Relationship between activated partial thromboplastin time,heparin and potassium levels

We performed a meta-analysis of five randomized, placebo-controlled trials to characterize the impact of plant sterols/stanols on plasma lipids in patients with type 2 diabetes. Upon meta-analysis, plant sterols/stanols significantly reduced total and LDL cholesterol, with a trend towards improvement in HDL. No beneficial effect on triglycerides was apparent.     

Prolonged activated partial thromboplastin time after prophylactic-dose unfractionated heparin in the post-operative neurosurgical setting: case series and management recommendations

Journal of Thrombosis and Thrombolysis - Primary brain tumors, both benign and malignant, pose a high risk of perioperative venous thromboembolism (VTE) due to the development of a prothrombotic...     

Laboratory controls of heparin therapy with thrombin time, partial thromboplastin time and activated recalcification time

For the laboratory control of a heparin therapy thrombin time, partial thromboplastin time and activated recalcification time are used. On account of distinct differences in the heparin sensitivity of these reactions an indication-related application is necessary. The ability of evidence and the possibility of establishing test-specific therapeutic regions are restricted by differences caused by reagents, individual variability and influence by accompanying haemostasiological changes. The own approach, taking into consideration the so-called heparin resistance, it presented.     

Clinical outcomes with unfractionated heparin monitored by anti-factor Xa vs. activated partial Thromboplastin time

Anti-factor Xa (anti-Xa) monitoring of unfractionated heparin (UFH) is associated with less time to achieve therapeutic anticoagulation compared to the activated partial thromboplastin time (aPTT). However, it is unknown whether clinical outcomes differ between these methods of monitoring. The aim of this research was to compare the rate of venous thrombosis and bleeding events in patients that received UFH monitored by anti-Xa compared to the aPTT. A retrospective review of electronic health records identified adult patients that received UFH given intravenously (IV) for ≥2 days, with either anti-Xa or aPTT monitoring at an academic tertiary care hospital. This was a pre/post study design conducted between January 1 to December 30, 2014 (aPTT), and January 1 to December 30, 2016 (anti-Xa). All UFH adjustments were based on institutional nomograms. The primary outcome was venous thrombosis and the secondary outcome was bleeding, both of which occurred between UFH administration and discharge from the index hospitalization. A total of 2500 patients were in the anti-Xa group and 2847 patients aPTT group. Venous thrombosis occurred in 10.2% vs 10.8% of patients in the anti-Xa and aPTT groups, respectively (P = .49). Bleeding occurred in 33.7% vs 33.6% of patients in the anti-Xa and aPTT groups, respectively (P = .94). Anti-Xa monitoring was not an independent predictor of either outcome in multivariate logistic regression analyses. Our study found no difference in clinical outcomes between anti-Xa and aPTT-based monitoring of UFH IV.     

Sensitivity of the thrombin clotting time and activated partial thromboplastin time to low level of antithrombin III during heparin therapy

Summary. The thrombin clotting time (TCT) has been used at our institution, along with the activated partial thromboplastin time (aPTT), for monitoring heparin therapy. We have observed that, in some patients, a discrepancy develops between the heparin levels predicted by the TCT and the aPTT with the TCT consistently predicting a lower heparin level than the aPTT. An inverse relationship was noted between the functional antithrombin III (AT-III) level and the magnitude of this discrepancy.     

Prolonged activated partial thromboplastin time in pregnancy: a brief report

BACKGROUND: Limited data are available regarding causes of prolonged activated partial thromboplastin time (aPTT) in otherwise normal pregnancies. We retrospectively evaluated clinical data of pregnant women in whom an elevated aPTT was noted on routine prenatal testing. Our intent was to identify various causes of prolonged aPTT and to evaluate whether the pregnancies were adversely affected. METHODS: A retrospective review of medical records of 36 pregnant patients with a prolonged aPTT as the sole abnormal coagulation test seen in the outpatient department of a tertiary care hospital over a period of 4 years. RESULTS: Patients' median age was 26 (range, 19-41) years and median duration of gestation period was 19 (range, 8-38) weeks. Fifteen patients were primigravida. Of 36 patients, repeated aPTT values were normal in 24 (67%) patients, whereas 12 (33%) patients had persistently elevated aPTT values. Factor XI deficiency was found in 5 patients, lupus anticoagulant in 3 patients, elevated anticardiolipin antibody in 2 patients, and low von Willebrand Factor level in 1 patient. Overall, 23 patients delivered. No patients experienced excessive bleeding or thromboembolism. CONCLUSION: Factor XI deficiency and antiphospholipid antibody were 2 major abnormalities identified in patients with prolonged aPTT. These coagulopathies were not associated with excessive bleeding or thromboembolism. Repeat normal aPTT in approximately 2 thirds of patients suggests that proper sample collection and processing are important for coagulation assays to avoid erroneous clotting times.     

Diagnostic uses of the activated partial thromboplastin time and prothrombin time

The activated partial thromboplastin time (APTT) and prothrombin time (PT) have three principal uses. In screening for coagulation disorders (or increased risk of postoperative hemorrhage), the tests add no information to the preoperative care of patients without clinical findings indicative of increased bleeding risk. Furthermore, the prevalence of asymptomatic congenital coagulopathies is so low that false-positive test results greatly outnumber true-positive results. Thus, clinicians may use clinical assessment to screen and should reserve coagulation tests to investigate patients with abnormal findings. In evaluating abnormal bleeding, these tests are sufficiently sensitive that if both are negative, further investigation of the coagulation system is obviated. If one or both tests are positive, the pattern of results directs further attention to limited segments of the coagulation sequence. In monitoring anticoagulation therapy, the APTT and PT tests appear to contribute to the safety and effectiveness of heparin and warfarin therapies, respectively.     

Disagreement between bedside and laboratory activated partial thromboplastin time and international normalized ratio for various novel anticoagulants.

During studies on warfarin, heparin and various anticoagulants with novel mechanisms of action, the activated partial thromboplastin time (aPTT) and the (apparent) international normalized ratio (INR) from a bedside monitor (Coagucheck Plus(R)) were compared with laboratory assay results. Data were compared using the Bland and Altman method of comparison where systematic differences result in significant slopes of the regression line. During heparin treatment, the bedside monitor largely underestimated the aPTT (slope = -0.80). During treatment with the direct thrombin inhibitor napsagatran (slope = 0.99), the pentasaccharides Org31540/SR90107A (slope = 0.77) and SanOrg34006 (slope = 0.35), and warfarin (slope = 0.60), the bedside monitor underestimated the aPTT at lower aPTT levels, while at higher aPTT levels it overestimated the laboratory values. The bedside monitor slightly overestimated the INR during treatment with warfarin (slope = 0.33). Apparent INR was largely overestimated during treatment with Org31540/SR90107A (slope = 1.38), SanOrg34006 (slope = 0.97), Napsagatran (slope = 1.23), and recombinant tissue factor pathway inhibitor (slope = 1.48, P < 0.001 for all regression lines). These results indicate that a substantial disagreement in aPTT or (apparent) INR exists between the bedside monitor and laboratory assay during treatment with the studied 'classic' and novel anticoagulants. The amount of disagreement depended on the anticoagulant given.     

Is the activated partial thromboplastin time suitable to screen for von Willebrand factor deficiencies?

The diagnostic approach to von Willebrand factor deficiencies is challenging and requires discretionary use of laboratory resources. Although extensive preoperative testing is not recommended, the activated partial thromboplastin time may be useful, especially in selected categories of patients. To establish the diagnostic sensitivity of this test to identify isolate von Willebrand factor deficiencies, 204 consecutive patients underwent a routine preoperative screening consisting of activated partial thromboplastin time, von Willebrand factor antigen, intrinsic pathway clotting factors activity, lupus anticoagulants and thrombin time. Thirty-seven patients were diagnosed with haemostasis disturbances other than von Willebrand factor deficiencies and were excluded from the evaluation. Isolated von Willebrand factor deficiency was diagnosed in 11 of the remaining 167 patients. A significant correlation was observed between von Willebrand factor antigen and activated partial thromboplastin time. Receiver operating characteristic curve analysis showed an area under the curve of 0.982 (95% confidence interval: 0.972-0.992; P < 0.001). At the 1.17 upper limit of the activated partial thromboplastin time, sensitivity and specificity were 100 and 85%, respectively, with negative and positive predictive values of 100 and 31%, respectively. These results demonstrate that activated partial thromboplastin time has an excellent diagnostic sensitivity and a satisfactory specificity for identifying isolated von Willebrand factor deficiencies.