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Platelet Function Analyzer (platelet + function_analyzer)
Selected AbstractsDecreased Platelet Function in Cavalier King Charles Spaniels with Mitral Valve RegurgitationJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 5 2003Inge Tarnow With aggregometry, increased platelet activity has been reported in Cavalier King Charles Spaniels (CKCS) without mitral regurgitation (MR). In contrast, dogs with MR have been found to have decreased platelet activity. The purpose of this study was to test an easy bedside test of platelet function (the Platelet Function Analyzer [PFA-100]) to see if it could detect an increase in platelet activity in CKCS without MR and a decrease in platelet activity in CKCS with MR. This study included 101 clinically healthy dogs 1 year of age: 15 control dogs of different breeds and 86 CKCS. None of the dogs received medication or had a history of bleeding. The PFA-100 evaluates platelet function in anticoagulated whole blood under high shear stress. Results are given as closure times (CT): the time it takes before a platelet plug occludes a hole in a membrane coated by agonists. The CT with collagen and adenosine-diphosphate as agonists was similar in control dogs (median 62 seconds; interquartile interval 55,66 seconds) and CKCS with no or minimal MR (55; 52,64 seconds). The CT was higher in CKCS with mild MR (regurgitant jet occupying 15,50% of the left atrial area) (75; 60,84 seconds; P= .0007) and in CKCS with moderate to severe MR (jet 50%) (87; 66,102 seconds; P < .0001). CKCS with mild, moderate, and severe, clinically inapparent MR have decreased platelet function. The previous finding of increased platelet reactivity in nonthrombocytopenic CKCS without MR could not be reproduced with the PFA-100 device. [source] Casual Chocolate Consumption and Inhibition of Platelet FunctionPREVENTIVE CARDIOLOGY, Issue 4 2007Bryan Bordeaux DO Observational studies have associated reduced cardiovascular mortality with chocolate consumption. Feeding studies of high-dose, flavanol-rich chocolate show antiplatelet effects, but the effect of casual chocolate consumption on platelet function is unknown. Healthy adults (N=1535) were proscribed from consuming foods affecting platelet function, including chocolate, for 48 hours and completed a 24-hour dietary recall before ex vivo platelet testing with the Platelet Function Analyzer (PFA)-100 (Dade Behring, Inc, Deerfield, IL) test and in vivo testing with urinary 11-dehydro thromboxane B2 (Tx-M) measurements. Some participants (n=141) reported ignoring the prohibition of consuming chocolate before platelet testing. Despite having similar baseline characteristics, chocolate consumers had longer PFA closure times (130 vs 123 seconds, P=.005) and decreased Tx-M levels (175 vs 290 ng/mol creatinine, P=.03). Chocolate remained a significant independent predictor of both ex vivo and in vivo platelet function testing after adjusting for confounders. The authors concluded that even consuming modest amounts of commercial chocolate has important antiplatelet effects. [source] Preliminary evaluation of hemostasis in neonatal foals using a viscoelastic coagulation and platelet function analyzerJOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 1 2009Barbara L. Dallap Schaer VMD, DACVECC, DACVS Abstract Objectives , To compare coagulation and platelet function parameters measured using a viscoelastic analyzer in 3 groups: foals presenting to a neonatal intensive care unit with presumed sepsis, normal foals, and adult horses. Design , Preliminary prospective trial. Setting , Veterinary teaching hospital. Animals , Ten clinically healthy foals, 13 clinically healthy adult horses, and 17 foals sequentially admitted for suspected sepsis. Intervention , A single citrated (3.8%) blood sample collected at admission was submitted for coagulation evaluation using a viscoelastic analyzer. Measurements and Main Results , Time to initial clot formation (ACT), clot rate (CR), platelet function, and time to peak parameters were collected from the signature generated with the associated software. Peak clot strength was collected manually from signature tracings. Signalment, presenting complaint, blood culture results, clinical progression, and outcome were collected from the medical record. Kruskal-Wallis testing was used to determine differences in coagulation parameters between groups, as well as to identify any associations between coagulation variables, foal variables, and outcome. Normal foals were more likely to have increased platelet function (P=0.04) compared with normal adult horses. Prolonged ACT (P=0.004) and decreased CR (P=0.03) were associated with foals with positive blood culture. There was a trend toward prolonged ACT and increased likelihood of death (P=0.06). Conclusions , Healthy foals differ in values measured by the viscoelastic coagulation and platelet function analyzer compared with healthy adult horses. ACT and CR abnormalities were more likely to be observed in foals with positive blood cultures. The viscoelastic coagulation and platelet function analyzer may be useful in identifying early hemostasic and platelet dysfunction in critically ill foals, particularly those that are septic. [source] Variables influencing Platelet Function Analyzer-100TM closure times in healthy individualsBRITISH JOURNAL OF HAEMATOLOGY, Issue 5 2005Hannelore Haubelt Summary We investigated the relationship between platelet function analyzer (PFA-100TM) closure times (CT) and bleeding time (BT), platelet aggregation (PA) induced by ADP, arachidonic acid, and collagen, blood cell counts, and von Willebrand factor (VWF) in 120 well-characterised healthy individuals. Pre-analytical and analytical conditions were standardised comprehensively. In a substantial number of cases the differences between duplicate measurements exceeded 15%. The reference range (5th and 95th percentiles) for CT with the collagen/epinephrine (CEPI) and the collagen/ADP (CADP) cartridge was 93,223 s and 64,117 s respectively. Re-examination of 11 individuals with CEPI-CT above the 95th percentile revealed considerable batch-to-batch variation of CEPI-CT. Males had significantly longer CADP than females (P = 0·002). CEPI and CADP-CT measured pm were significantly longer than corresponding values determined am (P = 0·003 and P < 0·0001 respectively). Blood group O was associated with greater CEPI and CADP-CT and lower VWF levels compared with non-O blood groups (P = 0·008, P = 0·0003 and P < 0·0001 respectively). Linear regression analysis revealed association between CEPI-CT, CADP-CT and VWF (P < 0·0001), but no relationship was found between CT and BT or between CT and PA. We conclude that VWF plasma levels modulate PFA-100TM CT to a greater extent than platelet function. Establishment of reliable reference ranges and careful standardisation of pre-analytical and analytical conditions is a prerequisite for obtaining reliable PFA-100TM results. Duplicate measurements are necessary. [source] | ||||||||||