University Health Network, Toronto, Canada.
Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada.
J Oncol Pharm Pract. 2024 Jul;30(5):823-829. doi: 10.1177/10781552231189695. Epub 2023 Jul 27.
Cancer and cancer-related treatments are significant independent risk factors for malignant hematology (MH) patients in developing venous thromboembolism (VTE). Treatment of VTE in MH patients at the Princess Margaret Cancer Centre is predominantly initiated with low molecular weight heparin (LMWH) in accordance with guidelines. While guidelines recommend against LMWH use in patients with thrombocytopenia, prescribers may order LMWH conditionally based on platelet values. Currently, there is a lack of consistent practice with variation in both the use of conditional orders as well as the threshold of platelet values for conditional orders. The objectives of the study were to (a) describe the use of conditionally ordered LMWH based on platelet values; (b) determine its safety by measuring administration concordance with conditional orders and bleeding event rates during inpatient admission; and (c) determine its efficacy by measuring the rate of worsening VTE or recurrence during inpatient admission.
Electronic records of MH inpatients admitted between January 2017 and December 2019 and who were administered at least one dose of an LMWH for the treatment of VTE were screened.
One hundred and eight patients were screened to obtain 50 eligible patients with a median age of 59 years (SD = ±18.8 years). The most frequent MH diagnosis was acute lymphoblastic leukemia (30%). Sixty percent ( = 30) of patients received conditional orders. Out of 571 administrations, 543 (95%) were administered concordantly ((1) = 472, < 0.0001). In this group of patients, 8 patients had either documented bleeding or experienced a drop in hemoglobin >10 g/L within a 72 h time frame. No patients experienced a recurrent VTE during inpatient treatment (for up to 40 days post-admission).
It appears that conditionally ordered LMWH can be concordantly administered and is safe and effective in the treatment of VTE in MH patients experiencing thrombocytopenia. There were no reports of worsening or new VTE in our small sample.
癌症和与癌症相关的治疗是导致恶性血液病（MH）患者发生静脉血栓栓塞（VTE）的重要独立危险因素。按照指南，玛格丽特公主癌症中心的 MH 患者 VTE 的治疗主要以低分子肝素（LMWH）开始。尽管指南建议避免在血小板减少症患者中使用 LMWH，但医生可能会根据血小板值有条件地开出 LMWH。目前，在使用有条件的医嘱以及有条件的医嘱血小板值阈值方面，都缺乏一致的实践，存在差异。本研究的目的是：（a）描述基于血小板值使用有条件的 LMWH；（b）通过测量有条件医嘱的给药一致性和住院期间出血事件发生率来确定其安全性；（c）通过测量住院期间 VTE 恶化或复发的发生率来确定其疗效。
筛选 2017 年 1 月至 2019 年 12 月期间入院的 MH 住院患者的电子病历，筛选出至少接受过一次 LMWH 治疗 VTE 的患者。
筛选出 108 名患者，其中 50 名符合条件的患者纳入研究，中位年龄为 59 岁（标准差 = ±18.8 岁）。最常见的 MH 诊断为急性淋巴细胞白血病（30%）。60%（ = 30）的患者接受了有条件医嘱。在 571 次给药中，543 次（95%）给药一致（(1) = 472， < 0.0001）。在这组患者中，有 8 名患者有记录的出血或血红蛋白在 72 小时内下降 > 10 g/L。在住院治疗期间（最长 40 天），没有患者发生复发性 VTE。
似乎可以有条件地开出 LMWH，并且在 MH 血小板减少症患者中治疗 VTE 时，它既安全又有效。在我们的小样本中，没有恶化或新发 VTE 的报告。
