 74 patients, respectively), a venous thrombosis phenotype, accounting for the largest number of patients (n = 461 and n = 297 patients, respectively), and a skin-central nervous system-heart phenotype (n = 280 and n = 64 patients, respectively). The clinical characteristics of the patients differed significantly between the three phenotypes, but there was no difference in antiphospholipid antibody profile between the groups.

CONCLUSIONS

We identified three phenotypes of APS defined based on preferential associations of organ involvements and differences in presentation. These observations may help clinicians to detect organ involvement and to manage treatment.

Non-severe burn injury causes sustained platelet hyperreactivity

Individuals who present to a hospital for treatment of a burn of any magnitude are more frequently hospitalised for ischemic heart disease, even decades after injury. Blood platelets are key mediators of cardiovascular disease. To investigate platelet involvement in post-burn cardiovascular risk, platelet reactivity was assessed in patients at 2- and 6-weeks after non-severe (TBSA < 20%) burn injury, and in a murine model 30 days after 8% TBSA full-thickness burn injury. Platelets were stimulated with canonical agonists and function reported by GPIIb/IIIa PAC1-binding site, CD62P expression, and formation of monocyte-platelet aggregates. In vivo thrombosis in a modified Folts model of vascular injury was assessed. Burn survivors had elevated frequencies of circulating monocyte-platelet aggregates, and platelets were hyperreactive, primarily to collagen stimulation. Burn plasma did not cause hyper-reactivity when incubated with control platelets. Platelets from burn injured mice also demonstrated increased response to collagen peptides but did not show any change in thrombosis following vascular injury. This study demonstrates the persistence of a small but significant platelet hyperreactivity following burn injury. Although our data does not suggest this heightened platelet sensitivity modulates thrombosis following vascular injury, the contribution of sub-clinical platelet hyperreactivity to accelerating atherogenesis merits further investigation.

Natural Anticoagulant Protein Levels in Patients With Beta-Thalassemia Major: A Case-Control Study

Background

β-thalassemia is a group of inherited blood disorders that affect the production of β-globin chains, leading to the reduction or absence of these chains. One of the complications observed in patients with β-thalassemia major (β-TM) is thrombosis, especially in those who receive frequent blood transfusions. This may be due to a decrease in the levels of the natural anticoagulants: protein C (PC), total protein S (PS), and antithrombin (AT).

Methods

In this case-control study, patients with β-TM, who had received at least 20 packed cell transfusions during their lifetime, were included. Patients with other underlying diseases like bleeding or thrombotic disorders were excluded. Totally, 118 patients with β-TM and 120 healthy individuals were included.

Results

The mean level of PC and AT was significantly lower in patients with β-TM (48.2 ± 65.4 and 57.42 ± 13.6, respectively) compared to the control group (97.1 ± 21.46 and 81.79 ± 14.3, respectively), with P value of 0.001 and 0.01, respectively. Although the difference was not statistically significant (P = 0.1), a similar trend was observed for total PS (61.12 ± 21.12 for patients versus 72.2 ± 35.2 for the control group). Of note, the decrease in PC, AT, and total PS levels compared to the control group was 50.36%, 27.5%, and 15.34%, respectively.

Conclusions

It seems that β-TM patients who receive prolonged blood transfusions frequently are at an increased risk of decreased in natural anticoagulants levels and therefore potentially are at risk of thrombosis.

The effects of dienogest and combined oral contraceptives on protein S-specific activity in endometriosis patients

OBJECTIVE

One serious side effect of combined oral contraceptives (COCs) is venous thromboembolism. Reduced activity in activated protein C-related coagulation pathways is attributable to low protein S activity in one-third of Japanese patients with deep vein thrombosis. Herer, we quantified the behavior of protein S-specific activity in response to dienogest (DNG) and COCs using the protein S-specific activity assay system to explore its potential utility as a thrombosis marker.

STUDY DESIGN

This was a prospective cohort study. Female patients aged 20 - 49 years who were starting drug treatment for endometriosis using DNG or COCs were enrolled. Blood samples were taken before treatment and at the first, third, and sixth months of treatment. To analyze the primary endpoints, changes in total protein S antigen levels, total protein S activity, and protein S-specific activity from baseline to each time point were estimated using a linear mixed-effects model. All statistical analyses were performed in the SAS software version 9.4 (SAS Institute, Cary, NC). A two-sided P < 0.05 was considered statistically significant.

RESULTS

64 patients took DNG and 34 patients took COCs. Protein S-specific activity did not change significantly from baseline in the six months after treatment started in either group. In the DNG group, total protein S activity and total protein S antigen levels increased slightly from baseline levels after the treatment. The means for total protein S activity and total protein S antigen levels in the COC group remained within reference limits, but they both decreased markedly in the first month and stayed low. Protein S-specific activity in four women remaind below the reference limit throughout the whole study period, suggesting they may have potential protein S deficiencies.

CONCLUSION

The effects of DNG on protein S were negligible, though both total protein S activity and antigen levels decreased soon after COC treatment began and remained low. As there was no VTE event during the study, further studies with larger numbers of patients will be needed to confirm that protein S-specific activity can be a surrogate maker of VTE risk.

Risk of thrombosis, hemorrhage and leukemic transformation in patients with myeloproliferative neoplasms: A nationwide longitudinal cohort study

INTRODUCTION

There are few large-scale, population-based studies detailing the risks of thrombosis, hemorrhage, leukemic transformation in patients with myeloproliferative neoplasms (MPNs), including essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF).

METHODS

We performed a nationwide longitudinal cohort study using the Korean National Health Insurance System (NHIS) database. MPN patients (n = 11,991) and their 1:4 age- and sex-matched controls (n = 47,964) were enrolled. The risk of thrombosis, hemorrhage, leukemic transformation was estimated using a Cox proportional hazards regression, and stratified analyses were performed for related factors.

RESULTS

During a median of 7.8 years of follow-up, 30.1 % of MPN patients (3614/11,991) and 19.0 % of the matched controls (9141/47,964) developed arterial thrombosis, 11.6 % of MPN patients (1397/11,991) and 6.4 % of the matched controls (3099/47,964) developed venous thrombosis and 18.7 % of MPN patients (2251/11,991) and 12.1 % of the matched controls (5836/47,964) developed hemorrhage. 4.9 % of MPN patients (597/11,991) and 0.1 % of matched controls (50/47,964) developed leukemia. The overall risk of developing thrombosis, hemorrhage, leukemic transformation was higher in MPN patients (adjusted hazard ratio [aHR] 1.695, 95 % confidence interval [CI]: 1.629-1.765 for arterial thrombosis, aHR 1.963, 95 % CI: 1.838-2.096 for venous thrombosis, and aHR 1.714, 95 % CI: 1.630-1.802 for hemorrhage) than in the controls. Patients with MPNs had a 10-year cumulative incidence of leukemic transformation of 6.2 %.

CONCLUSION

The patients with MPNs have a higher risk of thrombosis, hemorrhage, and leukemic transformation than matched controls. Strategies are warranted to reduce the risk of thrombosis, hemorrhage, and leukemic transformation in MPN patients.

Shear Histories Alter Local Shear Effects on Thrombus Nucleation and Growth

Our goal was to determine the impact of physiological and pathological shear histories on platelet nucleation and thrombus growth at various local shear rates. We designed and characterized a microfluidic device capable of subjecting platelets to shear histories reaching as high as 6700 s- 1 in a single passage. Time-lapse videos of platelets and thrombi are captured using fluorescence microscopy. Thrombi are tracked, and the degree of thrombosis is evaluated through surface coverage, platelet nucleation maps, and ensemble-averaged aggregate areas and intensities. Surface coverage rates were the lowest when platelets deposited at high shear rates following a pathological shear history and were highest at low shear rates following a pathological shear history. Early aggregate area growth rates were significantly larger for thrombi developing at high shear following physiological shear history than at high shear following a pathological shear history. Aggregate vertical growth was restricted when depositing at low shear following a pathological shear history. In contrast, thrombi grew faster vertically following physiological shear histories. These results show that physiological shear histories pose thrombotic risks via volumetric growth, and pathological shear histories drastically promote nucleation. These findings may inform region-based geometries for biomedical devices and refine thrombosis simulations.

Impact of very low dose rivaroxaban in addition to dual antiplatelet therapy on endogenous fibrinolysis in acute coronary syndrome: The VaLiDate-R study

BACKGROUND

Impaired endogenous fibrinolysis is adverse cardiovascular risk factor in acute coronary syndrome (ACS) patients. Addition of very low dose rivaroxaban (VLDR) to dual antiplatelet therapy (DAPT) reduces cardiovascular events but increases bleeding.

OBJECTIVE

We aimed to assess whether addition of VLDR to DAPT can enhance endogenous fibrinolysis.

METHODS

In a prospective, open-label trial, we assessed endogenous fibrinolysis in whole blood, in 549 patients with ACS using the Global Thrombosis Test (GTT) and Thromboelastography (TEG). Patients (n = 180) who demonstrated impaired endogenous fibrinolysis (lysis time [LT] >2000s with the GTT) were randomised 1:1:1 to (i) clopidogrel 75 mg daily; (ii) clopidogrel 75 mg daily plus rivaroxaban 2.5 mg twice daily; or (iii) ticagrelor 90 mg twice daily, for 30 days, in addition to aspirin. Fibrinolytic status was assessed at 0, 2, 4 and 8 weeks. The primary outcome was the change in LT from admission to week 4. We also measured thrombotic occlusion time (OT) at high shear, and rivaroxaban level.

RESULTS

There was no difference between the groups with respect to LT or clot lysis with TEG, and no change in these parameters compared to baseline during study drug allocation. In the rivaroxaban plus clopidogrel group, OT was prolonged compared to the other groups, although rivaroxaban levels were low, suggesting non-compliance.

CONCLUSION

Addition of rivaroxaban 2.5 mg twice daily to DAPT does not affect endogenous fibrinolysis of thrombus formed at either high or low shear. Further studies are needed to determine whether higher doses of rivaroxaban can favourably modulate fibrinolysis.

CONDENSED ABSTRACT

Impaired endogenous fibrinolysis is a strong risk factor in ACS. We aimed to assess whether adding very low dose rivaroxaban (VLDR) to DAPT can enhance fibrinolysis. Fibrin and clot lysis were assessed in whole blood. ACS patients with impaired fibrinolysis were randomised 1:1:1 to clopidogrel 75 mg daily; clopidogrel 75 mg plus VLDR; or ticagrelor 90 mg twice daily, in addition to aspirin. At 30-days, there was no difference in lysis time between the groups, nor change from baseline. VLDR does not improve fibrinolysis at high or low shear. Further studies are needed to determine whether alternative antithrombotic regimens can enhance endogenous fibrinolysis.

Thromboembolic events in burn patients: An analysis of risk factors and different anticoagulants

BACKGROUND

Burn patients are in a state of activated coagulation, putting them at risk for thromboembolic events. Additionally, certain patient-related factors are associated with an increased risk of thrombus formation. This study aimed to evaluate the incidence of thromboembolic events and identify potential risk factors, including patient characteristics, surgical treatment, anticoagulation strategies, and laboratory parameters.

METHODS

A single-centre retrospective cohort study was conducted on all patients with burns treated between 2002 and 2020. Medical reports of patients with and without thromboembolic events were descriptively analysed. The association of time to thromboembolic events with total body surface area (TBSA) was assessed by cause-specific Cox models adjusted for different covariates. The association of time to thromboembolic events with type and dosage of anticoagulants was assessed using a cause-specific Cox proportional hazards model with time-dependent covariates, applied to a matched subset of patients.

RESULTS

The incidence of thromboembolic events was 8.1% in a cohort of 642 patients. We found a statistically significant increase in the hazard for thromboembolic events by a factor of 1.02 (95% CI 1.00 to 1.03; P ≤ 0.05) per percent increase in TBSA. We identified former alcohol abuse (HR=2.54, CI 1.33 to 4.84, P = 0.005) and higher body mass index (HR=1.06, 95% CI 1.00 to 1.12, P = 0.046) as potential risk factors for the development of thromboembolic events. We further noted inadequate median anti-Factor-X activity levels and elevated C-reactive protein and procalcitonin levels at the time of the event.

CONCLUSION

Our results showed a moderate risk of thromboembolic events among burn patients, underlining the importance of close monitoring with regard to thrombus formation. In particular, patients with higher TBSA, alcohol abuse and BMI may be evaluated more regularly for thromboembolic events. Anti-Factor-X activity levels should be determined regularly and therapy should be adjusted if necessary.

Management of DOAC-related bleeding in cancer patients: a single center-case series

Venous thromboembolism (VTE) and stroke carry significant mortality and morbidity in cancer patients. Direct oral anticoagulants (DOACs) have been demonstrated to be effective for the treatment of VTE and prevention of stroke in atrial fibrillation (AF). Bleeding rates are variable and are based on the cancer type and the patient's specific risk factors. There are approved specific antidotes for DOAC-associated bleeding. Other strategies are available for bleeding reversal, including the use of prothrombin complex concentrate (PCC). No randomized studies have compared head-to-head the efficacy and safety of reversal agents. We aim to examine the safety and effectiveness of hemostatic agents in cancer patients with DOAC-related major bleeding. A retrospective chart review study of patients at MD Anderson Cancer Center with DOAC-related major bleeding between 2014 and 2019. Bleeding severity and clinical hemostasis were described based on ISTH guidelines and the Sarode criteria, respectively. The rates of thrombotic complications and mortality at 30-day from the index bleeding event were described. We identified 23 patients with DOAC-related major bleeding; 14 patients received PCC and 9 patients received andexanet alfa. The most common sites of bleeding were the gastrointestinal tract and intracranial. Effective hemostasis and 30-day mortality were similar to reported results from other reports of outcomes of reversal agents for DOAC related-bleeding in non-cancer patients. One patient in each treatment group experienced a thrombotic event. Further larger scale studies are needed to confirm our findings in cancer patients.

Pulmonary embolism impacts clinical outcomes of intubated patients with acute respiratory distress syndrome related to COVID-19

BACKGROUND

Pulmonary embolism (PE) in critically ill patients with acute respiratory distress syndrome (ARDS) caused by COVID-19 is a major complication which might impact survival. We aimed to determine the prevalence of PE and assess its impact of PE on clinical outcomes in intubated patients with ARDS due to COVID-19.

METHODS

All intubated patients with ARDS due to COVID-19 admitted to the intensive care unit (ICU) of Geneva University Hospitals between March 9, 2020, and May 31, 2022, were included. A retrospective analysis was conducted on the occurrence of PE and its association with clinical outcomes. The primary outcome was ventilator-free days during the first 28 days after ICU admission. Linear regressions were performed to investigate the association between PE and outcomes.

RESULTS

Among the 370 intubated patients with ARDS related to COVID-19, 58 (15.7%) presented with PE. Patients with PE had significantly fewer ventilator-free days than patients without PE (median (IQR) of 3 (0-11) days versus 12 (0-19) days; p < 0.001). Mortality did not differ significantly between groups (12/58 [20.7%] of patients with PE versus 71/312 [22.8%] of patients without PE; p = 0.72). Duration of IMV, and ICU and hospital LOS were significantly longer among patients with PE. The need for ECMO support was similar among both groups.

CONCLUSIONS

The occurrence of PE in patients with ARDS due to COVID-19 had a significant impact on clinical outcomes. They had fewer ventilator-free days, longer duration of IMV, and longer ICU and hospital lengths of stay. However, pulmonary embolism was not associated with higher mortality.

ETHICS APPROVAL

Ethical committee of Geneva (BASEC #: 2020-00917).

Prediction of mortality in acute pulmonary embolism in cancer-associated thrombosis (MAUPE-C): derivation and validation of a multivariable model

Optimal risk stratification of patients with cancer and pulmonary embolism (PE) remains unclear. We constructed a clinical prediction rule (CPR) named 'MAUPE-C' to identify patients with low 30 days mortality. The study retrospectively developed and internally validated a CPR for 30 days mortality in a cohort of patients with cancer and PE (both suspected and unsuspected). Candidate variables were chosen based on the EPIPHANY study, which categorized patients into 3 groups based on symptoms, signs, suspicion and patient setting at PE diagnosis. The performance of 'MAUPE-C' was compared to RIETE and sPESI scores. Univariate analysis confirmed that the presence of symptoms, signs, suspicion and inpatient diagnosis were associated with 30 days mortality. Multivariable logistic regression analysis led to the exclusion of symptoms as predictive variable. 'MAUPE-C' was developed by assigning weights to risk factors related to the β coefficient, yielding a score range of 0 to 4.5. After receiver operating characteristic (ROC) curve analysis, a cutoff point was established at ≤ 1. Prognostic accuracy was good with an area under the curve (AUC) of 0.77 (95% CI 0.71-0.82), outperforming RIETE and sPESI scores in this cohort (AUC of 0.64 [95% CI 0.57-0.71] and 0.57 [95% CI 0.49-0.65], respectively). Forty-five per cent of patients were classified as low risk and experienced a 2.79% 30 days mortality. MAUPE-C has good prognostic accuracy in identifying patients at low risk of 30 days mortality. This CPR could help physicians select patients for early discharge.

Target sign in COVID-19, radiological interpretation and diagnostic contribution of digital thoracic tomosynthesis

INTRODUCTION

Our objectives are: To describe the radiological semiology, clinical-analytical features and prognosis related to the target sign (TS) in COVID-19. To determine whether digital thoracic tomosynthesis (DTT) improves the diagnostic ability of radiography.

MATERIAL AND METHODS

Retrospective, descriptive, single-centre, case series study, accepted by our ethical committee. Radiological, clinical, analytical and follow-up characteristics of patients with COVID-19 and TS on radiography and DTT between November 2020 and January 2021 were analysed.

RESULTS

Eleven TS were collected in 7 patients, median age 35 years, 57% male. All TS presented with a central nodule and a peripheral ring, and in at least 82%, the lung in between was of normal density. All TS were located in peripheral, basal regions and 91% in posterior regions. TS were multiple in 43%. Contiguous TS shared the peripheral ring. Other findings related to pneumonia were associated in 86% of patients. DTT detected 82% more TS than radiography. Only one patient underwent a CT angiography of the pulmonary arteries, positive for acute pulmonary thromboembolism. Seventy-one per cent presented with pleuritic pain. No distinctive laboratory findings or prognostic worsening were detected.

CONCLUSIONS

TS in COVID-19 predominates in peripheral and declining regions and can be multiple. Pulmonary thromboembolism was detected in one case. It occurs in young people, frequently with pleuritic pain and does not worsen the prognosis. DTT detects more than 80 % of TS than radiography.

Thrombosis recurrence and major bleeding in non-anticoagulated thrombotic antiphospholipid syndrome patients: Prospective study from antiphospholipid syndrome alliance for clinical trials and international networking (APS ACTION) clinical database and repository ("Registry")

BACKGROUND

Long-term anticoagulant therapy is generally recommended for thrombotic antiphospholipid syndrome (TAPS) patients, however it may be withdrawn or not introduced in routine practice.

OBJECTIVES

To prospectively evaluate the risk of thrombosis recurrence and major bleeding in non-anticoagulated TAPS patients, compared to anticoagulated TAPS, and secondly, to identify different features between those two groups.

PATIENTS/METHODS

Using an international registry, we identified non-anticoagulated TAPS patients at baseline, and matched them with anticoagulated TAPS patients based on gender, age, type of previous thrombosis, and associated autoimmune disease. Thrombosis recurrence and major bleeding were prospectively analyzed using Kaplan-Meier method and compared using a marginal Cox's regression model.

RESULTS

As of June 2022, 94 (14 %) of the 662 TAPS patients were not anticoagulated; and 93 of them were matched with 181 anticoagulated TAPS patients (median follow-up 5 years [interquartile range 3 to 8]). The 5-year thrombosis recurrence and major bleeding rates were 12 % versus 10 %, and 6 % versus 7 %, respectively (hazard ratio [HR] 1.38, 95 % confidence interval [CI] 0.53 to 3.56, p = 0.50 and HR 0.53; 95 % CI 0.15 to 1.86; p = 0.32, respectively). Non-anticoagulated patients were more likely to receive antiplatelet therapy (p < 0.001), and less likely to have more than one previous thrombosis (p < 0.001) and lupus anticoagulant positivity (p = 0.01).

CONCLUSION

Fourteen percent of the TAPS patients were not anticoagulated at recruitment. Their recurrent thrombosis risk did not differ compared to matched anticoagulated TAPS patients, supporting the pressing need for risk-stratified secondary thrombosis prevention trials in APS investigating strategies other than anticoagulation.

SER recommendations on treatment of refractory Behçet's syndrome

OBJECTIVE

To develop multidisciplinary recommendations based on available evidence and expert consensus for the therapeutic management of patients with refractory Behçet's syndrome (BS) (difficult to treat, severe resistant, severe relapse) to conventional treatment.

METHODS

A group of experts identified clinical research questions relevant to the objective of the document. These questions were reformulated in PICO format (patient, intervention, comparison and outcome). Systematic reviews of the evidence were conducted, the quality of the evidence was evaluated following the methodology of the international working group Grading of Recommendations Assessment, Development, and Evaluation (GRADE). After that, the multidisciplinary panel formulated the specific recommendations.

RESULTS

4 PICO questions were selected regarding the efficacy and safety of systemic pharmacological treatments in patients with BS with clinical manifestations refractory to conventional therapy related to mucocutaneous and/or articular, vascular, neurological parenchymal and gastrointestinal phenotypes. A total of 7 recommendations were made, structured by question, based on the identified evidence and expert consensus.

CONCLUSIONS

The treatment of most severe clinical manifestations of BS lacks solid scientific evidence and, besides, there are no specific recommendation documents for patients with refractory disease. With the aim of providing a response to this need, here we present the first official Recommendations of the Spanish Society of Rheumatology for the management of these patients. They are devised as a tool for assistance in clinical decision making, therapeutic homogenisation and to reduce variability in the care of these patients.

Impact of rise and fall phases of shear on platelet activation and aggregation using microfluidics

Blood flow disorders are often the result of the non-physiological narrowing of blood arteries caused by atherosclerosis and thrombus. The blood then proceeds through rising-peak-decreasing phases as it passes through the narrow area. Although abnormally high shear is known to activate platelets, the shear process that platelets undergo in small arteries is complex. Thus, understanding how each shear phase affects platelet activation can be used to improve antiplatelet therapy and decrease the risk of side effects like bleeding. Blood samples were sheared (68.8 ms,5200 s-1) in vitro by the microfluidic technique, and platelet activation levels (P-selectin and integrin αIIbβ3) and von Willebrand factor (vWF) binding to platelets were analyzed by flow cytometry. Post-stenosis platelet aggregation was dynamically detected using microfluidic technology. We studied TXA2, P2Y12-ADP, and integrin αIIbβ3-fibrinogen receptor pathways by adding antiplatelet drugs, such as acetylsalicylic acid (ASA, an active ingredient of aspirin that inhibits platelet metabolism), ticagrelor (hinders platelet activation), and tirofiban (blocks integrin αIIbβ3 receptor) in vitro, respectively, to determine platelet activation function mediated by transient non-physiological high shear rates. We demonstrated that platelets can be activated under transient pathological high shear rates. The shear rise and fall phases influenced shear-induced platelet activation by regulating the binding of vWF to platelets. The degree of platelet activation and aggregation increased with multiple shear rise and fall phases. ASA did not inhibit shear-mediated platelet activation, but ticagrelor and tirofiban effectively inhibited shear-mediated platelet activation. Our data demonstrated that the shear rise and fall phases play an important role in shear-mediated platelet activation and promote platelet activation and aggregation in a vWF-dependent manner. Blocking integrin αIIbβ3 receptor and hindering P2Y12-ADP were beneficial to reducing shear-mediated platelet activation.

Viruses and thrombocytopenia

Thrombocytopenia, characterized by a decrease in platelet count, is a multifaceted clinical manifestation that can arise from various underlying causes. This review delves into the intriguing nexus between viruses and thrombocytopenia, shedding light on intricate pathophysiological mechanisms and highlighting the pivotal role of platelets in viral infections. The review further navigates the landscape of thrombocytopenia in relation to specific viruses, and sheds light on the diverse mechanisms through which hepatitis C virus (HCV), measles virus, parvovirus B19, and other viral agents contribute to platelet depletion. As we gain deeper insights into these interactions, we move closer to elucidating potential therapeutic avenues and preventive strategies for managing thrombocytopenia in the context of viral infections.

Cyclophilin A is a ligand for RAGE in thrombo-inflammation

AIMS

Cyclophilin A (CyPA) induces leucocyte recruitment and platelet activation upon release into the extracellular space. Extracellular CyPA therefore plays a critical role in immuno-inflammatory responses in tissue injury and thrombosis upon platelet activation. To date, CD147 (EMMPRIN) has been described as the primary receptor mediating extracellular effects of CyPA in platelets and leucocytes. The receptor for advanced glycation end products (RAGE) shares inflammatory and prothrombotic properties and has also been found to have similar ligands as CD147. In this study, we investigated the role of RAGE as a previously unknown interaction partner for CyPA.

METHODS AND RESULTS

Confocal imaging, proximity ligation, co-immunoprecipitation, and atomic force microscopy were performed and demonstrated an interaction of CyPA with RAGE on the cell surface. Static and dynamic cell adhesion and chemotaxis assays towards extracellular CyPA using human leucocytes and leucocytes from RAGE-deficient Ager-/- mice were conducted. Inhibition of RAGE abrogated CyPA-induced effects on leucocyte adhesion and chemotaxis in vitro. Accordingly, Ager-/- mice showed reduced leucocyte recruitment and endothelial adhesion towards CyPA in vivo. In wild-type mice, we observed a downregulation of RAGE on leucocytes when endogenous extracellular CyPA was reduced. We furthermore evaluated the role of RAGE for platelet activation and thrombus formation upon CyPA stimulation. CyPA-induced activation of platelets was found to be dependent on RAGE, as inhibition of RAGE, as well as platelets from Ager-/- mice showed a diminished activation and thrombus formation upon CyPA stimulation. CyPA-induced signalling through RAGE was found to involve central signalling pathways including the adaptor protein MyD88, intracellular Ca2+ signalling, and NF-κB activation.

CONCLUSION

We propose RAGE as a hitherto unknown receptor for CyPA mediating leucocyte as well as platelet activation. The CyPA-RAGE interaction thus represents a novel mechanism in thrombo-inflammation.

Insight into antiphospholipid syndrome: the role and clinical utility of neutrophils extracellular traps formation

Antiphospholipid syndrome (APLS) is a systemic immune dysregulation distinguished by repetitive complications and pregnancy loss in the absence of definite etiology. Most research focuses on the laboratory detection and clinical features of APLS, but its precise etiology remains to be deeply explored. NETosis is a newly developed theory in the pathophysiology of APLS which may serve as the missing bridge between coagulation and inflammation reaching the disease progression and severity. We aimed in this study to navigate the prognostic role of NETosis in thrombotic APLS. Our study included 49 newly diagnosed APLS patients (both 1ry and 2ry) who met clinical and laboratory criteria as per the international consensus statement on the update of the classification criteria for definite APLS and were sub-classified according to the occurrence of thrombotic events in thrombotic and non-thrombotic types. In addition, 20 sex and age-matched reactive subjects and 20 sex and age-matched healthy volunteer controls were enrolled. NETosis formation was assessed by measuring serum Myeloperoxidase (MPO) and Histones level using the enzyme-linked immunosorbent assay (ELISA) technique. Both MPO and Histones levels were able to discriminate among APLS cases from normal controls, showing significant cutoffs of > 2.09 ng/ml for MPO and > 1.45 ng/ml for Histones (AUC values were 0.987and 1.000, respectively). These values can be used as predictors for NETosis pathophysiology in APLS patients. Additionally, these markers demonstrated a significant association with several prognostic indicators, including thrombosis, higher PT and INR, and lower hemoglobin (Hb) levels which are supposed to be ameliorated by using NETs inhibitors. In conclusion, we suggest that measuring NETosis markers, MPO, and Histones, in the early course of APLS using proposed cutoff values will facilitate the timely initiation of anti-NETosis therapy and improve the overall prognosis, particularly for patients with thrombotic APLS.

Spontaneous echo contrast and decreased umbilical vein blood flow may predict thrombus formation in fetal intra-abdominal umbilical vein varix

PURPOSE

Fetal intra-abdominal umbilical vein varix (FIUVV) can cause thrombosis, fetal growth restriction (FGR), and intrauterine fetal death (IUFD). However, its management and evaluation to avoid fetal risks have not been elucidated. The aim of this study was to develop a novel method to evaluate fetal risks, including FGR and fetal dysfunction via frequent ultrasound examinations.

METHODS

A 28-year-old pregnant woman was diagnosed with FIUVV via ultrasound at 26 weeks of gestation and admitted to our hospital. Ultrasound examinations were performed two to three times weekly to evaluate size and shape of the FIUVV and umbilical vein blood flow at the inflow and outflow sites of the FIUVV.

RESULTS

The outflow site of the FIUVV was constricted and collapsed, and the blood flow velocity at the inflow site of the FIUVV was decreased. At 32 weeks of gestation, spontaneous echo contrast (SEC), which indicates increased echogenicity, appeared. At 35 weeks of gestation, the patient noticed decreased fetal movement, and CTG showed non-reassuring fetal status. SEC in the FIUVV was remarkable. Fetal movement could not be confirmed at ultrasound. Cesarean section was performed and a 1,854-g healthy infant was delivered with an umbilical cord arterial pH of 7.266.

CONCLUSION

The echographic changes, such as decreased umbilical vein blood flow and SEC, in FIUVV observed in this case could indicate thrombus formation, which can lead to fetal dysfunction. Frequent ultrasound examinations can help determine the timing of delivery and improve the neonatal prognosis.

The Role of Leukocytes in Myeloproliferative Neoplasms Thromboinflammation

Classic myeloproliferative neoplasms lacking the Philadelphia chromosome are stem cell disorders characterized by the proliferation of myeloid cells in the bone marrow and increased counts of peripheral blood cells. The occurrence of thrombotic events is a common complication in myeloproliferative neoplasms. The heightened levels of cytokines play a substantial role in the morbidity and mortality of these patients, establishing a persistent proinflammatory condition that culminates in thrombosis. The etiology of thrombosis remains intricate and multifaceted, involving blood cells and endothelial dysfunction, the inflammatory state, and the coagulation cascade, leading to hypercoagulability. Leukocytes play a pivotal role in the thromboinflammatory process of myeloproliferative neoplasms by releasing various proinflammatory and prothrombotic factors as well as interacting with other cells, which contributes to the amplification of the clotting cascade and subsequent thrombosis. The correlation between increased leukocyte counts and thrombotic risk has been established. However, there is a need for an accurate biomarker to assess leukocyte activation. Lastly, tailored treatments to address the thrombotic risk in myeloproliferative neoplasms are needed. Therefore, this review aims to summarize the potential mechanisms of leukocyte involvement in myeloproliferative neoplasm thromboinflammation, propose potential biomarkers for leukocyte activation, and discuss promising treatment options for controlling myeloproliferative neoplasm thromboinflammation.

A Computational Investigation of the Effects of Temporal Synchronization of Left Ventricular Assist Device Speed Modulation with the Cardiac Cycle on Intraventricular Hemodynamics

Patients with advanced heart failure are implanted with a left ventricular assist device (LVAD) as a bridge-to-transplantation or destination therapy. Despite advances in pump design, the risk of stroke remains high. LVAD implantation significantly alters intraventricular hemodynamics, where regions of stagnation or elevated shear stresses promote thrombus formation. Third generation pumps incorporate a pulsatility mode that modulates rotational speed of the pump to enhance in-pump washout. We investigated how the timing of the pulsatility mode with the cardiac cycle affects intraventricular hemodynamic factors linked to thrombus formation. Computational fluid dynamics simulations with Lagrangian particle tracking to model platelet behavior in a patient-specific left ventricle captured altered intraventricular hemodynamics due to LVAD implantation. HeartMate 3 incorporates a pulsatility mode that modulates the speed of the pump every two seconds. Four different timings of this pulsatility mode with respect to the cardiac cycle were investigated. A strong jet formed between the mitral valve and inflow cannula. Blood stagnated in the left ventricular outflow tract beneath a closed aortic valve, in the near-wall regions off-axis of the jet, and in a large counterrotating vortex near the anterior wall. Computational results showed good agreement with particle image velocimetry results. Synchronization of the pulsatility mode with peak systole decreased stasis, reflected in the intraventricular washout of virtual contrast and Lagrangian particles over time. Temporal synchronization of HeartMate 3 pulsatility with the cardiac cycle reduces intraventricular stasis and could be beneficial for decreasing thrombogenicity.

Synthesis and evaluation of L-quebrachitol derivatives against platelet aggregation

Thrombosis plays an important role in the occurrence and development of cardiovascular and cerebrovascular diseases that contribute to high mortality and morbidity in patients. L-(-)-Quebrachitol (QCT), a natural product, was first isolated from quebracho bark. It can inhibit PAF receptor and decrease gastric damage induced by indomethacin, as a drug against platelet aggregation. Here, five QCT derivatives were synthesized and investigated for their inhibitory effects on platelet aggregation. Among them, compound 3a showed anticoagulant effects comparable to aspirin, while compound 4b showed dose-independent inhibitory activities in rats that were stronger than aspirin.

Strategies to reduce rates of severe endothermal heat-induced thrombosis following radiofrequency ablation

OBJECTIVE

Endothermal heat-induced thrombosis (EHIT) is a potential complication of radiofrequency ablation (RFA). Data on effective prophylaxis of EHIT are limited. In 2018, a high-volume, single institution implemented strategies to decrease the incidence of EHIT, including a single periprocedural prophylactic dose of low-molecular-weight heparin to patients with a great saphenous vein (GSV) diameter of ≥8 mm or saphenofemoral junction (SFJ) diameter of ≥10 mm and limiting treatment to one vein per procedure. The size threshold was derived from existing literature. The study objective was to evaluate the effects of these institutional changes on thrombotic complication rates after RFA.

METHODS

A retrospective cohort control study was conducted using the Vascular Quality Initiative database. Data were collected for patients who underwent RFA with a GSV diameter of ≥8 mm or SFJ diameter of ≥10 mm from January 2015 to July 2022. The clinical end points were thrombotic complications (ie, thrombophlebitis, EHIT, deep vein thrombosis) and bleeding complications. Patient demographic and procedural variables were included in the analysis, and significant variables after univariable logistic regression were included in a multivariable logistic regression.

RESULTS

After the policy change, the overall vein center EHIT rate decreased from 2.6% to 1.5%, with a trend toward significance (P = .096). The inclusion criterion of a GSV diameter of ≥8 mm or an SFJ diameter of ≥10 mm yielded 845 patients, of whom 298 were treated before the policy change and 547 after. There was a significant reduction in the rate of EHIT classified as class ≥III (2.34 vs 0.366; P = .020) after the institutional changes. Treatment of two or more veins and an increased vein diameter were associated with an increased risk of EHIT (P = .049 and P < .001, respectively). No significant association was found between periprocedural anticoagulation and all-cause thrombotic complications or EHIT (P = .563 and P = .885, respectively).

CONCLUSIONS

The institutional policy changes have led to lower rates of EHIT, with a reduction in severe EHIT rates in patients with an ≥8-mm diameter GSV or a ≥10-mm diameter SFJ treated with RFA. Of the changes implemented, restricting treatment to one vein was associated with a reduction in severe EHIT. No association was found with periprocedural low-molecular-weight heparin, although a type 2 error might have occurred. Alternative strategies to prevent thrombotic complications should be explored, such as increasing the dosage and duration of periprocedural anticoagulation, antiplatelet use, and nonpharmacologic strategies.

Renal damage and old age: risk factors for thrombosis in patients with ANCA-associated vasculitis

INTRODUCTION

Thrombosis in ANCA-associated vasculitis (AAV) was prevalent and has been neglected in Chinese patients. This study tried to describe the clinical characteristics, identify the risk factors, and investigate the causal relationship between AAV and venous thromboembolism (VTE) by two-sample Mendelian randomization (MR) analysis.

METHODS

In this retrospective, observational study, we included all hospitalized AAV patients from Jan 2013 to Apr 2022 in Peking Union Medical College Hospital. We collected their clinical data for multivariate regression analysis to determine the risk factors for thrombosis. The nomogram was constructed by applying these risk factors to predict thrombosis in AAV patients. As for MR analysis, we selected single nucleotide polymorphisms (SNPs) related to AAV from published genome-wide association studies and extracted the outcome data containing deep vein thrombosis (DVT) and pulmonary embolism (PE) from the UK biobank.

RESULTS

1203 primary AAV patients were enrolled, and thrombosis occurred in 11.3%. Multivariate regression suggested that older than 65 years, EGPA, neurological involvement, lung involvement, significantly elevated serum creatinine (> 500µmol/L), and elevated D-dimer were associated with thrombosis in AAV patients. The model demonstrated satisfied discrimination with an AUC of 0.769 (95% CI, 0.726-0.812). MR analysis showed that EGPA could increase the risk of developing DVT and PE (OR = 1.0038, 95%CI = 1.0035-1.0041, P = 0.009).

CONCLUSION

Thrombosis was not rare in Chinese patients with AAV. Renal damage and old age emerged as critical risk factors for thrombosis. EGPA might have a potential causal relationship with DVT and PE.

C-type lectin-like receptor 2: roles and drug target

C-type lectin-like receptor-2 (CLEC-2) is a member of the C-type lectin superfamily of cell surface receptors. The first confirmed endogenous and exogenous ligands of CLEC-2 are podoplanin and rhodocytin, respectively. CLEC-2 is expressed on the surface of platelets, which participates in platelet activation and aggregation by binding with its ligands. CLEC-2 and its ligands are involved in pathophysiological processes, such as atherosclerosis, cancer, inflammatory thrombus status, maintenance of vascular wall integrity, and cancer-related thrombosis. In the last 5 years, different anti- podoplanin antibody types have been developed for the treatment of cancers, such as glioblastoma and lung cancer. New tests and new diagnostics targeting CLEC-2 are also discussed. CLEC-2 mediates thrombosis in various pathological states, but CLEC-2-specific deletion does not affect normal hemostasis, which would provide a new therapeutic tool for many thromboembolic diseases. The CLEC-2-podoplanin interaction is a target for cancer treatment. CLEC-2 may be applied in clinical practice and play a therapeutic role.

Translational molecular imaging: Thrombosis imaging with positron emission tomography

A key focus of cardiovascular medicine is the detection, treatment, and prevention of disease, with a move towards more personalized and patient-centred treatments. To achieve this goal, novel imaging approaches that allow for early and accurate detection of disease and risk stratification are needed. At present, the diagnosis, monitoring, and prognostication of thrombotic cardiovascular diseases are based on imaging techniques that measure changes in structural anatomy and biological function. Molecular imaging is emerging as a new tool for the non-invasive detection of biological processes, such as thrombosis, that can improve identification of these events above and beyond current imaging modalities. At the forefront of these evolving techniques is the use of high-sensitivity radiotracers in conjunction with positron emission tomography imaging that could revolutionise current diagnostic paradigms by improving our understanding of the role and origin of thrombosis in a range of cardiovascular diseases.

Clinical profile and outcomes of hepatocellular carcinoma in primary Budd-Chiari syndrome

BACKGROUND

There is scant literature on hepatocellular carcinoma (HCC) in patients with Budd-Chiari syndrome (BCS).

AIM

To assess the magnitude, clinical characteristics, feasibility, and outcomes of treatment in BCS-HCC.

METHODS

A total of 904 BCS patients from New Delhi, India and 1140 from Mumbai, India were included. The prevalence and incidence of HCC were determined, and among patients with BCS-HCC, the viability and outcomes of interventional therapy were evaluated.

RESULTS

In the New Delhi cohort of 35 BCS-HCC patients, 18 had HCC at index presentation (prevalence 1.99%), and 17 developed HCC over a follow-up of 4601 person-years, [incidence 0.36 (0.22-0.57) per 100 person-years]. BCS-HCC patients were older when compared to patients with BCS alone (P = 0.001) and had a higher proportion of inferior vena cava block, cirrhosis, and long-segment vascular obstruction. The median alpha-fetoprotein level was higher in patients with BCS-HCC at first presentation than those who developed HCC at follow-up (13029 ng/mL vs 500 ng/mL, P = 0.01). Of the 35 BCS-HCC, 26 (74.3%) underwent radiological interventions for BCS, and 22 (62.8%) patients underwent treatment for HCC [transarterial chemoembolization in 18 (81.8%), oral tyrosine kinase inhibitor in 3 (13.6%), and transarterial radioembolization in 1 (4.5%)]. The median survival among patients who underwent interventions for HCC compared with those who did not was 3.5 years vs 3.1 mo (P = 0.0001). In contrast to the New Delhi cohort, the Mumbai cohort of BCS-HCC patients were predominantly males, presented with a more advanced HCC [Barcelona Clinic Liver Cancer C and D], and 2 patients underwent liver transplantation.

CONCLUSION

HCC is not uncommon in patients with BCS. Radiological interventions and liver transplantation are feasible in select primary BCS-HCC patients and may improve outcomes.

Aspirin Responsiveness in a Cohort of Pediatric Patients with Right Ventricle to Pulmonary Artery Conduits and Transcatheter Valve Replacement Systems

The aim of this study was to determine the rate of aspirin responsiveness in a cohort of pediatric patients with in situ xenograft valved right ventricle to pulmonary artery (RV-PA) conduits and/or transcatheter valve replacements (TVR). Aspirin is routinely prescribed to these patients. Optimizing anti-platelet therapy could promote valve longevity and reduce the risk of infective endocarditis in this at-risk group. This was a prospective, observational study. Patients were recruited from both ward and outpatient settings. Patients were eligible if under 18 years and taking aspirin. Non-response to aspirin was defined as > 20% platelet aggregation using light transmission platelet aggregometry (LTA) and < 50% platelet inhibition by thromboelastography with platelet mapping (TEGPM). Participants were invited to provide a confirmatory sample in cases of aspirin resistance and dose adjustments were made. Thirty patients participated. Median age was 9 years (2 months to 18 years). The majority (93%) had complex right ventricular outflow tract pathology. 13 (43%) had an RV-PA conduit and 24 (80%) had a TVR, with valve situated in conduit in 7 (23%) cases. Rate of aspirin non-response on initial testing was 23% (n = 7/30) with median LTA 74.55% (60-76%) and TEG 13.25% (0-44%) in non-responders. Non-responders were more likely to be under 1 year. Two patients required dose increases and one patient non-adherence to dose was identified. Four patients on repeat testing were responsive to aspirin by laboratory tests. The rate of aspirin non-response on laboratory testing in this cohort of patients was 23% and resulted in therapeutic intervention in 10%.

Ultra-high throughput-based screening for the discovery of antiplatelet drugs affecting receptor dependent calcium signaling dynamics

Distinct platelet activation patterns are elicited by the tyrosine kinase-linked collagen receptor glycoprotein VI (GPVI) and the G-protein coupled protease-activated receptors (PAR1/4) for thrombin. This is reflected in the different platelet Ca2+ responses induced by the GPVI agonist collagen-related peptide (CRP) and the PAR1/4 agonist thrombin. Using a 96 well-plate assay with human Calcium-6-loaded platelets and a panel of 22 pharmacological inhibitors, we assessed the cytosolic Ca2+ signaling domains of these receptors and developed an automated Ca2+ curve algorithm. The algorithm was used to evaluate an ultra-high throughput (UHT) based screening of 16,635 chemically diverse small molecules with orally active physicochemical properties for effects on platelets stimulated with CRP or thrombin. Stringent agonist-specific selection criteria resulted in the identification of 151 drug-like molecules, of which three hit compounds were further characterized. The dibenzyl formamide derivative ANO61 selectively modulated thrombin-induced Ca2+ responses, whereas the aromatic sulfonyl imidazole AF299 and the phenothiazine ethopropazine affected CRP-induced responses. Platelet functional assays confirmed selectivity of these hits. Ethopropazine retained its inhibitory potential in the presence of plasma, and suppressed collagen-dependent thrombus buildup at arterial shear rate. In conclusion, targeting of platelet Ca2+ signaling dynamics in a screening campaign has the potential of identifying novel platelet-inhibiting molecules.

Post-partum cerebral venous sinus thrombosis: A case report

INTRODUCTION

Cerebral venous sinus thrombosis (CVST) is a rare and life-threatening condition that may be encountered during pregnancy and puerperium. The diagnosis of CVST is a challenge because of its varied presentation.

CASE REPORT

A 28-year-old woman presented with headache, projectile vomiting, and generalized tonic-clonic seizures 10 days after delivery by cesarean section. She had an uneventful antenatal period of 38 weeks of gestation. High clinical suspicion and the availability of magnetic resonance venography helped in making a diagnosis of CVST. She was successfully managed with a low-molecular-weight heparin (LMWH) and anti-epileptic therapy with no residual complications.

DISCUSSION

Pregnancy induces several prothrombotic changes in the coagulation system that predispose to CVST. These changes persist for six to eight weeks after birth. Infection and cesarean section are the additional risk factors for CVST during puerperium. The symptoms of CVST depend on the sinuses and veins involved, raised intracranial pressure, and the extent of brain parenchymal injury.

CONCLUSION

Greater awareness of the disease and the availability of imaging modalities have contributed to the early diagnosis and favorable outcomes in these cases. LMWH is the main stay of treatment in this disease.

High-mobility group box 1 increases platelet surface P2Y12 and platelet activation in sickle cell disease

Thrombosis and inflammation are intimately linked and synergistically contribute to the pathogenesis of numerous thromboinflammatory diseases, including sickle cell disease (SCD). While platelets are central to thrombogenesis and inflammation, the molecular mechanisms of crosstalk between the 2 remain elusive. High-mobility group box 1 (HMGB1) regulates inflammation and stimulates platelet activation through Toll-like receptor 4. However, it remains unclear whether HMGB1 modulates other thrombotic agonists to regulate platelet activation. Herein, using human platelets, we demonstrate that HMGB1 significantly enhanced ADP-mediated platelet activation. Furthermore, inhibition of the purinergic receptor P2Y12 attenuated HMGB1-dependent platelet activation. Mechanistically, we show that HMGB1 stimulated ADP secretion, while concomitantly increasing P2Y12 levels at the platelet membrane. We show that in SCD patients, increased plasma HMGB1 levels were associated with heightened platelet activation and surface P2Y12 expression. Treatment of healthy platelets with plasma from SCD patients enhanced platelet activation and surface P2Y12, and increased sensitivity to ADP-mediated activation, and these effects were linked to plasma HMGB1. We conclude that HMGB1-mediated platelet activation involves ADP-dependent P2Y12 signaling, and HMGB1 primes platelets for ADP signaling. This complementary agonism between ADP and HMGB1 furthers the understanding of thromboinflammatory signaling in conditions such as SCD, and provides insight for therapeutic P2Y12 inhibition.

Validation of self-reported cardiovascular problems in childhood cancer survivors by contacting general practitioners: feasibility and results

BACKGROUND

Epidemiological studies often rely on self-reported health problems and validation greatly improves study quality. In a study of late effects after childhood cancer, we validated self-reported cardiovascular problems by contacting general practitioners (GPs). This paper describes: (a) the feasibility of this approach; and (b) the agreement between survivor-reports and reports from their GP.

METHODS

The Swiss Childhood Cancer Survivor Study (SCCSS) contacts all childhood cancer survivors registered in the Swiss Childhood Cancer Registry since 1976 who survived at least 5 years from cancer diagnosis. We validated answers of all survivors who reported a cardiovascular problem in the questionnaire. Reported cardiovascular problems were hypertension, arrhythmia, congestive heart failure, myocardial infarction, angina pectoris, stroke, thrombosis, and valvular problems. In the questionnaire, we further asked survivors to provide a valid address of their GP and a consent for contact. We sent case-report forms to survivors' GPs and requested information on cardiovascular diagnoses of their patients. To determine agreement between information reported by survivors and GPs, we calculated Cohen's kappa (κ) coefficients for each category of cardiovascular problems.

RESULTS

We used questionnaires from 2172 respondents of the SCCSS. Of 290 survivors (13% of 2172) who reported cardiovascular problems, 166 gave consent to contact their GP and provided a valid address. Of those, 135 GPs (81%) replied, and 128 returned the completed case-report form. Survivor-reports were confirmed by 54/128 GPs (42%). Of the 54 GPs, 36 (28% of 128) confirmed the problems as reported by the survivors; 11 (9% of 128) confirmed the reported problem(s) and gave additional information on more cardiovascular outcomes; and seven GPs (5% of 128) confirmed some, but not all cardiovascular problems. Agreement between GPs and survivors was good for stroke (κ = 0.79), moderate for hypertension (κ = 0.51), arrhythmias (κ = 0.41), valvular problems (κ = 0.41) and thrombosis (κ = 0.56), and poor for coronary heart disease (κ = 0.15) and heart failure (κ = 0.32).

CONCLUSIONS

Despite excellent GP compliance, it was found unfeasible to validate self-reported cardiovascular problems via GPs because they do not serve as gatekeepers in the Swiss health care system. It is thus necessary to develop other validation methods to improve the quality of patient-reported outcomes.

A Fibrin-Thrombin Based In Vitro Perfusion System to Study Flow-Related Prosthetic Heart Valves Thrombosis

Prosthetic heart valve (PHV) replacement has increased the survival rate and quality of life for heart valve-diseased patients. However, PHV thrombosis remains a critical problem associated with these procedures. To better understand the PHV flow-related thrombosis problem, appropriate experimental models need to be developed. In this study, we present an in vitro fibrin clot model that mimics clot accumulation in PHVs under relevant hydrodynamic conditions while allowing real-time imaging. We created 3D-printed mechanical aortic valve models that were inserted into a transparent glass aorta model and connected to a system that simulates human aortic flow pulse and pressures. Thrombin was gradually injected into a circulating fibrinogen solution to induce fibrin clot formation, and clot accumulation was quantified via image analysis. The results of valves positioned in a normal versus a tilted configuration showed that clot accumulation correlated with the local flow features and was mainly present in areas of low shear and high residence time, where recirculating flows are dominant, as supported by computational fluid dynamic simulations. Overall, our work suggests that the developed method may provide data on flow-related clot accumulation in PHVs and may contribute to exploring new approaches and valve designs to reduce valve thrombosis.

Between a rock and a hard place: anticoagulation management for ECMO

Anticoagulation is an essential component of optimal extracorporeal membrane oxygenation (ECMO) management. Unfractionated heparin is still the anticoagulant of choice in most centers due to longstanding familiarity with the agent. Disadvantages include alterations in drug responses due to its capability to bind multiple heparin-binding proteins that compete with antithrombin and the potential for heparin-induced thrombocytopenia. In such cases, direct thrombin inhibitors are the treatment of choice but pose difficulties in monitoring due to the limited experience and target ranges for non-aPTT-guided management (aPTT: activated partial thromboplastin time). The current trend toward low-dose anticoagulation, especially for venovenous ECMO, is supported by data associating bleeding complications with mortality but not thromboembolic events, which include circuit thrombosis. However, only prospective data will provide appropriate answers to how to individualize anticoagulation, transfusions, and bleeding management which is currently only supported by expert opinion. Empiric therapy for ECMO patients based on laboratory coagulation alone should always be critically questioned. In summary, only collaboration and future studies of coagulation management during ECMO will help us to make this life-saving therapy that has become part of daily life of the intensivist even safer and more effective. Until then, a fundamental understanding of coagulation and bleeding management, as well as pearls and pitfalls of monitoring, is essential to optimize anticoagulation during ECMO. This article is freely available.

Anti-hemostatic, antithrombotic, and chemical profiles of a curly-leaf variety of Petroselinum crispum (Apiaceae), a food and medicinal aromatic herb

Thrombosis is currently among the major causes of morbidity and mortality in the World. New prevention and therapy alternatives have been increasingly sought in medicinal plants. In this context, we have been investigating parsley, Petroselinum crispum (Mill.) Nym, an aromatic herb with two leaf varieties. We report here the in vitro, in vivo, and ex vivo anti-hemostatic and antithrombotic activities of a parsley curly-leaf variety. Aqueous extracts of aerial parts (PCC-AP), stems (PCC-S), and leaves (PCC-L) showed significant in vitro antiplatelet activity. PCC-AP extract exhibited the highest activity (IC50 2.92 mg/mL) when using ADP and collagen as agonists. All extracts also presented in vitro anticoagulant activity (APTT and PT) and anti-thrombogenic activity. PCC-S was the most active, with more significant interference in the factors of the intrinsic coagulation pathway. The oral administration of PCC-AP extract in rats caused a greater inhibitory activity in the deep vein thrombi (50%; 65 mg/kg) than in arterial thrombi formation (50%; 200 mg/kg), without cumulative effect after consecutive five-day administration. PCC-AP extract was safe in the induced bleeding time test. Its anti-aggregating profile was similar in ex vivo and in vitro conditions but was more effective in the extrinsic pathway when compared to in vitro results. Apiin and coumaric acid derivatives are the main compounds in PCC-AP according to the HPLC-DAD-ESI-MS/MS profile. We demonstrated for the first time that extracts from different parts of curly parsley have significant antiplatelet, anticoagulant, and antithrombotic activity without inducing hemorrhage, proving its potential as a source of antithrombotic compounds.

Antiplatelet and Anticoagulant Effects of Two New Phenylpropanoid Sucrose Esters and Other Secondary Metabolites from the Aerial Part of Canna edulis

This study isolated pure compounds from Canna edulis aerial parts and assessed their antiplatelet and anticoagulant potential. Structural elucidation resulted in the identification of two new compounds: caneduloside A (1) and caneduloside B (2), and eleven known compounds: 6'-acetyl-3,6,2'-tri-p-coumaroyl sucrose (3), 6¢-acetyl-3,6,2¢-triferuloyl sucrose (4), tiliroside (5), afzelin (6), quercitrin (7),  2-hydroxycinnamaldehyde (8), cinnamic acid (9), 3,4-dimethoxycinnamic acid (10), dehydrovomifoliol (11),  4-hydroxy-3,5-dimethoxybenzaldehyde (12), and (S)-(-)-rosmarinic acid (13). Compounds 3, 4, 6-9, 13 were previously reported for antithrombotic properties. Hence, antithrombotic tests were conducted for 1, 2, 5, 10-12. All tested compounds demonstrated a dose-dependent antiaggregatory effect, and 10 and 12 were the most potent for both ADP and collagen activators. Additionally, 10 and 12 exhibited anticoagulant effects, with prolonged prothrombin time and activated partial thromboplastin time. The new compound 1 displayed antiplatelet and anticoagulant activity, while 2 mildly inhibited platelet aggregation. C. edulis is a potential source for developing antithrombotic agents.

Classic paroxysmal nocturnal haemoglobinuria presenting with intestinal malabsorption syndrome, acute abdomen and acute kidney injury

A male patient in his 30s presented with complaints of acute abdominal pain, black stools and red-coloured urine. CT revealed thrombi in the splenic and left renal veins, leading to infarctions. An endoscopy displayed scalloping of the duodenal folds, indicative of intestinal malabsorption syndrome (IMS). Histopathological examination confirmed IMS. Due to the presence of intravascular haemolysis, haemoglobinuria and thrombotic complications, paroxysmal nocturnal haemoglobinuria (PNH) was suspected and subsequently confirmed by flow cytometry. Thus, a diagnosis of classic PNH with IMS and thrombotic complications was established. This unique case highlights the coexistence of PNH and IMS, resembling the complement hyperactivation, angiopathic thrombosis and protein-losing enteropathy disease, suggesting potential shared pathophysiology.

Atrial fibrillation-induced cardiomyopathy presenting with bilateral intermittent claudication associated with intracardiac thrombi

Systemic thromboembolism associated with atrial fibrillation (AF) is usually caused by thrombi in the left atrial appendage and acute onset. We experienced an unusual case of a woman in her 60s who presented to the outpatient district having bilateral intermittent claudication for more than 1 month, which turned out to be multiple thromboembolism from asymptomatic AF with tachycardia. She was also complicated with non-ischaemic dilated cardiomyopathy with reduced ejection fraction, consistent with arrhythmia-induced cardiomyopathy (AiCM), along with left atrial and left ventricular thrombi and thromboembolism in multiple organs. Rate control with beta-blockers was not effective. With the administration of amiodarone after adequate anticoagulation therapy, she returned to sinus rhythm, and the ejection fraction was restored. This case is instructive in that AiCM with AF can cause thrombosis in the left ventricle, and the patient may present with worsening intermittent claudication as a result of systemic embolism.

Postpartum ovarian vein thrombosis with left renal venous infarction after vaginal delivery

A primipara in her late 20s presented with abdominal pain and pain in the left flank 14 days after a ventouse delivery. She was treated with antibiotics, antiemetics and analgesics with the initial differential diagnosis of cystitis, pyelonephritis or nephrolithiasis. Despite the treatment, the patient experienced increased colic pain and nausea. An ultrasound showed an enlarged left kidney, suggesting pyelonephritis, and thereby, the antibiotic treatment was adjusted accordingly. Despite additional pain medication, pain relief could not be achieved. The diagnosis of ovarian venous thrombosis was considered, and an abdominal CT scan confirmed the diagnosis. The patient was treated with anticoagulant therapy. Hypercoagulability work-up revealed a heterozygous mutation of the Factor V Leiden. Our patient awaits a haematologic follow-up.

Chemical prophylaxis and venous thromboembolism following elective spinal surgery: A systematic review and meta-analysis

Background

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is a potentially devastating complication after surgery. Spine surgery is associated with an increased risk of postoperative bleeding, such as spinal epidural hematomas (SEH), which complicates the use of anticoagulation. Despite this dilemma, there is a lack of consensus around perioperative VTE prophylaxis. This systematic review investigates the relationship between chemoprophylaxis and the incidence rates of VTE and SEH in the elective spine surgical population.

Methods

A comprehensive literature search was performed using PubMed, Embase, and Cochrane databases to identify studies published after 2,000 that compared VTE chemoprophylaxis use in elective spine surgery. Studies involving patients aged < 18 years or with known trauma, cancer, or spinal cord injuries were excluded. Pooled incidence rates of VTE and SEH were calculated for all eligible studies, and meta-analyses were performed to assess the relationship between chemoprophylaxis and the incidences of VTE and SEH.

Results

Nineteen studies met our eligibility criteria, comprising a total of 220,932 patients. The overall pooled incidence of VTE was 3.2%, including 3.3% for DVT and 0.4% for PE. A comparison of VTE incidence between patients that did and did not receive chemoprophylaxis was not statistically significant (OR 0.97, p=.95, 95% CI 0.43-2.19). The overall pooled incidence of SEH was 0.4%, and there was also no significant difference between patients that did and did not receive chemoprophylaxis (OR 1.57, p=.06, 95% CI 0.99-2.50).

Conclusions

The use of perioperative chemoprophylaxis may not significantly alter rates of VTE or SEH in the elective spine surgery population. This review highlights the need for additional randomized controlled trials to better define the risks and benefits of specific chemoprophylactic protocols in various subpopulations of elective spine surgery.