Activated Clotting Time Research Articles

Comprehensive Intraprocedural Unfractionated Heparin Protocol During Catheter Ablation of Atrial Fibrillation in the Presence of Direct Oral Anticoagulants and Wide Spectrum of Body Mass Index.

Data on optimal dosing of unfractionated heparin (UFH) in the presence of a direct oral anticoagulant (DOAC) to achieve and maintain an activated clotting time (ACT) of ≥300 seconds during catheter ablation of atrial fibrillation (CA-AF) are limited and prevalence of obesity adds to the unpredictable response to UFH. One hundred seventeen consecutive patients undergoing CA-AF were prospectively administered weight-adjusted, weight-based UFH using a pre-specified detailed protocol and retrospectively analyzed. Due to lack of distribution of UFH into muscle or adipose tissue and lower degree of vascularity in the latter compartment, each patient's ideal and actual weights were used to determine the adjusted-weight for use in all UFH doses. A UFH bolus of 200 units/kg was administered intravenously followed by an infusion of 35 units/kg/hour. The mean age was 65 years, and 85 patients (72.6%) were male. The average body mass index (BMI) was 30 (range 18-50) kg/m2. After the initial UFH bolus dose, 99 patients (84.6%) achieved ACT ≥300 sec with a mean (± SD) of 380 ± 79 sec. The mean time to reach an ACT ≥300 in all patients was 14.6 ± 12.4 minutes. Among all measured ACT values, 423 (90.8%) were ≥300 seconds. These results were consistent within all BMI categories. There were no intraprocedural thrombotic or hemorrhagic complications. Two patients (1.7%) sustained groin vascular access site hematoma without subsequent intervention and 7 patients (6%) experienced minor oozing post-procedurally. Our comprehensive weight-adjusted, weight-based UFH protocol, during CA-AF in presence of a DOAC, rapidly achieved and maintained an effective ACT irrespective of BMI.

Heart Transplantation from Donors with Heparin-Induced Thrombocytopenia

Purpose Heparin-induced thrombocytopenia (HIT) is an immune-mediated condition associated with thrombocytopenia and thrombotic complications. The condition is increasingly recognized in hospitalized patients including severely injured trauma patients. Because these patients may eventually be considered for organ donation, management of the HIT screen positive donor has become an important issue in transplant surgery. We describe the recent management of 2 cardiac allograft donors with HIT. Methods At organ recovery, both male adult donors were hemodynamically stable with a normal appearing heart and no evidence of thrombosis. The donor underwent a routine multiple organ allograft recovery with argatroban infused over 15 minutes immediately before aortic cross-clamping after confirming activated clotting time (ACT) of greater than 400 sec. The cardiac allograft was flushed in the donor operating room with a total of 4 liters of cold Celsior solution. These hearts were transplanted in patients with dilated cardiomyopathy and cardiac sarcoidosis by modified bicaval anastomosis technique using heparin for anticoagulation therapy during cardiopulmonary support. Both were bridged with implantable left ventricular assist device (Heart Mate II and Jarvik 2000, respectively). Results This management strategy resulted in successful multiple organ transplants (Case 1: heart, two single lungs, liver, 2 kidney, case 2: heart, bilateral lung, liver, pancreas, 2 kidneys). Neither of the heart and other recipients demonstrated signs or symptoms of HIT, or neither had any postoperative thrombotic complications.. Conclusion Based on this experience, a treatment algorithm for managing HIT donors using argatroban is proposed for heart donors as well as other organ donors

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

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

Argatroban Anticoagulation for Adult Extracorporeal Membrane Oxygenation: A Systematic Review.

Heparin is the widely used anti-coagulation strategy for patients on extracorporeal membrane oxygenation (ECMO). Nevertheless, heparin-induced thrombocytopenia (HIT) and acquired anti-thrombin (AT) deficiency preclude the use of heparin requiring utilization of an alternative anticoagulant agent. Direct thrombin inhibitors are being proposed as potential alternatives with argatroban as one of the main agents. We aimed to review the evidence with regard to safety and efficacy of argatroban as a potential definitive alternative to heparin in the adult patient population undergoing ECMO support. A web-based systematic literature search was performed in Medline (PubMed) and Embase from inception until June 18, 2020. The search identified 13 publications relevant to the target (4 cohort studies and 9 case series). Case reports and case series with less than 3 cases were not included in the qualitative synthesis. The aggregate number of argatroban treated patients on ECMO was n = 307. In the majority of studies argatroban was used as a continuous infusion without loading dose. Starting doses on ECMO varied between 0.05 and 2 μg/kg/min and were titrated to achieve the chosen therapeutic target range. The activated partial thormboplastin time (aPTT) was the anticoagulation parameter used for monitoring purposes in most studies, whereas some utilized the activated clotting time (ACT). Optimal therapeutic targets varied between 43-70 and 60-100 seconds for aPTT and between 150-210 and 180-230 seconds for ACT. Bleeding and thromboembolic complication rates were comparable to patients treated with unfractionated heparin (UFH). Argatroban infusion rates and anticoagulation target ranges showed substantial variations. The rational for divergent dosing and monitoring approaches are discussed in this paper. Argatroban appears to be a potential alternative to UFH in patients requiring ECMO. To definitively establish its safety, efficacy and ideal dosing strategy, larger prospective studies on well-defined patient populations are warranted.

Point-of-Care Measurement of Kaolin Activated Clotting Time during Cardiopulmonary Bypass: A Single Sample Comparison between ACT Plus and i-STAT.

Heparin anticoagulation monitoring by point-of-care activated clotting time (ACT) is essential for cardiopulmonary bypass (CPB) initiation, maintenance, and anticoagulant reversal. Concerns exist regarding the comparability of kaolin activated ACT devices. The current study, therefore, evaluated the agreement of ACT assays using parallel measurements performed on two commonly used devices. Measurements were conducted in a split-sample fashion on both the ACT Plus (Medtronic, Minneapolis, MN) and i-STAT (Abbott Point of Care, Princeton, NJ) analyzers. Blood samples from 100 adult patients undergoing elective cardiac surgery with CPB were assayed at specified time points: before heparinization, following systemic heparinization, after CPB initiation, every 30 minutes during CPB, and following protamine administration. A cutoff value of 400 seconds (s) was used as part of the local protocol. Measurements were compared using t tests or Wilcoxon signed-rank tests, linear regression, and Bland-Altman analyses. Parallel ACT measurements demonstrated a good linear correlation (r = .831, p < .001). The overall median difference between both measurements was significantly different from zero, amounting to 87 (14-189) (p < .001), with limits of agreement of -124 and 333s. The i-STAT-derived ACT values were systematically lower than the ACT Plus values, which was more pronounced during CPB. Fourteen patients received additional heparin during CPB at a median ACT Plus value of 414s, with a concomitant median i-STAT value of 316s. Assuming 308s as the theoretical i-STAT cutoff value based on the linear regression equation and an ACT Plus threshold of 400s, 29 patients would have received additional heparin. Based on these results, kaolin point-of-care ACT devices cannot be used interchangeably. Device-specific predefined target values are warranted to avert heparin overdosing during CPB.

Routine fixed-dose heparin vs. ACT-guided heparin administration for elective PCI and its influence on patient in-hospital outcome: a retrospective study.

Activated clotting time (ACT)-based heparin dosing during percutaneous intervention (PCI) is recommended by Society guidelines. However, the relationship between ACT and outcome in the setting of elective PCI has not been sufficiently studied. We sought to evaluate the in-hospital outcome of patients undergoing elective PCI while receiving fixed-dose heparin without ACT measurement versus those with ACT-guided management. This retrospective study included consecutive patients undergoing elective PCI in a single-center between 11/2015 and 12/2018. Patients were divided into two groups, depending on whether ACT was measured. Heparin-only anticoagulation and non-femoral procedures were allowed. Patient demographics, procedural data and in-hospital outcomes were collected. The primary outcome was in-hospital major adverse cardiovascular events (MACE), secondary (safety) outcomes were in-hospital definite stent thrombosis, Bleeding Academic Research Consortium bleeding, access-related complications (any) as well as peri-procedural complications. In total, 500 procedures were included in the study, 151 ACT and 349 fixed-dose. Patient demographics and medical history in both groups were well balanced, but those having ACTs were younger (63.2 ± 10.9 vs. 66.5 ± 11.3; P = 0.003) and less likely to have a history of coronary artery disease (74 vs. 82%; P = 0.032) or kidney failure. Procedural data were similar; however, total heparin dose and procedure length were higher in the ACT group (6232 ± 1388 vs.5032 ± 417 units; P < 0.001; 40.1 ± 14.0 vs. 30.3 ± 12.7 min; P < 0.001). Primary and secondary outcome events were rare and similar (MACE 1.1 vs. 1.3%; P = 0.86). A fixed-dose heparin injection (5000 IU) approach for elective PCI while omitting ACT offers slightly shortened procedural time and similar in-hospital safety profile.

Point-of-Care Measurement of Kaolin Activated Clotting Time during Cardiopulmonary Bypass: A Single Sample Comparison between ACT Plus and i-STAT

Heparin anticoagulation monitoring by point-of-care activated clotting time (ACT) is essential for cardiopulmonary bypass (CPB) initiation, maintenance, and anticoagulant reversal. Concerns exist regarding the comparability of kaolin activated ACT devices. The current study, therefore, evaluated the agreement of ACT assays using parallel measurements performed on two commonly used devices. Measurements were conducted in a split-sample fashion on both the ACT Plus (Medtronic, Minneapolis, MN) and i-STAT (Abbott Point of Care, Princeton, NJ) analyzers. Blood samples from 100 adult patients undergoing elective cardiac surgery with CPB were assayed at specified time points: before heparinization, following systemic heparinization, after CPB initiation, every 30 minutes during CPB, and following protamine administration. A cutoff value of 400 seconds (s) was used as part of the local protocol. Measurements were compared using t tests or Wilcoxon signed-rank tests, linear regression, and Bland–Altman analyses. Parallel ACT measurements demonstrated a good linear correlation (r = .831, p &lt; .001). The overall median difference between both measurements was significantly different from zero, amounting to 87 (14–189) (p &lt; .001), with limits of agreement of −124 and 333s. The i-STAT-derived ACT values were systematically lower than the ACT Plus values, which was more pronounced during CPB. Fourteen patients received additional heparin during CPB at a median ACT Plus value of 414s, with a concomitant median i-STAT value of 316s. Assuming 308s as the theoretical i-STAT cutoff value based on the linear regression equation and an ACT Plus threshold of 400s, 29 patients would have received additional heparin. Based on these results, kaolin point-of-care ACT devices cannot be used interchangeably. Device-specific predefined target values are warranted to avert heparin overdosing during CPB.

Antiphospholipid Syndrome and Cardiac Bypass: The Careful Balance between Clotting and Bleeding

Antiphospholipid syndrome (APS) is an acquired autoimmune condition characterized by the presence of antiphospholipid antibodies (lupus anticoagulant, anticardiolipin antibody, and anti-β2 glycoprotein-I antibody) which leads to clinical thrombosis via a multifactorial mechanism of action. Despite the propensity to form clot in vivo, these antibodies interfere with the assembly of the prothrombinase complex on phospholipids in in vitro assays, leading to prolongation of activated clotting time and activated partial thromboplastin time. This disconnect between what occurs in vivo and in vitro makes monitoring anticoagulation during cardiac surgery particularly complex. We present a patient with APS undergoing coronary artery bypass grafting with cardiopulmonary bypass. We delineate our strategy for managing anticoagulation in the presence of this syndrome using the Hepcon Hemostasis Management System Plus (Medtronic, Inc. Minneapolis, MN) device by targeting whole blood heparin concentration to monitor anticoagulation.

Is a fixed low-dose protamine better at reducing postoperative bleeding in off pump coronary artery bypass grafting?

Protamine is used ubiquitously in all cardiac surgeries for reversal of heparin. Risk of postoperative bleeding is increased with inadequate heparin reversal or due to anticoagulant side effects of protamine; hence, it is important to dose protamine properly. This study compares 80% protamine dose with full dose on postoperative bleeding and transfusion needs in OPCAB. The aim of our study was to find whether lower dose of protamine could reduce postoperative bleeding and need for blood product transfusions in off pump coronary artery bypass grafting as compared to the regular dose of protamine. This was a double-blinded randomised controlled trial where patients posted for off pump CABG meeting the inclusion criteria were included in the study. Ninety patients were randomised to two groups, group F receiving full dose of protamine of 1 mg per mg heparin used, and group L received 0.8 mg per mg. Postoperative activated clotting time, bleeding at 1 h, 4 h, 24 h and total drainage till drains removal and blood product transfusion requirements were noted.Statistical analysis used: SPSS software. Both groups were matched in demographics, preoperative cessation of heparin and aspirin and platelet counts. Both groups received equal heparin dose, activated clotting time before protamine, activated clotting time post protamine in OT and ICU were equal as were the conduits used. There was no significant difference between the groups in post-operative drainage over time or in the need for blood product transfusions. Eighty per cent of the dose of protamine can adequately reverse the heparin used during off pump cardiac surgery without any increase in incidence of postoperative bleeding or need for blood product transfusions.

Variability of Activated Clotting Time by Site of Sample Draw During Percutaneous Coronary Intervention: A Prospective Single-Center Study

The activated clotting time (ACT) assay is used to monitor and titrate anticoagulation therapy with unfractionated heparin during percutaneous coronary intervention (PCI). Observations at our institution suggested a considerable difference between ACT values drawn from varying arterial sites, prompting the current study. Patients undergoing PCI with unfractionated heparin therapy were prospectively enrolled. Simultaneous arterial blood samples were drawn from the access sheath and the coronary guide catheter. Differences between Hemochron ACT values were determined, and potential interactions with clinical variables were analyzed. Immediately postprocedure, the simultaneous mean guide and sheath ACTs were 327 ± 62 seconds and 257 ± 44 seconds, respectively, with a mean difference of 70 ± 60 seconds (P < .001). Nearly all (90%) ACT values obtained via the guide catheter were higher than the concurrent ACT drawn from the sheath. Logistic regression analysis demonstrated that lower weight-adjusted heparin doses and absence of diabetes were associated with a greater difference between the ACT values. We conclude that the ACT value is substantially greater when assessed via the guide catheter versus the access sheath. Although the biological mechanisms require further study, this difference should be considered when managing anticoagulation during PCI and when reporting ACT as part of research protocols.

Dose estimation for bivalirudin during pediatric cardiopulmonary bypass.

A typical adult-based bivalirudin regimen during cardiopulmonary bypass uses a loading dose of 1mgkg-1 and a circuit prime (volume L×13mg) with a subsequent intravenous infusion 2.5mgh-1 kg-1 . Dose in children remains unknown. We wished to determine a practical bivalirudin dosing schedule for children undergoing surgery with cardiopulmonary bypass. Published pharmacokinetic parameters in children who were anticoagulated for cardiac catheterization using bivalirudin were compared to adult by scaling for size using allometry. An infusion regimen suitable for children was determined using a bivalirudin target concentration (13mgL-1 ) common in adults for effect during cardiopulmonary bypass. Predicted bivalirudin infusion rates in children were compared to regimens published as case reports. Current pediatric bivalirudin infusion rates are based on those used in adults with titration during cardiopulmonary bypass to achieve activated clotting times longer than 400s. Bivalirudin clearance (mLmin-1 kg-1 ) can be estimated in children by scaling adult parameters using allometry. Clearance decreases through childhood and higher infusion rates in children would achieve target concentration rapidly without the need to titrate initial infusion rate. An infusion rate of 4.5mgh-1 kg-1 in a 10kg infant, 4mgh-1 kg-1 in a 20kg child and 3.5mgh-1 kg-1 in a child 30-40kg will target an activated clotting time slower than 400s. Adult regimens could be used in those children heavier than 50kg. Bivalirudin infusion in children should be started after loading dose at rates greater than those used in adults. Dose in neonates remains uncertain because neither pharmacokinetics nor coagulation pharmacodynamics have been adequately characterized.

Protocol driven periprocedural anticoagulation for left atrial ablation.

A weight-based heparin dosing policy adjusted for preprocedural oral anticoagulation was implemented to reduce the likelihood of subtherapeutic dosing during left atrial catheter ablation procedures. We hypothesized that initiation of the protocol would result in a greater prevalence of therapeutic activated clotting time (ACT) values and decreased time to therapeutic ACT during left atrial ablation procedures. A departmental protocol was initiated for which subjects received intravenous unfractionated heparin (UFH) to achieve and maintain a goal of ACT >300 s. Initial bolus dose was adjusted for pre-procedure oral anticoagulation and weight as follows: 50 units/kg for those receiving warfarin, 75 units/kg for those not anticoagulated, and 120 units/kg for those on direct oral anticoagulants (DOACs). A UFH infusion was initiated at 10% of the bolus per hour. One hundred consecutive left atrial ablation procedures treated with Protocol Guided heparin dosing were compared with a retrospective consecutive cohort of Usual Care heparin dosing. When the Usual Care and Protocol Guided cohorts were compared, significant findings were limited to those on pre-procedure DOAC. The initial UFH bolus increased from 99.3 ± 24.8 to 118.2 ± 22.8 units/kg (p < .001), the proportion of therapeutic ACT on the first draw after heparin administration increased from 57.7% to 76.6% (p = .010), and the time to therapeutic ACT after UFH administration decreased from 37.8 ± 19.8 to 30.2 ± 16.4 min (p = .032). A weight-based protocol for periprocedural UFH administration resulted in a higher proportion of therapeutic ACT values and decreased the time to therapeutic ACT for those on pre-procedure DOAC.

Case-control study of postprocedural arterial puncture site hemorrhage after neuroendovascular treatment.

ABSTRACTPuncture site hemorrhage following femoral artery catheterization is a significant cause of morbidity. The aim of this case-control study was to identify predictors of postprocedural arterial hemorrhage at the puncture site. We retrospectively reviewed 255 patients who underwent endovascular treatment at our institution over a 23-month period and classified them into a hemorrhage group and a non-hemorrhage group. Puncture site hemorrhage occurred in 15 patients (5.9%). Clinical factors associated with a significantly increased risk of puncture site bleeding included patients whose postoperative activated clotting time of ≥300 seconds before removal of the sheath (9 patients, 11.8%; P<0.05), those who received triple antiplatelet therapy (n=4, 17.4%; P<0.05) and the group administered heparin postoperatively (7 patients, 13.2%; P<0.05). The effects of low on-treatment platelet reactivity, i.e., P2Y12 reaction units <95%, sheath size, hemostasis method used, and operating time were not clinically significant. Our findings suggest an increased risk of puncture site hemorrhage in patients who either had an activated clotting time ≥300 seconds before the postoperative removal of the sheath, had received triple antiplatelet therapy, or were administered heparin postoperatively.

Outcomes of uninterrupted vs interrupted Periprocedural direct oral Anticoagulants in atrial Fibrillation ablation: A meta-analysis.

BackgroundStudies indicate that uninterrupted anticoagulation (UA) is superior to interrupted anticoagulation (IA) in the periprocedural period during catheter ablation of atrial fibrillation. Still IA is followed in many centers considering the bleeding risk. This meta‐analysis compares interrupted and uninterrupted direct oral anticoagulation during catheter ablation of atrial fibrillation.MethodsA systematic search into PubMed, EMBASE, and the Cochrane databases was performed and five studies were selected that directly compared IA vs UA before ablation and reported procedural outcomes, embolic, and bleeding events. The primary outcome of the study was major adverse cerebro‐cardiovascular events.ResultsThe meta‐analysis included 840 patients with UA and 938 patients with IA. Median follow‐up was 30 days. Activated clotting time (ACT) before first heparin bolus was significantly longer with UA (P = .006), whereas mean ACT was similar between the two groups (P = .19). Total heparin dose needed was significantly higher with IA (mean, ‒1.61; 95% CI, ‒2.67 to ‒0.55; P = .003). Mean procedure time did not vary between groups (P = .81). Overall complication rates were low, with similar major adverse cerebro‐cardiovascular event (P = .40) and total bleeding (P = .55) rates between groups. Silent cerebral events (SCEs) were significantly more frequent with IA (log odds ratio, ‒0.90; 95% CI, ‒1.59 to ‒0.22; P < .01; I 2, 33%). Rates of major bleeding, minor bleeding, pericardial effusion, cardiac tamponade, and puncture complications were similar between groups.ConclusionsUA during atrial fibrillation ablation has similar bleeding event rates, procedural times, and mean ACTs as IA, with fewer SCEs.

Thromboelastometry, Thromboelastography, and Conventional Tests to Assess Anticoagulation During Extracorporeal Support: A Prospective Observational Study.

Optimal anticoagulation monitoring in patients with extracorporeal membrane oxygenation (ECMO) is fundamental to avoid hemorrhagic and thromboembolic complications. Besides conventional coagulation tests, there is growing interest in the use of viscoelastic hemostatic assays (VHA), in particular of tromboelastography (TEG). Evidence on the use of rotational thromboelastometry (ROTEM) is lacking in this setting. The aim of the study was to evaluate ROTEM as a tool for assessing hemostasis during ECMO, by comparing it to TEG and conventional coagulation assays. We conducted a prospective, observational, single-center study on adult patients on ECMO support anticoagulated with unfractioned heparin (UFH). Kaolin reaction time (R, min) for TEG and INTEM clotting time (CT, sec) for ROTEM were analyzed and compared with conventional coagulation tests. In the study period, we included 25 patients on ECMO support (14 V-A and 11 V-V); 84 data points were available for the analysis. Median UFH infusion rate was 15 [11-18] IU/min/kg. Median values for activated partial thromboplastin time (aPTT) ratio, Kaolin TEG R time, and INTEM CT were 1.44 [1.21-1.7], 22 [13-40] min, and 201 [183-225] sec, respectively. INTEM CT (ROTEM) showed a moderate correlation with standard coagulation tests (R2 = 0.34 and 0.3 for aPTT and activated clotting time (ACT), respectively, p < 0.001). No significant correlation was found between INTEM CT and Kaolin R time (R2 = 0.01). Further studies are needed to identify an appropriate anticoagulation target for ROTEM during ECMO.

The prehospital use of younger age whole blood is associated with an improved arrival coagulation profile.

Recent in vitro data have shown that the hemostatic profile of whole blood (WB) degrades significantly after 14 days, yet the optimal storage remains debated. We hypothesized that arrival coagulation studies would be improved in patients receiving younger WB in the prehospital setting. This study was approved by our institutional institutional review board. We evaluated all trauma patients who received prehospital blood products by our helicopter service between July 2017 and July 2019. "Young" WB was defined as 14 days or less. Patients who received at least 1 U of young WB were classified as YOUNG, while the remainder was classified as OLD. Continuous data are presented as medians (25th-75th interquartile range) with comparisons performed using Wilcoxon rank sum. Assessments of clinical hemostatic potential included arrival platelet cell count and rapid thrombelastography. Multivariate regression analysis was also performed (Stata 12.1; College Station, TX). A total of 220 patients received prehospital WB during the study period. Of these, 153 patients received YOUNG WB, while 67 were transfused only OLD WB units. There were no differences in demographics, prehospital or arrival physiology, or Injury Severity Score among the two groups. The measures of clot initiation (activated clotting time) and kinetics (k time) were improved, as were the measures of clot acceleration/fibrinogen function (angle) and platelet function (maximum amplitude). As well, arrival platelet count was higher in the YOUNG cohort. No significant differences in postarrival transfusion were noted (p = 0.220). Multivariate analysis showed the greatest differences in maximum amplitude and α angle but failed to reach significance. Previous in vitro data have suggested deterioration of platelet function in cold-stored WB after 14 days. The current study demonstrated decreased global hemostasis by clinically available laboratory tests, especially related to fibrinogen and platelet interactions on univariate, but not multivariate analysis. This did not translate into increased transfusion requirements. Further studies are needed to determine the optimal storage duration for cold-stored WB for transfusion in the bleeding trauma patient, as well as rule out the presence of confounding variables. Therapeutic, level IV.

Direct carotid exposure approach in the treatment of anterior circulation unruptured intracranial aneurysms for elderly patients.

The direct carotid exposure approach (DCEA) is a technical option for elderly patients with severe vessel tortuosity due to arteriosclerosis. We evaluated complications related to antiplatelet/anticoagulant management and compared the DCEA to standard transfemoral/transbrachial approaches (TFBA) in the treatment of unruptured intracranial aneurysms for elderly patients. From August 2017 to August 2020, 52 patients (53 procedures) aged over 75 years with unruptured aneurysms in the anterior circulation were treated at our institution. All patients received dual antiplatelet drugs before the procedure. Eleven patients (21.2%) (12 procedures) were treated with the DCEA. The rest were treated with TFBA. The main indication of the DCEA was an unfavorable aortic arch or vessel tortuosity. Complications and the duration of the procedure were compared between the two groups. There were no significant differences between the two groups in age, aneurysm location, preoperative antiplatelet use, heparin use, or maximum activated clotting time (ACT) values. All endovascular treatments were successfully performed by DCEA. Among all parameters, the DCEA group had only bigger average aneurysm diameter (14 mm) and higher number of pipeline embolic device (PED) placement (58%). Time to the guiding-catheter placement was not significantly different between the groups (DCEA vs TFBA = 31.0 min vs 24.7 min, p = 0.178). No significant complications of DCEA, such as subcutaneous hematomas, were observed. . Even with the use of antiplatelet and anticoagulation therapy, the DCEA can be performed safely for unruptured aneurysms in elderly patients.

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.

Differences in activated coagulation times and heparin requirements during ablation procedures in patients with different oral anticoagulant drug regimens

Anticoagulation during percutaneous catheter ablation should be closely monitored with Activated Clotting Time (ACT). However, VKA or direct oral anticoagulant drugs (DOAC) may act differently on ACT and thus on heparin needs. The aim of this study was to compare ACT and heparin requirements during catheter ablation under various oral anticoagulant drug regimens and in controls. Sixty consecutive patients referred for ablation were retrospectively included: group 1 ( n = 15, VKA), group 2 ( n = 15, uninterrupted rivaroxaban), group 3 ( n = 15, uninterrupted apixaban) and group 4 ( n = 15, controls). Heparin requirements and ACT were compared throughout the procedure. Heparin requirements during the procedure were significantly lower in patients under VKA compared to DOAC and lower in DOAC patients compared to controls. First and averaged ACT values were significantly higher in patients under VKA compared to DOAC and similar in DOAC patients compared to controls. Furthermore, anticoagulation control as evaluated by the number/proportion of ACT > 300 as well as the time passed over 300 sec was significantly better in patients under VKA versus DOAC, but the differences were not significant between DOAC versus controls. Finally, the number of patients/ACT with excessive ACT values was significantly higher in VKA versus DOAC patients versus controls. There was no significant difference between DOAC drugs for ACT or heparin dosing throughout the procedure. VKA allowed less heparin requirement despite reaching higher ACT values and more efficient anticoagulation control (although with a higher risk for excessive values) compared to patients under long-term DOAC therapy and to controls.

Determinants of Abnormal Activated Clotting Time in Cardiac Catheterisation

Activated clotting time (ACT) is an important measure of blood coagulability during cardiac interventions. Ineffective ACT may predispose to peri-procedural complications. We sought to explore patient and procedural factors that may be associated with a non-therapeutic ACT.