Model construction and application for predicting pre-eclampsia by Sonoclot coagulation analyzer

Maternal age has significantly increased among Chinese women, thereby posing risk of pregnancy-related complications. Preeclampsia is a leading cause of maternal and perinatal morbidity and mortality, and coagulation analysis in conjunction with clinical signs and symptoms are generally used for its diagnosis with limited efficacy. Sonoclot coagulation analyzer is effective in assessing coagulation function used during cerebral surgery and cardiovascular surgery. However, its use has not been explored in preeclampsia. Here, we investigated the potential use of Sonoclot in diagnosing preeclampsia in obstetrics cases. Subjects meeting the screening criteria were divided either into a test group or a control group, according to whether they were preeclamptic or not. We recorded the Sonoclot-derived coagulation and the routine coagulation parameters including platelet function (PF), activated clotting time (ACT) and clot rate (CR), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (FIB), and platelet count. Regression analysis was done on the relevant parameters to assess the feasibility of Sonoclot analyzer in preeclampsia diagnosis. In parallel, changes in preeclampsia lncRNAs was also evaluated. Significant differences were recorded in PT and ACT between the two groups. In the monovariant logistic regression, PT and ACT appeared to be reliable predictor variables. In the multinomial logistic regression, a total of five regression steps were performed with decreasing AIC values. The K-fold cross validation resulted in an accuracy rate (ACC) of 77.5%, a false positive rate of 16.4%, and a false negative rate of 33.2%. lncRNAs ANRIL and HOXD-AS1 were found deregulated. Our findings indicate that Sonoclot may be useful for diagnosis of preeclampsia in obstetrics.

Contributing factors to heparin resistance during cardiopulmonary bypass

Since the risk factors for heparin resistance (HR) before cardiopulmonary bypass (CPB) have not been fully clarified, this study investigated the contributing factors for HR after the initial unfractionated heparin (UFH) dose of 500 IU/kg. We retrospectively analyzed the data of 371 patients who underwent CPB surgery, with the initial UFH dose of 500 IU/kg, between May 2017 and December 2021. We defined HR as the failure to achieve activated clotting time (ACT) of > 480 s after the initial UFH dose of 500 IU/kg. HR was observed in 36 patients (9.7%) (HR group), while HR was not observed in 335 patients (control group). The HR group included significantly more patients with preoperative use of UFH, with significantly higher white blood cell counts, fibrinogen, fibrinogen degradation products, D-dimer, and C-reactive protein, and lower hemoglobin and albumin. The multivariable logistic regression analysis identified albumin (OR: 3.09, 95% CI 1.3504-7.0845, p = 0.0075) and fibrinogen (OR: 0.99, 95% CI 0.9869-0.9963, p = 0.0003) as independent predictors for HR. Using the Youden index, the cutoffs of albumin and fibrinogen were calculated as 3.8 g/dL and 303 mg/dL, respectively. The receiver operating characteristic curves showed the predictive performance of albumin (area under the curve (AUC): 0.78, sensitivity: 65%, specificity: 81%) and fibrinogen (AUC: 0.77, sensitivity: 56%, specificity: 88%). The incidence of HR after the initial UFH dose of 500 IU/kg was 9.7%. The preoperative albumin < 3.8 g/dL and fibrinogen > 303 mg/dL were independent predictors for HR.

Investigation of real-world heparin resistance and anticoagulation management prior to cardiopulmonary bypass: report from a nationwide survey by the Japanese Association for Thoracic Surgery heparin resistance working group

OBJECTIVE

Heparin resistance is often encountered during cardiopulmonary bypass. Heparin dose and activated clotting time target values for the initiation of cardiopulmonary bypass are not yet universally standardized; further no consensus exists on the management of heparin resistance. This study aimed to investigate the current real-world practice on heparin management and anticoagulant treatment for heparin resistance in Japan.

METHODS

A questionnaire survey was conducted at medical institutions nationwide with which The Japanese Society of Extra-Corporeal Technology in Medicine members are affiliated, targeting surgical cases with cardiopulmonary bypass performed from January 2019 through December 2019.

RESULTS

Among 69% (230/332) of the participating institutions, the criterion for heparin resistance was defined as "the target activated clotting time value not reached even with an additional dose of heparin administration". Cases of heparin resistance were reported in 89.8% (202/225) of the responded institutions. Of note, 75% (106/141) of the responded institutions reported heparin resistance associated with antithrombin activity ≥ 80%. Antithrombin concentrate was used in 38.4% (238/619 responses) or third dose of heparin in 37.8% (234/619 responses) for advanced heparin resistance treatment. Antithrombin concentrate was found to be effective in resolving heparin resistance in patients having normal, as well as lower antithrombin activity.

CONCLUSION

Heparin resistance has occurred in many cardiovascular centers, even among patients with normal antithrombin activities. Interestingly, the administration of antithrombin concentrate resolved heparin resistance, regardless of the baseline antithrombin activity value.

Variability in Contemporary Heparin Prescription and Activated Clotting Time Monitoring During Percutaneous Coronary Intervention: Call for Up-To-Date Evidence-Based Guidelines

BACKGROUND

Unfractionated heparin (UFH) is the preferred anticoagulant agent in percutaneous coronary intervention (PCI) procedures for minimising the risk of thrombotic complications. Because of the narrow therapeutic range of UFH, some society guidelines have advocated the use of the activated clotting time (ACT) test to monitor anticoagulation intensity during PCI to reduce thrombotic and bleeding complications. We aimed to assess the current practice of UFH prescription and its monitoring in Australia and New Zealand (ANZ).

METHOD

We conducted an anonymous voluntary cross-sectional survey of interventional cardiologists (ICs) who were members of the Cardiac Society of Australia and New Zealand in 2022. The survey included 10 questions pertaining to the current practice of anticoagulation during PCI.

RESULTS

Of 430 ICs surveyed, 148 responded (response rate, 34.4%). Most ICs (84.4%) prescribed 70-100 IU/kg of UFH for PCI. Over half of ICs (58.7%) routinely measured ACT during PCI, whereas only 22.2% routinely measured ACT after PCI to guide additional UFH prescription. Among ICs who prescribed additional UFH, approximately half (48%) aimed for ACT ≥250 seconds. Factors that influenced post-PCI UFH prescription included vascular access site and concomitant antiplatelet or anticoagulant therapy.

CONCLUSIONS

The contemporary practice of UFH prescription during PCI and ACT monitoring in ANZ is variable and based on outdated evidence preceding current drug-eluting stents, antiplatelet therapies, and radial-first practice. Current society guideline recommendations lack clarity and agreement, reflecting the quality of the available evidence. Up-to-date clinical trials evaluating UFH prescription and ACT monitoring are needed to optimise clinical outcomes in contemporary PCI procedures.

Feasibility and safety values of activated clotting time-guided systemic heparinization in coil embolization for unruptured intracranial aneurysms

OBJECTIVE

This study aimed to evaluate the feasibility and safety values of activated clotting time (ACT)-guided systemic heparinization in reducing periprocedural thrombosis and bleeding complications during coil embolization of unruptured intracranial aneurysms.

METHODS

A total of 228 procedures performed on 213 patients between 2016 and 2021 were included in the retrospective analysis. The target ACT was set at 250 s. Logistic regression was performed to assess predictors for the occurrence of thrombosis and bleeding. Receiver operating characteristic (ROC) analyses were employed to determine the optimal cut-off values for ACT, heparinization, and procedure time.

RESULTS

Most (85.1%) of procedures were stent-assisted embolization. The mean baseline ACT was 128.8 ± 45.7 s. The mean ACT at 20 min after the initial intravenous heparin loading of 78.2 ± 18.8 IU/kg was 185 ± 46.4 s. The mean peak ACT was 255.6 ± 63.8 s with 51.3% (117 cases) achieving the target ACT level. Peak ACT was associated with symptomatic thrombosis (OR per second, 1.008; 95% CI, 1.000-1.016; P = 0.035) (cut-off value, 275 s; area under ROC (AUROC), 0.7624). Total administered heparin dose per body weight was negatively associated with symptomatic thrombosis (OR per IU/kg, 0.972; 95% CI, 0.949-0995; P = 0.018) (cut-off value, 294 IU/kg; AUROC, 0.7426) but positively associated with significant bleeding (OR, 1.008 per IU/kg; 95% CI, 1.005-1.012; P <0 .001) (cut-off value, 242 IU/kg; AUROC, 0.7391). Procedure time was significantly associated with symptomatic thrombosis (OR per minute, 1.05; 95% CI, 1.017-1.084; P value = 0.002) (cut-off value, 158 min; area under ROC, 0.8338).

CONCLUSION

This study demonstrated that ACT-guided systemic heparinization was feasible to achieve the target ACT value and proposes probable safety thresholds to prevent periprocedural complications through reducing procedure time during coil embolization of unruptured intracranial aneurysms in the stent era.

Relationship between estimated and observed heparin sensitivity indices in cardiac and thoracic aortic surgery

BACKGROUND

Little evidence exists on the relationship between the estimated heparin sensitivity index (HSI) based on commonly available clinical and laboratory data and observed HSI in the adult population. This retrospective study assessed the relationship between the observed and estimated HSIs.

METHODS

This study was conducted in an academic, single-institution setting. Patients aged ≥ 20 years who underwent cardiac and thoracic aortic surgery and requiring cardiopulmonary bypass were included. Clinical and laboratory data, including age, sex, and platelet count, were collected. The fibrinogen-albumin ratio index was calculated by dividing the fibrinogen value by the albumin value, multiplied by 10.The HSI was calculated using the formula: (activated clotting time after initial heparin administration-baseline activated clotting time)/initial heparin dose (IU/kg). The estimated HSI was based on the results of multiple regression analysis that included clinically relevant factors. The intraclass correlation coefficient between the observed and estimated HSIs was used to assess.

RESULTS

In total, 560 patients with valid activated clotting time (ACT) values after initial heparin administration were included in the final analysis to explore associated factors using the estimated HSI. Multiple regression analysis revealed that hemodialysis, platelet count, fibrinogen-to-albumin ratio index, baseline activated clotting time, and initial heparin dose were significantly associated with the HSI. The mean (standard deviation) observed and estimated HSIs were 1.38 (0.43) and 1.55 (0.13), respectively, with an intra-class correlation coefficient of 0.10.

CONCLUSIONS

The correlation between the observed and estimated HSIs was low, and a formula with high accuracy for estimating the HSI is needed.

Systemic anticoagulation in ECMO

While unfractionated heparin (UFH) remains the mainstay of anticoagulation during pediatric extracorporeal life support, direct thrombin inhibitors (DTIs) are increasingly used. In this article, we will review most recent evidence regarding utilization of both UFH and DTIs and compare their known advantages and disadvantages. We will present anticoagulation monitoring strategies during ECMO and outline the most recent Extracorporeal Life Support Organization's anticoagulation guidelines, however with the caveat that there are no true consensus recommendations for anticoagulation management in pediatric ECMO. With these updates, we will serve as the bedside clinician's refresher on common practices for anticoagulation during "routine" ECMO. We will additionally highlight special circumstances, including high risk surgical procedures during ECMO, in which adjustments in anticoagulation and/or addition of antifibrinolytic therapy might mitigate risk.

Development and Validation of a Nomogram Model Affecting the ACT Targeting Rate During Radiofrequency Ablation of Atrial Fibrillation in China

CONTEXT

A nomogram model affecting the activated clotting time (ACT) targeting rate during radiofrequency ablation of atrial fibrillation (RFCA) in China.

PURPOSE

The aim of this study is to develop and validate a nomogram model for predicting the activated clotting time targeting rate after the initial bolus heparin dosages during the radiofrequency catheter ablation of atrial fibrillation in China.

METHODS AND RESULTS

A retrospective observational study was conducted on the data of 465 patients with atrial fibrillation who underwent radiofrequency catheter ablation (RFCA) from October 2019 to June 2022. All patients were randomized into a training cohort (70%; n = 325) and a validation cohort (30%; n = 140). Independent risk factors were identified using univariate and multifactorial logistic regression analysis. The predictive nomogram model was established using R software. The nomogram was developed and evaluated based on differentiation, calibration, and clinical efficacy using concordance statistic (C-statistic), calibration plots, and decision curve analysis (DCA), respectively. The nomogram was established using three variables, including sex (OR 1.01, 95% CI 0.29-1.76, P = 0.007), heparin dose (OR 0.04; 95%CI 0.02-0.05, P < 0.001), and the baseline ACT (OR 0.03; 95%CI 0.02-0.04, P < 0.001). The C-statistic of the nomogram was 0.736 (95%CI 0.675-0.732) in the training cohort and 0.700 (95%CI 0.622-0.721) in the validation cohort. The calibration plots showed good agreement between the predictions and observations in the training and validation cohorts. The clinical decision curve also proves that the map is useful in clinical settings.

CONCLUSION

The nomogram model has good discrimination and accuracy, which can screen attainment groups intuitively and individually, and has a certain predictive value for the probability of ACT reaching the target after the adequate dosage of initial heparin in Chinese patients with atrial fibrillation.

Safety of a single bolus administration of heparin without the measurement of activated clotting time during cryoballoon ablation: a prospective randomized controlled trial

BACKGROUND

Single-shot ablation has emerged as an effective technique for index atrial fibrillation (AF) ablation, with an advantage of short procedure time. Although recent guidelines recommend peri-procedural uninterrupted oral anticoagulants (OACs), the intra-procedural anticoagulation strategy remains uncertain under non-vitamin K OACs (NOACs). We investigated procedural safety of a single bolus administration of heparin without activated clotting time (ACT) measurement during cryoballoon ablation (CBA).

METHODS

Two hundred patients (64.2 ± 10.0 years, 70% with non-paroxysmal AF) who underwent CBA with uninterrupted NOACs were randomly assigned to No-ACT group and ACT group. A bolus of heparin (100 U/kg) was routinely administered immediately after transseptal puncture. In the ACT group, an additional injection of heparin (30 U/kg) was administered if ACT at 30 min after the initial bolus was < 300 s.

RESULTS

There were no differences in baseline characteristics including CHA₂DS₂-VASc score between the two groups. The left atrium indwelling and procedure times were 60.4 ± 13.1 min and 78.9 ± 13.9 min, respectively, and not significantly different between the two groups. The mean ACT was 335.2 ± 59.9 s in the ACT group. Any bleeding rate was 3.2% in all patients and there was no statistically significant difference in bleeding complications between the two groups. In the ACT group, groin hematoma, laryngopharyngeal bleeding, and hemoptysis occurred in 3, 1, and 1 patient, respectively. Cardiac tamponade occurred in 1 patient in the No-ACT group. No thromboembolic events occurred during the 30-day follow-up after CBA.

CONCLUSIONS

Single bolus administration of heparin without ACT measurement is a feasible anticoagulation strategy for CBA in patients with uninterrupted NOAC intake.

Assays to Monitor Bivalirudin

Bivalirudin (Angiomax, Angiox) is a parenteral direct thrombin inhibitor (DTI) that is used for patients with heparin-induced thrombocytopenia (HIT), where heparin cannot be used due to the risk of thrombosis. Bivalirudin is also licensed for use in cardiology procedures (e.g., percutaneous transluminal coronary angioplasty; PTCA). Bivalirudin is a synthetic analogue of hirudin found in the saliva of the medicinal leech and has a relatively short half-life of ~25 min. Several assays can be used to monitor bivalirudin; these include the activated partial thromboplastin time (APTT), activated clotting time (ACT), ecarin clotting time (ECT), an ecarin-based chromogenic assay, thrombin time (TT), the dilute TT, and the prothrombinase-induced clotting time (PiCT). Drug concentrations can also be measured using liquid chromatography tandem mass spectrometry (LC/MS) and clotting or chromogenic-based assays with specific drug calibrators and controls.

Editor's Choice - Sex Differences in Response to Administration of Heparin During Non-Cardiac Arterial Procedures

OBJECTIVE

Females are more prone to complications during non-cardiac arterial procedures (NCAPs) than males. The current study investigated the difference in the effect of peri-procedural prophylactic heparin in males and females, using the activated clotting time (ACT). This was a retrospective analysis of a prospective multicentre cohort study.

METHODS

All patients undergoing elective NCAP using heparin and ACT measurements between January 2016 and March 2020 were included. Two heparin dosage protocols were used: weight based dosing of 100 IU/kg (international units per kilogram) or a bolus of 5 000 IU. The primary outcome was the anticoagulatory effect of heparin after five minutes, measured by ACT. Secondary outcomes were the effect of heparin after 30 minutes, bleeding complications, and arterial thromboembolic complications (ATECs).

RESULTS

A total of 778 patients were included; 26% were female. After 100 IU/kg (n = 300), females more often reached longer ACT (< 200 seconds: 22% vs. 25%, p = .62; 200 - 250 seconds: 41% vs. 53%, p = .058; 251 - 280 seconds, 26% vs. 15%, p = .030). The mean ACT after 100 IU/kg heparin was 233 seconds (95% confidence interval [CI] 224 - 243) for females and 226 seconds (95% CI 221 - 231) for males (p = .057). After a bolus of 5 000 IU of heparin (n = 411), females reached significantly higher levels of anticoagulation than males (mean ACT 204 seconds vs. 190 seconds: p ≤ .001; ACT < 200 seconds: 44% vs. 66%; p < .001; ACT 200 - 250 seconds: 47% vs. 30%, p = .001; ACT 251 - 280 seconds: 7.8% vs. 2.3%, p = .009). Thirty minutes after heparin administration, 58% of all patients had an ACT < 200 seconds. ATECs did not differ between females and males (6.9% vs. 5.1%, p = .33) but bleeding complications were higher in females (27% vs. 16%, p = .001).

CONCLUSION

Heparin leads to significantly longer ACT in females during NCAP. Further research is needed to investigate whether individually based heparin protocols lead to fewer bleeding complications and lower incidence of ATECs.

Transcatheter aortic valve implantation under lower activated clotting time in a patient with hemorrhagic gastric cancer: a case report

BACKGROUND

Perioperative management of transcatheter aortic valve implantation (TAVI) in patients with a high risk of bleeding requires careful consideration.

CASE PRESENTATION

A 74-year-old man complained of chest pain and was admitted to our hospital. Close examination revealed severe aortic stenosis (AS) and hemorrhagic gastric cancer. Hemorrhage from gastric cancer was controlled using endoscopic hemostasis. While both gastric cancer and AS required surgery, we decided to perform transfemoral transcatheter aortic valve implantation (TAVI) under monitored anesthesia. To reduce bleeding from gastric cancer, we carefully adjusted the heparin dose to maintain the activated clotting time (ACT) between 180 and 200 s. TAVI with a balloon-expandable valve was completed without thrombotic complications. Laparoscopic distal gastrectomy was performed on the 6th day after TAVI.

CONCLUSIONS

We report the successful management of TAVI in a patient with hemorrhagic gastric cancer. In TAVI for patients with hemorrhagic diseases, careful consideration of antithrombotic therapy is required.

Activated clotting time in inpatient diagnostic and interventional settings

Monitoring for the anticoagulant effect of unfractionated (UFH) at the point of care using activated clotting time in real time is vital where risk of thrombosis is high. Although monitoring UFH effect is a routine and important task, changing from one ACT instrument type or technology to another must be preceded by a clinical and statistical evaluation to determine the suitability and repeatability and establish normal and treatable ranges of this newer instrument. In this multi-center prospective evaluation we tested 1236 paired ACT+ samples, and 463 paired ACT-LR samples (1699 total) from enrolled study subjects. Clinical settings included CVOR cardiopulmonary bypass, at the beside in extracorporeal life support (ELS), the Cardiac Catheterization Lab (CCL) during diagnostic studies and percutaneous coronary interventions (PCI), interventional radiology procedures and EP interventions. This study found more consistent clinical performance from the GEM Hemochron 100 as compared to the current clinical model, the Hemochron Signature Elite. The bias of GEM Hemochron 100 for ACT+ and ACT-LR was greatest in the setting of the CVOR where ACT levels were high. ACT-LR measurements by the GEM Hemochron 100 were comparable to the SE when performed in settings of CCL, ECM, EP and ICU. Results obtained for both ACT-LR and ACT+ in all clinical settings in this study using the GEM Hemochron 100 are as accurate and more repeatable as those with the current clinically available Signature Elite.

Satisfactory outcome with low activated clotting time in extracorporeal membrane oxygenation

Optimal anticoagulation is critical for successful extracorporeal membrane oxygenation (ECMO) to counterbalance the activation of the coagulation system initiated by the blood-biosurface reaction and mechanical stresses. Systemic anticoagulation is achieved mainly with unfractionated heparin (UFH). Activated clotting time (ACT) is a widely used laboratory parameter to monitor anticoagulation. The therapeutic range of ACT is 180-220 s. We investigated the effect of a lower target ACT (<150 s) during ECMO on safety and outcomes and compared it with those of a conventional target ACT (180-200 s). In this single-center, retrospective study, we reviewed 72 adult patients treated with ECMO from March 2017 to October 2019. We included 43 patients after applying the exclusion criteria and divided them into the low ACT group (<150 s, n = 14, 32.6%) and conventional ACT group (≥150 s, n = 29, 67.4%). There was no difference in the successful weaning from ECMO support (50% vs. 62.1%, p = 0.452) and discharge (50% vs. 41.4%, p = 0.594) rates between the groups. One patient in the conventional ACT group had intracranial hemorrhage. There was one thromboembolic complication case with an intra-circuit thrombus. To date, anticoagulation remains a challenge during ECMO. Our results suggest that a lower target ACT does not necessarily increase the thromboembolic risk during ECMO management. Clinicians may consider anticoagulation with lower ACT target for some patients with careful assessment and close monitoring. Further prospective trials are warranted to validate these results.

Do Opioid Addicts Require Higher Doses of Heparin During Percutaneous Coronary Intervention?

BACKGROUND

Patients who undergo percutaneous coronary intervention (PCI) receive anticoagulants, most commonly heparin to prevent thrombotic events during the procedure. Opioid addicts may require higher doses of heparin for PCI. We aimed to compare the effect of heparin on activated clotting time (ACT) between opioid addicts and non-addicts prior to and during PCI.

METHODS

This comparative study included 107 patients scheduled for elective PCI, of whom 50 were opioid addicts and 57 non-addicts. Patients' baseline characteristics including age, gender, weight, comorbidities, drug history, and smoking were recorded. Prothrombin time (PT), ýpartial thromboplastin time (PTT), international normalized ratio (INR), and platelet count were measured in venous blood samples collected from all participants. All patients underwent PCI through femoral access. They received 100 IU/kg heparin right at the beginning of the procedure. ACT was measured at 2 and 30 minutes.

FINDINGS

Age, gender, weight, and the amount of heparin used were comparable between groups. As for general characteristics, the number of patients with hyperlipidemia was significantly higher in non-addicts (P = 0.031), and cigarette smoking was higher in opioid addicts (P < 0.001). No significant difference was found between the groups regarding PT, PTT, INR, and platelet count (P > 0.050). ACT at 2 and 30 min were significantly lower in opioid addicts (P < 0.001). Taking other variables into account, ACT at 2 min was directly correlated with drug history of aspirin in opioid addicts (P = 0.031) and inversely correlated with cigarette smoking in non-addicts (P = 0.023).

CONCLUSION

Opioid addicts may require higher doses of heparin in PCI for the prevention of thrombotic complications compared to non-addicts.

ACTION-1: study protocol for a randomised controlled trial on ACT-guided heparinization during open abdominal aortic aneurysm repair

BACKGROUND

Heparin is used worldwide for 70 years during all non-cardiac arterial procedures (NCAP) to reduce thrombo-embolic complications (TEC). But heparin also increases blood loss causing possible harm for the patient. Heparin has an unpredictable effect in the individual patient. The activated clotting time (ACT) can measure the effect of heparin. Currently, this ACT is not measured during NCAP as the standard of care, contrary to during cardiac interventions, open and endovascular. A RCT will evaluate if ACT-guided heparinization results in less TEC than the current standard: a single bolus of 5000 IU of heparin and no measurements at all. A goal ACT of 200-220 s should be reached during ACT-guided heparinization and this should decrease (mortality caused by) TEC, while not increasing major bleeding complications. This RCT will be executed during open abdominal aortic aneurysm (AAA) surgery, as this is a standardized procedure throughout Europe.

METHODS

Seven hundred fifty patients, who will undergo open AAA repair of an aneurysm originating below the superior mesenteric artery, will be randomised in 2 treatment arms: 5000 IU of heparin and no ACT measurements and no additional doses of heparin, or a protocol of 100 IU/kg bolus of heparin and ACT measurements after 5 min, and then every 30 min. The goal ACT is 200-220 s. If the ACT after 5 min is < 180 s, 60 IU/kg will be administered; if the ACT is between 180 and 200 s, 30 IU/kg. If the ACT is > 220 s, no extra heparin is given, and the ACT is measured after 30 min and then the same protocol is applied. The expected incidence for the combined endpoint of TEC and mortality is 19% for the 5000 IU group and 11% for the ACT-guided group.

DISCUSSION

The ACTION-1 trial is an international RCT during open AAA surgery, designed to show superiority of ACT-guided heparinization compared to the current standard of a single bolus of 5000 IU of heparin. A significant reduction in TEC and mortality, without more major bleeding complications, must be proven with a relevant economic benefit. TRIAL REGISTRATION {2A}: NTR NL8421 ClinicalTrials.gov NCT04061798 . Registered on 20 August 2019 EudraCT 2018-003393-27 TRIAL REGISTRATION: DATA SET {2B}: Data category Information Primary registry and trial identifying number ClinicalTrials.gov : NCT04061798 Date of registration in primary registry 20-08-2019 Secondary identifying numbers NTR: NL8421 EudraCT: 2018-003393-27 Source(s) of monetary or material support ZonMw: The Netherlands Organisation for Health Research and Development Dijklander Ziekenhuis Amsterdam UMC Primary sponsor Dijklander Ziekenhuis Secondary sponsor(s) N/A Contact for public queries A.M. Wiersema, MD, PhD Arno@wiersema.nu 0031-229 208 206 Contact for scientific queries A.M. Wiersema, MD, PhD Arno@wiersema.nu 0031-229 208 206 Public title ACT Guided Heparinization During Open Abdominal Aortic Aneurysm Repair (ACTION-1) Scientific title ACTION-1: ACT Guided Heparinization During Open Abdominal Aortic Aneurysm Repair, a Randomised Trial Countries of recruitment The Netherlands. Soon the recruitment will start in Germany Health condition(s) or problem(s) studied Abdominal aortic aneurysm, arterial disease, surgery Intervention(s) ACT-guided heparinization 5000 IU of heparin Key inclusion and exclusion criteria Ages eligible for the study: ≥18 years Sexes eligible for the study: both Accepts healthy volunteers: no Inclusion criteria: Study type Interventional Allocation: randomized Intervention model: parallel assignment Masking: single blind (patient) Primary purpose: treatment Phase IV Date of first enrolment March 2020 Target sample size 750 Recruitment status Recruiting Primary outcome(s) The primary efficacy endpoint is 30-day mortality and in-hospital mortality during the same admission. The primary safety endpoint is the incidence of bleeding complications according to E-CABG classification, grade 1 and higher. Key secondary outcomes Serious complications as depicted in the Suggested Standards for Reports on Aneurysmal disease: all complications requiring re-operation, longer hospital stay, all complications.

Correlation between activated clotting time monitoring and heparin concentration measurement in a patient with antiphospholipid syndrome during cardiac valve surgery: a case report

Background

Anticoagulation management of patients with antiphospholipid syndrome (APS) undergoing cardiac surgery is challenging due to the prolongation of activated clotting time (ACT). Currently, no study has compared the utility of ACT monitoring using the Hemochron Jr. Signature+ and that of heparin concentration management using the Hemostasis Management System (HMS) Plus in patients with APS.

Case presentation

A 71-year-old woman with APS was scheduled to undergo an aortic valve replacement for aortic regurgitation. The ACT was measured using the Hemochron Jr. Signature+, and the heparin concentration was measured concurrently using the HMS Plus. ACT over 480 s corresponded to an adequate heparin concentration during cardiopulmonary bypass. The clinical course was uneventful, and no thrombotic or hemorrhagic complications were observed.

Conclusion

In the present patient with APS, the Hemochron Jr. Signature+ was useful as an anticoagulation management during cardiac valve surgery.

Intra-procedural anticoagulation and post-procedural hemoglobin fall in atrial fibrillation ablation with minimally interrupted direct oral anticoagulants: comparisons across 4 drugs

PURPOSE

Thromboembolic or hemorrhagic complications related to atrial fibrillation (AF) ablation are rare, and thus, it is difficult to compare their frequency across different direct oral anticoagulants (DOACs). We aimed to compare the intra-ablation blood coagulability and post-procedural hemoglobin fall as alternatives to those complications across 4 DOACs.

METHODS

We enrolled AF patients younger than 65 years old in 3 cardiovascular centers who skipped a single dose of apixaban, dabigatran, edoxaban, and rivaroxaban, prior to the ablation. Endpoints included the activated clotting time (ACT), heparin requirement during the ablation, and drop in the hemoglobin level 24 h after the procedure.

RESULTS

The time-course curves of the ACT differed significantly across the patients with apixaban (N = 113), dabigatran (N = 130), edoxaban (N = 144), and rivaroxaban (N = 81), with its highest level in the dabigatran group (P < 0.001). The average ACT was greater in the dabigatran group than in the other groups (312.3 ± 34, 334.4 ± 44, 308.1 ± 41, and 305.8 ± 34.7 s; P < 0.001). A significant difference was noted in total heparin requirement across the patient groups (3990.2 ± 1167.9, 3890.4 ± 955.3, 4423.8 ± 1051.6, and 3972 ± 978.7 U/m²/h; P < 0.001), with its greatest amount in the edoxaban group. The reduction in the hemoglobin level was similar (- 0.93 ± 0.92, - 0.88 ± 0.79, - 0.89 ± 0.97, - 0.95 ± 1.23 g/dL; P = 0.94). No inter-group difference was noted in the rate of major or minor bleedings (0.9%, 2.3%, 1.4%, and 3.7%; P = 0.51), and no thromboembolic events were encountered.

CONCLUSION

A difference in DOACs may have an impact on intra-ablation anticoagulation; however, it may not be on the procedural blood loss in the setting of a single skip.

Viscoelastic test-based bleeding risk score reliably predicts coagulopathic bleeding in decompensated cirrhosis and ACLF patients

BACKGROUND AND AIMS

Coagulopathic bleeding risk prediction is challenging in decompensated cirrhosis (DC) by conventional assays. Viscoelastic tests (VETs) are likely to be more useful for assessing coagulation status in these patients. We investigated whether the VET (Sonoclot) parameters with fibrinogen could predict coagulopathic bleeding in these patients.

PATIENTS AND METHODS

Coagulation parameters studied in 874 patients [124 compensated cirrhosis (CC), 521 DC, and 229 acute-on-chronic liver failure (ACLF)] and 190 controls. DC patients were enrolled in derivation (n = 266) and validation (n =  255) cohorts. Sonoclot variables [activated clotting time (ACT), clot rate (CR), platelet function (PF), time to peak (TP) and peak amplitude (PA)] and fibrinogen levels were measured. Coagulopathic bleeding was recorded along with 1-year survival.

RESULTS

DC patients had prolonged ACT (p < 0.001), depressed CR (p = 0.059), reduced PF (p = 0.09), longer TP (p < 0.001) and smaller PA (p < 0.001), compared to CC and controls (p < 0.001 each). In derivation cohort, 32.3% patients had coagulopathic bleeding. Cox regression analysis of derivation cohort revealed; ACT > 190 s, PF < 1.25 and fibrinogen < 1.2 g/l could predict coagulopathic bleeding and were used to develop a bleeding risk score. In validation cohort; this score was comparable, correlated to real events, and had similar bleed free events with time. The score was also useful in predicting bleed in ACLF patients. In DC patients, 1-year mortality was higher those who bled and received transfusions.

CONCLUSION

Viscoelasticity-based bleeding risk score using ACT, PF and fibrinogen, predicts coagulopathic bleeding in DC patients and should be useful in rationalizing transfusion of blood products. We designed a viscoelastic test-based bleeding risk score which is useful in advanced liver disease to predict the coagulation-related bleeding. This figure shows the lower bleeding-free events in advanced cirrhosis with each incremental bleeding risk score.

Incidence and predictors of calcified cerebral emboli detected in patients who underwent endovascular procedures

OBJECTIVES

There are very few reports on calcified cerebral emboli associated with endovascular procedures. We aimed to evaluate the incidence rates and predictors of calcified cerebral emboli in patients who underwent carotid artery stenting (CAS)/percutaneous transluminal angioplasty (PTA).

PATIENTS AND METHODS

Patient demographics, clinical characteristics, and operative records of patients who underwent CAS/PTA were retrospectively analyzed. A total of 211 consecutive patients with cervical internal carotid stenosis were included in this study. Patients were categorized according to the presence of calcified cerebral emboli in postoperative computed tomography (CT) into emboli and non-emboli groups. We defined calcified emboli as a CT value of 60-400 Hounsfield units.

RESULTS

On postoperative non-contrast CT, calcified emboli were detected in 5 of the 211 cases after CAS/PTA. The emboli were located in the middle cerebral artery (2/5), anterior cerebral artery (1/5), posterior cerebral artery (2/5). All of the cases of calcified cerebral emboli were clinically asymptomatic. The characteristics of patients showed no apparent difference in this study. Although the limited number may be attributed to a lack of statistical power, the average baseline activated clotting time (ACT) was lower in the emboli group than in the non-emboli group (117 vs 153, p < 0.05), and the operative time was longer in the emboli group than in the non-emboli group (147 vs 111, p < 0.05).

CONCLUSION

Calcified cerebral emboli may be more common than previously known. Lower average baseline ACT and longer operative time could be predictors of calcified cerebral emboli after endovascular procedures. 　.

Effects of rivaroxaban on activated clotting time in catheter ablation for atrial fibrillation in Chinese patients

PURPOSE

It has been observed that patients on rivaroxaban require more heparin and frequent activated clotting time (ACT) monitoring throughout the catheter ablation of atrial fibrillation, but the strategy of heparin injection varies in different studies. We sought to examine the determinants of heparin dosage in Chinese patients on rivaroxaban.

METHODS

We reviewed consecutive patients who received rivaroxaban before atrial fibrillation ablation and compared them to patients on no anticoagulant. The dosage of heparin required to achieve ACT > 300 s was evaluated. We then tested determinants of heparin dosage prospectively.

RESULTS

There were 124 patients on rivaroxaban (R group) and 42 on no anticoagulant (NA group) in retrospective study. Heparin dosage required to achieve target ACT was 0.89 ± 0.01 mg/kg in R group and 0.60 ± 0.01 mg/kg in NA group, P < 0.05. The bolus heparin dosage required was 0.77 ± 0.01 mg/kg (96.1 ± 1.1 U/kg) when baseline ACT > 200 s. In the prospective study, 80/90(88.9%) of patients in R group and 79/90(87.8%) in NA group achieved an ACT > 300 s after initial bolus injection of heparin. The ACT 60 min after target ACT (ACT60) in R group was higher than that in NA group (287.5 ± 28.3 VS 238.9 ± 29.5, P < 0.05). Rivaroxaban was the only independent predictor of ACT60. There was no significant difference in ACT or heparin dosage in patients with different duration on or withdrawal of rivaroxaban.

CONCLUSIONS

In patients undergoing atrial fibrillation ablation on rivaroxaban, the effective duration of heparin is prolonged and the procedural heparin requirement is significantly greater. Heparin dosage can be predicted by baseline ACT, but not influenced by duration on or withdrawal of rivaroxaban.

Point-of-care measurement of activated clotting time for cardiac surgery as measured by the Hemochron signature elite and the Abbott i-STAT: agreement, concordance, and clinical reliability

BACKGROUND

Since inadequate heparin anticoagulation and insufficient reversal can result in complications during cardiopulmonary bypass (CPB) surgery, heparin anticoagulation monitoring by point-of-care (POC) activated clotting time (ACT) measurements is essential for CPB initiation, maintainance, and anticoagulant reversal. However, concerns exist regarding reproducibility of ACT assays and comparability of devices.

METHODS

We evaluated the agreement of ACT assays using four parallel measurements performed on two commonly used devices each (i.e., two Hemochron Signature Elite (Hemochron) and two Abbott i-STAT (i-STAT) devices, respectively). Blood samples from 30 patients undergoing cardiac surgery on CPB were assayed at specified steps (baseline, after heparin administration, after protamine administration) with four parallel measurements (two of each device type) using commercial Kaolin activated assays provided by the respective manufactures. Measurements were compared between identical and different device types using linear regression, Bland-Altman analyses, and calculation of Cohen's kappa coefficient.

RESULTS

Parallel i-STAT ACTs demonstrated a good linear correlation (r = 0.985). Bias, as determined by Bland-Altman analysis, was low (- 3.8 s; 95% limits of agreement (LOA): - 77.8 -70.2 s), and Cohen's Kappa demonstrated good agreement (kappa = 0.809). Hemochron derived ACTs demonstrated worse linear correlation (r = 0.782), larger bias with considerably broader LOA (- 13.14 s; 95%LOA:-316.3-290 s), and lesser concordance between parallel assays (kappa = 0.554). Although demonstrating a fair linear correlation (r = 0.815), parallel measurements on different ACT-devices showed large bias (-20s; 95% LOA: - 290-250 s) and little concordance (kappa = 0.368). Overall, disconcordant results according to clinically predefined target values were more frequent with the Hemochron than i-STAT. Furthermore, while discrepancies in ACT between two parallel iSTAT assays showed little or no clinical relevance, deviations from parallel Hemochron assays and iSTAT versus Hemochron measurements revealed marked and sometimes clinically critical deviations.

CONCLUSION

Currently used ACT point-of-care devices cannot be used interchangeably. Furthermore, our data question the reliability of the Hemochron in assessing adequacy of heparin anticoagulation monitoring for CPB.

Factors other than body weight predicting heparin loading to acquire optimal activated clotting time in endovascular neurointerventions

OBJECTIVES

The aim of this study was to investigate the relationship between the activated clotting time (ACT) and heparin loading based on body weight (BW), and factors other than BW that may contribute to the ACT after heparin loading to establish a more accurate regimen for achieving ACT targets during endovascular neurointerventions.

PATIENTS AND METHODS

Japanese patients who underwent endovascular coiling of unruptured intracranial aneurysms or carotid artery stenting in our institution between January 2014 and November 2017 were enrolled. The ACT was measured before (pre-ACT) and 3 min after heparinization (post-ACT). The correlation between ACT and heparin loading based on BW and factors that may contribute to the ACT after heparin loading were analyzed retrospectively.

RESULTS

A total of 199 cases (109 males, age: 66 ± 12 years) were analyzed. There were positive correlations between the heparin loading per kg of BW and post-ACT, post-ACT - pre-ACT (ΔACT) (Spearman's r = 0.2946, 0.2633, P: <0.0001, 0.0002, respectively). Heparin loading per kg of BW, gender, hematocrit (Ht), estimate glomerular filtration rate (eGFR) were significant confounding factors to ΔACT. The calculated predicted ΔACT based on these significant factors was found to be highly correlated with ΔACT compared with the heparin loading per kg of BW. (Spearman's r = 0.5820, P = <0.0001).

CONCLUSION

Initial BW-based heparin loading is a simple way in endovascular neurointerventions. ACT after heparin loading based on BW has individual differences greatly, it is possible to estimate more accurately the heparin loading for acquiring the optimal ACT considering not only BW but also gender, Ht and eGFR.

Signature and Medtronic ACT Plus during cardiopulmonary bypass with acute normovolemic haemodilution

Objective

This study compared the activated clotting time (ACT) measured using the Hemochron Jr. Signature (HACT) with the ACT measured using the Medtronic ACT Plus (MACT) during cardiopulmonary bypass (CPB) with acute normovolemic haemodilution (ANH) in patients undergoing cardiac surgery.

Methods

The ACT was checked at baseline with both devices after inducing anaesthesia, and 400 to 800 mL of whole blood was withdrawn to induce moderate ANH. Before initiating CPB, a 300-IU/kg bolus dose of heparin was administered to maintain the HACT at >400 s; protamine was later given to reverse the anticoagulation. The ACT was checked using both devices at baseline, during heparinisation, and after protamine administration.

Results

In total, 106 pairs of samples from 29 patients were analysed. The ACT showed a good correlation between the two devices (r = 0.956). However, Bland–Altman analysis showed that the MACT was higher, particularly at baseline and during heparinisation. Multiple regression analysis showed that the blood glucose concentration significantly influenced the differences between the two ACT devices.

Conclusions

The HACT was lower than the MACT during CPB with ANH in patients undergoing cardiac surgery. Clinicians should be cautious when using each ACT device within generally accepted reference ACT values.

Point-of-care testing of activated clotting time in the ICU: is it relevant?

BACKGROUND

Over the past 50 years there have been significant advances in both the clinical techniques and equipment used in the intensive care environment. One traditionally used point-of-care test is activated clotting time (ACT), a coagulation test primarily used during cardiopulmonary bypass surgery to monitor the anticoagulation effects of heparin. The ACT test has since emerged into the intensive care environment to guide clinical assessment and management of haemostasis in postoperative cardiac patients.

OBJECTIVES

The aim of this integrative systematic review was to critique the available research evaluating the effectiveness of ACT point-of-care testing in the intensive care unit for adult patients following cardiopulmonary bypass and cardiac surgery and any impacts this may have on nursing care.

METHODS

A systematic search of Medline, CINAHL and PubMed was undertaken.

RESULTS

The search identified five research papers reporting on the use of ACT point-of-care testing in the intensive care unit for adult cardiac surgical patients. Meta-analysis was not performed due to the lack of homogeneity between the papers included.

CONCLUSIONS

There was a lack of clear evidence for the use of the ACT point-of-care test after cardiac surgery in the intensive care environment. This review has highlighted that conventional laboratory tests are generally more accurate and reliable than this point-of-care test in guiding nursing care management.

Successful intraprocedural anticoagulation with bivalirudin during pulmonary vein isolation in a patient with known heparin-induced thrombocytopenia type II

We report the case of a 56-year-old female who presented with symptomatic paroxysmal atrial fibrillation. Anamnestic heparin-induced thrombocytopenia (HIT) type II was suspected, and a rapid diagnostic test showed antibodies against platelet factor 4. The heparin-induced platelet activation-assay was negative. Radiofrequency pulmonary vein isolation with intraprocedural anticoagulation using bivalirudin was ultimately performed. Dosing was controlled by monitoring the activated clotting time. Post-procedural blood tests were normal. There were no thromboembolic or bleeding events. Bivalirudin is a therapeutic option for anticoagulation during pulmonary vein isolation procedures in patients with a history of HIT type II.

Differences in activated clotting time among uninterrupted anticoagulants during the periprocedural period of atrial fibrillation ablation

BACKGROUND

Close monitoring of intraoperative activated clotting time (ACT) is crucial to prevent complications during the periprocedural period of atrial fibrillation (AF) ablation. However, little is known about the ACT in patients receiving new oral anticoagulant agents (NOACs).

OBJECTIVE

The purpose of this study was to evaluate change in the ACT among anticoagulant agents used during the periprocedural period of AF ablation.

METHODS

We examined 869 consecutive patients who underwent AF ablation between April 2012 and August 2014 and received NOACs (n = 499), including dabigatran, rivaroxaban, and apixaban, or warfarin (n = 370) for uninterrupted periprocedural anticoagulation. Changes in intraprocedural ACT were investigated among the anticoagulant agents. Furthermore, the incidence of periprocedural events was estimated.

RESULTS

The average time in minutes required for achieving a target ACT >300 seconds was significantly longer in the dabigatran group (DG) and apixaban group (AG) than in the warfarin group (WG) and rivaroxaban group (RG) (60 and 70 minutes vs 8 and 9 minutes, respectively; P < .001). In addition, the proportion of patients who achieved the target ACT after initial heparin bolus was significantly lower in the DG and AG than in the WG and RG (36% and 26% vs 84% and 78%, respectively; P < .001). Furthermore, the incidence of periprocedural complications was equivalent among the groups.

CONCLUSION

The average time required to reach the target ACT was longer in the DG and AG than in the WG and RG.