MRCP2-0792

MRCP2-0792

A 50-year-old woman presents to the emergency department with shortness of breath. She has no significant past medical history and does not have any regular medications. She smokes ten cigarettes daily and lives alone.

Her observations are heart rate 110 beats per minute, blood pressure 120/88 mmHg, respiratory rate 18/minute, oxygen saturations 97% on 4L of oxygen and temperature 37ºC.

Clinical examination is unremarkable.

Blood tests:

Hb 138 g/L Male: (135-180)
Female: (115 – 160)
Platelets 180 * 109/L (150 – 400)
WBC 5.2 * 109/L (4.0 – 11.0)
Na+ 138 mmol/L (135 – 145)
K+ 4.2 mmol/L (3.5 – 5.0)
Urea 4.2 mmol/L (2.0 – 7.0)
Creatinine 88 µmol/L (55 – 120)
CRP 4 mg/L (< 5)
D-dimer 2000 ng/mL (<250)
Trop 8 ng/L (<15) A chest x-ray is normal. A CTPA demonstrates a large saddle embolus. There is no CT or echocardiographic evidence of right heart strain. She is commenced on a heparin infusion. She successfully manages to wean oxygen by day 5 of treatment and has some repeat blood tests prior to a switch to an oral anticoagulant. Blood tests: Hb 136 g/L Male: (135-180)
Female: (115 – 160)
Platelets 32 * 109/L (150 – 400)
WBC 4.6 * 109/L (4.0 – 11.0)

What is the most appropriate medication to switch to from the heparin infusion, given the likely diagnosis?