gms | German Medical Science

Objective: The term venous thrombembolism subsumes deep venous thrombosis (DVT) and pulmonary embolism (PE). The incidence of clinically silent DVT after craniotomy was reported to be up to 45%; symptomatic DVT occurs in up to 7% of the patients. PE is observed in 5% of the affected patients. D-dimer levels of more than 0.5 mg/l indicate venous thrombembolism with a sensitivity of 99.4% and a specificity of 38.2% in non-surgical patients. However, the test is believed to be unreliable in patients recently operated on.

Methods: In 70 patients scheduled for elective craniotomy for various intracranial pathologies, Doppler ultrasonography of the legs was performed pre- and postoperatively in order to check for DVT. D-Dimer levels were determined preoperatively and on the third, seventh and tenth day after surgery. Statistical analysis was carried out in order to define a (potentially higher) threshold of the D-Dimer level for neurosurgical patients with sensitivity and specificity comparable to a non-surgical collective.

Results: Postoperative DVT was observed in 40% of the patients. On the third day after surgery, D-Dimer levels of more than 2.0 mg/l indicated venous thromboembolism with a sensitivity of 92% and a specificity of 76%. In all patients with pulmonary embolism in the postoperative period (n = 6), D-Dimer levels of more than 4,0 mg/l were observed.

Conclusions: D-Dimer levels will indicate venous thrombembolism in neurosurgical patients after craniotomy with high sensitivity and surprisingly servicable specificity. However, the threshold for this test in our patients is four times higher than the usual threshold applied in a non-surgical patient group. Pulmonary embolism seems to be indicated by even higher D-Dimer levels.