12231Georgetown University Medical Center, Washington, DC, USA.
Biostatistics, 5635University of Minnesota, Minneapolis, MN, USA.
Clin Appl Thromb Hemost. 2021 Jan-Dec;27:1076029621996473. doi: 10.1177/1076029621996473.
Empiric management in suspected heparin-induced thrombocytopenia (HIT) is challenging due to imperfect prediction models, latency while awaiting test results and risks of empiric therapies. When there is high clinical suspicion for HIT, cessation of heparin and empiric non-heparin anticoagulation with FDA-approved argatroban is recommended. Alternatively off-label fondaparinux or watchful waiting have been utilized in clinical practice. Outcomes of patients empirically managed for HIT have not been compared directly in clinical trials and patients that ultimately do not have HIT are often overlooked. Clinicians need studies investigating empiric management to guide decision making in suspected HIT. In this study, adverse events (AE) were categorized and compared in patients being evaluated for HIT while undergoing empiric management by non-heparin anticoagulation with argatroban or fondaparinux, both at therapeutic or reduced doses, or watchful waiting with or without heparin. AE were defined as new thrombosis confirmed on imaging or new bleeding event after HIT was first suspected. A retrospective chart review of 312 patients tested for HIT at an academic hospital was conducted. 170 patients met inclusion criteria. Patients were excluded if the 4Ts score was < 4. The 4Ts score is a pretest probability for HIT based on thrombocytopenia degree, timing, alternative causes and presence of thrombosis. Included patients were divided according to management groups and compared with logistic regression analysis. Bleeding risk significantly differed between management groups (p = 0.002). Despite adjustment for bleeding risk, fondaparinux was associated with increased AE, (p = 0.03, OR = 5.81), while argatroban was not. There was no difference in AE based on time to initiation of empiric treatment and no advantage to reduced dosing with either anticoagulant. These findings challenge assumptions surrounding empiric HIT management.
由于不完善的预测模型、等待检测结果的潜伏期以及经验性治疗的风险，疑似肝素诱导的血小板减少症（HIT）的经验性管理具有挑战性。当高度怀疑 HIT 时，建议停止肝素，并使用 FDA 批准的阿加曲班进行经验性非肝素抗凝治疗。或者，在临床实践中也可以使用非标签依诺肝素或密切观察等待。在临床试验中，没有直接比较经验性治疗 HIT 的患者的结局，并且经常忽略最终没有 HIT 的患者。临床医生需要研究经验性管理，以指导疑似 HIT 患者的决策。在这项研究中，在使用阿加曲班或依诺肝素进行经验性治疗时，根据治疗或降低剂量进行非肝素抗凝治疗，或进行密切观察等待，同时或不使用肝素，对接受 HIT 评估的患者进行了分类和比较。不良事件（AE）定义为首次怀疑 HIT 后经影像学证实的新血栓形成或新出血事件。对一家学术医院进行 HIT 检测的 312 名患者进行了回顾性图表审查。符合纳入标准的 170 名患者。如果 4Ts 评分<4，则排除患者。4Ts 评分是基于血小板减少程度、时间、替代原因和血栓形成的 HIT 术前概率。纳入的患者根据管理组进行分组，并通过逻辑回归分析进行比较。管理组之间的出血风险差异显著（p = 0.002）。尽管调整了出血风险，但与依诺肝素相比，fondaparinux 与 AE 增加相关（p = 0.03，OR = 5.81），而 argatroban 则没有。根据开始经验性治疗的时间，AE 没有差异，并且两种抗凝剂的降低剂量没有优势。这些发现对围绕经验性 HIT 管理的假设提出了挑战。
