The clotting test that could reshape warfarin care in egypt

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Inclusion Criteria 1. Age ≥18 years 2. Confirmed diagnosis of rheumatic heart disease (echocardiographic evidence of rheumatic valve morphology, prior history of rheumatic fever, or cardiology consultant diagnosis recorded in medical records) 3. Electrocardiographically or holter-confirmed atrial fibrillation (paroxysmal, persistent, or permanent) 4. On warfarin therapy for at least 6 consecutive months prior to enrollment with the intent to continue 5. At least 3 recorded INR values in the preceding 12 months in the center's logbook (minimum data requirement for Rosendaal TTR calculation) 6. Willingness to attend scheduled follow-up visits for 12 months and to provide written informed consent Exclusion Criteria: 1. Anticipated cardiac surgery, valvuloplasty, or cardioversion within the next 6 months 2. Pregnancy or planned pregnancy during the study period 3. Active malignancy or other life-limiting condition with expected survival \<12 months 4. Current or recent (≤12 months) use of a direct oral anticoagulant or heparin as primary anticoagulation 5. Severe hepatic impairment (Child-Pugh C) or known bleeding diathesis 6. Residence in a geographic area making 12-month follow-up participation unreasonably burdensome (as judged by the site investigator) 7. Fewer than 3 documented INR values in the preceding 12 months (insufficient data for Rosendaal TTR calculation) 6. Presence of a mechanical prosthetic heart valve (MPHV) in any position (aortic or mitral), regardless of thrombogenicity category. Patients with bioprosthetic (tissue) valves are not excluded, provided the prescribed INR target is 2.0-3.0 and all other inclusion criteria are met. Patients with mechanical prosthetic heart valves (MPHVs) are excluded from this study. With all enrolled patients having native RHD-AF, a uniform INR therapeutic target of 2.0-3.0 applies to every participant, eliminating patient-specific target adjustments and rendering valve type non-informative as an analytical predictor. The overwhelming majority of warfarin-treated RHD-AF patients at Assiut University Heart Hospital have rheumatic mitral stenosis as the dominant lesion, making this a clinically homogeneous and internally valid study population. Patients with bioprosthetic (tissue) valves on warfarin for AF are not excluded, provided their prescribed INR target is 2.0-3.0 and all other inclusion criteria are satisfied. \-