ORCID Profile
0000-0003-1989-959X
Current Organisations
The Alfred Hospital
,
Royal Australasian College of Physicians
,
Royal College of Pathologists of Australasia
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Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 22-03-2022
Publisher: Wiley
Date: 09-08-2022
DOI: 10.1111/IMJ.15557
Abstract: Peripherally inserted central catheter (PICC) thrombosis is common. To explore the prevalence of symptomatic PICC thrombosis and pulmonary embolism (PE)/deep vein thrombosis (DVT) in cancer and non‐cancer cohorts. In active cancer, we assessed the Khorana risk score (KRS) and Michigan risk score (MRS) for predicting PICC thrombosis and modifications to improve discriminative accuracy. We reviewed consecutive cancer patients receiving chemotherapy through a PICC inserted April 2017 to July 2018. For each case, we identified a contemporaneous non‐cancer control. Among 147 cancer patients, median age 64 years, PICC duration 70 days (range, 2–452), 7% developed PICC thrombosis (95% confidence interval (CI) 3.6–12.2) and 4% (95% CI 2–9) PE/DVT. Among 147 controls, median age 68 years, PICC duration 18.3 days (range, 0.5–210), 0.7% (95% CI 0–4) developed PICC thrombosis and 2% (95% CI 0.4–6) PE/DVT. In our cancer cohort, no KRS 1 patients developed PICC thrombosis (95% CI 0–11) compared with 9% (95% CI 5–16) in KRS ≥ 1 ( P = 0.12). PICC thrombosis occurred in 4.7% (95% CI 1.5–11.7) MRS ≤ 3 compared with 10.9% (95% CI 4.1–22.2) MRS 3 ( P = 0.32). The addition of thrombocytosis, a variable from KRS, to MRS (modified MRS (mMRS)) improved discriminative value for PICC thrombosis (c‐statistic MRS 0.63 (95% CI 0.44–0.82), mMRS 0.72 (95% CI 0.58–0.85)). PICC thrombosis occurred in 1.4% (95% CI 0–8.3) mMRS ≤ 3 and 11.8% (95% CI 6.1–21.2) mMRS 3 ( P = 0.02). More patients were categorised as low risk using mMRS ≤ 3 (47%) than KRS 1 (22%). Cancer patients had longer PICC durations and higher PICC thrombosis rates than those without (7% vs 0.7%). mMRS more accurately classified low PICC thrombosis risk than KRS (47% vs 22%). Prospective validation of mMRS is warranted.
Publisher: American Society of Hematology
Date: 24-05-2019
DOI: 10.1182/BLOODADVANCES.2019000092
Abstract: Tranexamic acid (TXA) is an antifibrinolytic agent that blocks plasmin formation. Because plasmin is known to promote inflammatory and immunosuppressive responses, we explored the possibility that plasmin-mediated immunosuppression in patients undergoing cardiac surgery can be directly reversed by TXA and decrease postoperative infection rates. The modulatory effect of TXA on inflammatory cytokine levels and on innate immune cell activation were evaluated with multiplex enzyme-linked immunosorbent assay and flow cytometry, respectively. Postoperative infection rates were determined in patients undergoing cardiac surgery and randomized to TXA (ACTRN12605000557639 www.anzca.edu.au). We demonstrate that TXA-mediated plasmin blockade modulates the immune system and reduces surgery-induced immunosuppression in patients following cardiac surgery. TXA enhanced the expression of immune-activating markers while reducing the expression of immunosuppressive markers on multiple myeloid and lymphoid cell populations in peripheral blood. TXA administration significantly reduced postoperative infection rates, despite the fact that patients were being administered prophylactic antibiotics. This effect was independent of the effect of TXA at reducing blood loss. TXA was also shown to exert an immune-modulatory effect in healthy volunteers, further supporting the fibrin-independent effect of TXA on immune function and indicating that baseline plasmin levels contribute to the regulation of the immune system in the absence of any comorbidity or surgical trauma. Finally, the capacity of TXA to reduce infection rates, modulate the innate immune cell profile, and generate an antifibrinolytic effect overall was markedly reduced in patients with diabetes, demonstrating for the first time that the diabetic condition renders patients partially refractory to TXA.
Publisher: Wiley
Date: 16-08-2021
DOI: 10.1111/BJH.17750
Publisher: Wiley
Date: 2023
DOI: 10.1111/IMJ.15983
Abstract: The Health Roundtable, a national benchmarking body, identified our institution as an outlier with a high number of postoperative venous thromboembolism (VTE) events. We performed a retrospective study to determine the accuracy of hospital coding for the incidence and severity of postoperative VTE. Of 232 patients identified from ICD‐10 coding, 52 (22.4%) were incorrectly coded. Approximately one third ( n = 68) of all VTE were asymptomatic, diagnosed incidentally. Thus, coding data are inherently flawed with inaccuracy and overrepresent the true number of VTE events, with a substantial proportion of limited clinical relevance.
Publisher: Wiley
Date: 11-2022
DOI: 10.1111/IMJ.15951
Abstract: Cannula provoked upper extremity superficial vein thrombophlebitis (UESVT) is common. Retrospective audit of 93 consecutive patients, 51% male, median age 57 years (range 20-91), with symptomatic UESVT revealed varied management including symptomatic management (37%), prophylactic (37%) and higher dose anticoagulation (27%). There was 2% (95% confidence interval (CI) 0-7.6) thrombus extension and 1% (95% CI 0-5.9) major bleeding, both limited to cancer. We argue anticoagulation is unnecessary in most UESVT patients.
Publisher: AMPCo
Date: 04-07-2019
DOI: 10.5694/MJA2.50262
Abstract: Antiphospholipid syndrome is characterised by recurrent thrombosis (arterial, venous, microvascular) and/or pregnancy complications in the presence of persistent antiphospholipid antibodies (lupus anticoagulant, anti-β2-glycoprotein 1 and anticardiolipin). It can be a primary disease or associated with another autoimmune disease (especially systemic lupus erythematosis). Testing for antiphospholipid antibodies should be considered in patients < 50 years of age with unprovoked venous or arterial thromboembolism, thrombosis at unusual sites or pregnancy complications. The mainstay of treatment is antithrombotic therapy and recommendations vary based on arterial, venous or pregnancy complications. If associated with systemic lupus erythematosis, hydroxychloroquine is recommended both as primary and secondary prophylaxis. Antithrombotic treatment is gold standard and effective.
Publisher: Wiley
Date: 21-04-2022
DOI: 10.1111/IMJ.15783
Abstract: Vaccine‐induced thrombotic thrombocytopenia (VITT) is a rare, but serious, syndrome characterised by thrombocytopenia, thrombosis, a markedly raised D‐dimer and the presence of anti‐platelet factor‐4 (PF4) antibodies following COVID‐19 adenovirus vector vaccination. VITT occurs at a rate of approximately 2 per 100 000 first‐dose vaccinations and appears exceedingly rare following second doses. Our current understanding of VITT pathogenesis is based on the observations that patients with VITT have antibodies that bind to PF4 and have the ability to form immune complexes that induce potent platelet activation. However, the precise mechanisms that lead to pathogenic VITT antibody development remain a source of active investigation. Thrombosis in VITT can manifest in any vascular bed and affect multiple sites simultaneously. While there is a predilection for splanchnic and cerebral venous sinus thrombosis, VITT also commonly presents with deep vein thrombosis and pulmonary embolism. Pillars of management include anticoagulation with a non‐heparin anticoagulant, intravenous immunoglobulin and ‘rescue’ therapies, such as plasma exchange for severe cases. VITT can be associated with a high mortality rate and significant morbidity, but awareness and optimal therapy have significantly improved outcomes in Australia. A number of questions remain unanswered, including why VITT is so rare, reasons for the predilection for thrombosis in unusual sites, how long pathological antibodies persist, and the optimal duration of anticoagulation. This review will provide an overview of the presentation, diagnostic workup and management strategies for patients with VITT.
Publisher: Wiley
Date: 10-02-2019
DOI: 10.5694/MJA2.50004
Abstract: Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is the third most common cardiovascular disease and, globally, more than an estimated 10 million people have it yearly. It is a chronic and recurrent disease. The symptoms of VTE are non-specific and the diagnosis should actively be sought once considered. The mainstay of VTE treatment is anticoagulation, with few patients requiring additional intervention. A working group of experts in the area recently completed an evidence-based guideline for the diagnosis and management of DVT and PE on behalf of the Thrombosis and Haemostasis Society of Australia and New Zealand (www.thanz.org.au/resources/thanz-guidelines). The diagnosis of VTE should be established with imaging it may be excluded by the use of clinical prediction rules combined with D-dimer testing. Proximal DVT or PE caused by a major surgery or trauma that is no longer present should be treated with anticoagulant therapy for 3 months. Proximal DVT or PE that is unprovoked or associated with a transient risk factor (non-surgical) should be treated with anticoagulant therapy for 3-6 months. Proximal DVT or PE that is recurrent (two or more) and provoked by active cancer or antiphospholipid syndrome should receive extended anticoagulation. Distal DVT caused by a major provoking factor that is no longer present should be treated with anticoagulant therapy for 6 weeks. For patients continuing with extended anticoagulant therapy, either therapeutic or low dose direct oral anticoagulants can be prescribed and is preferred over warfarin in the absence of contraindications. Routine thrombophilia testing is not indicated. Thrombolysis or a suitable alternative is indicated for massive (haemodynamically unstable) PE. Most patients with acute VTE should be treated with a factor Xa inhibitor and be assessed for extended anticoagulation.
Publisher: Wiley
Date: 19-08-2022
DOI: 10.1111/EJH.13842
Abstract: Idiopathic upper extremity deep vein thrombosis (UEDVT) management is controversial and ranges from anticoagulation alone to the addition of further interventions such as thrombolysis and decompressive surgery. The objective of this systematic review was to assess the effects of anticoagulation alone compared to anticoagulation with additional interventions such as thrombolysis or decompressive surgery on the incidence of recurrent UEDVT and post‐thrombotic syndrome (PTS) in patients with idiopathic UEDVT (including those associated with the oral contraceptive pill). A systematic search was conducted for studies which focused on acute UEDVT treatment defined as therapies starting within 4 weeks of symptom onset. We limited studies to those that recruited 10 or more subjects and involved at least 6 weeks to 12 months anticoagulation alone or together with additional interventions with at least 6‐month follow‐up. Primary outcomes were symptomatic recurrent radiologically confirmed UEDVT and PTS. Secondary outcomes were symptomatic venous thromboembolism, bleeding and mortality. We found seven studies which reported recurrent UEDVT rates and five that reported PTS rates. All studies were retrospective or cross‐sectional. None compared anticoagulation alone to anticoagulation with additional intervention. Study heterogeneity precluded meta‐analysis and risk of bias was moderate to serious. Recurrent UEDVT occurred in 0% to 12% post‐anticoagulation alone and 0% to 23% post‐additional interventions. PTS rates varied from 4% to 32% without severe PTS. Only limited studies reported on our secondary outcomes. There is limited evidence behind idiopathic UEDVT management. Prospective comparative studies in this area are essential.
Publisher: AMPCo
Date: 11-06-2021
DOI: 10.5694/MJA2.51135
Publisher: Wiley
Date: 24-06-2022
Abstract: The aim of the present study was to describe the burden of patients presenting to the ED with symptoms occurring after receiving a COVID‐19 vaccination. This was a retrospective cohort study performed over a 4‐month period across two EDs. Participants were eligible for inclusion if it was documented in the ED triage record that their ED attendance was associated with the receipt of a COVID‐19 vaccination. Data regarding the type of vaccine (Comirnaty or ChAdOx1) were subsequently extracted from their electronic medical record. Primary outcome was ED length of stay (LOS) and secondary outcomes included requests for imaging and ED disposition destination. During the study period of 22 February 2021 to 21 June 2021, 632 patients were identified for inclusion in the present study, of which 543 (85.9%) had received the ChAdOx1 vaccination. The highest proportion of COVID‐19 vaccine‐related attendances occurred in June 2021 and accounted for 21 (8%) of 262 total daily ED attendances. Patients who had an ED presentation related to ChAdOx1 had a longer median ED LOS (253 vs 180 min, P 0.001) compared to Comirnaty and a higher proportion had haematology tests and imaging requested in the ED. Most patients ( n = 588, 88.8%) were discharged home from the ED. There was a notable proportion of ED attendances related to recent COVID‐19 vaccination administration, many of which were associated with lengthy ED stays and had multiple investigations. In the majority of cases, the patients were able to be discharged home from the ED.
Publisher: Wiley
Date: 06-09-2021
DOI: 10.5694/MJA2.51229
Publisher: Elsevier BV
Date: 12-2022
DOI: 10.1111/JTH.15881
Abstract: Vaccine-induced thrombotic thrombocytopenia (VITT) is a rare complication of adenovirus-based vaccines aimed to prevent and minimize COVID-19 and related pathophysiology. To describe patterns of testing for anti-platelet factor 4 (PF4) antibodies using various ELISA assays in a large Australian cohort and comparative functional platelet activation assays in a subset. Asserachrom HPIA IgG ELISA was performed in 1284 patients over a period of 12 months, supplemented in select cohorts by comparative ELISA using three other methods (n = 78-179), three different functional assays (flow cytometry, serotonin release assay, and/or Multiplate n = 476), and rapid immunological chemiluminescence anti-PF4 assay (n = 460), in a multicenter study. For first episode presentations, 190/1284 (14.8%) ELISA tests were positive. Conversely, most (445/460 96.7%) chemiluminescence anti-PF4 test results were negative. All functional assays showed associations of higher median ELISA optical density with functional positivity and with high rates of ELISA positivity (64.0% to 85.2%). Data also identified functional positivity in 14.8%-36.0% of ELISA negative s les, suggesting false negative VITT by HPIA IgG ELISA in upward of one third of assessable cases. To our knowledge, this is the largest multicenter evaluation of anti-PF4 testing for investigation of VITT. Discrepancies in test results (ELISA vs. ELISA or ELISA vs. functional assay) in some patients highlighted limitations in relying on single methods (ELISA and functional) for PF4 antibody detection in VITT, and also highlights the variability in phenotypic test presentation and pathomechanism of VITT.
Publisher: Wiley
Date: 15-08-2023
DOI: 10.1111/BJH.19039
Abstract: Congenital fibrinogen disorders or CFDs are heterogenous, both in clinical manifestation and array of culprit molecular lesions. Correlations between phenotype and genotype remain poorly defined. This review examines the genetic landscape discovered to date for this rare condition. The question of a possible oligogenic model of inheritance influencing phenotypic heterogeneity is raised, with discussion of the benefits and challenges of sequencing technology used to enhance discovery in this space. Considerable work lies ahead in order to achieve diagnostic and prognostic precision and subsequently provide targeted management to this complex cohort of patients.
No related grants have been discovered for Huyen Tran.