Is Restenosis/Reocclusion after Femoropopliteal Percutaneous Transluminal Angioplasty (PTA) the Consequence of Reduced Blood Flow, Inflammation, and/or Hemostasis Disturbances?

Percutaneous transluminal angioplasty (PTA) is an established method for treatment of peripheral artery disease (PAD) of the femoropopliteal artery. However, in up to 50% of patients restenosis and/or reocclusion remain a frequent complication occurring in the first year after the procedure. In this study, we focused on the influence of compromised postprocedural infrapopliteal runoff of the affected limb, on the hypercoagulability as detected by a global hemostasis assay and on genetic predisposition to hypercoagulability and on the regulation of the inflammation through the nuclear receptor related 1 protein (NuRR1). Consecutive PAD patients treated by femoropopliteal PTA because of disabling claudication or critical limb ischemia were followed up by vascular ultrasound imaging at 1, 6, and 12 months after the procedure. Venous blood samples for hemostasis, inflammation, and gene analysis were obtained before and 24 h after PTA. One month after femoropopliteal PTA, 23% of patients with compromised runoff developed the combined end point restenosis/reocclusion in comparison to 11% with good runoff (p = 0.03). After 6 months, the differences were no longer significant. It was concluded that compromised postprocedural infrapopliteal runoff predisposes to early restenosis/reocclusion after femoropopliteal PTA and that the deterioration of infrapopliteal runoff in the year after femoropopliteal PTA is accompanied by worsening of long-term femoropopliteal patency. Patients were genotyped for the prothrombotic gene polymorphisms: platelet receptor glycoprotein IIIa T1565C, coagulation factor V G1691A, coagulation factor II G20210A, coagulation factor XII C(-4)T, and plasminogen activator inhibitor-1 4G5G. We were not able to show any association between these polymorphisms and the restenosis/reocclusion rate in patients treated with femoropopliteal PTA. Furthermore, no association between thrombin generation and restenosis/reocclusion rate was established. NuRR1 haplotypes significantly increased the restenosis/reocclusion rate after PTA (adjusted relative risks were 1.6, 95% CI 1.1–2.3 for haplotype 2 and 2.0, 95% CI 1.3–2.8 for haplotype 3). To conclude, this study suggested a significantly higher restenosis/reocclusion rate in patients with compromised runoff compared to patients with a good runoff 1 month after the procedure. Hypercoagulability was not associated with the restenosis/reocclusion rate, and the prothrombotic polymorphisms were equally distributed among patient with and without restenosis/reocclusion, suggesting minor or no role in restenosis/reocclusion. Haplotypes 2 and 3 in the NuRR1 gene significantly increased the restenosis/reocclusion rate, suggesting significant role of inflammation. In this ongoing study, further analysis on a larger group of patients is warranted

Laboratory Methodology Important in the Diagnosis and Prognosis of Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease, characterized by thrombosis and pregnancy complications with persistently elevated levels of antiphospholipid antibodies (aPL). Recently, a unique mathematical calculation has been presented to assess the risk of thrombosis in patients with APS called antiphospholipid score or global antiphospholipid syndrome score (GAPSS). This new approach in the diagnosis of APS leads to the assessment of the risk of thrombosis considering the results of different aPL (lupus anticoagulants (LA), anticardiolipin antibodies (aCL), antibodies against β2GPI (anti-β2GPI), and phosphatidylserine-dependent antiprothrombin antibodies (aPS/PT) (isotypes IgG and IgM). This chapter provides an overview of the algorithm strategy for APS diagnosis with the aims of characterizing in detail the laboratory methodology of criteria aPL (LA, aCL, and anti-β2GPI) and noncriteria aPL, such as IgA aCL and IgA anti-β2GPI, anti-domain I β2GPI, and antiprothrombin antibodies. In order to improve APS diagnosis, several new approaches in aPL detection have recently been suggested, such as multiline immunodot assay, detection of aPL by flow cytometry using beads with particular surface properties, and the newly developed automated BioPlex system technology for parallel detection of aCL and anti-β2GPI antibodies of IgG, IgA, and IgM isotypes. A completely different and promising approach in future research lies in the potential of microRNAs as biomarkers for risk of thrombosis and/or obstetric complication

Biological Variation in Rotational Thromboelastometry in Patients with Atrial Fibrillation Receiving Rivaroxaban

Rotational thromboelastometry (ROTEM) is a viscoelastic hemostasis test used primarily in the management of bleeding after trauma or in cardiac surgery. To allow safe and valid clinical interpretation of test results, objective specifications for analytical performance are needed, which are generally based on biological variation within (CVI) and between (CVG) individuals. The aim of this study was to evaluate biological variation in ROTEM in patients receiving rivaroxaban. Sixty patients with atrial fibrillation on stable rivaroxaban therapy were included, from whom blood was collected on six occasions: three times at trough and three at peak rivaroxaban concentrations. ROTEM® Extem and LowTF were measured as well as rivaroxaban concentration, PT, APTT, and anti-Xa. Within- (CVI) and between-subject (CVG) biological estimates were calculated. Knowledge of these biological variation components will help to establish the appropriate objective analytical performance specifications for ROTEM analysis

Anticoagulant Drugs

Anticoagulant drugs are among the most frequently prescribed drugs in everyday clinical practice. In the past decades, several new direct oral anticoagulants were developed that changed the anticoagulant therapy landscape considerably. This book provides an extensive overview of all the known anticoagulants that can be useful for studying different aspects of the haemostatic system or as a starting point for new drug development. It is also a valuable tool for clinicians providing a description of the mode of action and management of therapy for anticoagulant drugs used in everyday clinical practice in different clinical settings, including direct oral anticoagulants dabigatran, rivaroxaban, apixaban and edoxaban

Acute effects of high intensity interval training versus moderate intensity continuous training on haemostasis in patients with coronary artery disease

Abstract Exercise training is associated with an acute net increase in coagulation, which may increase the risk of atherothrombosis in coronary artery disease (CAD) patients. We sought to compare the acute haemostatic effects of a bout of moderate-intensity continuous (MICT) and high-intensity interval training (HIIT) in patients with CAD. Patients after a recent myocardial infarction were randomized into a HIIT or MICT session of exercise training on a stationary bike. Blood was sampled at baseline, after the exercise bout and after a one-hour resting period. We measured overall haemostatic potential (OHP), overall coagulation potential (OCP), fibrinogen, D-dimer and von Willebrand factor (vWF) and calculated overall fibrinolytic potential (OFP). Linear mixed models for repeated measures were constructed to assess the treatment effect. A total of 117 patients were included. OCP, OHP, fibrinogen, D-dimer and vWF significantly increased after exercise and returned to baseline after a one-hour rest, OFP decreased after exercise and returned to baseline levels after a one-hour rest. Linear mixed models showed a significant difference between HIIT and MICT in fibrinogen (p 0.043) and D-dimer (p 0.042). Our study has shown that an exercise bout is associated with a transient procoagulant state in patients with CAD, with similar exercise-induced haemostatic changes for HIIT and MICT

Clot time ratio (CTR) and relation to treatment outcome in patients with atrial fibrillation treated with Rivaroxaban

Abstract Background There are situations where information about the anticoagulant effects of Rivaroxaban could be clinically useful. Methods for measuring Rivaroxaban concentrations are not available at all medical laboratories while the test MRX PT DOAC for measuring the functional effects of Rivaroxaban, in CTR (Clot Time Ratio), can be made available around the clock. The objectives of this study were to investigate CTR in trough and peak samples during Rivaroxaban treatment of atrial fibrillation and to correlate the findings to bleeding episodes. Methods 3 trough- and 3 peak samples from 60 patients (30 on 20 mg daily and 30 on 15 mg daily) were analyzed with PT DOAC. Patients were monitored for 20 months, and bleeding and thrombotic events were documented. Descriptive statistics were used to summarize the data and non-parametric t-test for comparison between groups. ROC curves for the prediction of DOAC plasma levels > 50 ng/mL as determined with LC-MS/MS and anti-FXa methods were computed. Results There was a significant difference between trough and peak CTR (median CTR 1.33 vs. 3.57, p  0.98 at the upper limit of the PT DOAC reference interval and the negative predictive value of PT DOAC for the prediction of DOAC plasma levels > 50 ng/mL was > 0.96. Conclusions The sample size was too low to draw any firm conclusions but is seems that MRX PT DOAC might be a useful laboratory test in situations where the effect of Rivaroxaban needs evaluation

Biocompatibility parameters with standard and increased dose of citrate in hemodialysis

Background: The dose of citrate needed in regional citrate anticoagulation (RCA) to achieve optimal biocompatibility is unknown. We performed a randomized trial comparing two doses (ACTRN12613001340729). Methods: In 30 patients a single hemodialysis with either standard (2.7 mmol/L) or increased dose of citrate (4 mmol/L) was performed. C5a-desArg, myeloperoxidase (MPO), thrombin-antithrombin complex (TAT), and platelet factor 4 (PF4) were measured and the inner surface of the dialyzer fibers was evaluated with scanning electron microscopy (SEM). Results: A good separation of anticoagulation effect was achieved (post-filter ionized calcium 0.20 vs. 0.31 mmol/L, p < 0.05). There was no effect of citrate dose on any of the biocompatibility parameterstransient and parallel increase in PF4 after 30 min and parallel increase in TAT after 4 h were observed. There were no visually detected clotting problems within the circuit and no significant hypocalcemia in either group. SEM clotting score was excellent and comparable in both groups (p = 0.59). Conclusions: Given the excellent results in both groups, absence of between group differences and inability of the increased dose of citrate to completely blunt the small residual increase in PF4 and TAT, we conclude that the standard dose of citrate seems sufficient in RCA for chronic hemodialysis

Biological Variation in Rotational Thromboelastometry in Patients with Atrial Fibrillation Receiving Rivaroxaban

Rotational thromboelastometry (ROTEM) is a viscoelastic hemostasis test used primarily in the management of bleeding after trauma or in cardiac surgery. To allow safe and valid clinical interpretation of test results, objective specifications for analytical performance are needed, which are generally based on biological variation within (CVI) and between (CVG) individuals. The aim of this study was to evaluate biological variation in ROTEM in patients receiving rivaroxaban. Sixty patients with atrial fibrillation on stable rivaroxaban therapy were included, from whom blood was collected on six occasions: three times at trough and three at peak rivaroxaban concentrations. ROTEM® Extem and LowTF were measured as well as rivaroxaban concentration, PT, APTT, and anti-Xa. Within- (CVI) and between-subject (CVG) biological estimates were calculated. Knowledge of these biological variation components will help to establish the appropriate objective analytical performance specifications for ROTEM analysis