Delayed-Onset Heparin-Induced Thrombocytopenia Following Aortic Valve Replacement

Yasuo Kondo＊	Noriyuki Takashima＊	Tomoaki Suzuki＊＊
Tohru Asai＊＊

（Division of Cardiovascular Surgery, Koto Memorial Hospital＊, Higashiomi, Japan, and Division of Cardiovascular Surgery, Shiga University of Medical Science＊＊, Otsu, Japan）

Some 50% of patients who undergo cardiac surgery will have heparin-induced thrombocytopenia（HIT）antibodies, only 1% will develop typical clinical HIT. Especially delayed-onset HIT is not well-known and extremely rare. A 83-year-old man underwent aortic valve replacement（AVR）with a bioprosthetic valve（Mitroflow 21mm）and pulmonary vein isolation（PVI). Intravenous unfractionated heparin（8,000I.U./day）was administered for 5 days after surgery. He had a good recovery and was discharged to home with a platelet count of 100,600/μl on POD 15 on warfarin. On POD 18, he was readmitted to our hospital due to cerebral infarction with hemiparesis. As MRI revealed a multiple left hemispheric infarction, the presence of cardiogenic cerebral infarction was suspected. Continuous intravenous administration of unfractionated heparin（15,000I.U./day）was started. On POD 24, the platelet count fell to 27,000/μl, and a contrast CT scan revealed a giant thrombus in the aortic arch. He was found to have HIT antibodies, supporting a diagnosis of HIT. After cessation of heparin therapy and administration of vitamin K antagonist, argatroban was administered. He recovered neurologically and was discharged on POD 58. He remains well at 3 years follow up. If a patient has an unexplained and severe thrombocytopenia after cardiovascular surgery, delayed-onset HIT should be taken into consideration.

 

Jpn. J. Cardiovasc. Surg. 47:113-117（2018）

Keywords：delayed-onset;HIT;argatroban;thrombocytopenia