Craniotomy with prosthetic heart valves: a clinical dilemma.

The authors report two cases of spontaneous intracranial haemorrhage after elective craniotomy for resection of cerebral tumour. Both patients had mechanical aortic valve prostheses and were on regular warfarin therapy. In both cases, warfarin therapy was discontinued 5 days prior to surgery and unfractionated heparin administered intravenously until 12 h before surgery. Both patients were re-anticoagulated with subcutaneous low molecular weight heparin within the first week postcraniotomy-both developed life-threatening intracranial haemorrhage requiring urgent evacuation. The authors emphasize the risk of re-anticoagulation without postoperative imaging and the disadvantages of therapeutic dose, low molecular weight heparin in the postoperative period.