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Platelet count, indices (mean volume, young&mdash, immature platelet fraction) and aggregation are widely used laboratory parameters to investigate primary hemostasis. We performed a systematic, thorough evaluation of the influence of the time-interval since blood draw from 20 healthy individuals and of the anticoagulation of collected blood on such parameters. Blood was anticoagulated with citrate, K2-ethylenediaminetetraacetic acid (EDTA) and hirudin and analyzed 5, 30, 60, 120 and 180 min after blood draw. Multiple electrode aggregometry (MEA) was performed with either hirudin (half-diluted with NaCl) or citrate samples (half-diluted with NaCl or CaCl2 3 mM). Platelet count and indices (Sysmex XN-20) were rather stable over time with EDTA blood. MEA results were lower with citrate blood than with hirudin blood, supplementation with calcium was partially compensatory. MEA results were also lower when performed less than 30 or more than 120 min after blood draw. Platelet clumping, quantitatively estimated with microscope examination of blood smears, was more important in hirudin blood than citrate or EDTA blood and could explain some of the differences observed between preanalytical variables. The results stress once more the importance of preanalytical variables in hemostasis laboratory testing. Decision thresholds based on those tests are only applicable within specific preanalytical conditions.

BackgroundPoint of care devices for performing targeted coagulation substitution in patients who are bleeding have become increasingly important in recent years. New on the market is the Quantra. It is a device that uses sonorheometry, a sonic estimation of elasticity via resonance, which is a novel ultrasound-based technology that measures viscoelastic properties of whole blood. Several studies have already shown the comparability of the Quantra with devices already established on the market, such as the rotational thromboelastometry (ROTEM) device. ObjectiveIn contrast to existing studies, this study is the first prospective interventional study using this new system in a cardiac surgical patient cohort. We will investigate the noninferiority between an already existing coagulation algorithm based on the ROTEM/Multiplate system and a new algorithm based on the Quantra system for the treatment of coagulopathic cardiac surgical patients. MethodsThe study is divided into two phases. In an initial observation phase, whole blood samples of 20 patients obtained at three defined time points (prior to surgery, after completion of cardiopulmonary bypass, and on arrival in the intensive care unit) will be analyzed using both the ROTEM/Multiplate and Quantra systems. The obtained threshold values will be used to develop a novel algorithm for hemotherapy. In a second intervention phase, the new algorithm will be tested for noninferiority against an algorithm used routinely for years in our department. ResultsThe main objective of the examination is the cumulative loss of blood within 24 hours after surgery. Statistical calculations based on the literature and in-house data suggest that the new algorithm is not inferior if the difference in cumulative blood loss is

Introduction : There is ongoing controversy concerning the clinical value of platelet function monitoring in patients undergoing percutaneous coronary interventions (PCI). Patients at risk of high on-treatment platelet aggregation (HPR) may benefit most from such monitoring. Aim : To define the factors related to HPR on aspirin and clopidogrel, looking at a wider spectrum of variables than those assessed in some previous studies. Material and methods: We assessed platelet function in 908 patients on clopidogrel and aspirin after PCI using the multielectrode aggregometry system Multiplate to define which clinical, procedural and laboratory factors are related to on-treatment platelet aggregation in response to aspirin and clopidogrel either as linear values or using established cutoff values for HPR. Results : We found that in PCI patients on clopidogrel and aspirin, age (OR per year 1.06; 95% CI: 1.024–1.097; p = 0.001), gender (OR = 0.319; 95% CI: 0.139–0.731; p = 0.007), active smoking (OR = 2.57; 95% CI: 1.29–5.15; p = 0.008), diabetes ( = 37.6; 95% CI: 16.5–58.8; p = 0.001) and hypertension ( = 26.9; 95% CI: 6.73–47.1; p = 0.009) are independently linked to platelet aggregation values treated as linear values and as dichotomous variables at the accepted cutoffs. The same is true for stented segment length (OR per mm 1.033; 95% CI: 1.010–1.057; p = 0.009) and stent inflation pressure (OR per atmosphere 0.862; 95% CI: 0.772–0.963; p = 0.002). Conclusions : The study shows that, contrary to some earlier data, in the tested cohort women are better clopidogrel responders, but more often aspirin low-responders. Older age, active smoking, diabetes and hypertension all predispose to HPR. A novel finding is that stented segment length is an independent predictor of lower response both to aspirin and clopidogrel, possibly as a marker of more diffuse atherosclerosis.

Background Hypocoagulability and impaired platelet function have been associated with a high risk of death in sepsis. The aim of this cohort study was to determine whether sepsis-induced hypocoagulability and platelet dysfunction (assessed by ROTEM® and MULTIPLATE®, respectively) are increased in sepsis patients who died within 28 days after diagnosis compared with patients who died between 29 and 90 days after diagnosis. Methods Consecutive patients admitted to the intensive care unit of Padova University Hospital from March 2015 to March 2018 for severe sepsis were considered. We collected blood samples from all patients to determine ROTEM® and MULTIPLATE® parameters. Each enrolled patient underwent a 90-day follow-up and the mortality rate was recorded. Results Of 120 patients, 36 (30%) died within 28 days post-diagnosis (Group A), 23 (19%) died between days 29 and 90 post-diagnosis (Group B), and 61 (51%) were alive after 90 days (survivors). The clotting time in the ROTEM® test and clot formation time in the EXTEM test were significantly more prolonged in Group A than in B. Both groups showed a significantly higher hypocoagulability than survivors in the EXTEM test. MULTIPLATE® platelet function analysis showed that platelet function was significantly lower in Group A than in Group B. Conclusions The present study showed that the combination of thromboelastometry and impedance aggregometry may help identifying sepsis patients at high risk of short-term death. Larger studies are warranted to corroborate our results.

P2Y12 inhibitor discontinuation is essential before most surgical interventions to limit bleeding complications. Based on pharmacokinetic data, fixed discontinuation durations have been recommended. However, as platelet function recovery is highly variable among patients, a more individualized approach based on platelet function testing (PFT) has been proposed. The aim of this retrospective single-centre study was to determine whether PFT using whole blood adenosine diphosphate&ndash, multiple electrode aggregometry (ADP&ndash, MEA) was associated with a safe reduction of preoperative waiting time. Preoperative ADP&ndash, MEA was performed for 29 patients on P2Y12 inhibitors. Among those, 17 patients underwent a coronary artery bypass graft. Twenty one were operated with an ADP&ndash, MEA &ge, 19 U (quantification of the area under the aggregation curve), and the waiting time was shorter by 1.6 days (median 1.8 days, IQR 0.5&ndash, 2.9), by comparison with the current recommendations (five days for clopidogrel and ticagrelor, seven days for prasugrel). Platelet function recovery was indeed highly variable among individuals. With the 19 U threshold, high residual platelet inhibition was associated with perioperative platelet transfusion. These results suggest that preoperative PFT with ADP&ndash, MEA could help reduce waiting time before urgent surgery for patients on P2Y12 inhibitors.

Background: Excessive platelet activation and aggregation plays an important role in the pathogenesis of ischemic stroke. Correlation between platelet reactivity and ischemic lesions in the brain shows contradictory results and there are not enough data about the potential role of stroke etiology and its relationships with chronic lesions. The aim of this study is to assess the relationship between platelet reactivity and the extent of ischemic lesions with the particular role of etiopathogenesis. Methods: The study involved 69 patients with ischemic stroke, including 20 patients with large-vessel disease and 49 patients with small-vessel disease. Evaluation of platelet reactivity was performed within 24 h after the onset of stroke using two aggregometric methods (impedance and optical), while ischemic volume measurement in the brain was performed using magnetic resonance imaging (in diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) sequences) at day 2&ndash, 5 after the onset of stroke. Results: In the large-vessel disease subgroup, a correlation was found between platelet reactivity and acute ischemic focus volume (correlation coefficient (R) = 0.6858 and p = 0.0068 for DWI, R = 0.6064 and p = 0.0215 for FLAIR). Aspirin-resistant subjects were significantly more likely to have a large ischemic focus (Odds Ratio (OR) = 45.00, 95% Confidence Interval (CI) = 1.49&ndash, 135.36, p = 0.0285 for DWI, OR = 28.00, 95% CI = 1.35&ndash, 58.59, p = 0.0312 for FLAIR) than aspirin-sensitive subjects with large-vessel disease. Conclusion: In patients with ischemic stroke due to large-vessel disease, high on-treatment platelet reactivity affects the extent of acute and chronic ischemic lesions.

P2Y inhibitor discontinuation is essential before most surgical interventions to limit bleeding complications. Based on pharmacokinetic data, fixed discontinuation durations have been recommended. However, as platelet function recovery is highly variable among patients, a more individualized approach based on platelet function testing (PFT) has been proposed. The aim of this retrospective single-centre study was to determine whether PFT using whole blood adenosine diphosphate-multiple electrode aggregometry (ADP-MEA) was associated with a safe reduction of preoperative waiting time. Preoperative ADP-MEA was performed for 29 patients on P2Y inhibitors. Among those, 17 patients underwent a coronary artery bypass graft. Twenty one were operated with an ADP-MEA ≥ 19 U (quantification of the area under the aggregation curve), and the waiting time was shorter by 1.6 days (median 1.8 days, IQR 0.5-2.9), by comparison with the current recommendations (five days for clopidogrel and ticagrelor, seven days for prasugrel). Platelet function recovery was indeed highly variable among individuals. With the 19 U threshold, high residual platelet inhibition was associated with perioperative platelet transfusion. These results suggest that preoperative PFT with ADP-MEA could help reduce waiting time before urgent surgery for patients on P2Y inhibitors.

Background Dengue virus (DENV) causes the hospitalisation of an estimated 500,000 people every year. Outbreaks can severely stress healthcare systems, especially in rural settings. It is difficult to discriminate patients who need to be hospitalized from those that do not. Earlier work identified thrombocyte count and subsequent function as a promising prognostic marker of DENV severity. Herein, we investigated the potential of quantitative thrombocyte function tests in those admitted in the very early phase of acute DENV infections, using Multiplate™ multiple-electrode aggregometry to explore its potential in triage. Methods In this prospective cohort study all patients aged ≥13 admitted to Universitas Airlangga Hospital in Surabaya, Indonesia with a fever (≥38 °C) between 25 January and 1 August 2018 and with a clinical suspicion of DENV, were eligible for inclusion. Exclusion criteria were a thrombocyte count below 100 × 109/L and the use of any medication with a known anticoagulant effect, nonsteroidal anti-inflammatory drugs and acetyl salicylic acid. Clinical data was collected and blood was taken on admission, day 1 and day 7. Samples were tested for acute DENV, using Panbio NS1 ELISA. Platelet aggregation using ADP-, TRAP- and COL-test were presented as Area Under the aggregation Curve (AUC). Significance was tested between DENV+, probably DENV, fever of another origin, and healthy controls (HC). Results A total of 59 patients (DENV+ n = 10, DENV probable n = 25, fever other origin n = 24) and 20 HC were included. We found a significantly lower thrombocyte aggregation in the DENV+ group, compared with both HCs and the fever of another origin group (p Conclusion Thrombocyte aggregation induced by Adenosine diphosphate, Collagen and Thrombin receptor activating peptide-6 is impaired in human DENV cases, compared with healthy controls and other causes of fever. This explorative study provides insights to thrombocyte function in DENV patients and could potentially serve as a future marker in DENV disease.

Antiplatelet therapy are widely used for prevention of cardiovascular related morbidity. APT is associated with greater risk of intracranial hemorrhage (ICH) after head trauma, also in bleeding progression in traumatic or spontaneous ICH. Platelet transfusion is the only therapeutic option for severe bleeding but its benefit remains controversial. Around 30% of treated patients are resistant to their APT. Multiplate® allows assessment of APT effectiveness. A normal Multiplate® questions the responsibility of APT in the hemorrhage and thus the benefit of platelet transfusion. The aim was to demonstrate that using Multiplate® for patients on APT with ICH requiring urgent neurosurgical procedure reduced platelet transfusion. Methods: his was a retrospective, observational study. All adults on APT with ICH requiring urgent neurosurgical procedure were included. They all had a Multiplate® to assess platelet function. We estimated that platelet transfusion reduction would correlate with APT non responsive rate in general population, approximately 30%. Surgical patients were compared according to their transfused or non-transfused status and safety of this targeted transfusion strategy was validated with patient’s outcome including occurrence of a bleeding complication. A logistic regression was performed to identify potential factors associated with hemorrhagic complication. Results: over the 2 years study period, 77 patients on APT with ICH, underwent urgent neurosurgical procedure. Among these patients, platelet transfusion saving was possible for 21 patients (27.2%) due to an ineffective APT. This results is in accordance to our hypothesis of approximately 30% transfusion reduction. Occurrence of bleeding complication, hospital length of stay and in-hospital mortality were similar in the transfused and non-transfused group. Conclusion: a targeted transfusion strategy using Multiplate® has reduced platelet use in nearly one-third of patients on APT admitted for I CH and requiring urgent neurosurgical intervention. This strategy is safe for patients and reflects current guidelines that aim to optimize APT neutralization., Les agents antiplaquettaires (AAP) sont utilisés pour la prévention des maladies cardiovasculaires. Ils sont associés à un risque accru d'hémorragie intracrânienne (HIC) après un traumatisme crânien et une progression des saignements après HIC spontanée. La transfusion de plaquettes est la seule option thérapeutique en cas d'hémorragie grave mais son bénéfice reste controversé. Environ 30 % des patients traités sont résistants à leur AAP. Le Multiplate® évalue l'efficacité d’un AAP, normal, il questionne la responsabilité de l'AAP dans l'hémorragie et donc le bénéfice de la transfusion plaquettaire. L'objectif était de montrer que l'utilisation du Multiplate® pour les patients traités par AAP avant une neurochirurgie urgente réduisait la transfusion de plaquettes. Méthodes : il s'agissait d'une étude rétrospective, observationnelle. Tous les adultes sous AAP avec HIC nécessitant une prise en charge neurochirurgicale et ayant un Multiplate® ont été inclus. Nous avons estimé que la réduction transfusionnelle serait corrélée avec le taux de patient résistant aux AAP dans la population générale, soit 30 %. Les patients ont été comparés selon leur statut transfusé ou non transfusé. La sécurité a été évaluée en suivant l’évolution des patients notamment la survenue d'une complication hémorragique. Une régression logistique a été effectuée pour identifier des potentiels facteurs associés à une complication hémorragique. Résultats : 77 patients ont été inclus en 2 ans. Une transfusion a été épargnée pour 21 patients (27,2 %) du fait d’un AAP inefficace. Ce résultat est conforme à notre hypothèse d'une réduction d'environ 30 % des transfusions. L’évolution des patients était similaire dans le groupe transfusé et non-transfusé. Conclusion : un protocole transfusionnelle utilisant le Multiplate® a épargné une transfusion chez près d'un tiers des patients traités par AAP admis pour une H IC et nécessitant une neurochirurgie urgente. Cette stratégie est sûre et reflète les recommandations actuelles qui tendent à optimiser la neutralisation des AAP.

Extracorporeal (veno-venous) membrane oxygenation (vvECMO) has been shown to have negative effects on platelet number and function. This study aimed to gain more information about the impact of vvECMO on platelet function assessed by multiple electrode aggregometry (MEA). Twenty patients with the indication for vvECMO were included. Platelet function was analyzed using MEA (Multiplate&reg, ) before (T-1), 6 h (T0), one (T1), two (T2), three (T3), and seven (T4) days after the beginning of vvECMO. Median aggregational measurements were already below the normal reference range before vvECMO initiation. Platelet aggregation was significantly reduced 6 h after vvECMO initiation compared to T-1 and spontaneously recovered with a significant increase at T2. Platelet count dropped significantly between T-1 and T0 and continuously decreased between T0 and T4. At T4, ADP-induced platelet aggregation showed an inverse correlation with the paO2 in the oxygenator. Platelet function should be assessed by MEA before the initiation of extracorporeal circulation. Although ECMO therapy led to a further decrease in platelet aggregation after 6 h, all measurements had recovered to baseline on day two. This implies that MEA as a whole blood method might not adequately reflect the changes in platelet function in the later stages of extracorporeal circulation.

Erst mit Beginn dieses Jahrhunderts wurde deutlich, dass Thrombozyten neben ihrer essentiellen Bedeutung für die Blutgerinnung eine substantielle Rolle im Rahmen von Entzündungen spielen. So war es naheliegend, Untersuchungen zu Thrombozytenzahlen und -variablen sowie der Thrombozytenfunktion bei gesunden und kranken equinen Individuen durchzuführen. Da bei humanen Patienten positive Einflüsse einer Hemmung der Thrombozytenfunktion auf eine reduzierte Thromboseneigung und den Erkrankungsverlauf von SIRS-Patienten ermittelt werden konnten, sollte zudem die Möglichkeit der oralen medikamentösen Hemmung der Thrombozytenfunktion beim Pferd überprüft werden.Das Hämatologiegerät ADVIA® 2120 ist eine Standardmethode in der Messung von Thrombozytenzahlen sowie deren Variablen. Die eigenen Untersuchungen konnten jedoch zeigen, dass equine Thrombozyten durch die etablierten Antikoagulantien K3-EDTA und Zitrat nicht ausreichend aufgekugelt werden und die Messergebnisse insbesondere der Variablen MPV und MPC hierdurch beeinflusst sein können. In künftigen Studien könnte überprüft werden, ob durch Verwendung anderer Antikoagulantien wie dem CTAD (Citrate, Theophylline, Adenosine and Dipyridamole) validere Messergebnisse erreicht werden könnten.Die Etablierung von Referenzintervallen auf Basis einer klinisch unauffälligen Referenzpopulation ist in der Labordiagnostik oftmals ein logistisches und finanzielles Problem. Dies wird noch verstärkt, wenn wie in der vorliegenden Untersuchung für den ADVIA® 2120 und den Multiplate® Analyzer innerhalb einer Spezies zum Teil klinisch relevante rasseabhängige Unterschiede ermittelt werden können. Hier könnten statistische Verfahren aus der Humanmedizin, im Rahmen derer Referenzintervalle anhand aller in einem Labor vorhandenen Daten geschätzt werden, auch für die Veterinärmedizin ein sinnvolles Werkzeug darstellen.Thrombozytopenien und Thrombozytosen treten beim Pferd mit einer Prävalenz von 3,4 % bzw. 3,1 % im Vergleich mit anderen Spezies deutlich seltener auf. Da es sich in der vorliegenden Untersuchung um ein bereits vorselektiertes Patientenmaterial handelt, ist anzunehmen, dass die Prävalenz in der gesamten Pferdepopulation deutlich geringer ist. In Verbindung mit systemischen Entzündungen sowie Neoplasien sind die Abweichungen in der Thrombozytenzahl negativ prognostisch, wobei der Schweregrad keine Rückschlüsse auf das Überleben zulässt.Erstmals konnte in dieser Arbeit gezeigt werden, dass die Prävalenz einer EDTA-induzierten Pseudothrombozytopenie beim Equiden bis zu 5 % beträgt. Sie sollte insbesondere bei einer Thrombozytopenie ohne klinische Anzeichen einer Blutungsneigung als Ursache in Betracht gezogen werden. Gleiches gilt für das Auftreten von > 250 Clumps (Thrombozytenaggregate) in Messungen mit dem ADVIA® 2120. Verifizieren lässt sich die EDTA-PTCP durch eine Messung aus mit Zitrat antikoagulierten Blut innerhalb von 4 bis 6 Stunden nach Blutentnahme.Im Rahmen dieser Arbeit gelang es zum ersten Mal, beim Equiden aus Thrombozyten-Leukozyten-reichem Plasma aktivierte Thrombozyten sowie Thrombozyten-Leukozyten-Aggregaten mittels Fluoreszenz-Durchflusszytometrie unter Verwendung zweier geringfügig modifizierter humaner Protokolle nachzuweisen. Zudem konnte erstmals gezeigt werden, dass bei Aktivierung der Thrombozyten auch beim Pferd eine Exprimierung von CD154 (CD40L) stattfindet. Der Nachweis RNA-reicher Thrombozyten gelang auf diesem Wege jedoch nicht. Desgleichen konnten bei Pferden mit 2 humanen ELISAs lösliche Formen der Glykoproteine CD40L und CD62P im Serum nicht nachgewiesen werden.Eine Zunahme von Thrombozytenaktivierung und der Thrombozyten-Leukozyten-Aggregate konnte darüber hinaus erstmalig bei equinen Patienten mit SIRS gezeigt werden. Mittels Impedanzaggregometrie am Multiplate® Analyzer konnten jedoch bei diesen Patienten keine signifikanten Unterschiede der Thrombozytenfunktion ermittelt werden. Dies ist mutmaßlich darauf zurückzuführen, dass die Impedanzaggregometrie im Vollblut erheblich vom Schweregrad der Erkrankung beeinflusst ist. Während bei leichter erkrankten Patienten eine Erhöhung der Aggregationswerte erwartet werden kann, gilt für schwer erkrankte Patienten das Gegenteil. Da in der eigenen Untersuchung sehr wahrscheinlich alle Schweregrade einer SIRS vertreten waren, hoben sich die folglich entgegengesetzt auftretenden Aggregationen in der Summe mutmaßlich auf.Im Rahmen der Untersuchungen konnte zum ersten Mal gezeigt werden, dass niedrige Thrombozytenzahlen bei equinen SIRS-Patienten mit einer erhöhten Mortalität assoziiert sind. Darüber hinaus ergaben sich Hinweise, dass niedrige Aggregationswerte des COLtest, ADPtest und ADPtestHS am Multiplate® Analyzer sowie eine Erhöhung der prozentualen Anteile aktivierter Thrombozyten sowie Thrombozyten-Leukozyten-Aggregate ebenfalls mit einer erhöhten Mortalität assoziiert sein könnten.Thrombozytenzahl, Thrombozytenaggregation, Thrombozytenaktivierung sowie Thrombozyten-Leukozyten-Aggregate könnten somit auch beim Pferd aussagekräftige Variablen in diagnostischen Algorithmen zur Prognose bei SIRS-Patienten darstellen.Bei klinisch unauffälligen Warmblütern konnte durch die orale Gabe von Clopidogrel in einer einmaligen Anfangsdosis von 6-6,5 mg/kg sowie einer täglichen Erhaltungsdosis von 1,2-1,4 mg/kg sowohl die ADP-induzierte als auch die Arachidonsäure-induzierte Aggregation gehemmt werden. Die orale Verabreichung von Acetylsalicylsäure verursachte in der gleichen Pferdegruppe lediglich eine mäßige Hemmung der Arachidonsäure-induzierten Aggregation. Zudem konnte eine dauerhafte Hemmung nicht erreicht werden. Bei 3 der 10 Pferde konnte darüber hinaus eine Aspirin-Resistenz vermutet werden. So erscheint im Gegensatz zu Clopidogrel der Nutzen der ASS für einen Einsatz in der Thromboseprophylaxe und -therapie beim Pferd aufgrund des mutmaßlich eher geringen hemmenden Effektes fraglich.Es bleibt in weiteren Untersuchungen zu überprüfen, ob sich durch die orale Gabe von Clopidogrel die im Rahmen dieser Arbeit nachgewiesenen Reaktionen insbesondere der Thrombozytenaktivierung und der Thrombozyten-Leukozyten-Aggregate bei equinen SIRS-Patienten beeinflussen lassen und ob hierdurch der Krankheitsverlauf positiv beeinflusst werden kann., It was not until the early 21st century that it became clear that, in addition to their primary role in hemostasis, platelets are multifunctional and act as key players in inflammatory processes. It therefore seemed apposite to investigate platelet biology in healthy and diseased horses. Since it had been demonstrated that inhibition of platelet function reduces the mortality of severe disease in human ICU patients, a further purpose of the studies was to determine the efficacy of oral antiplatelet drugs in horses.The ADVIA® 2120 automated hematology system is a standard method of measuring platelet numbers and variables in veterinary laboratory diagnostics. However, the results of the own study demonstrated that adequate sphering due to the established anti-coagulants K3-EDTA and citrate was not archived in equine platelets and that this phenomenon may influence measurement results, in particular the variables MPC and MPV. Further studies are required to investigate whether the use of other anticoagulants as CTAD (citrate, theophylline, adenosine and dipyridamole) could provide more valid results for the measurement of the platelet variables.The establishment of reference intervals based on a healthy clinical reference population often represents a logistical and financial challenge in laboratory diagnostics. This situation is further complicated by the fact that in the present study clinically relevant breed-related differences were determined for the ADVIA® 2120 and the Multiplate® Analyzer measurements. Statistical methods used in human medicine in which reference intervals are estimated on the basis of all the data available in a laboratory can probably pose an option as valuable tool in veterinary medicine too.The prevalence of thrombocytopenia and thrombocytosis determined in a German referral equine internal medicine center was, at levels of 3.4 % and 3.1 % respectively, lower than in other species. Given that a referral clinic population is subject to preselection, it seems extremely probable that the prevalence in the whole population is even lower. Although both thrombocytopenia and thrombocytosis are correlated with a negative outcome in horses with systemic inflammatory conditions and neoplastic disorders, survival is not impacted by the extent of the variation.For the first time, the present study demonstrated a prevalence of up to 5 % for the EDTA-induced pseudothrombocytopenia in equids. This in vitro phenomenon should be considered especially in patients with no clinical signs of an increased bleeding tendency and a thrombocytopenia or more than 250 clumps (platelet aggregates) measured with the ADVIA® 2120. The EDTA-PTCP may be verified by platelet counting in citrated blood samples within 4-6 hours after sampling.This is the first study to measure equine activated platelets and platelet-leukocyte-aggregates in platelet-rich-plasma with flow-cytometry using modified human protocols. It is also the first study to demonstrate that CD40L is expressed in equine platelets during activation. Measurement of juvenile, immature, RNA-rich platelets using this method nevertheless failed. Similarly, a soluble form of glycoproteins CD40L and CD62P could not be quantified in equine plasma samples using commercial human ELISAs.Moreover, for the first time the study identified increased numbers of activated platelets and platelet-leukocyte-aggregates in clinical cases of equine SIRS. Measurement of whole blood impedance aggregometry with the Multiplate® Analyzer failed to verify differences in these patients compared to healthy controls. This could be explained by the fact that whole blood impedance aggregometry is mainly influenced by the severity of disease. In less severe cases platelet aggregation is usually increased, whereas in severe cases the opposite reaction occurs. As the equids included in the SIRS group probably exhibited all the degrees of disease severity, it is probable that the higher and lower aggregations were offset on balance in the final count.As far as the survival of equids with SIRS is concerned, the study for the first time reveals a correlation between low platelet counts and increased mortality. Furthermore, there were indications of increased mortality in patients with decreased aggregations of the COLtest, ADPtest and ADPtestHS on the Multiplate® Analyzer and increased numbers of activated platelets and platelet-leukocyte-aggregates.Platelet count, platelet aggregation, platelet activation and platelet-leukocyte-aggregates may therefore represent valuable variables in diagnostic and prognostic algorithms in equine SIRS.Oral clopidogrel with a loading dose of 6-6.5 mg/kg and daily maintenance doses of 1.2-1.4 mg/kg induced an inhibition of ADP- and arachidonic acid-induced platelet function in healthy horses. Oral administration of acetylsalicylic acid (aspirin) in the same group of horses only led to a moderate inhibition of the arachidonic acid-induced platelet function. An aspirin resistance was suspected in three horses. In view of its presumably low inhibitory effects in contrast to clopidogrel, the efficacy of aspirin in preventing and treating thrombotic diseases in horses appears doubtful.Further studies are accordingly required to evaluate the efficacy of clopidogrel as a platelet inhibitor in equine SIRS and to evaluate the potentially positive impact of platelet inhibition on survival.

Background As the incidence of cardiovascular diseases increases, the use of antiplatelet therapy is widely recognized. This presents clinicians with the challenge of balancing the risk of thrombotic and bleeding complications. Platelet dysfunction is one of the causes of postoperative bleedings and their etiology is not fully understood. Platelets receptors point-of-care investigation is of a remarkable value in assessing patients risk of bleeding. Reliable assessment of platelet function can improve treatment. The aim of this study was to evaluate the activity of platelet receptors in patients qualified for cardiac surgery, taking into account organ dysfunctions and pharmacological therapy applied in these patients. Methods Seventy-one cardiac surgical patients were analyzed before surgery using multiple electrode aggregometry with the use of the ADP test and ASPI test. The cut-off values were determined based on the manufacturer’s recommendations. Patients were divided into four groups: Group I (33/71 patients, without platelet dysfunctions), Group II (6/71 patients, ADP

Background Perioperative bleeding and the subsequent requirements for transfusion are considered to be major risk factors for morbidity and mortality in adult cardiac surgery. The etiology of perioperative bleeding can be difficult to identify and often remains unclear. In order to deliver prompt diagnostics and goal-directed therapy, several point-of-care devices are available. Their use, especially in the frame of transfusion-algorithms, has shown a reduction of blood loss, transfusion requirements, morbidity, mortality and cost. The aim of this study is to confirm the superiority of PoC-based transfusion-algorthims compared to therapy based on standard coagulation parameters in the context of adult cardiac surgery with high risk for perioperative bleeding. Methods In a single-center randomized-controlled trial we included 26 patients undergoing cardiac surgery procedures with a high risk for excessive perioperative bleeding. The management of coagulation-active products except packed red blood cells was based on two newly designed algorithms, one that used conventional coagulation-tests measured a central laboratory, while the other used point-of-care results of Multiplate\textregistered{} and ROTEM\textregistered{}. Primary end point was the cumulative chest tube blood loss in 24 hours postoperatively, secondary end points were the chest tube blood loss over the time course, the use of transfusions or coagulation products and the results of standard coagulation parameters over the time course. Both groups had diagnostics performed at identical time points with equal definitions of bleeding and the same therapeutical options peri- and postoperatively. Blood loss from chest drainage, transfusion requirements and parameters of hemostasis were recorded from the induction of anaesthesia until at least 24 h postoperatively. In all patients, attending physicians were blinded to the results of coagulation-tests irrelevant to the patient's study group's transfusion algorithm. For data analysis, non-parametrical tests for independent samples were used. Results Perioperative chest tube output after 24 h did not differ with a median of 360 ml (interquartile range 299-599 ml) in the conventional group and 380 ml (interquartile range 310-590 ml) in the point-of-care group (p = 0,77, r = 0,0602). Further, there were no differences between the groups in terms of basic patient characteristics, transfusion requirements, coagulation test results or outcome. Conclusion In this trial we could neither show a reduction of perioperative blood loss or transfusion requirements nor differences in coagulation test results comparing two algorithms based on conventional coagulation testing or point-of-care measurements., Perioperative Blutungen und der einhergehende Tranfusionsbedarf stellen wesentliche Ursachen für Morbidität und Mortalität in der Kardiochirurgie dar. Die Ätiologie einer perioperativen Blutung kann vielfältig sein. Zur zeitnahen ätiologischen Einordnung und gezielten Therapieentscheidung stehen seit einigen Jahren verschiedene Point-of- Care-(PoC)-Geräte zur Verfügung. Deren Einsatz, insbesondere im Rahmen von Transfusionsalgorithmen, konnte eine Verringerung von Transfusionsbedarf und Blutverlust bei geringerer Morbidität, Mortalität und Kosten zeigen. Ziel der vorliegenden Arbeit ist die Bestätigung dieser Überlegenheit von PoC-basierten Algorithmen gegenüber einer Therapie auf Grundlage von Standardlaborparametern bei kardiochirurgischen Operationen mit hohem Risiko für perioperative Blutungen. Methoden In einer Single-Center randomisiert-kontrollierten Studie wurden 26 Patienten eingeschlossen, die sich kardiochirurgischen Operationen mit hohem Risiko für perioperative Blutungen unterzogen. Die Therapie mit gerinnungsaktiven Produkten außer Erythrozytenkonzentraten erfolgte anhand von Therapiealgorithmen basierend auf Messwerten der PoC- bzw. Zentrallabor-basierten Gerinnungsanalytik. Die Kontrollgruppe wurde mittels eines Protokolls basierend auf Standardlaborparametern behandelt, die Studiengruppe mit einem Algorithmus auf Grundlage von Point-of-Care-Methoden (Multiplate ® und ROTEM®). Als primäres Zielkriterium galt der kumulative Drainageblutverlust in 24 h posterativ, als sekundäre der Verlauf des Drainageblutverlusts, die Menge an nötigen Transfusions- und gerinnungsaktiven Produkten und der Verlauf von Standardgerinnungsparametern. Die peri- und postoperativen Zeitpunkte zur Bestimmung der jeweiligen Gerinnungsparameter waren in beiden Gruppen gleich, ebenso die Definition für eine transfusionsbedürftige Blutung und mögliche Therapieoptionen. Die Erhebung von Drainageblutverlust, Transfusionsbedarf und Gerinnungsparametern erfolgte von Beginn der Narkoseeinleitung bis mindestens 24 h postoperativ. Alle behandelnden Ärzte waren für die Ergebnisse der Gerinnungstests verblindet, die für nicht für den Transfusionsalgorithmus der Gruppe ihres jeweiligen Patienten relevant waren. Die Auswertung erfolgte mit Hilfe von nicht-parametrischen Tests für unabhängige Stichproben. Ergebnisse Der perioperative Drainageblutverlust betrug in der Kontrollgruppe 360 ml (Interquartilbereich 299-599 ml) und in der Studiengruppe 380 ml (Interquartilbereich 310- 590 ml) nach 24 h (p = 0,77, r = 0,0602). Des Weiteren unterschieden sich die Gruppen nicht signifikant hinsichtlich präoperativer Patientencharakteristika, Transfusionsbedarf, dem Verlauf der Standardgerinnungsparameter oder dem Outcome. Schlussfolgerung Eine Verringerung von Draingeblutverlust und Transfusionsbedarf bzw. eine Veränderung des Verlaufs von Standardgerinnungsparametern konnte mit einem PoC-Protokoll im Vergleich mit einem Standard-Algorithmus nicht gezeigt werden.

Stanford type A aortic dissections often present to the hospital requiring emergent surgical intervention. Initial diagnosis is usually made by computed tomography; however transesophageal echocardiography (TEE) can further characterize aortic dissections with specific advantages: It may be performed on an unstable patient, it can be used intra-operatively, and it has the ability to provide continuous real-time information. Three-dimensional (3D) TEE has become more accessible over recent years allowing it to serve as an additional tool in the operating room. We present a case series of three patients presenting with type A aortic dissections and the advantages of intra-operative 3D TEE to diagnose the extent of dissection in each case. Prior case reports have demonstrated the use of 3D TEE in type A aortic dissections to characterize the extent of dissection and involvement of neighboring structures. In our three cases described, 3D TEE provided additional understanding of spatial relationships between the dissection flap and neighboring structures such as the aortic valve and coronary orifices that were not fully appreciated with two-dimensional TEE, which affected surgical decisions in the operating room. This case series demonstrates the utility and benefit of real-time 3D TEE during intra-operative management of a type A aortic dissection.

Objective: Objective platelet function assessment after cardiac surgery can predict postoperative blood loss, guide transfusion requirements and discriminate the need for surgical re-exploration. We conducted this study to assess the predictive value of point-of-care testing platelet function using the Multiplate® device. Methods: Patients undergoing isolated coronary artery bypass grafting were prospectively recruited ( n = 84). Group A ( n = 42) patients were on anti-platelet therapy until surgery; patients in Group B ( n = 42) stopped anti-platelet treatment at least 5 days preoperatively. Multiplate® and thromboelastography (TEG) tests were performed in the perioperative period. Primary end-point was excessive bleeding (>2.5 ml/kg/h) within first 3 h postoperative. Secondary end-points included transfusion requirements, re-exploration rates, intensive care unit and in-hospital stays. Results: Patients in Group A had excessive bleeding (59% vs. 33%, P = 0.02), higher re-exploration rates (14% vs. 0%, P < 0.01) and higher rate of blood (41% vs. 14%, P < 0.01) and platelet (14% vs. 2%, P = 0.05) transfusions. On multivariate analysis, preoperative platelet function testing was the most significant predictor of excessive bleeding (odds ratio [OR]: 2.3, P = 0.08), need for blood (OR: 5.5, P < 0.01) and platelet transfusion (OR: 15.1, P < 0.01). Postoperative "ASPI test" best predicted the need for transfusion (sensitivity - 0.86) and excessive blood loss (sensitivity - 0.81). TEG results did not correlate well with any of these outcome measures. Conclusions: Peri-operative platelet functional assessment with Multiplate® was the strongest predictor for bleeding and transfusion requirements in patients on anti-platelet therapy until the time of surgery. Study registration: ISRCTN43298975 (http://www.controlled-trials.com/ISRCTN43298975/).

Statistical analysis is one of the foundations of evidence-based clinical practice, a key in conducting new clinical research and in evaluating and applying prior research. In this paper, we review the choice of statistical procedures, analyses of the associations among variables and techniques used when the clinical processes being examined are still in process. We discuss methods for building predictive models in clinical situations, and ways to assess the stability of these models and other quantitative conclusions. Techniques for comparing independent events are distinguished from those used with events in a causal chain or otherwise linked. Attention then turns to study design, to the determination of the sample size needed to make a given comparison, and to statistically negative studies.

SummaryElevated platelet turnover contributes to high platelet reactivity. High platelet reactivity after percutaneous coronary intervention (PCI) is associated with major adverse cardiovascular events (MACE). The purpose of this study was to determine the prognostic value of platelet turnover and function with regard to MACE after PCI with stent implantation. In this prospective observational study, 486 consecutive patients after PCI on aspirin and clopidogrel were included to determine platelet turnover (mean platelet volume (MPV), reticulated platelet fraction (RPF)) and platelet function (multiple electrode aggregometry (MEA), vasodilator-stimulated phosphoprotein-phosphorylation (VASP-P) assay). At six-months follow-up, MACE occurred in 10.7 % of patients. RPF (odds ratio [OR]=1.173 (95% confidence interval [CI 95 %] 1.040–1.324), p=0.009) and MPV (OR=1.459 (CI 95 % 1.059–2.008), p=0.021) were univariable predictors of MACE, whereas VASP-P (OR=1.016 (CI 95 % 1.000–1.032), p=0.052) and MEA (OR=0.999 (CI 95 % 0.980–1.017), p=0.895) failed to predict MACE. RPF remained the only platelet variable independently associated with MACE. The best model to predict MACE included: troponin I (OR=1.007 (CI 95 % 1.002–1.012), p=0.009), RPF (OR=1.136 (CI 95 % 1.001–1.288), p=0.048), CRP (OR=1.008 (CI 95 % 1.001–1.014), p=0.023) and history of myocardial infarction (OR=2.039 (CI 95 % 1.093–3.806), p=0.025). RPF (OR=1.211 (CI 95 % 1.042–1.406), p=0.012) was also independently associated with in-hospital bleedings. In conclusion, RPF as index of platelet turnover is an independent predictor of MACE and bleeding events in PCI patients on dual antiplatelet therapy. Since RPF can reliably be quantified along with routine haemograms, RPF might easily be applied in the setting of cardiovascular risk prediction.

Nicorandil is a commonly used antianginal agent, which has both nitrate-like and ATP-sensitive potassium (K ATP ) channel activator properties. Activation of potassium channels by nicorandil causes expulsion of potassium ions into the extracellular space leading to membrane hyperpolarization, closure of voltage-gated calcium channels and finally vasodilatation. However, on the other hand, being an activator of K ATP channel, it can expel K + ions out of the cells and can cause hyperkalemia. Here, we report a case of nicorandil induced hyperkalemia unresponsive to medical treatment in a patient with diabetic nephropathy.

Objective: The management of patients with traumatic brain injury (TBI), nontraumatic intracerebral hemorrhage (ICH) as well as subarachnoid hemorrhage (SAH) remains a highly demanding challenge in critical care medicine. The use of antithrombotic agents and subsequent impairment of the haemostatic [for full text, please go to the a.m. URL], 66. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)

Das Ziel dieser Studie war die Charakterisierung des Zusammenhangs zwischen einem nicht adäquaten Ansprechen auf die antithrombozytäre Therapie mit Clopidogrel und dem BMI des Patienten. Hierfür wurden 157 Patienten mittels Multiplate®-Impedanz-Aggregometrie untersucht, welche eine Aufsättigungsdosis von 600mg Clopidogrel mit anschließender koronarer Stentimplatation erhielten. Die Bestimmung der ADP-induzierten Thrombozytenaggregation erfolgte vor der Gabe der Initialdosis sowie ein zweites Mal mindestens sechs Stunden nach der Clopidogrelgabe. Das Patientenkollektiv bestand aus 37 normalgewichtigen (BMI < 25), sowie 120 übergewichtigen Patienten (BMI >= 25). Anhand von Tertilbildung erfolgte die Bestimmung der so genannten „low“-Responder. Das Ausgangsniveau der Thrombozytenaggregation war unabhängig vom Gewicht der Patienten (p = 0,849). In den postinterventionell gemessenen Aggregationswerten zeigten sich zwischen den beiden Gruppen statistisch signifikante Unterschiede (p = 0,007). Dies wurde durch die nicht parametrische Korrelation zwischen dem BMI des Patienten und der nach Gabe von 600mg Clopidogrel bestimmten Thrombozytenaggregationswerte (rs = 0,26, p = 0,001) bestätigt. Durch die Regressionsanalyse konnte ein erhöhter BMI als Einflussfaktor bestätigt werden, zugleich wurden andere klinischen Faktoren als mögliche Einflussfaktoren ausgeschlossen. Letzlich ist davon auszugehen, dass Patienten mit einem hohen BMI reduziert auf die Therapie mit Clopidogrel ansprechen, was mit einem erhöhten Risiko für kardiovaskuläre Ereignisse insbesondere nach koronaren Interventionen verbunden ist. The purpose of this trial was the characterization of the correlation between a reduced response of the antiplatelet therapy with Clopidogrel and the patient’s BMI. Therefore 157 patients, which got a dose of 600mg Clopidogrel followed by a coronary stent implantation, were examined by the use of Multiplate® impedance aggregation measurement. The measurement of the ADP induced platelet aggregation were done once before the initial dose of 600mg Clopidogrel and also a second time at least six hours after the Clopidogrel administration. In the collective of the patients there were 37 patients with normal weight (BMI < 25) and 120 overweight patients (BMI >= 25). By dividing the patients into tertiles we were able to identify the so-called „low“- responders. The base level of the platelet aggregation was independent of the patient’s weight (p = 0,849). The levels of the platelet aggregation measured after the intervention showed significant differences between both groups (p = 0,007). This was also confirmed by the nonparametric correlation between the patient’s BMI and the measured levels of platelet aggregation after a dose of 600mg Clopidogrel (rs = 0,26, p = 0,001). Applying a regression analysis it was shown that the increased BMI is the only influencing factor, while other clinical factors were excluded. As a conclusion there is a correlation between an increased BMI and a reduced response to the antiplatelet therapy with Clopidogrel. This could be related to an increased risk for cardiovascular incidents, especially after a coronary stent implantation.

The effects of detergent sclerosants, sodium tetradecyl sulphate (STS) and polidocanol (POL), on coagulation, antithrombotic and fibrinolytic mechanisms were investigated in vitro. All samples were spiked with each sclerosant at therapeutic concentrations. Coagulation was investigated in clotting tests and functional assays for clotting factors in plasma. Fibrinogen was measured by the Clauss method and factor (F) XIII by ELISA. At low concentrations, sclerosants shortened phospholipid-dependent clotting times. At high concentrations, STS prolonged all clotting times and destroyed fibrinogen, FV, FVII, FX and FXIII. Lytic activity in whole blood (WB), albumin and saline was investigated by absorbance densitometry. Both agents induced haemolysis, platelet, platelet microparticle (PMP) and endothelial lysis at high concentrations. The lytic effect was neutralised by albumin and plasma proteins. Antithrombotic mechanisms were investigated in functional assays for activated protein C (APC), PC, protein S, antithrombin and FXa in normal plasma (NP). High concentration STS demonstrated anti-IIa, anti-Xa and anti-Va activity and potentiated the anticoagulant effects of APC. POL induced APC resistance. Fibrinolytic enzymes/inhibitors were measured by ELISA in WB and plasma, and plasminogen by a chromogenic assay in NP. Inhibitors of fibrinolysis were elevated at low concentrations of sclerosants. Fibrinolytic enzymes/inhibitors were destroyed by high concentration STS. Clot formation was assessed by thromboelasotometry in WB. Both agents induced strong clots at low concentrations, weak clots at mid-range and prevented clot formation at high concentrations. In turbidity measurements, neither agent had a lytic effect on cross-linked fibrin but STS destroyed non-cross-linked fibrin. Platelet and PMP counts were assessed by flow cytometry and platelet activation by ELISA for soluble markers and by flow cytometry for CD62p, CD63 and calcium. Platelet aggregation was assessed by light transmission and impedance aggregometry, and by flow cytometry for glycoprotein (GP)IIb/IIIa. At low concentrations, both agents induced platelet activation, released phosphatidylserine+ PMPs but inhibited aggregation by suppressing the activation of GPIIb/IIIa. In conclusion, detergent sclerosants interfered with coagulation, antithrombotic and fibrinolytic mechanisms. Both agents activated platelets, released procoagulant PMPs and potentiated prothrombotic and antifibrinolytic mechanisms at low concentrations. At high concentrations, both agents prevented clot formation. High concentration STS exhibited more anticoagulant activity than POL.

Objectives Use of potent antiplatelet drugs requires evaluation of platelet function. While platelet function in elective cases is usually assessed in a central laboratory environment, there is also an urgent need for rapid perioperative point-of-care assessment. Recently, multiple electrode platelet aggregometry has been developed and assumed to measure platelet function independent from platelet count. We tested the hypothesis that results of multiple electrode platelet aggregometry are affected by platelet count, in particular if platelet count is below normal range. Methods Whole blood samples from 20 healthy volunteers were prepared containing platelet concentrations of 50,000, 100,000, 150,000, 200,000, and 250,000 μl-1 while maintaining hematocrit. Platelet aggregation was induced by collagen, thrombin receptor activating peptide 6 (TRAP-6), adenosine-diphoshate (ADP), and arachidonic acid, respectively, and aggregation was measured by multiple electrode platelet aggregometry (Multiplate™). Results Results of multiple electrode platelet aggregometry significantly decreased in blood samples with platelet count below normal range. Compared to results measured in blood samples with platelet count within normal range, aggregometry results decreased by 18.4% (p < 0.001) and 37.2% (p < 0.001) in blood samples with a platelet count of 100.000 and 50.000 μl-1, respectively. On the other hand, large interindividual variation has been observed and some blood samples showed normal results even with platelet counts of 50.000 μl-1. Conclusion The results obtained with Multiplate™ Analyzer are influenced by platelet function as well as platelet count thus displaying the overall platelet aggregability within the blood sample rather than platelet function alone.

As innovative technology continues to be developed and is implemented into the realm of cardiac surgery, surgical teams, cardiothoracic anesthesiologists, and health centers are constantly looking for methods to improve patient outcomes and satisfaction. One of the more recent developments in cardiac surgical practice is minimally invasive robotic surgery. Its use has been documented in numerous publications, and its use has proliferated significantly over the past 15 years. The anesthesiology team must continue to develop and perfect special techniques to manage these patients perioperatively including lung isolation techniques and transesophageal echocardiography (TEE). This review article of recent scientific data and personal experience serves to explain some of the challenges, which the anesthetic team must manage, including patient and procedural factors, complications from one-lung ventilation (OLV) including hypoxia and hypercapnia, capnothorax, percutaneous cannulation for cardiopulmonary bypass, TEE guidance, as well as methods of intraoperative monitoring and analgesia. As existing minimally invasive techniques are perfected, and newer innovations are demonstrated, it is imperative that the cardiothoracic anesthesiologist must improve and maintain skills to guide these patients safely through the robotic procedure.

One of the dreaded mechanical complications of mitral valve replacement (MVR) is rupture of the left ventricle (LV). This report describes the early diagnosis and successful repair of rupture of posterior wall of LV in an elderly patient who underwent MVR. We have discussed the risk factors and perioperative issues implicated in such complication. The anesthesiologist as an intra-operative echocardiographer can aid in identifying the patient at risk. Though important surgical steps are necessary to prevent the complication; nonetheless, the anesthesiologist needs to take key measures in the perioperative period.