Enoxaparin increases the incidence of postoperative intracranial hemorrhage when initiated preoperatively for deep venous thrombosis prophylaxis in patients with brain tumors.

OBJECTIVE: Prophylactic therapies have demonstrated efficacy in reducing the incidence of deep venous thrombosis (DVT) in neurosurgical patients. Retrospective analysis of patients undergoing neurosurgical procedures at the University of Michigan demonstrated a high incidence (14%) of postoperative DVT among patients with intracranial neoplasms treated with sequential compression device (SCD) prophylaxis alone. Therefore, we investigated the efficacy and safety of the low-molecular weight heparin enoxaparin in preventing DVT in patients with brain tumors. The goal of the study was to compare SCD, enoxaparin, and combined SCD/enoxaparin prophylaxis among patients requiring surgery for treatment of intracranial neoplasms. METHODS: Eligible patients were randomized to SCD, enoxaparin, or combined therapy. Treatment was initiated before the induction of anesthesia and was continued throughout the hospital stay. Patients were screened for DVT, using duplex imaging, on four occasions in the first 1 month after surgery. The incidences of DVT and serious adverse events were compared between groups using analysis of variance and the Dunnet two-sided t test. RESULTS: Sixty-eight patients completed the study. Postoperative DVT occurred in 3 of 22 (13.6%) SCD-treated patients, 1 of 23 (4.3%) enoxaparin-treated patients, and 4 of 23 (17.4%) SCD/enoxaparin-treated patients. Differences were not statistically significant. Postoperative intracranial hemorrhage did not occur in patients in the SCD-treated group, whereas 5 of 46 patients receiving low-molecular weight heparin suffered clinically significant intracranial hemorrhage. The study was terminated because of the increased incidence of adverse events in the enoxaparin-treated groups. CONCLUSION: Enoxaparin therapy initiated at the time of anesthesia induction increases postoperative intracranial hemorrhage.

Long-term prognostic significance of dobutamine echocardiography in patients with suspected coronary artery disease: results of a 5-year follow-up study.

OBJECTIVES: This study sought to assess the long-term prognostic utility of dobutamine stress echocardiography in predicting fatal and nonfatal cardiac events. BACKGROUND: Although dobutamine stress echocardiography has improved sensitivity and specificity for detection of coronary artery disease, little is known of its predictive value for long-term cardiac events. Therefore, we followed up 120 consecutive patients who underwent dobutamine echocardiography for suspected coronary disease from March 1989 to August 1991. METHODS: All patients presenting for coronary angiography for chest pain were eligible for recruitment. Follow-up was 100% complete at 5 years (range 3.0 to 6.1). Cardiac events were defined as cardiac death or nonfatal myocardial infarction or the need for coronary revascularization (coronary angioplasty or bypass surgery). RESULTS: Positive (n = 78) and negative (n = 42) dobutamine test groups differed in their rates of coronary artery bypass graft surgery (37.2% vs. 9.5%, p < 0.001, respectively) and mortality. Of 26 total deaths, 22 occurred in the group with positive dobutamine test results (28% vs. 9.5%, p < 0.018); all 7 cardiac deaths occurred in this group as well (9% vs. 0%, p < 0.045). By multivariate regression analysis, positive results on dobutamine echocardiography remained independently predictive of future cardiac death after left ventricular ejection fraction and other clinical variables were accounted for. CONCLUSIONS: A positive finding on dobutamine echocardiography is an independent predictor of long-term cardiac mortality, whereas a negative finding confers a significantly reduced likelihood of cardiac death as much as 5 years from initial testing. We conclude that dobutamine stress echocardiography can be used to predict which patients with suspected coronary artery disease are at low risk for cardiac death and do not require concurrent nuclear or invasive testing.

Improved liquid chromatographic determination of procainamide and N-acetylprocainamide in serum.

A liquid chromatographic method for the determination of procainamide (PA) and N-acetylprocainamide (NAPA) in serum has been developed. This method utilizes isocratic conditions, ambient temperature, and a conventional fixed-wavelength 280-nm detector. Sample pretreatment involves extraction of PA and NAPA, along with p-amino-N-(2-dipropylaminoethyl)-benzamide hydrochloride as internal standard, into an organic phase and reextraction into an aqueous acidic phase. Using this sample pretreatment, interferences due to commonly used drugs are eliminated. The method accurately measures PA and NAPA to levels as low as 1 mg/L.

Liquid chromatographic determination of quinidine in serum and urine.

A liquid chromatography method for the determination quinidine in serum and urine has been developed. This method uses isocratic conditions, ambient temperature, a conventional fixed wavelength, 254-nm detector, and is free of potential interference from quinidine metabolites. Sample pretreatment involves extraction of quinidine along with quinine, an internal standard, into an organic phase and reextraction into an aqueous acidic phase. In this manner, interference due to commonly used drugs are eliminated. The method is capable of accurately measuring quinidine to levels as low as 0.5 mg/L.