Alternatives to warfarin--the next generation of anticoagulants

Predictive Value of Combined Plasma D-Dimer, SCUBE1, and Right Ventricular Tei Index for the Prognosis of Elderly Patients with Acute Pulmonary Thromboembolism

Acute pulmonary thromboembolism (APTE) has become a non-negligible clinical concern due to its high mortality and complex symptoms. Early diagnosis and prognostic assessment of APTE are of great significance for the long-term benefits of patients, especially elderly patients. Elderly patients with pulmonary embolism (n = 250) who presented to our hospital from January 2018 to July 2021 were recruited into this study. In addition, 50 healthy elderly people with no history of allergies were selected as the control group. An enzyme-linked immunosorbent assay (ELISA) method was used to determine concentrations of D-dimer and signal peptide-CUB-EGF domain-containing protein-1 (SCUBE1) in their plasma. Right ventricular volume contraction time (ICT), ejection time (ET), and isovolumic relaxation time (IRT) were determined by Doppler ultrasound. Right ventricular Tei index was calculated as (ICT + IRT)/ET. High plasma D-dimer, plasma SCUBE1, and right ventricular Tei index are risk factors for poor prognosis in APTE patients after treatment. Plasma D-dimer, plasma SCUBE1, and right ventricular Tei index have predictive value for poor prognosis in APTE patients. Their combined detection (0.256*DD +0.04*SCUBE1 + 10.188*Tei) can improve the sensitivity and specificity of prediction. There is a predictive value of combined plasma D-dimer, SCUBE1, and right ventricular Tei index for the prognosis of elderly patients with APTE.

Genotype-guided dosing of warfarin through modeling and simulation

Current genotype-guided algorithms for warfarin dosing fail to deliver optimal performance in two aspects: 1) these algorithms are not able to achieve the same level of benefits in non-white populations, since they were developed based on multivariate regression analysis with mostly European/White data and did not include genetic variants found frequently in non-white populations; 2) these algorithms do not account for the dynamic dose/response relationship and were limited in their usefulness to guide dosing during the initiation phase, as the possession of variant VKORC1 and/or CYP2C9 polymorphisms has been associated with a more rapid attainment of target international normalized ratio (INR) and higher risk of over-anticoagulation even in genotype-guided patients. To address these shortcomings, we report on the novel use of a previously published kinetic/pharmacodynamic (K/PD) model to develop a warfarin dosing nomogram to be used across genotypes and ethnicities. Our approach leverages data from both ethnically diverse and European patients, while accounting for the differential dose/response behaviors due to VKORC1 and CYP2C9 genotypes. According to simulations, the utilization of our dosing nomogram could enable effective attainment of therapeutic INR within one week in both ethnically diverse and European populations, while maintaining uniform INR response profiles across genotypes. Furthermore, in silico clinical trial simulations using the K/PD model could be a feasible approach to help to further refine our dosing nomogram to be more applicable in the clinical setting and explore possible outcomes even before prospective clinical trials are initiated.

Environment-wide association study to identify factors associated with hematocrit: evidence from the Guangzhou Biobank Cohort Study

PURPOSE

In randomized controlled trials reducing high hematocrit (Hct) in patients with polycythemia vera protects against cardiovascular disease (CVD) events, whereas increasing Hct in anemia patients causes CVD events. Hct is influenced by environmental and lifestyle factors. Given limited knowledge concerning the drivers of Hct, we took an agnostic approach to identify drivers of Hct.

METHODS

We used an environment-wide association study to identify environmental and lifestyle factors associated with Hct in 20443 older Chinese adults (mean age = 62.7 years) from the Guangzhou Biobank Cohort Study. We evaluated the role of 25 nutrients, 40 environmental contaminants, two metals (only available for 10405 participants), and six lifestyle factors in relation to Hct, adjusted for sex, age, recruitment phase, and socioeconomic position.

RESULTS

In a mutually adjusted model vitamin A, serum calcium, serum magnesium, and alcohol use were associated with higher Hct, whereas physical activity was associated with lower Hct.

CONCLUSIONS

Despite the difficulty of ascertaining causality, finding both expected (vitamin A and physical inactivity) and novel factors (serum calcium, serum magnesium and alcohol use) strongly associated with Hct illustrates the utility of environment-wide association study to generate hypotheses regarding the potential contribution of modifiable exposures to CVD.

Height, its components, and coagulability among older Chinese: the Guangzhou biobank cohort study

OBJECTIVES

The causal role of some cardiovascular risk factors, such as HDL cholesterol, has been increasingly challenged and attention is returning to all elements of Virchow's triad, i.e., hypercoagulability (including viscosity) as well as endothelial function and blood flow. We examined the life course origins of coagulability.

METHODS

We used multivariable linear regression to assess whether childhood influences, proxied by height and its components, were associated with hematocrit (Hct), hemoglobin (HGB), and other hematological parameters in 28,595 older Chinese adults (mean age = 61.8 years) from the Guangzhou Biobank Cohort Study.

RESULTS

Adjusted for age, sex, and recruitment phase, leg length was negatively associated with platelets (PLT) (-0.83 × 10(9) /l per centimeter (cm), 95% confidence interval (CI) -1.01 to -0.65). Sitting height and height were positively associated with Hct (0.05% per cm, 95% CI 0.04-0.07 for sitting height; 0.02% per cm, 95% CI 0.01-0.02 for height), HGB (0.21 g/l per cm, 95% CI 0.17-0.25; 0.07 g/l per cm, 95% CI 0.04-0.09) and negatively associated with PLT (-1.2 × 10(9) /l per cm, 95% CI -1.4 to -1.0; -0.83 × 10(9) /l per cm, 95% CI -0.95 to -0.70). Further adjustment for potential confounders did little to change the estimates.

CONCLUSIONS

For the first time we provide anthropometric evidence for the different roles of prepubertal and pubertal influences in relation to Hct and HGB. Whether factors that promote leg growth but reduce growth of sitting height may help to prevent cardiovascular events, via effects on hypercoagulability or viscosity, overall or in specific subgroups, remains to be determined.

Latest developments in anticoagulant drug discovery

Thromboembolic diseases have increased in number over the past years. Oral anticoagulants impair the formation and progression of thrombotic processes and are therefore of great importance in the treatment of these diseases. Until recently, vitamin K antagonists were used to block the coagulation system. But these agents display a lot of interactions besides their narrow therapeutic range and have potential risk of hemorrhage complications. Therefore, other factors of the coagulation cascade are currently being explored as therapeutic targets for the development of novel anticoagulants. This review will provide an overview of new drugs promising more effectiveness in the treatment of arterial and venous embolism. Furthermore, pharmacodynamics and drug interactions regarding new anticoagulants will be reported.

Analysis of the projected utility of dabigatran, rivaroxaban, and apixaban and their future impact on existing Hematology and Cardiology Anticoagulation Clinics at The Johns Hopkins Hospital

The purpose of this study is to determine the percentage of patients in the Johns Hopkins Anticoagulation Clinics that are potential candidates for the new oral anticoagulants, dabigatran, rivaroxaban, and apixaban. A retrospective chart review was conducted of patients managed in the Johns Hopkins Cardiology and Hematology Anticoagulation Clinics between November 1, 2009 and October 31, 2010. Data elements collected include demographics, primary indication for anticoagulation, renal function, hepatic function, and concomitant medications. These factors were considered against product labeling guidelines and inclusion/exclusion criteria from clinical studies to derive candidacy status for each oral anticoagulant for each patient. Patients who met at least one caution or contraindication criteria were deemed "non-candidates"; potential dosage reductions of the new oral anticoagulants were not considered. Four hundred ninety-one patients participated in the study. Among participants, 63% would be dabigatran candidates, 62% rivaroxaban candidates, and 70% would be candidates for apixaban. Dabigatran use would be cautioned against in 34%, rivaroxaban in 18 %, and apixaban in 30%. Four percent had contraindications to dabigatran, whereas 21% had contraindications to rivaroxaban. More than 60% of patients in the Johns Hopkins Anticoagulation Clinics appear to be potential candidates for each of the new oral anticoagulants, assuming they are eventually approved for the same indications as warfarin. Many patients fell into the "cautioned" category, which demonstrates the complexity associated with selecting candidates for these new agents.