| 1. |
- Andersson Shams Hakimi, Caroline, et al.
(författare)
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Effects of fibrinogen and platelet supplementation on clot formation and platelet aggregation in blood samples from cardiac surgery patients.
- 2014
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Ingår i: Thrombosis research. - : Elsevier BV. - 1879-2472 .- 0049-3848. ; 134:4, s. 895-900
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Tidskriftsartikel (refereegranskat)abstract
- Bleeding after cardiac surgery may be caused by surgical factors, impaired haemostasis, or a combination of both. Transfusion of blood products is used to improve haemostasis, but little is known about what combination is optimal. We hypothesized that addition of both fibrinogen and platelets to blood samples from cardiac surgery patients would improve clot formation and platelet aggregation to a greater extent than if the components were added separately.
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| 2. |
- Andersson Shams Hakimi, Caroline, et al.
(författare)
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Effects of fibrinogen and platelet transfusion on coagulation and platelet function in bleeding cardiac surgery patients.
- 2019
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Ingår i: Acta anaesthesiologica Scandinavica. - : Wiley. - 1399-6576 .- 0001-5172. ; 63:4, s. 475-482
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Tidskriftsartikel (refereegranskat)abstract
- Excessive bleeding is a significant problem in cardiac surgery. Fibrinogen and platelet concentrate transfusion are used clinically to improve haemostasis and reduce bleeding but little is known about their functional effects on coagulation and platelet function in patients with ongoing bleeding.Forty-two patients with ongoing bleeding after cardiac surgery were included in an observational study. Patients received either fibrinogen concentrate (n = 16), platelet concentrate (n = 12), or both fibrinogen and platelets (n = 14), median doses 2 g fibrinogen and 2 units platelets given at one occasion. Blood samples were collected before and after transfusion. Coagulation (clotting time and clot stability) was analysed with rotational thromboelastometry, and platelet function with impedance aggregometry. In addition, platelet count and fibrinogen concentration was measured. Chest drain output was measured before and after the transfusion.Fibrinogen infusion resulted in an increase in fibrinogen concentration and clot stability (P = 0.001), but had no effect on platelet aggregation. Platelet transfusion did not significantly affect coagulation, but improved arachidonic acid- and TRAP-induced platelet aggregation (P = 0.017 and 0.034 respectively) and increased platelet count. Combined fibrinogen and platelet transfusion shortened clotting time (P = 0.005) and increased clot stability (P = 0.001), and improved arachidonic acid- and TRAP-induced platelet aggregation (P = 0.004 and 0.016 respectively), and increased fibrinogen concentration and platelet count. The median bleeding volume was 150 (25th-75th percentile 70-240) mL/h before, and 60 (40-110) mL/h after transfusion of fibrinogen and/or platelet concentrate (P < 0.001).The results demonstrate improved coagulation and platelet function following fibrinogen and platelet transfusion in patients bleeding after cardiac surgery.
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| 3. |
- Andersson Shams Hakimi, Caroline, et al.
(författare)
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In vitro assessment of platelet concentrates with multiple electrode aggregometry.
- 2015
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Ingår i: Platelets. - : Informa UK Limited. - 0953-7104 .- 1369-1635. ; 26:2, s. 132-137
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT Storage impairs platelet function. It was hypothesized that multiple electrode aggregometry in vitro could be used to follow aggregability in platelet concentrates over time and that the results predict the efficacy of platelet transfusion in an ex vivo transfusion model. In vitro platelet aggregability was assessed in apheresis and pooled buffy coat platelet concentrates (BCs) (n = 13 each) using multiple electrode aggregometry with different agonists 1, 3, 5 and 7 days after preparation. In the ex vivo transfusion model, whole blood samples from nine healthy volunteers were collected every second day. The samples were supplemented with stored platelets (+146 × 10(9) × l(-1)) from the same unit 1, 3, 5 and 7 days after preparation. Platelet aggregability was assessed in the concentrate and in the whole blood samples before and after platelet supplementation. There was a continuous reduction in in vitro platelet aggregability over time in both apheresis and pooled BCs. The same pattern was observed after ex vivo addition of apheresis and pooled BCs to whole blood samples. The best correlation between in vitro aggregability and changes in aggregation after addition was achieved with collagen as agonist (r = 0.67, p
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| 4. |
- Andersson Shams Hakimi, Caroline, et al.
(författare)
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The Effect of Ex Vivo Factor XIII Supplementation on Clot Formation in Blood Samples From Cardiac and Scoliosis Surgery Patients.
- 2018
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Ingår i: Clinical and applied thrombosis/hemostasis : official journal of the International Academy of Clinical and Applied Thrombosis/Hemostasis. - : SAGE Publications. - 1938-2723. ; 24:4, s. 677-683
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Tidskriftsartikel (refereegranskat)abstract
- Excessive perioperative bleeding remains a substantial problem. Factor XIII (FXIII) contributes to clot stability, and it has therefore been suggested that supplementation with FXIII concentrate may improve perioperative hemostasis. We evaluated the effects of increasing doses of FXIII, alone or in combination with fibrinogen or platelet concentrate, in blood samples from 2 considerably different groups of surgical patients: cardiac and scoliosis surgery patients. Whole-blood samples were collected immediately after operation from cardiac and scoliosis surgery patients. The samples were supplemented with 3 clinically relevant doses of FXIII concentrate (+20%, +40%, and +60%), alone or in combination with a fixed dose of fibrinogen concentrate (+1.0 g/L) or fresh apheresis platelets (+92 × 10(9)/L). Clot formation was assessed with rotational thromboelastometry (ROTEM). When the highest dose of FXIII concentrate was added, EXTEM clotting time was shortened by 10% in both cardiac and scoliosis surgery patients (95% confidence intervals: 2.4%-17% and 3.3%-17%, respectively), and FIBTEM maximum clot firmness was increased by 25% (9.3%-41%) in cardiac patients, relative to baseline. When fibrinogen was added, the dose-dependent effect of FXIII on clot stability was maintained, but the total effect was markedly greater than with FXIII alone, +150% (100%-200%) and +160% (130%-200%) for the highest FXIII dose in cardiac and scoliosis patients, respectively. Ex vivo supplementation with clinically relevant doses of FXIII improved clot formation moderately in blood samples from cardiac and scoliosis surgery patients, both alone and when given in combination with fibrinogen or platelet concentrate.
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| 5. |
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| 6. |
- Hansson, Emma C., 1985, et al.
(författare)
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Platelet function recovery after ticagrelor withdrawal in patients awaiting urgent coronary surgery
- 2017
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Ingår i: European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery. - : Oxford University Press (OUP). - 1010-7940 .- 1873-734X. ; 51:4, s. 633-637
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Dual antiplatelet therapy with ticagrelor and aspirin is associated with an increased risk of perioperative bleeding complications. Current guidelines recommend therefore discontinuation of ticagrelor 5 days before surgery to allow sufficient recovery of platelet function. It is not known how the time to recovery varies between individual patients after discontinuation of ticagrelor. METHODS: Twenty-five patients accepted for urgent coronary artery bypass surgery and treated with ticagrelor and aspirin were included in a prospective observational study. Platelet aggregation was evaluated with impedance aggregometry at five timepoints 12-96 h after discontinuation of ticagrelor. In a subset of patients (n = 15), we also tested the ex vivo efficacy of platelet concentrate supplementation on platelet aggregation. RESULTS: There was a gradual increase in mean adenosine diphosphate-induced platelet aggregation after discontinuation of ticagrelor. After 72 h, mean aggregation was 38 +/-23 aggregation units (U), which is above a previously suggested cut-off of 22 U, when patients can be operated without increased bleeding risk. However, there was a large interindividual variability (range 488 U at 72 h) and 6/24 patients (25%) had <22 U after 72 h. Ex vivo administration of platelet concentrate did not improve adenosine diphosphate-induced aggregation at any timepoint after ticagrelor discontinuation. CONCLUSIONS: Adenosine diphosphate-induced aggregation was acceptable after 72 h in the majority of patients but with a large interindividual variability. Due to the large variability, platelet function testing may prove to be a valuable tool in timing of surgery in patients with ongoing or recently stopped ticagrelor treatment. Adenosine diphosphate-induced aggregation was not improved by addition of platelet concentrate.
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| 7. |
- Singh, Sukhi, 1990, et al.
(författare)
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Adrenaline enhances in vitro platelet activation and aggregation in blood samples from ticagrelor-treated patients
- 2018
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Ingår i: Research and Practice in Thrombosis and Haemostasis. - : John Wiley & Sons. - 2475-0379. ; 2:4, s. 718-725
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Tidskriftsartikel (refereegranskat)abstract
- Background: Temporarily improved platelet reactivity may reduce the bleeding in patients on antiplatelet therapy who have ongoing bleeding or who are in need of acute surgery. Adrenaline can bind to adrenergic alpha(2A)-receptors on platelets and potentially enhance platelet reactivity.Objective: To assess if adrenaline can improve adenosine diphosphate (ADP)-induced platelet aggregation and activation in blood samples from patients on dual antiplatelet therapy with acetylsalicylic acid (ASA) and the ADP-receptor antagonist ticagrelor.Methods: Blood samples were collected from a total of forty acute coronary syndrome patients on dual antiplatelet therapy with ASA and ticagrelor. ADP-induced platelet aggregation (by impedance aggregometry) and activation (by flow cytometry) were assessed before and after supplementation with adrenaline and/or platelet concentrate.Results: Adrenaline supplementation (770 nmol L-1) increased median ADP-induced aggregation from 15 (25-75th percentiles: 10-20) to 26 (18-38) aggregation units. The effect was independent of concomitant platelet supplementation. Adrenaline also increased ADP-induced platelet activation: from 40% (36-54%) to 83% (74-88%) platelets with active fibrinogen receptor (binding PAC-1) and from 13% (7-21%) to 35% (18-50%) P-selectin-expressing platelets.Conclusions: Adrenaline potentiated ADP-induced platelet aggregation and activation in blood samples from ticagrelor-treated patients. Adrenaline infusion may be a new method to enhance platelet function in ticagrelor-treated patients who are in need of acute surgery or have ongoing bleeding. In vivo studies are needed to confirm the present results.
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| 8. |
- Singh, Sukhi, 1990, et al.
(författare)
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Adrenaline Improves Platelet Reactivity in Ticagrelor-Treated Healthy Volunteers
- 2019
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Ingår i: Thrombosis and Haemostasis. - : Georg Thieme Verlag KG. - 0340-6245 .- 2567-689X. ; 119:5, s. 735-743
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Administration of agents that enhance platelet reactivity may reduce the perioperative bleeding risk in patients treated with the adenosine diphosphate (ADP)-receptor antagonist ticagrelor. Adrenaline potentiates ADP-induced aggregation and activation in blood samples from ticagrelor-treated patients, but it has not previously been evaluated in vivo.METHODS: Ten healthy male subjects were included in an interventional study. A loading dose of ticagrelor (180 mg) was administered, followed 2 hours later by a gradually increased intravenous adrenaline infusion (0.01, 0.05, 0.10 and 0.15 µg/kg/min; 15 minutes at each step). Blood pressure, heart rate, platelet aggregation (impedance aggregometry), platelet activation (flow cytometry), clot formation (rotational thromboelastometry) and adrenaline plasma concentration were determined before and after ticagrelor administration and at the end of each adrenaline step.RESULTS: = 0.007).CONCLUSION: Infusion of adrenaline at clinically relevant doses improves in vivo platelet reactivity and clot formation in ticagrelor-treated subjects. Adrenaline could thus potentially be used to prevent perioperative bleeding complications in ticagrelor-treated patients. Studies in patients are necessary to determine the clinical importance of our observations.TRIAL REGISTRY NUMBER: ClinicalTrials.gov NCT03441412.
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| 9. |
- Singh, Sukhi, 1990, et al.
(författare)
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Platelet storage lesion in interim platelet unit concentrates: A comparison with buffy-coat and apheresis concentrates.
- 2017
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Ingår i: Transfusion and Apheresis Science. - : Elsevier BV. - 1473-0502. ; 56:6, s. 870-874
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Tidskriftsartikel (refereegranskat)abstract
- Platelet storage lesion is characterized by morphological changes and impaired platelet function. The collection method and storage medium may influence the magnitude of the storage lesion. The aim of this study was to compare the newly introduced interim platelet unit (IPU) platelet concentrates (PCs) (additive solution SSP+, 40% residual plasma content) with the more established buffy-coat PCs (SSP, 20% residual plasma content) and apheresis PCs (autologous plasma) in terms of platelet storage lesions. Thirty PCs (n=10 for each type) were assessed by measuring metabolic parameters (lactate, glucose, and pH), platelet activation markers, and in vitro platelet aggregability on days 1, 4, and 7 after donation. The expression of platelet activation markers CD62p (P-selectin), CD63 (LAMP-3), and phosphatidylserine was measured using flow cytometry and in vitro aggregability was measured with multiple electrode aggregometry. Higher platelet activation and lower in vitro aggregability was observed in IPU than in buffy-coat PCs on day 1 after donation. In contrast, metabolic parameters, expression of platelet activation markers, and in vitro aggregability were better maintained in IPU than in buffy-coat PCs at the end of the storage period. Compared to apheresis PCs, IPU PCs had higher expression of activation markers and lower in vitro aggregability throughout storage. In conclusion, the results indicate that there are significant differences in platelet storage lesions between IPU, buffy-coat, and apheresis PCs. The quality of IPU PCs appears to be at least comparable to buffy-coat preparations. Further studies are required to distinguish the effect of the preparation methods from storage conditions.
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