Evaluation of self-testing INR in a French GUCH population with mechanical valve

Background The Coaguchek INRange® is a self testing meter to measure the INR, that is reimbursed by French Social Security since August 2017 for patients with mechanical valve. Methods We evaluated the use of this anticoagulation method in a French population of GUCH (Grown-Up patients with Congenital Heart Disease) with mechanical valve. Results Since September 2018, 52 patients of 37 ± 11 years old were asked to attend a training of 2 hours on anticoagulation and Coaguchek INRange® use, provided by specialized nurses, before getting home with the machine. Patients had to attend a 3 months re-evaluation appointment. Twenty-nine (56%) patients had an aortic mechanical valve, 12 (23%) a mitral one, 8 (15%) a double aortic and mitral one, 2 (4%) a double aortic and pulmonary one and 1 (2%) a tricuspid one. 28 patients (54%) had a mechanical valve for ≥ 10 years (group 1). In group 1, patients were older (41 ± 10 years old vs. 34 ± 10, P = 0.01). Fluindione was the preferred oral anticogulant (30 patients, 57%), and more frequent in group 1 (18 patients, 64%). In group 1, 61% of patients usually managed themselves dosage adjustment whereas in the other group, 52% of patients referred to their doctor. Thirty-one patients (62%) had a higher target of INR than recommended in the last European guidelines. Concerning follow-up, 26 patients (50%) did not attend the 3 months appointment and had to be rescheduled or contacted by phone. Eight patients (15%) did not use the device at 3 months: 5 for variation > 15% compared to laboratory plasma technique and 3 for not trusting the new device. INR at 3 months was obtained in only 40 (77%) patients, and was in the attended target in 62% of cases. Conclusion GUCH patients with mechanical valves, especially when present for ≥ 10 years, seem to validate Coaguchek, even though evaluation is hard since a great proportion of them did not attend follow-up appointment, stick to their old INR target and did not use the device as often as recommended.