Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA; Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA.
Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA.
J Pediatr. 2015 Jan;166(1):144-50. doi: 10.1016/j.jpeds.2014.09.017. Epub 2014 Oct 14.
To characterize heparin-induced thrombocytopenia (HIT) at a single pediatric center including the prevalence and the accuracy of the 4Ts scoring system as a predictor of HIT.
In this retrospective cohort study, we identified 155 consecutive patients <21 years old with sufficient data for 4Ts scoring. The 4Ts scoring system is a validated pretest tool in adults that predicts the likelihood of HIT using clinical features. Hospital-wide exposure to unfractionated and low molecular weight heparin was determined by querying the hospital pharmacy database.
The majority of patients with suspected HIT (61.2%) were on surgical services. Prediction of HIT risk using initial 4Ts scoring found 3 (2%) had high risk 4Ts scores, 114 (73%) had intermediate risk 4Ts scores, and the remaining 38 (25%) had low risk 4Ts scores. HIT was confirmed in 0/38 patients with low risk 4Ts scores, 2/114 patients with intermediate-risk 4Ts scores, and all 3 patients with high-risk 4Ts scores presented with HIT with thrombosis. Of 12 positive HIT screening tests, results were falsely positive in 66.6% of patients with intermediate risk 4Ts scores and 100% of patients with low risk 4Ts scores. The prevalence of HIT was 0.058% and HIT with thrombosis was 0.046% in pediatric patients on unfractionated heparin.
The prevalence of HIT appears significantly lower in pediatric patients compared with adults. Application of the 4Ts system as a pretest tool may reduce laboratory evaluation for HIT in heparin-exposed children with low risk 4Ts scores, decreasing unnecessary further testing, intervention, and cost.
描述一家儿科中心的肝素诱导血小板减少症（HIT）特征，包括 4Ts 评分系统的流行率和准确性作为 HIT 的预测指标。
在这项回顾性队列研究中，我们确定了 155 名年龄小于 21 岁且有足够 4Ts 评分数据的连续患者。4Ts 评分系统是一种在成人中经过验证的术前工具，可使用临床特征预测 HIT 的可能性。通过查询医院药房数据库确定全医院接触未分级和低分子量肝素的情况。
怀疑患有 HIT 的大多数患者（61.2%）在外科病房。使用初始 4Ts 评分预测 HIT 风险，发现 3 名（2%）患者有高风险 4Ts 评分，114 名（73%）患者有中风险 4Ts 评分，其余 38 名（25%）患者有低风险 4Ts 评分。在低风险 4Ts 评分的 38 名患者中，0/38 例患者确诊为 HIT，中风险 4Ts 评分的 114 名患者中有 2/114 例患者确诊为 HIT，高风险 4Ts 评分的所有 3 例患者均出现 HIT 伴血栓形成。在 12 例阳性 HIT 筛查试验中，中风险 4Ts 评分的患者中有 66.6%的结果为假阳性，低风险 4Ts 评分的患者中有 100%的结果为假阳性。在接受未分级肝素治疗的儿科患者中，HIT 的患病率为 0.058%，伴血栓形成的 HIT 患病率为 0.046%。
与成人相比，儿科患者的 HIT 患病率明显较低。应用 4Ts 系统作为术前工具可减少低风险 4Ts 评分的肝素暴露儿童的 HIT 实验室评估，减少不必要的进一步检测、干预和成本。
