The effects of ambient particulate matter air pollution on platelets and hemostasis.

Introduction: Elevated ambient pollution exposure is potentially linked to thromboembolism. However, the mechanisms by which particulate matter (PM) interferes with the balance of hemostatic system remain unclear. This study investigates PM-mediated hemostatic changes in individuals across unique seasonal variations of ambient pollution. Methods: This prospective study was conducted between February and July 2020 during alterations in ambient pollution in Chiang Mai, Thailand. Blood tests from 30 healthy subjects were assessed at four-week intervals, four times in total. Various coagulation tests, including prothrombin time (PT), activated partial thromboplastin time (aPTT), von Willebrand factor (vWF), platelet count, and platelet functions, were evaluated. A mixed-effects model was used to analyze the impact of high PM2.5 and PM10 on hemostatic parameters. Results: Thirty male subjects with mean age of 38.9 ± 8.2 years, were included. High levels of PM2.5 and PM10 were significantly associated with PT shortening, with no such effect observed in aPTT. PM2.5 and PM10 values also positively correlated with vWF function, while vWF antigen levels remained unchanged. Soluble P-selectin showed a strong positive association with PM2.5 and PM10 levels. Platelet function analysis revealed no correlation with PM values. Conclusion: Short-term exposure to elevated PM2.5 and PM10 concentrations was linked to shortened PT and enhanced vWF function in healthy individuals. Exploring the impact of these changes on clinically relevant thrombosis is crucial. Additional studies on the pathogenesis of pollution-related thrombosis are warranted for maintaining good health.

Engraftment Syndrome in Autologous Hematopoietic Stem Cell Transplant Patients: Incidence, Associated Risk Factors, Features, and Outcomes.

BACKGROUND Autologous stem cell transplantation (ASCT) is the standard treatment for multiple myeloma (MM) and refractory/relapsed (R/R) lymphoma patients. Engraftment syndrome (ES) is a non-infectious febrile syndrome during ASCT. This study focused on the incidence, risk factors, manifestations, and outcomes of patients with ES receiving ASCT. MATERIAL AND METHODS This retrospective cohort study included MM and R/R lymphoma patients who underwent ASCT at Chiang Mai University Hospital from January 2014 to September 2020. ES was diagnosed by the consensus of independent reviewers based on clinical manifestations, laboratory, and radiological findings. RESULTS We included 124 patients, of whom 67 (54.1%) had lymphoma. The mean age was 48.0±12.3 years. The incidence of ES was 36.3%. The ES group had a significantly higher proportion of patients with fever, elevated liver enzymes, elevated bilirubin, hypoalbuminemia, and weight gain compared to the non-ES group. TNC more than 10×108 cells/kg was an independent risk factor for ES (odds ratio 2.94 with a 95% confidence interval of 1.15-7.50, P=0.024). ES was associated with longer length of stay (22.5±8.2 vs 16.9±6.4 days, P<0.001) but was not associated with overall survival (OS). CONCLUSIONS The incidence of ES in this cohort was 36.3%. Features observed in ES patients were fever, elevated liver enzymes, elevated bilirubin, and hypoalbuminemia. TNC of more than 10×108 cells/kg was an independent risk factor. ES was associated with longer length of stay but not survival outcomes.

Incidence of venous thromboembolism and predictive ability of age-adjusted international prognostic index for prediction of venous thromboembolism in Asian patients with diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is one of the malignancies at high risk for the development of venous thromboembolism (VTE). We aimed to evaluate the incidence of VTE and the predictive ability of the age-adjusted international prognostic index (aaIPI) for the prediction of VTE among DLBCL patients. This was a retrospective cohort study including adult patients with newly diagnosed DLBCL. Differences in VTE occurrence within one year after diagnosis of DLBCL were estimated across aaIPI groups using the Kaplan-Meier model, Cox's model, and Gray's model with deaths regarded as competing events. Five hundred and ninety-one newly diagnosed DLBCL patients with a median age of 58 (range 16-93) years were included in this study. At a median follow-up time of 365 (range 2-365) days, VTE events were objectively diagnosed in 32 patients, giving a one-year cumulative incidence of VTE of 5.4% (95% confidence interval [CI], 3.7-7.6). Patients with aaIPI ≥ 2 had a significantly higher risk of VTE than patients with aaIPI < 2 (hazard ratio, 3.5; 95% CI, 1.6-7.8; p = 0.001 based on Cox's model and sub-distribution hazard ratio, 3.0; 95% CI, 1.3-6.7; p = 0.007 using Gray's model). The C-statistic of aaIPI was 0.65 (95% CI, 0.58-0.72). We demonstrated that the incidence of VTE in Asian DLBCL patients was not uncommon. The aaIPI was effective in determining the risk of VTE in DLBCL patients, even when including death as a competing event. aaIPI may be helpful in identifying patients at higher risk of VTE in DLBCL patients.

Comparison of risk prediction scores for cancer-associated thrombosis in ambulatory cancer patients not receiving thromboprophylaxis: A prospective cohort study in a South-East Asian population.

INTRODUCTION: To date, there is limited data regarding the incidence and risk prediction of cancer-associated thrombosis among South-East Asian patients who do not receive thromboprophylaxis. MATERIALS AND METHODS: This was a prospective cohort study conducted at a tertiary medical center from June 2020 to December 2021 in Thailand. We enrolled cancer patients aged ≥ 18 years, with ECOG score ≤ 1, scheduled to receive the first cycle of chemotherapy. We measured incidence of venous thromboembolism (VTE), all-cause mortality and performance of risk prediction scores. RESULTS: A total of 457 patients were included with a mean age of 58.18 ± 12.60 years. By the end of 6 months period, VTE had occurred in 30 patients (6.56 %, 95%CI 4.36-9.21). The median time to the first thrombosis was 1.94 months (IQR 0.26-3.19). Cancer associated thrombosis incidence was 14.58 % for Khorana score ≥ 3, 6.67 % for scores 1-2 and 2.13 % for score 0. C-statistics were 0.50 (95%CI 0.41-0.60) for Khorana score cut-off ≥ 2, 0.57 (95%CI 0.49-0.65) for Khorana score ≥ 3, 0.55 (95%CI 0.46-0.65) for PROTECHT score ≥ 3, and 0.57 (95%CI 0.49-0.65) for CONKO score ≥ 3. Classifying cholangiocarcinoma as very-high-risk increased the Khorana score cut-off ≥ 3's C-statistic to 0.62 (95%CI 0.53-0.71). CONCLUSIONS: A significant proportion of ambulatory South-East Asian cancer patients without thromboprophylaxis developed VTE. Further prospective studies investigating the benefit of thromboprophylaxis in high-risk patients with active cancer are warranted.

Longitudinal Profiles of Anti-Platelet Factor 4 Antibodies in Thai People Who Received ChAdOx1 nCoV-19 Vaccination.

Anti-platelet factor 4 (anti-PF4) antibodies were identified as pathogenic antibodies for vaccine-induced immune thrombocytopenia and thrombosis (VITT) in subjects receiving ChAdOx1 nCoV-19 vaccinations. We performed a prospective cohort study to determine the prevalence of anti-PF4 and the effect of the ChAdOx1 nCoV-19 vaccine on anti-PF4 in healthy Thai subjects. Anti-PF4 antibodies were measured before and four weeks after receiving the first vaccination. Participants with detectable antibodies were scheduled for repeat anti-PF4 analysis at 12 weeks after the second vaccination. Of 396 participants, ten participants (2.53%; 95% confidence interval [CI], 1.22-4.59) were positive for anti-PF4 before receiving vaccinations. Twelve people (3.03%; 95% CI, 1.58-5.23) had detectable anti-PF4 after the first vaccination. There was no difference in the optical density (OD) values of anti-PF4 antibodies when comparisons were made between pre-vaccination and four weeks after the first vaccination (p = 0.0779). There was also no significant difference in OD values in participants with detectable antibodies. No subjects experienced thrombotic complications. Pain at the injection site was associated with an increased risk of being anti-PF4 positive at an odds ratio of 3.44 (95% CI, 1.06-11.18). To conclude, the prevalence of anti-PF4 was low in Thais and did not significantly change over time.

Impact of antiphospholipid antibodies on thrombotic events in ambulatory cancer patients.

BACKGROUND: Despite the conflicting data, the positivity of antiphospholipid antibodies (aPL) in cancer patients may be associated with an increased risk of thrombosis. OBJECTIVE: To identify the prevalence and impact of aPL on venous thromboembolic events (VTE) and arterial thrombosis (ATE) in ambulatory cancer patients. METHODS: In this single-center, prospective cohort study, we enrolled newly diagnosed ambulatory cancer patients receiving chemotherapy. Non-cancer controls were age- and sex-matched. Participants were evaluated for aPL. Primary outcomes were the composite outcome of VTE or ATE and the prevalence of aPL positivity in cancer patients. Secondary outcomes included the risk of VTE and ATE in cancer patients and all-cause mortality at six-month follow-up duration. RESULTS: There were 137 cases and 137 controls with mean age of 56.0±12.3 and 55.5±12.1 years, respectively. Cancer patients were more likely to have positive aPL compared to controls, with the risk difference of 9.4% (95%CI 1.5 to 17.5). Composite of ATE or VTE occurred in 9 (6.6%) in cancer patients and 2 (1.5%) in controls. Cancer patients with aPL positivity were associated with higher risk of ATE or VTE (risk ratio [RR] 3.6, 95% CI 1.04-12.4). Positive LA in cancer patients were associated with higher risk of composites of ATE or VTE (RR 5.3 95%CI 1.3-21.0), whereas the anti-ß2-GPI positivity were associated with increased risk of VTE (RR 4.7, 95%CI 1.1-19.2). CONCLUSION: aPL was more prevalent in active cancer patients and positive aPL in cancer patients was associated with arterial or venous thrombosis.

Impact of dabigatran dose on drug levels in asian patients with atrial fibrillation or venous thromboembolism: evidence from pharmacological to clinical outcomes.

Dabigatran is commonly used in atrial fibrillation (AF) or venous thromboembolism (VTE). However, there was limited data on dabigatran levels in Asian patients. This study aimed to investigate plasma levels of dabigatran 110 mg (D110) or 150 mg (D150) twice daily and their impact on clinical outcomes in Thai patients. This was a prospective cohort study including patients who were diagnosed with AF or VTE and were prescribed either D110 or D150. Plasma dabigatran levels were measured using the diluted thrombin time method. All patients were observed for bleeding and thrombotic complications for 12 months after enrollment. Ninety patients were included in the study (45 in the D110 group and 45 in the D150 group). For the D110 group, there was no significant difference in trough and peak levels in patients with creatinine clearance (CrCl) < 50 ml/min compared to those with CrCl ≥ 50 ml/min. For the D150 group, patients with CrCl < 50 ml/min had significantly higher trough and peak levels compared to those with CrCl ≥ 50 ml/min (P = 0.016 for trough, P = 0.005 for peak). Multivariate regression analysis showed females and low CrCl were independent risk factors for high dabigatran levels. Most patients (83.33%) who experienced bleeding complications had peak levels within the expected range. D150 was associated with higher plasma dabigatran levels, especially in those with impaired renal function.

The association between pre-transfusion hemoglobin levels and thalassemia complications.

OBJECTIVES: To evaluate any association between pre-transfusion hemoglobin (Hb) levels and thalassemia complications and to identify the Hb cutoff values to predict thalassemia complications. METHODS: We performed a cross-sectional study in thalassemia patients who attended the Adult Hematology Clinic of the tertiary care University Hospital from October 2017 to October 2018. A point-biserial correlation was used to identify any association between Hb levels and thalassemia complications. A receiver operating characteristic (ROC) curve was used to identify the diagnostic ability of Hb levels to predict thalassemia complications and identify Hb cutoff values. RESULTS: Out of the 102 patients, there were 53 transfusion dependent thalassemia (TDT) patients and 49 non-transfusion dependent thalassemia (NTDT) patients. In theTDT group, Hb levels showed a negative correlation with severe hepatic iron overload and hypogonadism. The cutoff Hb levels to predict severe hepatic iron overload and hypogonadism were ≤7.01 and 6.81 g/dL, respectively, at which points the area under the ROC curve (AUC) were 0.721 and 0.708, respectively. In the NTDTgroup, Hb levels were negatively correlated with hepatic iron overload, osteoporosis, and pulmonary hypertension. The cutoff values of Hb levels to predict hepatic iron overload, osteoporosis, and pulmonary hypertension were ≤8.24, 7.16, and 7.16 g/dL, respectively, at which points the AUC were 0.923, 0.715, and 0.725, respectively. CONCLUSIONS: Lower Hb level was associated with more frequent complications in both TDT and NTDT patients. The Hb cutoff levels to predict these complications were identified.