Time in Therapeutic Range With Vitamin K Antagonists in Congenital Heart Disease: A Multicentre Study

Utility of a pharmacist-managed Anticoagulation Program in patients with congenital heart disease

BACKGROUND

Warfarin remains the preferred anticoagulant for many patients with CHD. The complexity of management led our centre to shift from a nurse-physician-managed model with many providers to a pharmacist-managed model with a centralized anticoagulation team. We aim to describe the patient cohort managed by our Anticoagulation Program and evaluate the impact of implementation of this consistent, pharmacist-managed model on time in therapeutic range, an evidence-based marker for clinical outcomes.

METHODS

A single-centre retrospective cohort study was conducted to evaluate the impact of the transition to a pharmacist-managed model to improve anticoagulation management at a tertiary pediatric heart centre. The percent time in therapeutic range for a cohort managed by both models was compared using a paired t-test. Patient characteristics and time in therapeutic range of the program were also described.

RESULTS

After implementing the pharmacist-managed model, the time in therapeutic range for a cohort of 58 patients increased from 65.7 to 80.2% (p < .001), and our Anticoagulation Program consistently maintained this improvement from 2013 to 2022. The cohort of patients managed by the Anticoagulation Program in 2022 included 119 patients with a median age of 24 years (range 19 months-69 years) with the most common indication for warfarin being mechanical valve replacement (n = 81, 68%).

CONCLUSIONS

Through a practice change incorporating a collaborative, centralized, pharmacist-managed model, this cohort of CHD patients on warfarin had a fifteen percent increase in time in therapeutic range, which was sustained for nine years.