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Objective To investigate the predictive value of HIT-antibodies(HIT-Ab) detection for new thrombus in suspected Heparin-Induced thrombocytopenia (HIT). Methods Retrospective cohort study. 472 suspected HIT patients were collected from July 2016 to November 2018, and all subjects under-went a 4Ts score and were sent for HIT-Ab tests. According to the results of HIT-Ab, there were four groups:412 cases of negative HIT-Ab (0-0.9 U/ml), 45 cases of weak-positive HIT-Ab (1.0-4.9 U/ml), 12 cases of moderate-positive HIT-Ab (5.0-15.9 U/ml), and 3 cases of strong-positive HIT-Ab (≥16.0 U/ml) respective-ly. Ultrasound or CT examination was used to confirm new thrombosis as a standard to evaluate the value of HIT-Ab for predicting new thrombus. The diagnostic efficacy of HIT-Ab for HIT was evaluated in clinically confirmed HIT. Results The incidence rates of new thrombus in each group were: 15.8％ in Negative HIT-Ab group (62/412), 48.9％in Weak-positiveHIT-Ab group (22/45), 75.0％in Moderate-positive HIT-Ab group (9/12), and100％in Strong-positive HIT-Ab group (3/3)(P<0.00). When HIT-Ab≥1.0 U/ml, the speci-ficity for diagnosing new thrombus was 93.0％, the sensitivity was 34.2％, the negative predictive value (NPV) was 84.2％, and the positive predictive value (PPV) was 56.5％. The diagnostic rates of HIT in each group were:negative 0％(0/412), weak-positive 62.2％(28/45), moderate-positive (12/12) and strong-positive (3/3) were 100％. When HIT-Ab≥ 1.0 U/ml, the specificity for HIT diagnosis was 96.0％, the sensitivity was 100％, NPV was 100％, and PPV was 71.5％. Conclusions In suspected HIT patients, the incidence of new thrombosis increases with the elevated HIT-Ab level. HIT-Ab detection can be used as a crucial tool for new thrombosis prediction and HIT diagnosis in suspected HIT patients. Clinicians can develop treatment strategies based on HIT-Ab levels.
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Heparin-induced thrombocytopenia (HIT) is an adverse reaction after exposure to heparin. Clinical manifestations include reduction in platelet count and high risk of thrombosis. HIT often cause high disability and mortality due to the concealed feature, non-specific clinical manifestations, and the delayed diagnosis and treatment. Clinical laboratories should provide important support for early identification, diagnosis, and treatment of HIT to avoid missed diagnosis and over-diagnosis.
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Objective To discuss the diagnostic value of HIT-antibodies in suspected HIT patients with heart diseases.Methods A single center study.We collected 242 blood samples of suspected HIT patients whose platelet count decreased after heparin application during July 1 st ,2012 to June 30th ,2016 in Wuhan Asia Heart Hospital and detected the concentration of HIT antibodies , meanwhile the 4T′s score were calculated.Among the study objects , there are 206 patients received cardiac surgery , 28 received cardiac interventional therapy and 8 received drug therapy.And we divided them into HIT group (44, median age 57.5, 23 females ) and non-HIT group ( 198, median age 63.5, 87 females ) according to clinical diagnosis.Quantitative data was analyzed by independent t-test or Mann-Whitney U test.Qualitative data was analyzed by Fisher′s exact test.We drew ROC curve according to the statistical analysis to determine the optimal threshold value of antibodies in diagnosis of HIT andsensitivity , specificity, negative likelihood ratio, positive likelihood ratio of the HIT antibody detection .Therefore, we can assess the value of HIT antibody detection in HIT clinical diagnosis and treatment .Moreover, we used the optimal threshold value of antibodies to testify the suspected HIT patients .Results The HIT antibody concentration of HIT group (44) and non-HIT group ( 198 ) are 3.2 ( 95% CI:1.8 -5.5 ) U/ml and 0.4 ( 95% CI:0.3 -0.4 ) U/ml, respectively.The concentration of HIT group is much higher than the non-HIT group(P<0.000).When the cut-off value of HIT-Ab is set at 0.9 U/ml, sensitivity and specificity are 93.2%and 91.9%, respectively. And negative likelihood ratio and positive likelihood ratio are 0.07 and 11.53, respectively.When the cut-off value of HIT-Ab is set at 0.6 U/ml, sensitivity and specificity are 100.0%and 73.7%.HIT-Ab and 4T′s score of ROC-AUC are 0.971 and 0.745, respectively.The diagnosis value of HIT-Ab in HIT is significantly higher than the 4T′s score ( P<0.000).Conclusions HIT antibody detection is a simple and effective auxiliary diagnostic method in HIT exclusion .And HIT antibody detection is more optimal than the 4T′s score in HIT diagnosis and treatment .
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Objective@#To investigate the association between D-dimer levels and clinical events in patients with mechanical heart valve replacement under oral anticoagulation therapy.@*Methods@#This prospective study included 640 consecutive patients underwent mechanical heart valve replacement in Wuhan Asia Heart Hospital between January 2013 and June 2014.Patients were assigned to abnormal D-dimer group (D-dimer level>cut off value, n=88) and normal D-dimer group (D-dimer level≤cut off value, n=552) according to D-dimer levels measured at 3 months after the initiation of oral anticoagulation therapy.All patients were followed up for 24 months or until the observation of the end points, which included thrombotic events, bleeding events and all-cause deaths.The anticoagulation therapy was monitored once per 1-2 months by the international normalized ratio (INR), and the target value was 1.8-3.0.@*Results@#During a follow-up period of 24 months, rates of total clinical events (19.30%(17/88) vs. 5.8%(32/552), P<0.01), thrombotic events (11.4%(10/88) vs. 2.3%(13/552), P<0.01), and all-cause deaths (8.0%(7/88) vs. 2.0%(11/552), P<0.01) were all significantly higher in abnormal D-dimer group than in normal D-dimer group.There were no significant difference in bleeding events between the two groups (2.3%(2/88) vs. 3.1%(17/552), P=0.77). Multivariate Cox regression analysis showed that high D-dimer level was an independent risk factor of total clinical events (HR=3.86, 95%CI 1.92-7.76, P<0.01), thrombotic events(HR=5.29, 95%CI 2.12-13.10, P<0.01), and all-cause deaths(HR=5.32, 95%CI 1.71-16.60, P<0.01), but which was not correlated with bleeding events(HR=1.36, 95%CI 0.27-6.84, P=0.71).@*Conclusion@#Elevated D-dimer levels are linked with clinical events in patients with mechanical heart valve replacement under oral anticoagulation therapy.
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Objective To evaluate the interference of ALP on cTnI assays. Methods One normal mixed plasma sample and 2 abnormal mixed plasma samples with different cTnI levels were prepared, and then divided them into 8 groups respectively. One group was randomly chosen as control while different amounts of ALP were added into the other seven groups. The concentrations of cTnI and ALP in each plasma portion were detected by ACCESS2 (Beckman-Coulter, Inc ) and AXSYM (Abbott Laboratories )separately. The results of the seven tested groups were then compared with those of the control, so as to evaluate whether ALP could interfere with the cTnI assay. Results When the chemiluminescent Access cTnI assay was carried out for detection of normal plasma, the concentration of ALP was up to 3 716 U/L and did not interfere with the test results of cTnI [(0. 04 ±0.01) μg/L] compared with those of the control portion [(0. 04 ± 0. 01 ) μg/L] (t = 0. 40, P ＞ 0. 05 ). Once the concentration of ALP went beyond 917 U/L, the AXSYM cTnI assay results [( 0.08 ± 0. 01 ) μg/L] were higher than those of the normal control ( t =-4. 89, P＜0. 01 ); When the concentration of ALP was up to 3 534 U/L, the test results of abnormal plasma cTnI detected by the Access assay [( 13.41 ±0. 17) μg/L] did not show significant differences from those of the control [(13.48±0.16) μg/L] (t=0. 52,P＞0.05).Conclusions High concentration ofALP did not interfere with the Access cTnI assay or lead to false positive results. However, the high level of ALP( ＞ 917 U/L) could interfere with the AXSYM cTnI assay and cause a false positive result.