Effect of platelet count on secretion capacity: formulization and use of the formulae for evaluation of platelet secretion in thrombocytopenic patients

Abstract

The correlation between platelet count and bleeding time is nonlinear. The bleeding time prolongs more prominently as platelet count decreases toward 10 000 microl(-1); however, it becomes stable near 100 000 microl(-1). Clinical observations suggest that platelet functional capacity may also play a role in bleeding complications during thrombocytopenia. However, no routine method has been described for evaluation of platelet function during thrombocytopenia. To test if platelet functional capacity is affected by the cell count, as suggested by the platelet count-bleeding time correlation. To evaluate lumiaggregometry as a possible tool for studying platelet functions and prediction of bleeding in thrombocytopenic patients. Collagen-induced ATP release was studied in different dilutions of 22 healthy platelet-rich plasmas. The relationship between platelet count and ATP release was formulized. ATP release was also tested in 24 thrombocytopenic (10 000-50 000 microl(-1). ) patients, and the results were compared with expected levels derived from the formulae. ATP release increased in a cubic fashion as platelet count elevated. ATP secretion values were within normal limits or increased in patients with idiopathic thrombocytopenic purpura. However, some patients with megakaryocyte deficiency had a secretion defect. ATP secretion was decreased in four out of seven patients with bleeding symptoms compared with no persons without bleeding (P = 0.003). Platelet functional capacity is affected by the cell count. Lumiaggregometry is potentially useful in evaluating platelet functions during thrombocytopenia.

Differences in platelet function in patients with acute myeloid leukemia and myelodysplasia compared to equally thrombocytopenic patients with immune thrombocytopenia: a rebuttal

“…However, we do not agree with their suggestion that their study was the first to examine and define differences in platelet function in patients with equivalent degrees of thrombocytopenia due to ITP or acute myelogenous leukemia/myelodysplastic syndrome (AML/MDS). We have previously proposed a method, depending on lumiaggregometry, for studying platelet functions in thrombocytopenic patients and evaluated platelet dysfunction using this method in AML and ITP too . Our findings were similar to those of Psaila et al .…”

“…Moreover, we observed that the test result correlated well with bleeding symptoms. As we previously commented, methods evaluating platelet functions in thrombocytopenic patients could have an impact on platelet transfusion strategies . Further studies are definitely needed on this topic.…”

An overview of platelet indices and methods for evaluating platelet function in thrombocytopenic patients

“…Platelet granule defects actually seem to be relatively common in pathological states, for example myelodysplastic syndrome . Platelet secretion defects may therefore potentially contribute to bleeding risk in thrombocytopenia .…”

Pooperacinio pakraujavimo priežastys neurochirurgijoje

“…Suskirsčius pacientus į grupes pagal priešoperacinę trombocitų koncentraciją, pacientų grupėje, kurioje buvo trombocitopenija < 60×10 9 /l, pakraujavimų dažnis buvo 100 %, grupėje pacientų, kurių trombocitų kiekis > 60×10 9 /l -6,2 %, p < 0,01, reliatyvi rizika esant trombocitopenijai < 60×10 9 /l padidėja 16 kartų, 95 % PI [11][12][13][14][15][16][17][18][19][20][21][22][23].…”

“…Kraujavimo laikas nerekomenduojamas kaip rutininis patikrinimo testas prieš operaciją, nes chirurginiams pacientams, neturintiems kraujavimo rizikos veiksnių, kraujavimo laikas retai būna kliniškai smarkiai pailgėjęs, prarasto kraujo kiekis ligoniams, turintiems pailgėjusį kraujavimo laiką, neviršija netekto kraujo kiekio ligoniams, turintiems normalų kraujavimo laiką, pailgėjęs kraujavimo laikas nebūtinai yra pagausėjusio kraujavimo priežastis [18]. Kraujavimo laikas priklauso ne tik nuo trombocitų funkcijos, bet ir nuo jų kiekio, smarkiai prailgėja, kai trombocitų koncentracija sumažėja iki 10×10 9 /l, ir stabilizuojasi, kai trombocitų koncentracija yra apie 100×10 9 /l [19].…”