Warfarin Compliance after Mechanical AVR in the Pediatric Population: Case Series from a Developing Country

Background and Aim: Mechanical prosthetic heart valves exert a lifelong thromboembolic complication requiring continuous antithrombotic therapy. Vitamin K antagonist is the recommended therapy of choice along with meticulous INR monitoring to achieve and maintain an INR of 2.0 - 3.0. The study aimed to assess the compliance of anticoagulant therapy in pediatric patients after AVR and to highlight the challenges faced during follow-ups. Methods: A retrospective study was conducted at NICVD Hospital in Kara-chi, Pakistan for a time frame of 2 years from 2020-2021 where 7 patients were selected. Data were collected using hospital medical records and then validated through a phone call mediated structured questionnaire-based in-terview. Results: 2 out of 7 patients in the case series were compliant to regular follow-ups and had their INR in the desired range owing to their higher education status and access to INR clinic for regular follow-up in urban set-ting. Younger patients in the case series were non-compliant. 4 out of 7 patients who were on dual anti-coagulant regimens including warfarin and aspirin were either closer or within the range than compared to those on single drug regimen. Conclusion: Compliance was observed in patients who had fa-vorable demographics and higher education. Multiple recent trials including PROACT and PROACT XA are underway to develop novel treatment options apart from warfarin after mechanical aortic valve replacement. Home-based INR testing kits provide easy access to regular testing in remote areas. Mul-ti-center studies are required for in-depth analysis regarding reasons of non-compliance in pediatric population.