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INR Testing Frequency Mechanical Valve — EECC MCQ

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EasyValvular Heart DiseaseINR Testing Frequency Mechanical ValveEECC

A 60-year-old man with a mechanical mitral valve on warfarin (target INR 3.0) asks about point-of-care INR testing. He has been testing at home with a CoaguChek device and achieving excellent TTR (82%). What is the recommended frequency of INR testing for mechanical valve patients?

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Correct answer: B — For patients self-monitoring INR, testing every 1-2 weeks is recommended — more frequent than clinic-based testing (typically every 4-6 weeks), which is one reason home monitoring achieves better TTR and reduces thromboembolic events

INR monitoring frequency per the 2025 ESC VHD Guidelines: (1) clinic-based testing: typically every 4-6 weeks when stable (more frequently during initiation, dose changes, or interacting medications); (2) home self-monitoring (PSM/PSA): every 1-2 weeks — the more frequent testing enables earlier detection of out-of-range values and faster dose adjustments, explaining the superior TTR and improved outcomes seen in meta-analyses. This patient's TTR of 82% is excellent (>70% is the goal; >75% is considered very well-controlled). Home monitoring is particularly valuable for: (1) mechanical valve patients (strict INR targets with narrow therapeutic windows); (2) patients in rural areas/limited clinic access; (3) motivated patients who prefer self-management; (4) patients with labile INR on clinic-based testing. Training, regular quality control of the device, and access to support (HCP contact for dose decisions if self-monitoring only) are essential.

Reference: ESC/EACTS (2025): VHD Guidelines