Prolonged activated partial thromboplastin time after prophylactic-dose unfractionated heparin in the post-operative neurosurgical setting: case series and management recommendations.

Primary brain tumors, both benign and malignant, pose a high risk of perioperative venous thromboembolism (VTE) due to the development of a prothrombotic state. Perioperative pharmacologic thromboprophylaxis with subcutaneous (SC) unfractionated heparin (UFH) has significantly reduced VTE associated morbidity. Recent reports suggest an association between prolonged activated partial thromboplastin time (aPTT) due to prophylactic SC UFH and increased bleeding risk. We present three patients with normal baseline coagulation parameters in whom pharmacologic thromboprophylaxis with SC UFH resulted in a marked prolongation of the aPTT, leading to adverse outcomes in two patients. These cases demonstrate the uncertain kinetics of SC UFH and effect on aPTT, suggesting the significance of routine aPTT monitoring in high-risk settings. Given the wide variation in presentations of therapeutic or supratherapeutic values of aPTT in the perioperative neurosurgical setting, we propose a practical standardized approach to the evaluation and management of aPTT prolongation following prophylactic SC UFH administration.

Low molecular weight heparin versus rivaroxaban in the treatment of venous thromboembolism in gastrointestinal malignancies.

: Due to their ease of use, the direct oral anticoagulants (DOACs) are an attractive treatment option for cancer-associated venous thromboembolism (VTE) and have been readily adopted by many clinicians. A recent published study comparing a DOAC (edoxaban) to the current standard-of-care low molecular weight heparin dalteparin for the treatment of cancer-associated thrombosis showed that edoxaban was noninferior to dalteparin for recurrent VTE, but the risk of major bleeding was higher. We present three patients with high-risk gastrointestinal malignancies complicated by cancer-associated VTE with progression of thrombosis while treated with the oral direct Xa inhibitor rivaroxaban. Upon switching therapy to low molecular weight heparin, we found that these patients had clinical and radiologic improvement of VTE. More studies are needed to evaluate the efficacy of rivaroxaban in high-risk gastrointestinal-VTE. We suggest that in some patients, DOACs may not be sufficient for the treatment of VTEs related to high-risk gastrointestinal malignancies.

Outcomes in women receiving low-molecular-weight heparin during pregnancy.

To assess the rate and type of maternal and infant complications among pregnant women receiving low-molecular-weight heparin (LMWH). Retrospective study of pregnant women on LMWH referred to two university hematology clinics from January 2001 to December 2010. We recorded the number of pregnancies, indication, dose and dose adjustments for LMWH, pregnancy outcomes (live births, maternal and infant complications) and side effects of LMWH. There were 89 pregnancies in 76 women. The most common indication for LMWH was a history of adverse outcome of pregnancy associated with thrombophilia. LMWH was adjusted in 75 and 45% of pregnancies in women on therapeutic and prophylactic doses, respectively. Live birth rate was 97%. There were 25 maternal and 11 infant complications. Side effects were minimal and included decreased bone mineral density and bleeding. LMWH use among pregnant women is associated with successful pregnancy outcomes. Although side effects were minimal, maternal and infant complications occurred in 28 and 12% of cases, respectively.