Retrospective study of clinical settings, indications and consequences of measurement of direct oral anticoagulant plasma levels in Northern Tasmania, Australia.

BACKGROUND: Routine monitoring of direct oral anticoagulant (DOAC) levels is not recommended but may be useful in certain clinical situations. There is a knowledge gap regarding the clinical use of DOAC levels in Australian hospitals. AIMS: To evaluate the clinical settings, indications and changes to anticoagulant management associated with DOAC levels in a tertiary hospital in Northern Tasmania, Australia. METHODS: Patients with one or more DOAC levels (dabigatran, rivaroxaban or apixaban) requested between January 2017 and December 2022 were identified. Retrospective chart review was performed to evaluate the clinical settings, indications, adequacy of request information and changes to clinical management associated with the measurement of DOAC levels. RESULTS: One hundred and twenty-nine DOAC measurements (54 rivaroxaban, 66 apixaban and nine dabigatran) were performed in 98 patients between January 2017 and December 2022. Annual requests for DOAC levels increased significantly between 2017 and 2019 and remained stable between 2020 and 2021 but declined in 2022. Overall, the most common indication for a DOAC level was renal impairment, followed by bleeding and recurrent thrombosis. Approximately 25% of requests were for acute bleeding with a reversal/haemostatic agent given in 45% of patients, while 10% were prior to urgent surgery. Measurement of DOAC levels was associated with a change in management in 50% of cases. 10% of requests did not specify anticoagulant history. CONCLUSION: Trends in requests for DOAC levels have changed over time. Clinician education regarding the importance of providing specific anticoagulant history is essential. Future prospective studies investigating the clinical utility of DOAC levels in different clinical settings are needed.

Age-adjusted cut-off using the IL D-dimer HS assay to exclude pulmonary embolism in patients presenting to emergency.

BACKGROUND/AIM: The ADJUST-PE study showed that an age-adjusted D-dimer (AADD) (age years × 10 ng/mL if >50 years) combined with an unlikely pre-test probability (PTP) can increase the proportion of older patients in whom pulmonary embolism (PE) can be safely excluded, but the IL D-dimer HS assay was not assessed. To assess the ability of the IL D-dimer HS assay to exclude PE using the AADD. METHODS: Retrospective analysis of consecutive patients presenting with symptoms of acute PE to one of three Monash Health Emergency Departments (January 2013-January 2014) who had computed tomography pulmonary angiography. In the group with D-dimer, efficiency (proportion of PE excluded based on a combination of unlikely PTP and negative D-dimer) was determined using (i) current laboratory (200 ng/mL), (ii) conventional (230 ng/mL) and (iii) modified (375 ng/mL if age ≥60 years) AADD cut-offs. RESULTS: A total of 176 patients with D-dimers was included (mean age = 58.5 years; 54.0% males; 71.0% age >50 years). Prevalence of PE in the overall, unlikely and likely PTP groups, was 17.0, 13.0 and 24.6% respectively. In the unlikely PTP group (115 patients), efficiency for the current, conventional, modified and AADD cut-offs was 9.6, 24.3, 30.4 and 37.4% respectively. CONCLUSION: The absolute increase in efficiency of an AADD compared to conventional cut-off using the IL D-dimer HS assay is modest (~10%) and requires prospective validation. Modifying our cut-off to 230 ng/mL and systematic implementation of a clinical algorithm, including D-dimer testing and PTP, is likely a more important first step.

The danger of wearing an anorak.

Campaigns to reduce road traffic accidents have paid little attention to the way headgear could interfere with vision. Binocular visual field measurement was undertaken in six healthy volunteers wearing four different types of anorak. All four anoraks greatly reduced the horizontal and superior field of vision. The anorak producing the worst reduction resulted in a width of vision of 99 degrees and only 15 degrees of vision above eye level, versus 167 degrees and 52 degrees respectively without an anorak. Anorak wearers should turn their heads to look sideways before crossing the road.