Nine years ago, I had an episode of chest pain that unexpectedly changed the course of my life.
At first, the concern was a possible pulmonary embolism. I had blood tests, was started on anticoagulant injections, and came back a few days later for a CT scan. The scan did not show a clot on my lung, but it did find something else: a 5.2 cm aneurysm at the root of my aorta.
Further tests showed that I had a functionally bicuspid aortic valve. Eight weeks later, I was admitted to James Cook University Hospital for open-heart surgery: an aortic valve replacement and repair of the aneurysm with a Dacron sleeve.
Because I now had a mechanical aortic valve, I was started on warfarin and told I would need to take it for the rest of my life.
I went home just under a week after surgery on 5 mg of warfarin daily, with regular INR checks from the anticoagulation team. Over the first week at home, I became more and more breathless. I was told some breathlessness was normal after surgery, but it kept getting worse. Eventually, I could barely walk 100 yards without stopping to catch my breath.
An INR check showed my INR was 9.7.
I was told to stop taking warfarin and return for daily INR checks. Shortly afterwards, I called into the A&E department where I worked at the time, just to say hello and show my colleagues I was still alive. By the time I arrived, I was so breathless I could barely speak. The consultant on duty took one look at me, put me in a room, and admitted me.
An echocardiogram showed fluid around my heart, most likely blood. I was transferred back to James Cook and monitored closely. Over the next couple of days, I deteriorated further until I could not breathe properly even sitting up in bed. I was taken back to theatre, where they drained 800 ml of blood from around my heart, with more drained afterwards on the ward.
After another week in hospital, I was discharged home again. Thankfully, I have been fine since.
That experience made warfarin and INR monitoring feel very real, very quickly.
Like many people on warfarin, I was given the yellow anticoagulation book. It works, but I never liked having to carry it around or rely on paper for something that had become such an important part of my life. I looked for an app that could help me track my INR, warfarin doses, reminders and notes, but nothing felt quite right. Some apps did not feel native to the iPhone. Others were missing features I wanted. I kept hoping Apple might eventually add proper INR and warfarin tracking to the Health app, but it never came.
So I decided to build it myself.
INR Mate is the app I wanted as both a patient and a clinician: clear, private, practical, and designed specifically for people who take warfarin.
It helps you record INR results, log warfarin doses, set reminders, review trends and export information for appointments. It does not give dosing advice, diagnose, treat, or replace your anticoagulation team.
Warfarin dosing decisions should always be made with your healthcare team.
INR Mate exists for a simple reason: I wanted people taking warfarin to have a better way to keep clear, useful records without relying on paper diaries, scattered notes or generic medication trackers.