Higher Activated Clotting Time Research Articles

Relation between antithrombin-III activity and activated clotting time for cardiopulmonary bypass.

Heparin resistance (HR) is observed before cardiopulmonary bypass (CPB), despite with normal antithrombin III (AT-III) levels. The relationships between preoperative AT-III activity and activated clotting time (ACT) after the first heparin dose should be clarified. We retrospectively analyzed the data of 818 patients who underwent CPB surgery, with the initial heparin of 300, 400, and 500IU/kg, between 2017 and 2021. We defined HR as the failure to achieve ACT after the initial heparin dose (Post ACT) of > 480s.There were no significant correlations between the AT-III activity and Post ACT in all patients, including 143 patients with AT-III activity < 80% and 675 patients with AT-III activity of ≥ 80%. Also, there were no significant correlations between the AT-III activity and Post ACT in 74 patients who received heparin of 300IU/kg, in 186 patients with 400IU/kg, and in 339 patients with 500IU/kg. After identifying smoking, HR, activated partial thromboplastin time, fibrinogen degradation products (FDP), and ACT as influencing factors, multiple comparisons using the Steel-Dwass test showed significant difference in FDP and HR among the patients who received heparin of 300IU/kg, 400IU/kg, and 500IU/kg. There is no association between preoperative AT-III activity and ACT after the first heparin administration for CPB, even in different dose of heparin. Rather, the higher the initial UFH dose is, the higher ACT may be, regardless of the AT-III activity.

Platelet reactivity and activated clotting time predict hemorrhagic site complications in patients with chronic coronary syndromes undergoing percutaneous coronary interventions.

Radial access is preferred in patients with chronic coronary syndromes (CCSs) treated with ad hoc percutaneous coronary intervention (PCI). Antithrombotic and antiplatelet treatment before PCI may affect outcomes at vascular access sites. QuikClot Radial is a kaolin-based band that may shorten hemostasis time. Using point-of-care testing, we investigated the effect of antithrombotic and antiplatelet treatment on access-site complications. This prospective observational study included consecutive patients with CCS on chronic aspirin therapy referred for ad hoc PCI. The activated clotting time (ACT), global thrombosis test and VerifyNow P2Y 12 test were done sequentially after unfractionated heparin (UFH) and clopidogrel administration. Patients were monitored for radial artery patency, bleeding and local hematoma until discharge. We enrolled 40 patients [mean age, 68.8 ± 8.8 years; men, 30 (75%)] who received UFH (median dose, 8000 IU; interquartile range, 7000-9000 IU) and clopidogrel (600 mg). All radial arteries remained patent during follow-up. Local bleeding and hematomas were noted in 11 patients (27.5%) each. Patients with bleeding had lower mean platelet activity at 2 h [122.5 ± 51 platelet reactivity units (PRU) vs. 158.7 ± 43 PRU, P = 0.04] and higher ACT (216.9 ± 40 s vs. 184.6 ± 28 s, P = 0.006) than patients without bleeding. An ACT >196 s at 2 h predicted bleeding or hematoma (AUC, 0.72; 95% CI, 0.56-0.85, P = 0.008). Lower platelet activity and higher ACT after PCI were associated with higher bleeding risk at a vascular access site. Point-of-care testing of ACT after the procedure may help identify patients with CCS undergoing PCI who are at higher risk of access-site bleeding.

Detail analysis of puncture site complications in neuro-endovascular therapy: A single-center analysis

ObjectivePuncture site complications in neuro-endovascular therapy, which represent a significant cause of morbidity, are often difficult to treat. Vascular closure devices have evolved in endovascular therapy. We analyzed risk factors for puncture site complications and examined the efficacy of hemostasis methods in neuro-endovascular therapy. MethodsThis retrospective, observational, single-center study was conducted from January 2021 to January 2023. We enrolled 202 puncture sites of patients who underwent neuro-endovascular therapy at Kawaguchi Municipal Medical Center and analyzed the complications requiring additional intervention. ResultsThere were 12 (5.94 %) puncture site complications. No patient had permanent puncture-related complications. Univariate analyses revealed that a higher risk of puncture site complications was significantly associated with multiple antiplatelet agents (p = 0.03), hypertension (p = 0.03), scheduled treatment (p < 0.01), higher activated clotting time (ACT) immediately before sheath removal (≥310 s, p < 0.01), and the non-use of Perclose (manual compression or Angio-seal, p < 0.01). Multivariate analyses revealed that puncture site complications were significantly higher in patients with an ACT immediately before sheath removal ≥ 310 s (HR: 10.4, 95 % CI: 2.45–44.15, p < 0.01), scheduled treatment (HR: 10.16, 95 % CI: 1.81–56.95, p < 0.01), and the non-use of Perclose (HR: 21.97, 95 % CI: 2.42–199.34, p < 0.01). ConclusionA higher ACT immediately before sheath removal was significantly associated with puncture site complications. Perclose is an efficient device, and it may reduce the risk of puncture site complications.

Direct Oral Anticoagulants Affect Activated Clotting Time During and Bleeding Events After Percutaneous Coronary Intervention

Inappropriately high activated clotting time (ACT) during percutaneous coronary intervention (PCI) is associated with an increased risk of bleeding events. However, whether the prescription of direct oral anticoagulants (DOACs) affects ACT kinetics during heparin use and adverse clinical events in patients who underwent PCI remains unclear. We aimed to evaluate the relations between ACT changes during and adverse clinical events after PCI in patients who were prescribed DOAC. This observational study included 246 patients who underwent PCI at the 2 cardiovascular centers who were not receiving warfarin and whose ACT was recorded immediately before and 30minutes after injection of unfractionated heparin. Patients were divided into 2 groups according to DOAC prescription at the time of the index PCI: DOAC users (n=31) and nonusers (n=215). Any bleeding and systemic thromboembolic events were investigated until 30days after PCI. The average age of this population was 70.5years, and 66.3% were male. Average ACT was significantly higher in DOAC users than nonusers both before and 30minutes after unfractionated heparin induction (157.2±30.1 vs 131.8±25.1seconds, p<0.001; 371.1±122.2 vs 308.3±82.2seconds, p<0.001; respectively). The incidence of systemic thromboembolism after PCI was low and comparable between the 2 groups (0% vs 3.7%, p=0.60). However, the rate of any bleeding event was significantly higher in DOAC users than in nonusers (16.1% vs 4.7%, p=0.028). Patients receiving DOAC have higher ACT during PCI and higher incidence of bleeding events than those not receiving DOAC.

Simple periprocedural precautions to reduce Doppler microembolic signals during AF ablation

BackgroundDoppler microembolic signals (MES) occur during atrial fibrillation ablation despite of permanent flushed transseptal sheaths, frequent controls of periprocedural coagulation status and the use of irrigated ablation cathetersPurposeTo investigate the number and type of MES depending on the procedure time, prespecified procedure steps, the activated clotting time (ACT) during the ablation procedure and the catheter contact force.MethodsIn a prospective trial, 53 consecutive atrial fibrillation patients underwent pulmonary vein isolation by super-irrigated “point-by-point” ablation. All patients underwent a periinterventional, continuous transcranial Doppler examination (TCD) of the bilateral middle cerebral arteries during the complete ablation procedure.ResultsAn average of 686±226 microembolic signals were detected by permanent transcranial Doppler. Thereby, 569±208 signals were differentiated as gaseous and 117±31 as solid MES. The number of MES with regard to defined procedure steps were as follows: gaseous: [transseptal puncture, 26 ± 28; sheath flushing, 24±12; catheter change, 21±11; angiography, 101±28; mapping, 9±9; ablation, 439±192; protamine administration, 0±0]; solid: [transseptal puncture, 8±8; sheath flushing, 9±5; catheter replacement, 6±6; angiography, not measurable; mapping, 2±5; ablation, 41±22; protamine administration, 0±0]. Significantly less MES occurred with shorter procedure time, higher ACT and the use of tissue contact force monitoring.ConclusionThe current study demonstrates that during atrial fibrillation ablation using irrigated, “point-by-point” RF ablation, masses of microembolic signals are detected in transcranial ultrasound especially in the period of RF current application. The number of MES depends on the total procedure time and the reached ACT during ablation. The use of contact force monitoring might reduce MES during RF ablation.

Heparin reversal with protamine sulfate is not required in atrial fibrillation ablation with suture hemostasis.

The utility of protamine sulfate for heparin reversal in catheter-based atrial fibrillation (AF) ablation is unclear when using the suture closure technique for vascular hemostasis. This study sought to address if protamine sulfate use for heparin reversal reduces vascular access complications in AF catheter ablation when suture techniques are used for postprocedural vascular hemostasis. This is a retrospective multicenter observational study of 294 consecutive patients who underwent catheter ablation for AF with subsequent vascular access hemostasis by means of a figure-of-eight suture or stopcock technique. A total of 156 patients received protamine for heparin reversal before sheath removal while 138 patients did not receive protamine. The two groups were compared for procedural activated clotting time (ACT), access site complications, and duration of hospital stay. Baseline demographic characteristics were comparable in both groups. Despite higher ACT before venous sheath removal in patients not receiving protamine (288.0 ± 44.3 vs 153.9 ± 32.0 seconds; P < .001), there was no significant difference in groin complications, postoperative thromboembolic events, or duration of hospital stay between the two groups. Suture failure requiring manual compression was rarely observed in this cohort (0.34%). With modern vascular access and sheath management techniques, for patients undergoing catheter ablation for AF, simple suture closure techniques can obviate the need for protamine administration to safely achieve hemostasis after removal of vascular sheaths.

Effects of platelet glycoprotein IIb/IIIa inhibition with abciximab on thrombin generation and activity during percutaneous coronary intervention

Background Antagonists of the platelet glycoprotein IIb/IIIa decrease acute ischemic complications after percutaneous coronary interventions (PCI). Abciximab (c7E3 Fab, ReoPro) has been reported to decrease thrombin generation in vitro. We investigated in vivo the effect of abciximab therapy on thrombin generation, thrombin activity, and the activated clotting time (ACT) during PCI. Methods We studied 32 consecutive patients who underwent PCI for unstable coronary syndromes. Group I (n = 11) was treated with heparin plus aspirin, and group II (n = 21) was treated with heparin plus aspirin plus standard-dose abciximab, administered 5 minutes after the initial heparin bolus. Patients received a standardized heparin bolus at time 0, and arterial blood specimens for prothrombin fragment F1.2, fibrinopeptide A (FPA), and ACT were obtained from the guiding catheter at 5 minutes, 10 minutes (ACT only), 20 minutes, and at the end of the PCI. Standard-dose abciximab was administered in group II only. Each patient served as his or her own control, and the changes against the baseline were compared between the 2 groups. Results There were no significant differences between the 2 groups regarding baseline characteristics, hematocrit, and platelet count. Group I patients had higher ACT and lower F1.2 and FPA compared with group II at baseline. Subsequent measurements demonstrated a gradual decrease in FPA and F1.2 in group II; the end of procedure versus baseline changes that occurred in F1.2 were significantly different compared with group I (decrease of 0.59 ± 0.22 nmol/L in group II vs increase of 0.22 ± 0.3 nmol/L in group I, P = .04), and a trend in the same direction was evident for FPA changes (decrease of 1.46 ± 1.16 ng/mL in group II vs increase of 2.25 ± 1.58 ng/mL in group I, P = .07). The ACT response to abciximab was variable, but a 6.3% increase (+20 sec) in ACT was documented 5 minutes after abciximab bolus in group II compared with the 3.4% decrease (–10 sec) observed in group I at the same time point ( P = .1). Conclusion Addition of abciximab to heparin plus aspirin during PCI was associated with a significant decrease in thrombin generation and a borderline decrease in thrombin activity. (Am Heart J 1999;138:49-54.)

Coronary Angioplasty in Patients with Unstable Angina, with Special Reference to Preceding Treatment with Antithrombin III and Heparin

Seventy-nine patients undergoing percutane ous transluminal coronary angioplasty (PTCA) for unsta ble angina were analyzed with respect to preceding an tithrombin treatment; group I comprised patients (n = 26) without antecedent antithrombin therapy; group II, pa tients (n = 30) with heparin infusion for ≥24 h, and group III patients (n = 23) with ongoing heparin infusion and given antithrombin III concentrate immediately before the procedure because of plasma antithrombin III &lt;85%. Immediate results were 89% (70 of 79) angiographic suc cess, five (6%) subacute occlusions (two subsequent non-Q wave infarctions), no emergency coronary artery bypass grafting (CABG), and no immediate mortality. There were no differences between the groups. From dis charge to 4 months, one patient died, one had a nonfatal infarction, and 24 (30%) had repeated PTCA or CABG. The cumulative 4-month event rate was 11 of 26 (42%) in group I, 10 of 30 (33%) in group II, and 7 of 23 (30%) in group III (NS). During PTCA, heparin bolus administra tion was guided by activated clotting time (ACT), aiming at&gt;300 s. Baseline ACT was significantly less in patients not treated with heparin (129 ± 34 s in group I vs. 179 ± 38 and 162 ± 29 s in groups II and III, respectively; p &lt; 0.05), but during the procedure, patients from all groups required the same amount of heparin (13,900 ± 4,800, 13,000 ± 6,800, and 13,000 ± 5,700 IU, respectively; NS) to reach similar maximum ACT levels (334 ± 36, 312 ± 32, and 319 ± 44 s, respectively; NS). Patients receiving warfarin ( n = 8) responded with a higher ACT (456 ± 110 s; p &lt; 0.05) on lower doses of heparin (10,000 ± 3,800 IU). In conclusion, patients with unstable angina receiv ing individualized antithrombotic therapy can be success fully treated with PTCA, with an acute complication rate and long-term results comparable with those expected in patients undergoing elective procedures. The value of an tithrombin III substitution must be evaluated in random ized trials. Preprocedural heparin infusion does not re duce the need of extra heparin during the procedure. Key Words: Antithrombin III—Heparin—PTCA (percutane ous transluminal coronary angioplasty)—Unstable angina pectoris.