Coagulation Status Using Clot Wave Analysis in Patients With Prolonged Immobilization.

Recombinant porcine factor VIII (rpFVIII) is a hemostatic agent for acquired hemophilia A (AHA). Cross-reaction of auto-antibodies against rpFVIII has been reported, although no data are available in Japanese patients. This study investigated the cross-reactivity and coagulation potential of rpFVIII in plasma samples from Japanese patients with AHA. Cross-reactivity was calculated as the ratio of anti-porcine FVIII inhibitor titer (pFVIII-INH) to human FVIII inhibitor titer. Comprehensive coagulation potential was assessed by clot waveform analysis (CWA) and thrombin generation assay (TGA) in samples spiked with rpFVIII (equivalent to 200 U/kg). Nine of 16 plasma samples (56.3%) had positive pFVIII-INH, with a median cross-reactivity of 1.2%. FVIII activity (FVIII:C) was restored to > 100% in all samples upon spiking with rpFVIII, but was weakly correlated with pFVIII-INH. CWA parameters and most TGA parameters were restored to normal upon spiking with rpFVIII; correlation of these parameters with FVIII:C was similar to that observed in controls. Overall, cross-reactivity to rpFVIII in Japanese patients was similar to that reported in Caucasian patients. Our results suggest that an initial clinical dose of 200 U/kg rpFVIII could restore coagulation potential to normal, and that FVIII:C monitoring after rpFVIII administration may be more informative than pFVIII-INH before administration.

Clot waveforms are generated by coagulation analyzers, such as the ACL-TOP, that utilize photo-optical turbidimetric methods to measure prothrombin time (PT) and activated partial thromboplastin time (aPTT), which are standard clotting tests (SCTs). Additional quantitative clot waveform analysis (CWA) parameters include maximum velocity of the PT curve (PT1d), maximum acceleration of the aPTT curve (aPTT2d), and their change in optical density (ODdelta). We explored the potential for CWA to contribute unique information compared to SCTs and quantitative fibrinogen assay (QFA) in dogs with clinical indications for laboratory evaluation of coagulation. We retrospectively evaluated the frequency and agreement between normal, high, and low values of CWA and SCTs for 203 dogs relative to reference intervals (RIs). Most dogs had SCTs within RIs, but most CWA values were high regardless of whether SCT values were within, below, or above the RI. Agreement between SCTs and CWA was slight (kappa <30%). Clinically significant bleeding was noted in 28 of 203 (14%) dogs. SCTs were not different between bleeders and non-bleeders. Median QFA, PT1d, aPTTdelta, and aPTT2d values were statistically significantly higher than RIs in non-bleeders compared to bleeders, whose median values were not below RI. Compared with SCTs, CWA identified differences between the 2 groups. However, wide overlap between the 2 groups limits the use of CWA to clinically discriminate between bleeders and non-bleeders in a heterogeneous population of dogs. Further studies on the diagnostic utility of CWA in coagulopathic dogs are needed.

This study aimed to compare the prothrombin time (PT), international normalised ratio (INR) and activated partial thromboplastin time (aPTT) values obtained using the photo-optical method and to assess these values according to the reference method, which was the mechanical method. Plasma samples from 340 patients, submitted to our hospital's biochemistry laboratory for PT, INR, and aPTT analyses, were assayed using the mechanical coagulometric measurement method in a Stago Compact Max3 automated coagulation analyser, which served as the reference device. The same samples were also analysed using the Sunbio UP5500 automated analyser with a simultaneous optical method. There were 30 turbid samples analysed in both devices without exclusion from the study. Correlation coefficient analysis was carried out using SPSS to assess intervariable correlations. Passing-Bablok regression analysis was performed in R software version 3.6.0 to compare PT, INR, and aPTT values between the two devices. Bland-Altman plots were used to analyse the agreement. A good level of statistically significant agreement was found between the PT and INR values measured by the Stago Compact Max3 and Sunbio UP 5500 devices (Interclass Coefficient Correlation (ICC): 0.627, p=0.001; p<0.01 and ICC: 0.653, p=0.001; p<0.01, respectively). Additionally, there was an excellent level of statistically significant agreement for the aPTT values (ICC: 0.902, p=0.001, p<0.01). The Bland-Altman analysis revealed the mean 95% limits of agreement values as 2.46 (lower limit: -2.44, upper limit: 7.37) for PT, 0.07 (lower limit: -0.32, upper limit: 0.46) for INR, and 2.45 (lower limit: -1.67, upper limit: 6.58) for aPTT. The Passing-Bablok regression results indicated a systematic difference for PT measurement but no proportional difference. No systematic or proportional differences were found for the measured INR and aPTT values between the Stago Compact Max3 and Sunbio UP 5500 devices. The intra-assay and interassay coefficient of variation (CV) values from level 1 and 2 controls of the optical method were below 5%. The results from the optical method were consistent and reliable compared to the mechanical method. PT and INR results showed statistically good agreement, while aPTT results demonstrated excellent agreement. Larger multicenter studies are needed to evaluate turbid samples.

BackgroundClot wave analysis (CWA) during activated partial thromboplastin time (aPTT) measures the speed and extent of fibrin polymerization in the plasma. This study aimed to evaluate the effects of hemodilution on CWA parameter, clotting factors, and thrombin generation assays in a dilutional model.Material/MethodsPlatelet-poor plasma obtained from 11 healthy male volunteers was diluted with 0.9% sodium chloride by 10–80% to analyze coagulation profiles, CWA, clotting factors, and thrombin generation assays. CWA includes 5 parameters: the time-dependent variable (aPTT), rate/acceleration (min1, min2, and max2), and magnitude of signal change (delta).ResultsCritically low activities of 30% for clotting factors and 100 mg/dl of fibrinogen were determined at dilutions of 70% and 60%, respectively. Peak thrombin and endogenous thrombin potential were significantly lower compared with baseline after 50% and 80% dilution, respectively. aPTT did not correlate with the decrease in the clotting factors up to dilutions of 50% and subsequently became abnormal values. As the change in rate/acceleration parameters parallels the time course of clotting factor activity in a dilution-dependent linear manner, these parameters indicate an intervention threshold at critically low activities of clotting factors. The strongest correlations were observed between clotting factors and aPTT, clotting factors and min2, delta and peak thrombin (r=0.95), and delta and fibrinogen (r=0.98).ConclusionsaPTT was significantly correlated with clotting factors, while the rate/acceleration parameters and delta changed with variation in thrombin and fibrinogen generation. These findings may help in evaluating coagulability.

Prothrombin time (PT) and activated partial thromboplastin time (aPTT) are coagulative screening tests used for the diagnosis of several pathologic conditions, such as liver failure, coagulation factor deficiencies, anti-phospholipid antibodies (lupus anticoagulant), and factor VIII inhibitors. A new test was developed several years ago to detect the amount of thrombin generated during plasma clotting, using low tissue factor concentrations and fluorogenic substrates, and it has since been used successfully in conditions ranging from hypocoagulable to hypercoagulable states. However, the test is expensive and difficult to perform in nonspecialized laboratories, and efforts have thus been made to find an economic and easily implementable test suitable for routine use, even in nonspecialist laboratories. To evaluate clot waveform analysis (CWA) of PT and aPTT, aiming to show the dynamics of clot formation; that is, the "hidden" features of both tests. CWA can be implemented by using an automated coagulometer with dedicated software. The aim of this review was to evaluate whether CWA is able to detect both hypercoagulative and hypocoagulative states. Using MedLine, we searched and retrieved articles relating to CWA. We only considered articles published in English, but with no limits in terms of article type, publication year, or geography. CWA was shown to be a reliable test in patients with both hypercoagulable and hypocoagulable states. It represents a simple and inexpensive global test that can easily provide information on the behavior of the coagulation system. Both the first and second derivatives are computed by using dedicated software implemented with an on-board algorithm in a routine automated coagulometer.

The mixing test is used to identify the pathway to follow-up testing and is also useful for the investigation of lupus anticoagulant (LA) positivity. "To completely correct" indicates clotting factor deficiency, while "to not correct" indicates the presence of a clotting factor inhibitor including LA. "Index of circulation anticoagulant" and/or "percent correction" is used to interpret the results of mixing studies, but it does not accurately differentiate factor inhibitors from LA. To precisely differentiate hemophilia A (HA), HA with inhibitor (HA-inh), and LA using the clot waveform analysis (CWA)-based mixing test. Plasma samples from HA, LA, and HA-inh including acquired HA were incubated with normal plasma in 9:1, 1:1, and 1:9 mix ratios. From activated partial thromboplastin time CWA at 0-minute (immediately) and 12-minute incubation, the ratios of CWA parameters at 12 minutes/0 minute (inhibitor index) were assessed. The inhibitor index values of CWA parameters obtained using the mixing test in a 1:1 ratio demonstrated a significant difference between HA-inh and LA but could not differentiate LA from HA-inh completely. Plasmas used for the mixing tests in 9:1 and 1:9 ratios were able to fully distinguish between HA-inh (>0.5 BU/mL) and LA. These indices significantly correlated with inhibitor titer below 40 BU/mL (r > 0.90), possibly estimating FVIII inhibitor titer from the inhibitor index. Plasmas in HA and LA could be distinguished by mixing in a 1:1 ratio at 0 minute (immediately). The inhibitor index from CWA-based mixing tests with a 12-minute incubation could differentiate among HA, HA-inh, and LA quickly.

Background: Hepatic function, coagulation disorders, and the risk of postoperative bleeding can all be detected with PT assay. When it comes to measuring "extrinsic route" coagulation factors, the PT is the most commonly used test. It is possible to check for a lack of intrinsic or common route factors by measuring the duration to trigger partial thromboplastin (aPTT). A solution to the problem of inconsistent PT measurements among laboratories was the creation of the International Normalized Ratio (INR). Laboratory-specific reference intervals can have a significant impact on the quality of patient treatment by influencing clinical decision-making. Objective: The purpose of this study is to determine if gender and age affect PT, International normalised ratio (INR), and aPTT levels in people without known liver disease or anticoagulant therapy. Method: Between July and December of 2021, patients without a past history of bleeding were admitted to the LUMHS Hyderabad civil hospital for minor surgical procedures (inguinal/umbilical hernia repair, caesarean section, rectal polyp excision, and diagnostic cystoscopy). There were 2274 patients in all, with 766 males and 1508 females. According to their chronological age, patients were separated into three groups. The study sampled 268 men and 22 women aged 0-14, 222 men and 1335 women aged 15-50, and 151 women and 276 men in the third age range (over the age of 50 year). Systemex CA-500 auto analyzer was used to conduct the analyses. Results: Males and females have considerably different PT and INR values. Men and women between the ages of 15 and 50 were more likely to have increased PT, INR, and aPTT readings than those between the ages of 0 and 14. Males and females between the ages of zero and fourteen had the lowest aPTT levels. Between the ages of 15 and 50, women and men had higher PT, INR, and aPTT values than women and men over 50. PT, INR, and aPTT reference values based on a 95% confidence interval for men and women, as well as sexes and ages. Conclusion: In this arena, a dearth of study has established that gender and age have little effect on PT, INR, and aPTT levels. Gender and age disparities in clinically used reference ranges for PT, INR, and aPTT must be taken into account. Keywords: Prothrombin Time, INR, APTT, Outcomes

Ad Integrum Functional and Volumetric Recovery in Right Lobe Living Donors: Is It Really Complete 1 Year After Donor Hepatectomy?

Optimal monitoring of bypass therapy in hemophilia A patients with inhibitors by the use of clot waveform analysis

Cardiovascular diseases remain a leading cause of mortality worldwide, with thrombosis as a major contributing factor, necessitating continued exploration of alternative and cost-effective anticoagulant agents. This study examined the anticoagulant activity of shallot (Allium ascalonicum) extracts using standard coagulation assays in human blood plasma. An experimental, quantitative design was employed using plasma obtained from fifteen healthy adult donors with blood type O. Aqueous shallot extracts were prepared at concentrations of 25%, 50%, and 75% and subjected to phytochemical screening. Anticoagulant activity was assessed using prothrombin time (PT) and activated partial thromboplastin time (aPTT) assays, with untreated plasma and heparin-treated plasma serving as negative and positive controls, respectively. Phytochemical analysis confirmed the presence of flavonoids, alkaloids, saponins, glycosides, and tannins in the extract. One-way analysis of variance revealed significant differences in PT (p = 0.014) and aPTT (p &lt; 0.001) values across treatment groups. Higher extract concentrations produced a dose-dependent prolongation of aPTT, while PT values showed significant but non-linear changes. The findings provide evidence that Allium ascalonicum extract demonstrates anticoagulant activity in human plasma under in vitro conditions, supporting further investigation of shallots as a potential natural anticoagulant source.

NUTTALL, G. A.; OLIVER, W. C.; BEYNEN, F. M.; SANTRACH, P. J.; STRICKLAND, R. A.; MURRAY, M. J. Author Information

Severe COVID-19 patients demonstrate hypercoagulability, necessitating thromboprophylaxis. However, less is known about the haemostatic profile in mild COVID-19 patients. We performed an age and gender-matched prospective study of 10 severe and 10 mild COVID-19 patients. Comprehensive coagulation profiling together with Thromboelastography and Clot Waveform Analysis were performed. FBC, PT, APTT, D-dimer, fibrinogen and CWA were repeated every 3 days for both groups and repeat TEG was performed for severe patients up till 15 days. On recruitment, severe patients had markers reflecting hypercoagulability including raised median D-dimer 1.0 μg/mL (IQR 0.6, 1.4) (p = 0.0004), fibrinogen 5.6 g/L (IQR 4.9, 6.6) (p = 0.002), Factor VIII 206% (IQR 171, 203) and vWF levels 265.5% (IQR 206, 321). Mild patients had normal values of PT, aPTT, fibrinogen and D-dimer, and slightly elevated median Factor VIII and von Willebrand factor (vWF) levels. Repeated 3-day assessments for both groups showed declining trends in D-dimer and Fibrinogen. CWA of severe COVID-19 group demonstrated hypercoagulability with an elevated median values of aPTT delta change 78.8% (IQR 69.8, 85.2) (p = 0.001), aPTT clot velocity (min1) 7.8%/s (IQR 6.7, 8.3) (p = 0.001), PT delta change 22.4% (IQR 19.4, 29.5) (p = 0.004), PT min1 7.1%/s (IQR 6.3, 9.0) (p = 0.02), PT clot acceleration (min 2) 3.6%/s2 (IQR 3.2, 4.5) (p = 0.02) and PT clot deceleration (max2) 2.9%/s2 (IQR 2.5, 3.5) (p = 0.02). TEG of severe patients reflected hypercoagulability with significant increases in the median values of CFF MA 34.6 mm (IQR 27.4,38.6) (p = 0.003), CRT Angle 78.9° (IQR 78.3, 80.0) (p = 0.0006), CRT A10 67.6 mm (IQR 65.8, 69.6) (p = 0.007) and CFF A10 32.0 mm (IQR 26.8, 34.0) (p = 0.003). Mild COVID-19 patients had absent hypercoagulability in both CWA and TEG. 2 severe patients developed thromboembolic events while none occurred in the mild COVID-19 group. Mild COVID-19 patients show absent parameters of hypercoagulability in global haemostatic tests while those with severe COVID-19 demonstrated parameters associated with hypercoagulability on the global haemostatic tests together with raised D-Dimer, fibrinogen, Factor VIII and vWF levels.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11239-021-02575-4.

The authors performed a study to evaluate whether preoperative assessment of prothrombin time (PT) is mandatory in patients undergoing routinely planned neurosurgical procedures. The charts of all patients admitted to general wards of the authors' department for routinely planned surgery (excluding trauma and ICU patients) between 2006 and 2010 were retrospectively reviewed. The authors assessed preoperative PT and the clinical courses of all patients, with special consideration for patients receiving coagulation factor substitution. All cases involving hemorrhagic complications were analyzed in detail with regard to pre- and postoperative PT abnormalities. Prothrombin time was expressed as the international normalized ratio, and values greater than 1.28 were regarded as elevated. Clinical courses and PT values of 4310 patients were reviewed. Of these, 33 patients (0.7%) suffered hemorrhagic complications requiring repeat surgery. Thirty-one patients (94%) had a normal PT before the initial operation, while 2 patients had slightly elevated PT values of 1.33 and 1.65, which were anticipated based on the patient's history. In the latter 2 cases, surgery was performed without prior correction of PT. Preoperatively, PT was elevated in 78 patients (1.8%). In 73 (93.6%) of the 78 patients, the PT elevation was expected and explained by each patient's medical history. In only 5 (0.1%) of 4310 patients did we find an unexpected PT elevation (mean 1.53, range 1.37-1.74). All 5 patients underwent surgery without complications, while 2 had received coagulation factor substitution preoperatively, as requested by the surgeon, because of an estimated risk of bleeding complications. None of the 5 patients received coagulation factor substitution postoperatively, and later detailed laboratory studies ruled out single coagulation factor deficiencies. There was no statistically significant association between preoperatively elevated PT levels and the occurrence of hemorrhagic complications (p = 0.12). Before the second procedure but not before the initial operation, 4 (12%) of the 33 patients had elevated PT. The findings suggest that the value of preoperative PT testing is limited in patients in whom a normal history can be ascertained. Close postoperative PT control is necessary in every neurosurgical patient, and better tests need to be developed to identify patients who are prone to hemorrhagic complications.

The authors evaluated the reliability of prothrombin time (PT) and activated partial thromboplastin time (aPTT) determination on a bedside coagulation monitor (CoaguChek Pro DM; Roche Diagnostics, Germany). Measurement of PT and aPTT was performed in 54 specimens and was compared with reference laboratory methods. The obtained values for PT and aPTT in healthy subjects on CoaguChek were close to the reference interval established by the manufacturer, as well as the laboratory reference interval. Despite the good correlation coefficients for PT (r = 0.958) and aPTT (r = 0.885), there was an important dispersion of values between 2 methods as shown by Bland and Altman plots. In the group of 19 patients on oral anticoagulant therapy, comparable values were observed in 14 cases, whereas discrepancy between 5 results could lead to a different therapeutic decision. CoaguChek aPTT determination was shown to be a good method for monitoring unfractionated heparin therapy. However, the results should not be compared with each other, and the same technique should always be chosen to monitor patients.

Possible international normalized ratio elevation associated with celecoxib and warfarin in an elderly psychiatric patient.