DOI: 10.1097/ANA.0000000000000047
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Issn Print: 0898-4921
Publication Date: 2014/04/01
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Excerpt
The occurrence of venous thromboembolism (VTE) in a neurosurgical patient can be a critical complication. Although the term includes both deep venous thrombosis (DVT) and pulmonary embolism (PE), the literature would suggest that a PE has proven lethal in up to 50% of affected neurosurgical patients. Recently, researchers from the Departments of Neurosurgery and Angiology at the University of Halle, Halle, Germany, attempted to examine D-dimer plasma levels as a marker for VTE after elective craniotomy.
The prospective study involved a single center during the time period from April 2010 to February 2012. Patients who were undergoing elective surgery for intracranial pathology by craniotomy and who were available for preoperative and postoperative Doppler ultrasonography were approached for inclusion in the study. Exclusion criteria included pregnancy, age <18 years, perioperative administration of blood products, abnormal blood coagulation studies, administration of antiplatelet agents, preoperative C-reactive protein levels >5 mg/L, liver disease, and preoperative detection of DVT. A total of 106 consecutive patients met the primary inclusion criteria and gave informed consent. Five patients were later excluded from the study as 3 had asymptomatic DVT on preoperative examination and 2 had abnormal preoperative blood coagulation results. The study group of 101 patients included 59 women and 42 men with an average age of 54±15.4 years and a body mass index of 26.9. Ten of the 101 patients were smokers.
61.4% of the patients had a pathologic condition, which was located in the supratentorium, whereas 38.6% had intratentorial lesions. All patients were treated with compression stockings from the point of surgical positioning until the fifth postoperative day, and all patients received subcutaneously administered low molecular weight heparin (certoparin, 3000 IU, once daily) from the first postoperative day until discharge. If VTE was diagnosed, therapeutic anticoagulation therapy was instituted with administration of low molecular weight heparin twice a day, the dosage depending on the patient’s weight and surgeon’s preference.
All study subjects received vascular ultrasound examination by the same examiner who was certified at level 3 by the German Society for Ultrasound in Medicine and who was blinded to D-dimer levels. The examinations took place on the day before surgery and between the third and sixth day after surgery. Diagnosis of DVT was based on direct thrombus detection by incomplete compressibility of the vessel, observation of lack of blood flow, or both. Cases of DVT were classified into symptomatic and asymptomatic subgroups (symptom criteria included tenderness on palpation, swelling, pain). PE was diagnosed by computed tomography examination, which was performed if a patient experienced acute dyspnea, unexplained loss of consciousness, thoracic pain, acutely reduced oxygen saturation, resting tachycardia >100 bpm, or acutely reduced blood pressure.
D-dimer plasma levels were assessed preoperatively and on the third, seventh, and 10th days after surgery with the Siemens Innovance D-dimer test. Statistical analysis was carried out using IBM SPSS Statistics 19. The mean values of D-dimer plasma levels before surgery and on the third, seventh, and 10th postoperative days were calculated for patients with and without VTE. After logarithmic transformation of these values, between-group comparisons were performed using the Mann-Whitney U test and the Student t test. For evaluation of discrimination points, a receiver operating characteristic curve analysis was conducted.
Data pertaining to nondichotomous variables were compared by parametric tests only when a Gaussian distribution was confirmed for evaluation of risk factors for VTE.
