FRCPath Haem Part 1 MCQs-Haemostasis 466

A 72-year-old man is admitted with septic shock complicated by acute kidney injury. Five days after receiving unfractionated heparin, his platelet count falls from 290 × 10⁹/L to 68 × 10⁹/L, and he develops a new femoral vein thrombosis. The 4Ts score is 7, and argatroban is commenced while awaiting immunological confirmation of heparin-induced thrombocytopenia (HIT).

His weight is 90 kg, and he has Child-Pugh B cirrhosis. Baseline coagulation tests are normal.

Argatroban is prepared according to the Leeds protocol and started appropriately.

Four hours later, his APTT ratio is 3.6 (APTT 108 seconds).

According to the Argatroban guideline, which of the following is the MOST appropriate next management step?

A. Continue the infusion unchanged and repeat the APTT in 24 hours.

B. Reduce the infusion rate by 50% immediately and repeat the APTT in 2 hours.

C. Stop the infusion until the APTT returns to the therapeutic range, then restart at half the previous infusion rate, and repeat the APTT 4 hours later.

D. Stop argatroban and commence intravenous unfractionated heparin because the APTT is excessively prolonged.

E. Measure an argatroban plasma concentration to determine whether dose adjustment is required before altering the infusion.