Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia; Sydney Centres for Thrombosis and Haemostasis Research, Westmead Hospital, Westmead, NSW, Australia.
Thromb Res. 2020 Apr;188:17-24. doi: 10.1016/j.thromres.2020.01.029. Epub 2020 Feb 1.
von Willebrand disease (VWD) is the most common inherited bleeding disorder and may alternatively arise as an acquired condition (AVWS). These represent deficiency and/or defects in von Willebrand factor (VWF). Closure times (CTs) obtained from the platelet function analyser (PFA) are highly sensitive to both VWD/AVWS. The current study has evaluated the utility of the PFA-100/-200 to exclude or detect laboratory identified VWD.
An evaluation of the success or otherwise of prospective PFA testing to help exclude or detect VWD using data from a locally maintained database. This database contains patient information, results of PFA testing, results of VWF testing, platelet count and hematocrit, and additional information, for a current total of 3678 entries representing over 2 decades of testing.
According to selection criteria, a total of 142 samples were identified as derived from patients with VWD. All but one of these were also identified to have abnormal PFA CTs. Additional data sets of patients with 'low VWF' (n = 137), or borderline normal VWF (n = 163) were also identified, as well as patients with thrombocytopenia and/or low hematocrit (n = 487). In these cohorts, PFA CTs were often (but not always) abnormal. There was a strong association between VWF test parameter values and PFA CTs. Additional study samples comprised cases with normal VWF parameters but prolonged CTs (n = 594), as well as cases with normal VWF and normal CTs (n = 1292), permitting calculation of sensitivity of abnormal PFA for VWD (99.3%), as well as specificity (68.5%), negative predictive value (99.9%) and positive predictive value (19.2%), for a prevalence of 7.0%. Comparatively, normal PFA CTs were better able to exclude VWD than normal test results for individual VWF parameters.
This study reports on an evaluation of PFA CTs for identification or exclusion of VWD. In our dataset, representing over 22 years of experience, normal PFA CTs were able to predict absence of VWD with higher sensitivity than individual VWF test results.
血管性血友病（VWD）是最常见的遗传性出血性疾病，也可作为获得性疾病（AVWS）出现。这些表现为血管性血友病因子（VWF）的缺乏和/或缺陷。从血小板功能分析仪（PFA）获得的闭合时间（CT）对 VWD/AVWS 高度敏感。本研究评估了 PFA-100/-200 在排除或检测实验室鉴定的 VWD 方面的效用。
对前瞻性 PFA 检测的成功与否进行评估，以帮助使用本地维护的数据库中的数据排除或检测 VWD。该数据库包含患者信息、PFA 检测结果、VWF 检测结果、血小板计数和血细胞比容以及其他信息，目前总共有 3678 项代表超过 20 年的检测。
根据选择标准，共确定 142 个样本来自 VWD 患者。除 1 个样本外，所有样本的 PFA CT 均异常。还确定了具有“低 VWF”（n=137）或边界正常 VWF（n=163）的其他数据集，以及血小板减少症和/或低血细胞比容的患者（n=487）。在这些队列中，PFA CT 通常（但不总是）异常。VWF 测试参数值与 PFA CT 之间存在很强的关联。额外的研究样本包括 VWF 参数正常但 CT 延长的病例（n=594），以及 VWF 和正常 CT 的病例（n=1292），可计算异常 PFA 对 VWD 的敏感性（99.3%），特异性（68.5%），阴性预测值（99.9%）和阳性预测值（19.2%），患病率为 7.0%。相比之下，正常的 PFA CT 能够比单个 VWF 参数的正常测试结果更好地排除 VWD。
本研究报告了对 PFA CT 用于识别或排除 VWD 的评估。在我们的数据集（代表超过 22 年的经验）中，正常的 PFA CT 能够以比单个 VWF 测试结果更高的敏感性预测 VWD 的不存在。
