Post-Discharge Antithrombotic Therapy Following Transcatheter Aortic Valve Implantation in Australian Patients.

BACKGROUND

Guidelines recommend antithrombotic therapy for patients following transcatheter aortic valve implantation (TAVI) to reduce the risk of ischaemic events and bioprosthetic valve thrombosis.

OBJECTIVE

To describe antithrombotic dispensing within 30 days of discharge for Australian patients receiving TAVI.

METHODS

We performed a state-wide retrospective cohort study using linked hospital and medicines dispensing data from January 2013 to December 2018 for all patients receiving TAVI in New South Wales, Australia. We identified patients dispensed oral anticoagulants (vitamin K antagonists [warfarin], direct oral anticoagulants [DOACs]) or clopidogrel within 30 days of discharge. We examined demographic and clinical predictors of antithrombotic dispensing.

RESULTS

Our cohort comprised 1,217 patients who underwent TAVI; median age was 84 years and 707 (58.1%) were male. Of these, 808 patients (66.4%) had an antithrombotic dispensed within 30 days of hospital discharge. One-third (33.7%) of these patients were dispensed an anticoagulant (16.1% warfarin; 17.6% DOACs) and two-thirds (66.3%) were dispensed clopidogrel. Patients undergoing TAVI were more likely to be dispensed an antithrombotic medicine within 30-days of hospital discharge if they had been dispensed antithrombotic medicines (RR 1.07; 95% CI 1.03-1.11) or angiotensin-converting-enzyme inhibitors/angiotensin II receptor blockers (RR 1.04; 95% CI 1.00-1.07) in the 6 months prior to admission. Patients with a history of haemorrhage were less likely to be dispensed an antithrombotic medicine within 30 days of hospital discharge (RR 0.93; 95% CI 0.89-0.98).

CONCLUSIONS

We observed gaps in best evidence pharmacotherapy for patients post-TAVI, with almost one third of patients not receiving antithrombotic medicines post-discharge. Further research is needed to quantify the impact of emerging clinical guidelines recommending single antiplatelet therapy, on adherence to best-practice care.