Shear-Induced Pathway of Platelet Function in Cardiac Surgery

1995 ◽  
Vol 21 (S 02) ◽  
pp. 66-70 ◽  
Author(s):  
Noriyuki Tabuchi ◽  
Izaak Tigchelaar ◽  
Willem Van Oeveren
Keyword(s):  
Cardiac Surgery ◽  
Cardiopulmonary Bypass ◽  
Platelet Function ◽  
Chest Drain ◽  
Clotting Time ◽  
Platelet Dysfunction ◽  
Excessive Bleeding ◽  
Activated Clotting Time ◽  
Proper Diagnosis

The contribution of platelet dysfunction to the impaired hemostasis after cardiac surgery remains to be established, because there is no sensitive method to assess platelet function. Measurement of the shear-induced pathway of platelet function, an important mechanism in inducing hemostasis, became possible by a novel shear-inducing technique, the in-vitro bleeding test (Thrombostat 4000). By using this test, the changes in platelet function during cardiopulmonary bypass and their contribution to hemostasis were investigated in patients undergoing cardiac surgery. Platelet function is quickly impaired shortly after the start of cardiopulmonary bypass, and partly recovered at the end of cardiopulmonary bypass. The function of aspirin-treated platelets is more severely affected than of nonaspirin platelets during cardiopulmonary bypass. Furthermore, the degree of platelet dysfunction at the end of the operation, but neither the platelet number nor the activated clotting time, was significantly correlated with blood loss from the chest drain after cardiac surgery. These results indicate the significant and variable effects of cardiopulmonary bypass on the shear-induced pathway of platelet function. Moreover, the impairment of this function of platelets appears to be a major cause of excessive bleeding in patients after cardiac surgery. Therefore, the routine use of the shear-inducing test seems helpful to make a proper diagnosis and design the therapy for bleeders after cardiac surgery.

Factors associated with errors in the heparin dose response test: recommendations to improve individualized heparin management in cardiopulmonary bypass

Perfusion ◽  
2020 ◽  
pp. 026765912095297
Author(s):  
Min-Ho Lee ◽  
William Riley
Keyword(s):  
Cardiopulmonary Bypass ◽  
Dose Response ◽  
Clotting Time ◽  
Critical Aspect ◽  
Heparin Dose ◽  
Factors Associated ◽  
Heparin Concentration ◽  
Activated Clotting Time

Background: A critical aspect of cardiopulmonary bypass (CPB) is to achieve full anticoagulation to prevent thrombosis and consumptive coagulation without using excessive amount of heparin. This can be achieved with heparin dose response (HDR) test in vitro to calculate an individualized heparin bolus to reach a target activated clotting time (ACT) and heparin concentration. However, we often observe that the measured ACT (mACT) with the calculated heparin bolus gives significant errors, both positive (mACT is higher than expected) and negative (mACT is lower), from expected ACT (eACT). Methods: We performed a retrospective study of 250 patients who underwent cardiac surgery to attain an error distribution of the mACT from eACT with calculated heparin bolus. In addition, it is aimed to identify possible patterns of baseline ACT (bACT), calculated heparin concentration (CHC) and HDR slope that are associated with the significant positive and negative errors. Results: We found that individualized heparin bolus by HDR test is consistently underestimated while it gave a significant number of positive and negative errors. Further analysis indicates that significant negative errors correlate with high bACT and slope and low CHC while significant positive errors with low bACT and slope and high CHC. Conclusion: The mACT can be substantially different from eACT. The accuracy of the HDR test appears to be dependent upon bACT, slope, and CHC. Based on our analysis, we provide several recommendations and a flow chart to improve the quality of individualized heparin management on CPB.

scholarly journals Anticoagulation in Cardiopulmonary Bypass

1977 ◽  
Author(s):  
C. Thomas Kisker ◽  
John A. Young ◽  
Donald B. Doty ◽  
Barbara J. Taylor
Keyword(s):  
Cardiopulmonary Bypass ◽  
Antithrombin Iii ◽  
Human Subjects ◽  
Mean Value ◽  
Clotting Time ◽  
Excessive Bleeding ◽  
Safe Level ◽  
Activated Clotting Time ◽  
Before And After ◽  
The Mean

Prolonging the activated clotting time (ACT) 2 to 3 times normal is said to provide a “safe” level of anticoagulation during cardiopulmonary bypass. To test this level of anticoagulation 9 monkeys were anticoagulated with heparin at the start of cardiopulmonary bypass so that ACT’s ranged from 201 sec to > 1000 sec (normal 91 sec). ACT, platelet count (P), fibrinogen (F), and fibrin monomer (FM) were measured at 10, 30, 60, 90, and 120 minutes during bypass. Antithrombin III (AT3) was measured before and after bypass. Six monkeys developed increased FM indicating active coagulation beginning from 10 to 60 minutes on bypass. ACT’s were > 200 sec in all animals at the time of FM detection. P fell below 100,000/mm3 in the 6 animals with elevated FM, but remained above 100,000/mm3 in the other 3 animals. The mean value of AT3 (69%) decreased to 24.4% after bypass in the 6 animals with elevated FM, but was 61% after bypass in the others. Scanning electron microscopy of the oxygenator membranes showed significant amounts of fibrin on the membranes used in monkeys who developed increased FM levels, but not on those with normal FM concentrations. F decreased from 167 mgm/dl to 80.5 mgm/dl in monkeys with elevated FM and to 117 mgm/dl in those with normal FM concentrations. Excessive bleeding did not occur in the animals without increased FM although ACT’s were in excess of 1000 sec. Subsequently three human subjects on cardiopulmonary bypass whose ACT’s were maintained above 400 sec have not shown increased FM levels. The results suggest that prolonging the ACT more than 2 - 3 times normal is required to prevent activation of clotting during cardiopulmonary bypass.

A comparative analysis of four activated clotting time measurement devices in cardiac surgery with cardiopulmonary bypass

Perfusion ◽  
2020 ◽  
pp. 026765912094935
Author(s):  
Han Li ◽  
Cyril Serrick ◽  
Vivek Rao ◽  
Paul M Yip
Keyword(s):  
Cardiac Surgery ◽  
Cardiopulmonary Bypass ◽  
System Analysis ◽  
Point Of Care ◽  
Measurement Range ◽  
Medical Decision ◽  
Clotting Time ◽  
Activated Clotting Time ◽  
Decision Points ◽  
Heparin Anticoagulation

Background: In cardiac surgery on cardiopulmonary bypass (CPB), heparin anticoagulation is monitored by point-of-care measurement of activated clotting time (ACT). The objective of this study was to compare four ACT systems in cardiac surgery in terms of their reproducibility, agreement and potential clinical impact at relevant medical decision points. Methods: The study included 40 cardiac surgery patients. Samples were taken at five time points before (T1), after heparinization for CPB (T2, T3, T4), and after heparin reversal (T5). The reproducibility, correlation, and differences in ACT values were assessed with two devices from each of the four ACT systems: Instrumentation Laboratory Hemochron Elite (Hmch), Medtronic HMS Plus (HMS), Abbott i-STAT, and Helena Abrazo. Subrange analyses were performed for low ACT values (results from T1, T5) and high ACT values (results from T2, T3, T4). Results: Within-system analysis showed strong linear correlation between paired measurements (R = 0.968-0.993). However, Hmch showed poorer reproducibility with highest proportion of values that exceed a difference of 10% and highest overall standard error of 74 seconds across the measurement range compared to that of the others (range 39-47 seconds, respectively). For inter-system comparison, using Hmch as reference, ACTs were strongly correlated as follows: HMS (R = 0.938), i-STAT (R = 0.911), and Abrazo (R = 0.911). Agreement analysis in the high ACT range showed HMS tended to have higher ACT values with +11% bias over Hmch, whereas i-STAT (–8% bias) and Abrazo (–13% bias) tended to underestimate. Post-protamine ACT results were dependent on device type where Hmch yielded highest post-protamine ACT (+13% higher than baseline) compared to –16% for HMS, –10% for iSTAT and 0% for Abrazo. Conclusions: Each device had individual reproducibility and biases, which may impact peri-operative heparin management. Careful validation must be undertaken when adopting a different method as decision limits would be affected. Clinicians should also be cautious using ACT as the only indicator for full heparin reversal.

Application of goal-directed therapy for the use of concentrated antithrombin for heparin resistance during cardiac surgery

Perfusion ◽  
2020 ◽  
pp. 026765912092608
Author(s):  
Alfred H Stammers ◽  
Stephen G Francis ◽  
Randi Miller ◽  
Anthony Nostro ◽  
Eric A Tesdahl ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Cardiopulmonary Bypass ◽  
Heparin Therapy ◽  
Sensitivity Index ◽  
Transfusion Rate ◽  
Clotting Time ◽  
Activated Clotting Time ◽  
Institutional Review ◽  
Number Of Factors ◽  
Heparin Resistance

The maintenance of anticoagulation in adult patients undergoing cardiopulmonary bypass is dependent upon a number of factors, including heparin concentration and adequate antithrombin activity. Inadequate anticoagulation increases the risk of thrombosis and jeopardizes both vascular and extracorporeal circuit integrity. The purpose of this study was to evaluate a goal-directed approach for the use of antithrombin in patients who were resistant to heparin. Following institutional review board approval, data were obtained from quality improvement records. A goal-directed protocol for antithrombin was established based upon heparin dosing (400 IU kg−1 body weight) and achieving an activated clotting time of ⩾500 seconds prior to cardiopulmonary bypass. Two groups of patients were identified as those receiving antithrombin and those not receiving antithrombin. Outcome measures included activated clotting time values and transfusion rates. Consecutive patients (n = 140) were included in the study with 10 (7.1%) in the antithrombin group. The average antithrombin dose was 1,029.0 ± 164.5 IU and all patients had restoration to the activated clotting time levels. Patients in the antithrombin group were on preoperative heparin therapy (80.0% vs. 24.6%, p = 0.001). Prior to cardiopulmonary bypass the activated clotting time values were lower in the antithrombin group (417.7 ± 56.1 seconds vs. 581.1 ± 169.8 seconds, p = 0.003). Antithrombin patients had a lower heparin sensitivity index (0.55 ± 0.17 vs. 1.05 ± 0.44 seconds heparin−1 IU kg−1, p = 0.001), received more total heparin (961.3 ± 158.5 IU kg−1 vs. 677.5 ± 199.0 IU kg−1, p = 0.001), more cardiopulmonary bypass heparin (22,500 ± 10,300 IU vs. 12,100 ± 13,200 IU, p = 0.016), and more protamine (5.4 ± 1.2 vs. 4.1 ± 1.1 mg kg−1, p = 0.003). The intraoperative transfusion rate was higher in the antithrombin group (70.0% vs. 35.4%, p = 0.035), but no differences were seen postoperatively. Utilization of a goal-directed algorithm for the administration of antithrombin for the treatment of heparin resistance is effective in patients undergoing cardiac surgery.

scholarly journals Comparison of activated clotting times measured using the Hemochron Jr. Signature and Medtronic ACT Plus during cardiopulmonary bypass with acute normovolemic haemodilution

2017 ◽  
Vol 46 (2) ◽  
pp. 873-882 ◽  
Author(s):  
Jung Min Lee ◽  
Eun Young Park ◽  
Kyung Mi Kim ◽  
Jong Chan Won ◽  
Tack Koon Jung ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Cardiac Surgery ◽  
Cardiopulmonary Bypass ◽  
Bolus Dose ◽  
Blood Glucose Concentration ◽  
Altman Analysis ◽  
Clotting Time ◽  
Bland Altman Analysis ◽  
Activated Clotting Time ◽  
Protamine Administration

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.

Reliability of the Heparin Management Test for Monitoring High Levels of Unfractionated Heparin

2000 ◽  
Vol 92 (6) ◽  
pp. 1594-1602 ◽  
Author(s):  
Fritz Mertzlufft ◽  
Andreas Koster ◽  
Roland Hansen ◽  
Anne Risch ◽  
Herrmann Kuppe ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Storage Time ◽  
Coagulation Factors ◽  
Clotting Time ◽  
Activated Clotting Time ◽  
Group I ◽  
Group Ii ◽  
And Storage

Background The authors assessed the heparin management test in vitro in volunteers and in vivo during cardiopulmonary bypass. Methods In vitro, the heparin management test was analyzed for heparin levels between 0 and 6 IU/ml using variations in hematocrit, platelets, procoagulants, and storage time. The in vivostudies consisted of two groups: In group I (cardiopulmonary bypass </= 90 min, n = 40), anticoagulation was performed according to the activated clotting time (with or without aprotinin); in group II (cardiopulmonary bypass >/= 180 min, with aprotinin) included use (n = 10) and nonuse of coumadin (n = 10) and anticoagulation according to the automated heparin dose-response assay. Tests were performed in duplicate (whole blood, two heparin management test analyzers) and compared with anti-Xa activity (plasma). Results In vitro, the results of the heparin management test (n = 1,070) correlated well with heparin concentration (r2 = 0.98). Dilution and storage time did not affect the heparin management test; a hematocrit of 60% and reduced procoagulants (10%) prolonged clotting time. In vivo, the correlation (heparin management test vs. anti-Xa) was strong in group I (r2 = 0.97 [with aprotinin] and 0.96 [without aprotinin]; n = 960) and group II without coumadin (r2 = 0.89, n = 516). In group II with coumadin, the overall correlation was r2 = 0.87 and 0.79 (n = 484), although the range varied widely (0.57-0.94, between-analyzer differences 0-47%). Conclusions The results of the heparin management test were influenced by hematocrit, plasma coagulation factors, and the heparin level, but not by use of aprotinin. The heparin management test provided reliable values in vitro in group I, and in group II without coumadin but was less reliable in group II with coumadin.

scholarly journals Utility of Platelet Function Tests: A Recent Review Round Up

2019 ◽  
Vol 03 (01) ◽  
pp. 24-27
Author(s):  
Sandeep Sharan ◽  
Ajay Gandhi ◽  
Poonam Malhotra Kapoor
Keyword(s):  
Cardiac Surgery ◽  
Coronary Artery ◽  
Platelet Function ◽  
Postoperative Bleeding ◽  
Platelet Dysfunction ◽  
Platelet Function Tests ◽  
Excessive Bleeding ◽  
Function Tests ◽  
Increased Risk ◽  
Hemostatic Therapy

AbstractPatients undergoing cardiac surgery are at risk of excessive bleeding and associated complications. Excessive bleeding during and after cardiac surgery has an incidence of ~20%. Massive bleeding and subsequent requirement for blood product administration and mediastinal re-exploration is associated with significant morbidity and mortality. Postoperative, nonsurgical bleeding in cardiac surgical patients is often multifactorial. Platelet dysfunction, excessive fibrinolysis, hypothermia, preoperative anemia, and deficiency of coagulation factors or their dilution are all suggested etiologies of postoperative bleeding. Among these, the most important is thought to be platelet dysfunction, which occurs as a result of the interplay of acquired and pharmacologically induced factors. Patients suffering from coronary artery disease are usually advised to stop antiplatelet medication a few days prior to coronary artery bypass grafting (CABG) to reduce the incidence of postoperative bleeding. However, patients who are still on antiplatelet drugs are at an increased risk of postoperative bleeding. Currently, the transfusion of blood and blood components to manage postoperative bleeding after CABG remains largely empirical, with considerable variation among institutions. Algorithm-based hemostatic therapy has been shown to be superior to empiric hemostatic therapy that is based on clinical judgment. Hence, there is a need to have objective tests to demonstrate platelet dysfunction before platelet transfusion. Several devices of platelet function tests have been reported in clinical studies to evaluate platelet dysfunction and quantify the need for antiplatelet therapy

Relationships between antithrombin activity, anticoagulant efficacy of heparin therapy and perioperative variables in patients undergoing cardiac surgery requiring cardiopulmonary bypass

Perfusion ◽  
2011 ◽  
Vol 26 (6) ◽  
pp. 487-495 ◽  
Author(s):  
V Muedra ◽  
S Bonanad ◽  
M Gómez ◽  
V Villalonga ◽  
F Sánchez ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Cardiopulmonary Bypass ◽  
Hematological Parameters ◽  
Inverse Correlation ◽  
Heparin Therapy ◽  
Additional Dose ◽  
Clotting Time ◽  
Post Intervention ◽  
Significant Inverse Correlation ◽  
Activated Clotting Time

Introduction: A study on 149 cardiopulmonary bypass (CPB) patients was performed to elucidate possible relationships between antithrombin (AT) activity and a subject’s clinical profile or surgery characteristics. Methods: An initial dose (300 IU/kg) of heparin was administered before CPB. Additional boluses (100 IU/kg) were administered if the activated clotting time (ACT)≤460 s. AT activity and hematological parameters were determined preoperatively, during and after CPB, and at 12, 24, 36, and 48 hours post-intervention. Results: 29.5% patients required an additional dose of heparin during CPB. Preoperative AT was 96.5 ± 13.9% in all but 4 patients. AT was significantly lower during CPB and upon leaving the operating room (59.7%-80.0%). A small, but significant, inverse correlation was observed between AT at the end of CPB and the patient’s age, as well as between basal preoperative AT and total heparin administered. Conclusions: Patient’s age could be a moderate indicator of AT activity drop and low preoperative AT activity could be a sign of reduced anticoagulant efficacy of heparin during CPB.

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