Introduction
In 2021 vaccine induced thrombocytopenia and thrombosis (VITT) emerged as an adverse event following COVID-19 vaccination. VITT is rare; nevertheless, it can lead to catastrophic thrombosis and secondary haemorrhage with high mortality.1 Studies show that patients with VITT have thrombocytopenia at presentation and subsequent coagulation abnormalities on available assays.2 At our district general hospital (DGH), patients with suspected VITT but normal platelet counts were found to have had further VITT investigations such as D-dimer, fibrinogen and in some cases, neuroimaging. Unnecessary diagnostic tests have a significant financial burden on healthcare.
Methods
We conducted a retrospective analysis of adult patients (>18 years old) presenting to the emergency department (ED) with acute headache following administration of at least one COVID-19 vaccination. We audited against standards published by the Royal College of Physicians and Royal College of Emergency medicine on management of suspected VITT in April 2021 and then re-audited against updated guidance published in May 2021 to close the loop.3
The audit period included patients presenting to the emergency department (ED) between 1 February 2021 and 31 August 2021. An anonymised electronic reporting form was developed to capture the following data: triage presentation, discharge destination, brand of vaccine, days since vaccination, platelet count, D-dimer, fibrinogen and neuroimaging.
Results
176 patients were included in the audit. 36 patients presented before formal guidance was issued. Seventy-two patients were included in audit cycle 1 and 68 patients were included in cycle 2. There was one case of VITT in a patient with thrombocytopenia. The median day of presentation to ED post vaccine dose was 7 days in cycle 1 and double that (14 days) in cycle 2. 67% of patients presented in the window for suspected VITT in the first cycle and 81% presented during the updated interval post-vaccine in cycle 2. In cycle 1, 2.8% of patients were thrombocytopenic; nevertheless, 37% and 31% of patients had a D-Dimer and fibrinogen sent respectively. In cycle 2 no patients were thrombocytopenic; nevertheless, 32% had a D-Dimer sent and 16% had a fibrinogen assay added. 25% of patients in cycle 1 had neuroimaging done with a normal platelet count and this increased to 40% in cycle 2.
Conclusion
VITT is a new occurrence following the roll-out of the COVID-19 vaccination program and guidance was only established in April 2021. Our data demonstrated that there were no cases of VITT with a platelet count of >150 × 109/L. Our data suggest we can be confident in the parameters set in national guidance. Our data also reflects current literature demonstrating that VITT is rare; nevertheless, when associated with significant clotting, abnormalities can be fatal.2
This audit shows that in the investigation of VITT at our DGH, that while the triaging of patients to a suspected diagnosis is high there is a poor adherence to subsequent laboratory and radiological guidance. Reasons for this are multifactorial. Nevertheless, requesting unnecessary blood tests and neuroimaging has financial implications.
- © Royal College of Physicians 2022. All rights reserved.
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