Department of Pulmonary and Critical Care Medicine, Shengjing Hospital of China Medical University, Sanhao Street, Shenyang, 110004, Liaoning, China.
BMC Pulm Med. 2021 Dec 1;21(1):391. doi: 10.1186/s12890-021-01757-3.
Acute pulmonary embolism (PE) is one of the leading causes of maternal mortality, and cesarean section is an established independent risk factor for PE. The diagnostic utility of D-dimer for PE in non-pregnant women has been well-established, but its role in women with suspected PE after cesarean section is unclear. Furthermore, the optimal threshold level in this patient population is unknown. Traditional D-dimer levels have low diagnostic specificity, resulting in many pregnant women being exposed to potentially harmful radiation despite negative diagnostic imaging results. This research aimed to optimize the clinical threshold for D-dimer to improve specificity while ensuring high sensitivity and to identify risk factors for PE after cesarean section.
This retrospective study of 289 women who underwent diagnostic imaging (ventilation/perfusion [V/Q] or computed tomographic pulmonary angiography [CTPA]) for suspected acute PE after cesarean delivery from 2010 to 2021 was conducted. Clinical data and laboratory indicators within 24 h postpartum including D-dimer levels were collected for analyses.
The final analysis included 125 patients, among whom 33 were diagnosed with acute PE (incidence of 11.42%, 95% confidence interval 7.7-15.1). The receiver operating characteristic curve analysis suggested that a D-dimer cut-off value of 800 ng/mL had specificity of 25.26% and sensitivity of 100% for detecting PE. The cut-off value was adjusted to 1000 ng/mL with a specificity of 34.74% and a sensitivity of 96.67%. Using a D-dimer cut-off value of 800 ng/mL (instead of the conventional value of 500 ng/mL) increased the number of patients excluded from suspected PE from 9.6 to 18.4% without additional false-negative results. Of note, a history of known thrombophilia was significantly more common in patients with PE than in those without (P < 0.05). No other independent risk factors were noted in our study.
The D-dimer cut-off value of 800 ng/mL ensures high sensitivity and increases specificity compared to the conventional threshold of 500 ng/mL. Utilizing this higher threshold can reduce the number of unnecessary CT and subsequently unnecessary radiation exposure, in women after cesarean delivery. Prospective studies should also be conducted to verify these results.
急性肺栓塞（PE）是孕产妇死亡的主要原因之一，剖宫产术是 PE 的独立危险因素。D-二聚体对非妊娠女性 PE 的诊断价值已得到充分证实，但在剖宫产后疑似 PE 女性中的作用尚不清楚。此外，该患者人群的最佳临界值尚不清楚。传统的 D-二聚体水平诊断特异性低，导致许多孕妇尽管诊断性影像学结果为阴性，但仍暴露于潜在的有害辐射下。本研究旨在优化 D-二聚体的临床临界值，在保证高灵敏度的同时提高特异性，并确定剖宫产后 PE 的危险因素。
这是一项回顾性研究，纳入了 2010 年至 2021 年间 289 例因剖宫产后疑似急性 PE 而行诊断性影像学检查（通气/灌注[V/Q]或计算机断层肺动脉造影[CTPA]）的女性患者。收集产后 24 小时内的临床数据和实验室指标，包括 D-二聚体水平。
最终分析纳入 125 例患者，其中 33 例诊断为急性 PE（发生率为 11.42%，95%置信区间 7.7-15.1）。受试者工作特征曲线分析提示，D-二聚体截断值为 800ng/ml 时，对 PE 的特异性为 25.26%，灵敏度为 100%。截断值调整为 1000ng/ml 时，特异性为 34.74%，灵敏度为 96.67%。使用 D-二聚体截断值 800ng/ml（而非常规值 500ng/ml）可使从疑似 PE 患者中排除的患者人数从 9.6%增加至 18.4%，且无额外的假阴性结果。值得注意的是，PE 患者中已知血栓形成倾向的病史明显比无 PE 患者更常见（P<0.05）。本研究未发现其他独立危险因素。
与传统的 500ng/ml 截断值相比，D-二聚体截断值 800ng/ml 具有更高的灵敏度和特异性。在剖宫产后女性中使用该更高的截断值可以减少不必要的 CT 检查数量，从而减少不必要的辐射暴露。还应开展前瞻性研究以验证这些结果。
