Preprocedural prophylaxis with blood products in patients with cirrhosis: Results from a survey of the Italian Association for the Study of the Liver (AISF).

INTRODUCTION: The concept of rebalanced hemostasis in cirrhosis challenges the policy of transfusing plasma or platelets before invasive procedures in patients with prolonged PT or severe thrombocytopenia. Recent guidelines recommend against plasma transfusion and suggest avoiding/minimizing platelet transfusions. AIM: We assessed how hepato-gastroenterologists manage prolonged PT/INR or severe thrombocytopenia before invasive procedures. METHODS: On May 2021, AISF members were sent a questionnaire addressing the PT/INR and platelet thresholds required before invasive procedures, the use of other markers of bleeding risk or other hemostatic treatments and the burden of pre-emptive plasma and platelet transfusions. RESULTS: Of 62 respondents, 94% and 100% use PT/INR and platelet count to assess bleeding risk, respectively. Only 37% and 32% require less conservative PT/INR or platelet counts thresholds for low-risk procedures, respectively. As for those applying single thresholds, 68% require PT/INR <1,5 and 86% require platelet counts ≥50 × 109/L. Half respondents use additional indicators of bleeding risk and 63% other hemostatic treatments. Low-risk procedures account for 70% of procedures, and for 50% and 59% of plasma and platelets units transfused, respectively. CONCLUSIONS: the survey indicates lack of compliance with guidelines that advise against plasma and platelet transfusions before invasive procedures and the need for prospective studies and inter-society consensus workshops.

Evaluation of procoagulant imbalance in Cushing's syndrome after short- and long-term remission of disease.

OBJECTIVE: Patients with Cushing's syndrome (CS) are at high risk of venous thromboembolism related to a hypercoagulability due to procoagulant imbalance. However, whether these alterations are reversible after disease remission is still unclear. The endogenous thrombin potential (ETP) measured with and without the addition of thrombomodulin provides a global representation of coagulation and previous data confirmed hypercoagulable profile in patients with active hypercortisolism. Aim of this study was to assess the short- and long-term modification of ETP in patients with CS after disease remission. DESIGN AND METHODS: Nineteen patients with CS for whom surgical remission was achieved, were prospectively evaluated for clinical characteristics, cortisol secretion profile and ETP at different time points: (i) before surgical intervention; (ii) after 6 months and (iii) 5 years from the time of persistent remission. Nineteen healthy subjects matched for age and gender were also evaluated as control group. RESULTS: Before surgery, patients showed higher ETP-ratio (with/without thrombomodulin) than controls (0.62 ± 0.09-vs-0.56 ± 0.09, p = 0.034). No significant correlation between ETP-ratio and cortisol secretion was found. 6 months after remission, ETP-ratio was still significantly increased compared to controls (0.64 ± 0.09-vs-0.56 ± 0.09, p = 0.01), but was similar to baseline (0.64 ± 0.09-vs-0.62 ± 0.09, p = 0.87). At 5 years, ETP-ratio showed a significant decrease (0.55 ± 0.14-vs-0.62 ± 0.09, p = 0.02) and was comparable to controls (0.55 ± 0.14-vs-0.56 ± 0.09, p = 0.7). CONCLUSIONS: Plasma hypercoagulability detected in patients with active hypercortisolism persists at short-term evaluation and seems to be completely reversible after long-term remission of disease. These data, as part of a whole evaluation of thrombotic risk, can contribute to make appropriate therapeutic choice in these patients.

Low drug levels and thrombotic complications in high-risk atrial fibrillation patients treated with direct oral anticoagulants.

Essentials Direct oral anticoagulants (DOACs) do not require laboratory monitoring currently. DOAC specific measurements were performed at trough in patients with atrial fibrillation. Patients who developed thromboembolic events showed lower DOAC plasma levels. This study supports the concept of measuring DOAC levels at steady state. SUMMARY: Background Direct oral anticoagulants (DOACs) are administered at fixed doses without the need for dose adjustment according to laboratory testing. High interindividual variability in drug blood levels has been shown with all DOACs. To evaluate a possible relationship between DOAC C-trough anticoagulant levels and thromboembolic events, 565 consecutive naive patients with atrial fibrillation (AF) were enrolled in this study performed within the START Laboratory Registry. Methods DOAC-specific measurements (diluted thrombin time or anti-activated factor II calibrated for dabigatran; anti-activated FX calibrated for rivaroxaban or apixaban) at C-trough were performed locally at steady state within 15-25 days after the start of treatment. For each DOAC, the interval of C-trough levels, from the limit of quantification to the highest value, was subdivided into four equal classes, and results were attributed to these classes; the median values of results were also calculated. Thromboembolic complications occurring during 1 year of follow-up were recorded. Results Thromboembolic events (1.8%) occurred in 10 patients who had baseline C-trough levels in the lowest class of drug levels. The incidence of thromboembolic events among patients with DOAC C-trough levels in the lowest level class was 2.4%, and that in the remaining groups was 0%. The patients with thrombotic complications also had a higher mean CHA2 DS2 -VASc score than that of the total patient population: 5.3 (95% confidence interval [CI] 4.3-6.3 versus 3.0 (95% CI 2.9-3.1). Conclusion In this study cohort, thrombotic complications occurred only in DOAC-treated AF patients who had very low C-trough levels, with a relatively high CHA2 DS2 -VASc score. Larger studies are warranted to confirm these preliminary observations.

Interlaboratory variability in the measurement of direct oral anticoagulants: results from the external quality assessment scheme.

Essentials Tests for direct oral anticoagulants (DOACs) are not widely applied. These tests are perceived to be difficult to run and subjected to large between-lab variation. We carried out proficiency testing surveys for DOAC testing in Italy. Interlab variability was small and similar to that of the international normalised ratio. SUMMARY: Background Tests for direct oral anticoagulants (DOACs) are not widely available. The perception that they are difficult to perform and are subject to large between-laboratory variation makes their implementation difficult. Aims We carried out proficiency-testing surveys for DOACs within the activity of the external quality-assessment scheme of the Italian Federation of Thrombosis Centers. Design Participants were provided with coded freeze-dried plasmas without or with graded concentrations of the three main DOACs, and asked to measure prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time and DOAC concentrations with dedicated tests. The results were centralized for statistical analysis. Results and conclusions All participants (n = 235) reported results for PT and APTT, and approximately one-third reported results for DOAC concentration. PT and APTT showed variable responsiveness to DOACs: PT was more responsive to rivaroxaban than to dabigatran or apixaban. APTT was more responsive to dabigatran than to rivaroxaban or apixaban. The thrombin time ratio (test/normal) was close to unity for plasmas without dabigatran, and was high (i.e. 7.6-fold or 15.4-fold longer than the plasma free from the drug) for plasmas containing dabigatran at low (i.e. 42 ng mL-1 ) or high (i.e. 182 ng mL-1 ) concentration. Dedicated tests were responsive to the respective drugs, and their interlaboratory variability was relatively small (overall coefficients of variation of 8.7%, 8.4% or 10.3% for dabigatran, rivaroxaban and apixaban, respectively) and was comparable to that observed within the same survey for the International Normalized Ratio (i.e. 11.4%). In conclusion, tests for DOAC measurement performed reasonably well in a national quality-control scheme. Regulatory authorities should urgently issue recommendations on their use, and clinical laboratories should make them available.

Comparison of five specific assays for determination of dabigatran plasma concentrations in patients enrolled in the START-Laboratory Register.

INTRODUCTION: Several specific assays are commercially available to determine dabigatran anticoagulant activity. Aims of this multicenter and multiplatform study were to compare five methods for dabigatran measurement and investigate their performances in the low concentration range. METHODS: Dabigatran levels were analyzed in 295 plasma samples from patients enrolled in the START-Laboratory Register by the following methods using dedicated calibrators and controls: STA-ECA II (Diagnostica Stago), standard and low range Hemoclot Thrombin Inhibitors (Hyphen BioMed), Direct Thrombin Inhibitor Assay (Instrumentation Laboratory), Direct Thrombin Inhibitor Assay (Siemens), Technoclot DTI (Technoclone). RESULTS: Methods showed variable agreement with the Hemoclot Thrombin Inhibitors assay used as reference test, with modest under- or overestimations (Bland-Altman bias from -17.3 to 4.0 ng/mL). Limits of detection and quantification varied depending on the assay (4-52 and 7-82 ng/mL, respectively). Between-run precision and accuracy were good for all methods for both quality control levels. Assay's repeatability assessed at very low dabigatran concentrations (from 10 to 60 ng/mL) was also acceptable, variability generally increased at lower drug levels. CONCLUSION: The five dabigatran-specific assays evaluated in this study provided reliable assessment of dabigatran plasma levels, although showing different performances.

International collaborative study for the calibration of proposed International Standards for thromboplastin, rabbit, plain, and for thromboplastin, recombinant, human, plain.

Essentials Two candidate International Standards for thromboplastin (coded RBT/16 and rTF/16) are proposed. International Sensitivity Index (ISI) of proposed standards was assessed in a 20-centre study. The mean ISI for RBT/16 was 1.21 with a between-centre coefficient of variation of 4.6%. The mean ISI for rTF/16 was 1.11 with a between-centre coefficient of variation of 5.7%. SUMMARY: Background The availability of International Standards for thromboplastin is essential for the calibration of routine reagents and hence the calculation of the International Normalized Ratio (INR). Stocks of the current Fourth International Standards are running low. Candidate replacement materials have been prepared. This article describes the calibration of the proposed Fifth International Standards for thromboplastin, rabbit, plain (coded RBT/16) and for thromboplastin, recombinant, human, plain (coded rTF/16). Methods An international collaborative study was carried out for the assignment of International Sensitivity Indexes (ISIs) to the candidate materials, according to the World Health Organization (WHO) guidelines for thromboplastins and plasma used to control oral anticoagulant therapy with vitamin K antagonists. Results Results were obtained from 20 laboratories. In several cases, deviations from the ISI calibration model were observed, but the average INR deviation attributabled to the model was not greater than 10%. Only valid ISI assessments were used to calculate the mean ISI for each candidate. The mean ISI for RBT/16 was 1.21 (between-laboratory coefficient of variation [CV]: 4.6%), and the mean ISI for rTF/16 was 1.11 (between-laboratory CV: 5.7%). Conclusions The between-laboratory variation of the ISI for candidate material RBT/16 was similar to that of the Fourth International Standard (RBT/05), and the between-laboratory variation of the ISI for candidate material rTF/16 was slightly higher than that of the Fourth International Standard (rTF/09). The candidate materials have been accepted by WHO as the Fifth International Standards for thromboplastin, rabbit plain, and thromboplastin, recombinant, human, plain.

Variability of cut-off values for the detection of lupus anticoagulants: results of an international multicenter multiplatform study.

Essentials Between-lab variations of cut-off values in lupus anticoagulant detection are unknown. Cut-off values were calculated in 11 labs each testing plasma from 120 donors with 3 platforms. Major variation was observed even within the same platform. Cut-off values determined in different labs are not interchangeable. SUMMARY: Background Cut-off values for interpretation of lupus anticoagulant (LA) detection are poorly investigated. Aims (i) To assess whether results from healthy donors were normally distributed and (ii) the between-laboratories differences in cut-off values for screening, mixing and LA confirmation when calculated as 99th or 95th centiles, and (iii) to assess their impact on the detection rate for LA. Methods Each of 11 laboratories using one of the three widely used commercial platforms for LA detection was asked to collect plasmas from 120 healthy donors and to perform screening, mixing and LA confirmation with two methods (activated partial thromboplastin time [APTT] and dilute Russell viper venom [dRVV]). A common set of LA-positive or LA-negative freeze-dried plasmas was used to assess the LA detection rate. Results were centralized (Milano) for statistical analysis. Results and conclusions (i) Clotting times or ratios for healthy subjects were not normally distributed in the majority of cases. The take-home message is that cut-off values should be determined preferably by the non-parametric method based on centiles. (ii) There were relatively large inter-laboratory cut-off variations even within the same platform and the variability was marginally attenuated when results were expressed as ratios (test-to-normal pooled plasma). The take-home message is that cut-off values should be determined locally. (iii) There were differences between cut-off values calculated as 99th or 95th centiles that translate into a different LA detection rate (the lower the centile the greater the detection rate). The take-home message is that cut-off values determined as the 95th centile allow a better LA detection rate.

Poor comparability of coagulation screening test with specific measurement in patients receiving direct oral anticoagulants: results from a multicenter/multiplatform study.

Essentials Prothrombin and partial thromboplastin time (PT/PTT) measure direct oral anticoagulants (DOACs). PT, PTT and specific tests for DOACs were performed on patients treated for atrial fibrillation. Normal PT/PTT don't exclude DOAC activity and their prolongation doesn't confirm DOAC action. The use of PT or PTT to evaluate DOAC activity could cause dangerous misinterpretations. SUMMARY: Background Prothrombin time (PT) and activated partial thromboplastin time (APTT) have been proposed to measure the effect of oral anti-activated factor X (FXa) or anti-activated FII drugs, respectively. Aims To evaluate the relationships and responsiveness of PT and APTT versus direct oral anticoagulant (DOAC) concentrations measured with specific coagulation tests performed with different platforms in four Italian anticoagulation clinics. Methods Six hundred and thirty-five patients with atrial fibrillation participated in the study: 240 were receiving dabigatran, 264 were receiving rivaroxaban, and 131 were receiving apixaban. Blood was taken at trough and peak within the first month (15-25 days) of treatment. PT, APTT, diluted thrombin time (dTT) calibrated for dabigatran and anti-FXa calibrated for rivaroxaban or apixaban were determined. Results For dabigatran, the correlation between APTT and dTT ranged from r = 0.80 to r = 0.62. For rivaroxaban, the correlation between the anti-FXa assay and PT ranged from r = 0.91 to r = 0.73. For apixaban, the correlation between the anti-FXa assay and PT was lower than for the two other drugs (r = 0.81 to r = 0.54). Despite the above significant correlations, the responsiveness of PT or APTT was relatively poor. A discrepancy between global testing and DOAC plasma concentrations was shown in a considerable proportion of patients, depending on the platform and drug, with values ranging from 6% to 62%. Conclusions Overall, poor responsiveness of the screening tests to DOAC concentrations was observed. PT and APTT normal values cannot exclude DOAC anticoagulant activity, and PT or APTT prolongation is not always associated with DOAC anticoagulant effect as determined with specific tests.

Evaluation of a new PT-INR monitoring system in patients with the antiphospholipid syndrome.

INTRODUCTION: Patients on anticoagulant therapy with vitamin K antagonists (VKA) need frequent INR monitoring. Reliability of point-of-care (POC) devices for measuring INR needs rigorous evaluation, particularly in patient with the antiphospholipid syndrome (APS). The aim of this study was to evaluate the accuracy of the ProTime InRhythm(™) System (here called device) for INR measurement in patients with APS on VKA. METHODS: We compared the device INR vs. the laboratory INR measurement for blood samples from 29 APS-positive and 31 APS-negative patients consecutively enrolled. APS was confirmed by positive serological and/or phospholipid-dependent coagulation tests. Chromogenic factor X assay was used to evaluate anticoagulation. Bland-Altman difference plot for paired INR (POC vs. laboratory) was used to evaluate agreement between the device and the laboratory. The device INR relationship with factor X chromogenic assay was evaluated by orthogonal regression analysis. RESULTS: Overall, 97% of the device INR measurements were similar to laboratory INR values with an absolute difference less than 0.4 units. Correlation coefficient for the device INR vs. factor X was -0.69 (P < 0.0001, CI 95% -0.80 to -0.52). CONCLUSIONS: The ProTime InRhythm System(™) is an accurate point-of-care device for measuring INR also in patients with and without APS.

OC-15 - Risk factors for cancer development after idiopathic venous thromboembolism.

INTRODUCTION: Idiopathic venous thromboembolism (VTE) is associated with the risk of cancer but the risk factors for cancer development in such patients are still uncertain. AIM: To assess risk factors for the development of cancer after a standard course of anticoagulation in patients with first episode of idiopathic VTE. MATERIALS AND METHODS: Subjects were enrolled in the three large prospective multicentre studies: PROLONG (NEJM 2006) PROLONG II (Blood 2010) and DULCIS (Blood 2014). Women whose index event was hormone related were excluded from the analysis. The development of cancer was recorded during a 2-year follow-up. RESULTS: 1,805 patients were enrolled (M/F: 510/453), mean age: 62, median: 67; range:18-87 years). Cancer developed in 55 patients (3% ; 1.7% pt-years) of whom 15 (2.0%; 1.1% pt-years) had PE with or without DVT and 40 (3.8%; 2.1% pt-years) had DVT without PE (p=0.03). The development of cancer was associated with DVT without PE (HR:1.8; 95% CI: 1.1-3.3) and age >65 (HR: 2.5; 95%: 1.3-4.9). Among patients with DVT, with or without PE, the development of cancer was associated with the presence of residual vein obstruction>4mm (RVO) at compression ultrasound (HR: 1.8, 95% CI: 1.1-3.3) and age>65 (HR: 2.8; 95% CI: 1.3-6.2). CONCLUSIONS: Age>65 years, DVT without PE and the presence of RVO are significantly associated with the risk of developing cancer after a first episode of idiopathic VTE over a two-year follow-up.

The thrombin generation assay distinguishes inhibitor from non-inhibitor patients with severe haemophilia A.

INTRODUCTION: Patients with haemophilia A (HA) have impaired thrombin generation (TG) capacity and TG assay (TGA) values are linearly related to plasma factor VIII (FVIII) levels. AIM: This study carried out in patients with unmeasurable FVIII (<1 IU dL(-1) ) was aimed at unravelling any difference in TG capacity in patients with or without inhibitors. METHODS: Blood samples were collected from patients in a non-bleeding state, after a 5-day wash-out period from last treatment. RESULTS: TGA was performed in 102 patients with severe HA (15% with high-responding inhibitors; 51% with null F8 mutations, that as expected were more prevalent in inhibitor than in non-inhibitor patients). TG capacity was significantly lower in inhibitor than non-inhibitor patients and in those with null mutations than in those with non-null mutations. When the TG capacity was evaluated only in patients with null mutations with and without inhibitors it was lower in the presence of inhibitors. CONCLUSIONS: This study shows a greater TG impairment in inhibitor patients irrespective of FVIII levels, inhibitor titre and F8 mutation type, suggesting a role for the TGA in unravelling functional interferences of anti-FVIII inhibitors on coagulation system activation.

Low thrombin generation during major orthopaedic surgery fails to predict the bleeding risk in inhibitor patients treated with bypassing agents.

INTRODUCTION: In the presence of high-titre inhibitors, haemostatic bypassing agents are used to control bleeding and perform surgery. In this setting, no specific laboratory test is yet available to guide drug choice, monitor treatment efficacy and predict the risk of bleeding. AIM: The aims of this study, carried out in patients candidate to orthopaedic surgery, were to assess the dose-dependent increase in thrombin generation (TG) after infusion of bypassing agents and to evaluate whether or not a correlation existed between the haemostatic efficacy of bypassing therapies and perioperative TG values. METHODS AND RESULTS: TG was measured in 16 inhibitor patients, 10 of whom underwent 11 major orthopaedic procedures. In the non-bleeding state, TG significantly improved 30 min after whichever dose (P < 0.01), with no dose-response relationship when values obtained after different rFVIIa doses were compared. TG significantly improved 30 min after the preoperative bolus (P < 0.05), while during the postoperative period TG values measured before and after dosing did not differ. Moreover, postoperative TG values were similar or even more impaired (P ≤ 0.05) than those measured before preoperative dosing. No difference was found by comparing procedures with and without bleeding complications and yet no bleeding occurred in spite of persistently low TG values in one-third of procedures. CONCLUSION: This study fails to support a definite role for the TG assay as a reliable laboratory tool to monitor the haemostatic efficacy of bypassing therapies and as a predictor of the risk of bleeding in inhibitor patients using these agents during orthopaedic surgery.

To measure or not to measure direct oral anticoagulants before surgery or invasive procedures.

Patients on direct oral anticoagulants (DOAC) may need interruption of treatment before surgery or invasive procedures. Owing to their favorable pharmacokinetics, DOAC could be interrupted for a fixed number of days before surgery or invasive procedures without laboratory testing. However, there are a number of issues that raise concerns about the safety of this strategy. In contrast, laboratory testing prior to surgery or invasive procedures would provide a direct assessment of the residual drug concentration and minimize the risk of bleeding. This forum is aimed at discussing the pros and cons of the two strategies and fostering discussion on this important issue. Overall, the laboratory strategy appears superior in terms of patient safety and should be considered in patients undergoing surgical or invasive procedures.