Resident Support Unit, Westmead Hospital, Sydney, New South Wales, Australia.
Intern Med J. 2013 Nov;43(11):1231-6. doi: 10.1111/imj.12225.
Prospective studies have shown that utilising qualitative D-dimers in those with a low Wells pre-test probability (PTP) of pulmonary embolism (PE) have significantly reduced the number of computed tomography pulmonary angiograms (CTPA) being performed. These studies have been based on a PE prevalence of approximately 6% in the low PTP group.
This study compares the diagnostic approach to PE in the study institution to well-established guidelines. The study also re-examines the cost-benefit analyses of qualitative d-dimers and CTPA in the low PTP group.
A retrospective study of 169 consecutive CTPA requested in the emergency department of a major teaching hospital during a 12-month period.
The prevalence of PE was 0% (0/65), 11.7% (9/77) and 0% (0/2) in the low, moderate and high Wells PTP groups respectively, and 6.3% (9/144) overall. PTP was documented in 10 (6.9%) cases, and the qualitative Clearview Simplify D-dimer was only ordered in 33.8% (22/65) of low PTP subjects. The false positive D-dimer rate was 90.2% (37/41). Cost-benefit analysis and assay performance defines a narrow range of low PTP PE prevalence between 1% and 5% for the utilisation of the qualitative D-dimer assay.
The overall prevalence of PE in subjects undergoing CTPA was significantly lower compared with data in the literature. The authors recommend warranted clinical suspicion of PE should be confirmed by a senior physician prior to placing a patient in the PE work-up pathway. In such patients, the qualitative D-dimer assay should be utilised if PTP is low, and the exclusionary efficiency of the D-dimer will be improved in the setting of higher PE prevalence in this subgroup. Hospitals should audit local PE prevalence, as cost-benefit analyses raises questions about the effectiveness of D-dimers when PE prevalence is very low in the low PTP subgroup.
前瞻性研究表明，在低 Wells 术前概率（PTP）的肺栓塞（PE）患者中使用定性 D-二聚体可显著减少进行计算机断层肺动脉造影（CTPA）的数量。这些研究的基础是低 PTP 组中 PE 的患病率约为 6%。
本研究比较了研究机构与既定指南的 PE 诊断方法。该研究还重新检查了低 PTP 组中定性 D-二聚体和 CTPA 的成本效益分析。
对一家大型教学医院急诊科在 12 个月期间连续进行的 169 例 CTPA 请求进行回顾性研究。
低、中、高 Wells PTP 组的 PE 患病率分别为 0%（0/65）、11.7%（9/77）和 0%（0/2），总体患病率为 6.3%（9/144）。记录了 10 例（6.9%）患者的 PTP，仅在 33.8%（22/65）的低 PTP 患者中订购了定性 Clearview Simplify D-二聚体。假阳性 D-二聚体率为 90.2%（37/41）。成本效益分析和分析性能定义了定性 D-二聚体检测的低 PTP PE 患病率在 1%至 5%之间的狭窄范围。
与文献中的数据相比，接受 CTPA 的患者中 PE 的总体患病率明显较低。作者建议，在将患者纳入 PE 检查途径之前，应由资深医生对 PE 的临床怀疑进行证实。在这种情况下，如果 PTP 较低，应使用定性 D-二聚体检测，如果在低 PTP 亚组中 PE 的患病率较高，则 D-二聚体的排除效率将会提高。医院应审核当地 PE 的患病率，因为成本效益分析提出了关于当低 PTP 亚组中 PE 的患病率非常低时 D-二聚体的有效性的问题。
