| Pulmonary thromboembolism (PTE) is a kind of frequent pulmonary vascular disease, which has much misdiagnosis, missed diagnosis and high mortality. How to diagnose PTE correctly and promptly has become a question many subjects in medicine paying close attention to. The diagnostic methods of PTE incluing spiral CT, EBT, ventilation-perfusion scanning and pulmonary arteriography are expensive, unpopular and are not easily practiced to the severe patients in bed. Therefore, serologic markers of PTE of early stage with high sensitivity and specificity, better feasibility and low cost are needed to be researched.The changes of endothelin-l(ET-l), lipoprotein a (LPa) and homocys-teine(Hcy) before and after the establishment of the model of pulmonary thromboembolism (PTE) in rabbits are dynamicly detected . The value of combined determination of ET-1, LPa, Hcy and D-dimer as serologic markers for early diagnosis of PTE is also evaluated in clinical diagnosis test.METHODSAltogether 30 rabbits were divided randomly into 2 groups:the control group and the PTE group and each group had 15 rabbits. PTE models were established by injection of auto-blood clots into the jugular vein of rabbits .The changes of the contents of ET-1, LPa and Hcy in plasma were measured in different time before and after PTE in rabbits. The formation and distribution of thrombosis were observed at dissection and upon microscopic after PTE. The serum or plasma ET-1, LPa, Hcy, D-dimer of 16 PTE patients and 20 none-PTE patients or healthy adults were detected by ELISA and RIA. Then, the ROC curves were described and analyzed.The best cut-off point was determinated.The sensitivity, specificity, Youden's index, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio of each or combined of serologic markers were compared under the corresponding cut-off point.RESULTS1. The injected blood clots thrombosis in the pulmonary ateries, hemorrhagic infarct and bleeding point were observrd in the PTE group.Endomembrane cells growing into the surface of the thrombosis , endotheliosis and inflammatory cell infiltration could be founded by microscopy.2. The plasma level of ET-1 increased significantly at lh,2h and 4h after embolism in PTE group, compared with pre-embolization and control group(P<0.05). The levels of LPa and Hcy in blood were significantly elevated at 24h and 48h after embolization (P<0.05).3. The positive rate and the blood level of ET-1, LPa, Hey and D-dimer were significantly elevated in the patients compared with control group (P<0.05).4. AUCs of ET-1, LPa, Hey and D-dimer were 0.831,0.771,0.867, 0.876; Sensitivities were 86.7%,73.3%,80.0%, 93.3%; specificities were 60.0%,66.7%,86.7%,73.3%;Youden's index were 0.467,0.399,0.667,0.666, respectively,when the best cut-off point(54 pg/L, 240 mg/L, 14 umol/L, 600jig/L) were defined.5. Sensitivities and negative predictive value in parallel combined test were elevated ,specificities and positive predictive rate were lower; Sensitivities, specificities, Youden's index, positive predictive value and negative predictive value (100%, 40%, 0.40, 62.5%, 100%) in parallel combined determination with D-dimer and Hey were higher than other tests.Specificities and positive predictive value in serial combined test were elevated , sensitivities and negative predictive value were lower; Sensitivities, specificities, Youden's index, positive predictive value and negative predictive value (66.67%, 100%, 0.667, 100%, 75%) in serial combined determination with D-dimer, ET-1 and LPa were higher than other tests.CONCLUSION1. The model of acute PTE successfully established in our study had more reproducibility and practicability than traditional model and was easily established.2. ET-1, LPa, Hey and D-dimer were involved in the early stage of PTE and may be benefited to early diagnosis of PTE as serologic markers.
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