Point-of-care monitoring of international normalized ratio among patients with mechanical valves in Jos, North-Central, Nigeria

Abstract

Background: Rheumatic heart disease is the leading cause of acquired valvular heart disease in low- and middle-income countries and sometimes requires mechanical valve replacement. Postsurgical management of these patients is vital and includes lifelong anticoagulation with close monitoring. This study aims to report our experience with anticoagulation monitoring of patients with mechanical heart valves using a handheld portable device. Patients and Methods: This retrospective review involved 12 patients that were enrolled in the anticoagulation clinic (AC) of a local nongovernmental organization, at different times between 2003 and 2012. Patients' sociodemographic variables, international normalized ratio (INR) assay results, and clinical status were routinely entered into a register and were retrieved for the present review. Results: The 12 patients comprised three males and nine females and were resident between 3.7 and 300 km from the AC. Their age ranged from 7 to 26 years (mean 14.1 ± 3.3 years, median 13 years) at the time of enrollment into the AC. Seven hundred and ninety-four INR assays were done during the period under review (mean 12.2 ± 5.4 INR assays per patient per year). Of the 794 assays, 38.5% were within target (INR levels between 2.5 and 3.5 or between 2.0 and 3.0 for patients with mechanical valves at the mitral and aortic positions, respectively) 35.7% were below the target range, and 25.7% were above the target range. Conclusion: Our experience with point-of-care INR testing in a clinic setting suggests that adopting this approach could improve the quality of anticoagulation monitoring by increasing patients' access to the device, the frequency of assays per patient, and, ultimately, the number of within-target INR assays.