Heparin-induced thrombocytopenia as a cause of persistent bleeding after cardiac pacemaker implantation

History and clinical findings: A cardiac pacemaker was to be implanted in a 74-year-old man, known for many years to have cardiac arrhythmias. Lown ty pe IVb, because of the onset of severe bradycardic episodes. After appropri ate preoperative preparation the patient's anticoagulant medication was cha nged over 5 days from phenprocoumon (Marcumar(R)) to heparin. the procedure and the immediate postoperative period were without complication. But two days later he had to be admitted to the intensive care unit because of card iac failure and bleeding into the operation site. Laboratory findings: One week after starting heparin the platelet count had fallen from 154 x 10(9)/l preoperatively to 92 x 10(9)/l. Haemoglobin conc entration was 8.9 g/dl, haematocrit 26.7%. The Quick value of 51%, partial thromboplastin time of 54.1 s, thrombin time of 17.6 s and plasma antithrom bin level of 61% provided no further diagnostic pointers. An HIPA test and a PF4/heparin immunoassay, performed as heparin-induced type II thrombocyto penia was suspected, subsequently confirmed the diagnosis. Treatment and course: After the cardiac status had stabilized the operative wound was explored, but no bleeding site found. Other causes having been e xcluded (liver failure, disseminated intravascular coagulopathy, septicemia , dilution thrombocytopenia), heparin was discontinued 2 days later. Recomb inant hirudin infusion, 0.025 mg/kg per hour, was begun. After 4 days the p latelet count had improved, the other clotting parameters were stable withi n the therapeutic anticoagulant range and the diffuse bleeding had stopped. Conclusion: When changing from phenprocoumon to heparin preoperatively one must be aware of the rare risk of acquired heparin-induced thrombocytopenia . Intravenous recombinant hirudin proved to be a safe treatment until oral anticoagulation had been established, quickly normalizing the platelet coun t.