Erroneous Activated Coagulation Time During Atrial Flutter Ablation

When performing left-sided catheter ablation, anticoagulation is used to prevent formation of thrombi that might embolize. After heparin administration, appropriate anticoagulation is confirmed by measuring Activated Coagulation Time (ACT). We report a case during which ACT results were erroneous, and review alternatives to the ACT under such circumstances.

Intraoperative Monitoring of Heparin: Comparison of Activated Coagulation Time and Whole Blood Heparin Measurements by Different Point-of-Care Devices with Heparin Concentration by Laboratory-Performed Plasma Anti-Xa Assay

BackgroundCardiac surgical interventions, extracorporeal membrane oxygenation, transcutaneous coronary-artery angioplasty, and stenting are carried out while patients are being treated with the anticoagulation drug heparin. Monitoring the level and reversal of heparinization during and at the conclusion of medical and surgical procedures is a critical issue in patient care.MethodsWe performed parallel testing of the ACCRIVA Hemochron Signature Elite ACT+ and Hemochron Response analyzer, iSTAT platform, and 2 Hepcon Hemostasis Management System (HMS) Plus analyzers for monitoring intraoperative heparin treatment. Laboratory anti-Xa assay was used as the criterion standard for heparin measurement.ResultsPoor correlation between the 2 Hemochron analyzers was identified at 0.78. Correlation between the analyzers on the i-STAT platform was 0.97. Regression analysis revealed that i-STAT values were generally lower, by 43 seconds, than Hemochron values. The correlation between Hepcon and i-STAT activated clotting time (ACT) results was 0.94. The i-STAT ACT results were generally 23 seconds lower than the Hepcon ACT values. Correlation coefficients on comparing Hepcon ACT and i-STAT ACT using laboratory anti-Xa assay were 0.83 and 0.87, respectively. The correlation between Hepcon heparin concentration and anti-Xa results was 0.85.ConclusionsACT monitoring with iSTAT offers good correlation between instruments and with the Hepcon ACT. Hepcon occupies a specific niche in cardiac operating departments because of its ability to provide additional information regarding heparin concentration; however, lack of suitable proficiency testing may impair its use. The iSTAT is a more reliable platform for broader, hospital-wide application.

Anticoagulation Monitoring Under ECMO Support: A Comparative Study Between the Activated Coagulation Time and the Anti-Xa Activity Assay

Purpose: Extra Corporeal Membrane Oxygenation (ECMO) is used in cases of severe respiratory and/or circulatory failure over periods of several days to several weeks. Its circuitry requires a closely monitored anticoagulation therapy that is empirically supported by activated clotting time (ACT)—a method often associated with large inter- and intraindividual variability. We aimed to compare the measurement of heparin activity with ACT and the direct measurement of the heparin activity (anti-Xa) in a large ECMO population. Methods: All patients treated by venoarterial or venovenous ECMO in our intensive care unit between January 2014 and December 2015 were prospectively included. A concomitant measurement of the anti-Xa activity and ACT was performed on the same sample collected twice a day (morning–evening) for unfractionated heparin adaptation with an ACT target range of 180 to 220 seconds. Results: One hundred and nine patients (men 69.7%, median age 54 years) treated with ECMO (70.6% venoarterial) were included. Spearman analysis found no correlation between anti-Xa and ACT (ρ < 0.4) from day 1 and worsened over time. Kappa analysis showed no agreement between the respective target ranges of ACT and anti-Xa. Conclusions: We demonstrate that concomitant measurement of ACT and anti-Xa activity is irrelevant in ECMO patients. Since ACT is poorly correlated with heparin dosage, anti-Xa activity appears to be a more suitable assay for anticoagulation monitoring.

Impact of tranexamic acid on coagulation parameters in patients undergoing total knee replacement surgeries under tourniquet: an observational study

Background: A growing body of evidence has shown Tranexamic Acid (TXA) is effective in decreasing perioperative blood loss and transfusion requirements in both primary and revision joint arthroplasty. TXA is a synthetic drug which limits blood loss through inhibition of fibrinolysis and clot degradation. It helps reduce requirement of colloids and crystalloids and hence provides better haemodynamic stability. The aim of this study was to detect the effect of tranexamic acid on coagulation parameters and effect on bleeding in knee replacement surgeries performed under tourniquet.Methods: Patients undergone surgeries of Total Knee Replacement (TKR) performed under tourniquet were included in the study. A single dosage of 20 mg/kg per body weight of tranexamic acid was administered after application of a tourniquet. Three times blood sample was collected, and coagulation parameters were recorded and compared. The first sample was collected at the time of TXA injection and application of a tourniquet, second after 4 hours and third after 24 hours post TXA injection. Coagulation parameters noted were analyzed using Statistical analysis by SPSS software. All parameters were compared in relation to baseline i.e. at the time of TXA injection.Results: On comparison of demographic profile, morbidity, sofa score and hemodynamic parameters there was the insignificant difference (P > 0.05). Repeated measures of ANOVA at 95% Confidential Interval P value was 0.000 which is less than the significant level that is 0.05 so that value of Platelet Function (PF), Activated Coagulation Time (ACT) and Clot Rate (CR) at 0 hrs, 04 hrs and 24 hrs was statistically significant. Correlation between blood loss and difference of the value of ACT at 0 hrs and 04 hrs is a small negative correlation but statistically nonsignificant (P value is 0.359).Conclusions: After TXA administration there is a change in coagulation parameters like an Activated Coagulation Time (ACT), Platelet Function (PF), and Clot Rate (CR) measured at three intervals, hence it can be a guide to detect early derangement in the coagulation profile in a patient undergoing knee replace surgery. TXA correlation between blood loss with changes in parameters of coagulation i.e. ACT, PF and CR were noted but not significant.

Перший досвід застосування синтетичного антитромбіну-ІІІ (Атенатив) у кардіохірургічній практиці

В наші дні основна кількість операцій на серці проводиться в умовах штучного кровообігу, що супроводжується порушенням гемостазу. Дефіцит антитромбіну-III становить 0,02–1% серед населення. Головним клінічним проявом недостатності антитромбіну-III є тромбози. В роботі проведено власне дослідження зв’язку між рівнем антитромбіну-ІІІ та результатом активованого часу згортання під час штучного кровообігу в кардіохірургічній практиці. Продемонстровано, що кількісна і/або якісна недостатність антитромбіну-ІІІ призводить до ранніх післяопераційних ускладнень і порушень у системі гемостазу. Протягом 2016 року на базі ДУ «Науково-практичний медичний центр дитячої кардіології та кардіохірургії» був проведений аналіз рівня антитромбіну-ІІІ у 11 пацієнтів, середній вік яких складав 50,2±27,2 року. У 5 (45,4%) пацієнтів було наявне супутнє захворювання: у 4 (36,4%) пацієнтів – інфекційний ендокардит, у 1 (9%) – НСV. Рівень антитромбіну-ІІІ в досліджуваній групі дорівнював 87,5%, у пацієнтів із наявною супутньою патологією – 110,4%, що свідчить про якісний дефіцит антитромбіну-ІІІ у пацієнтів із супутнім інфекційним захворюванням. Середні показники активованого часу згортання в досліджуваній групі пацієнтів становили 352,4±18,6 с, після додаткового введення синтетичного антитромбіну-ІІІ в умовах штучного кровообігу вони досягали 535±77 с. Ми рекомендуємо емпіричне використання синтетичного антитромбіну-ІІІ кардіохірургічним хворим при АСТ (activated coagulation time) менше 400 с для виключення інтраопераційних ускладнень у вигляді тромбозів.

Persistent pit viper envenomation in a cat

Case summary A 4-year-old female spayed, indoor/outdoor domestic mediumhair cat presented with multiple bleeding puncture wounds and hemorrhagic shock. The cat was diagnosed with suspected pit viper envenomation based on the location and appearance of the bite wounds, as well as the presence of severe coagulopathy with prolonged activated coagulation time (762 s), which responded to antivenom administration. The clinical course of the cat was unique owing to the prolonged clinical signs of envenomation that appeared as intermittent coagulopathy and hemorrhage over a 2 week period. Five vials of antivenom were administered and three units of packed red blood cells were transfused over a 7 day period. The cat made a complete recovery with cessation of hemorrhage and normalization of clotting times. Relevance and novel information This is the first report of persistent pit viper venom-induced coagulopathy in the feline veterinary literature.