Tania Rubia Flores da Rocha

A Prospective Study of Conventional and Expanded Coagulation Indices in Predicting Ulcer Bleeding After Variceal Band Ligation

BACKGROUND & AIMS There is controversy over whether coagulation status predicts bleeding caused by ulceration after esophageal varices band ligation (EVL). METHODS EVL was performed for primary (n = 45) or secondary (n = 105) prophylaxis in 150 patients with cirrhosis (Child A, n = 74, 49%; Child B, n = 42, 28%; Child C, n = 34, 23%). International normalized ratio (INR) and platelet counts were assessed in all. In 92 patients, levels of factor V, fibrinogen, D-dimer, protein C and protein S, von Willebrand factor, and thromboelastography (TEG) were assessed. Platelet count <50 x 10(3)/mm(3) and INR >1.5 were considered high-risk cutoff for bleeding. Conversely, platelet count >or=50 x 10(3)/mm(3) with INR <or=1.5 were safe cutoffs. RESULTS Overall, 11 patients (7.3%) had post-EVL ulcer bleeding. Bleeding occurred in 5 patients with Child A/B (4.3%) and 6 patients with Child C (17%) (P = .0174 for Child A/B versus Child C). Eight patients with bleeding were among the 110 below the cutoff for INR and platelet count, whereas only 3 of the patients with bleeding were among the 40 patients with purported high-risk values (P = 1.0). Among the 92 patients with expanded coagulation tests, bleeding occurred in 5. There was no difference in any of the coagulation parameters, including overall TEG patterns, between patients who did and did not bleed. CONCLUSIONS Post-EVL ulcer bleeding was associated with Child C status but not with conventional or expanded coagulation indices in cirrhotic patients without renal failure or infection undergoing elective EVL. These results call into question the common use of prophylactic procoagulants in the elective setting.

Platelet activation status decreases after menopause.

Objective. The aim of the study was to investigate the impact of the climacterium (before and after menopause) on platelet activation. Background. Platelet activation has been associated to the risk of cardiovascular disease. There is much speculation about the relationship between platelet function and sex steroids, due to peculiarities of platelet action between the genders, including concerns about the influence of low estradiol status in menopausal women. Methods. By means of a cross-sectional study design, 37 female patients divided into two groups were compared. Group A consisted of ten women, mean age 43.9 years, in the premenopausal period, with normal estrogen levels; and Group B comprised 27 patients, mean age 53.0 years, who had all reached menopause. Platelet activation markers, namely P-selectin and glycoprotein IIb–IIIa complex (GPIIb–IIIa), were evaluated by flow cytometry with monoclonal antibodies. A binding index was calculated for both parameters (percentage of positive platelets × mean fluorescence of positive platelets). Also, thromboxane A2 was quantified by means of its main plasma metabolite, thromboxane B2, by enzyme immunoassay. Results. P-selectin and GPIIb–IIIa expression results revealed lower platelet activation status after menopause, as there was a decrease in both the percentage of P-selectin +  platelets and of GPIIb–IIIa mean fluorescence of positive platelets, lowering both binding indices. P-selectin binding index differed significantly between Group A (12.3 ± 3, n = 10) and Group B (6.2 ± 2.9, n = 27; mean ± standard deviation (SD), p < 0.001). GPIIb–IIIa binding index also differed significantly between both groups (Group A: 18.8 ± 2.3, n = 10 vs. Group B: 16.2 ± 3.1, n = 27; mean ± SD, p < 0.0018). Plasma concentration of thromboxane B2 was 1.07 ± 0.5 pg/well before menopause (Group A, n = 10) and 1.9 ± 4.1 pg/well after menopause (Group B, n = 27), not significantly different (mean ± SD, baseline × therapy, p = 0.85). Conclusions. After the menopause, climacteric women – whose estradiol status is low – have a decreased activation platelet status compared with premenopausal women. Nevertheless, further studies on a larger sample are necessary for conclusive data regarding cardiovascular disease.

In vitro effect of the herbicide glyphosate on human blood platelet aggregation and coagulation

O glifosato [N-(phosphonomethyl)-glycine] e um herbicida pos-emergente nao seletivo de amplo espectro muito utilizado na agricultura. Dados da literatura referentes aos efeitos desse produto na saude humana sao contraditorios. Em estudos previos demonstramos que ratos previamente tratados com glifosato apresentavam lesoes hepaticas e sangramento sem alteracoes quantitativas de plaquetas. O objetivo do presente estudo e investigar os efeitos in vitro do glifosato (GP) na agregacao plaquetaria e coagulacao sanguinea em humanos. A agregacao plaquetaria foi determinada em plasma rico em plaquetas (PRP) usando os agentes adenosina difosfato (ADP) 6µM, epinefrina 6µM e colageno 4µg/mL. Pre-tratamento com GP 500µg/mL demonstrou significativa hipofuncao dos tres agentes agregantes. O efeito inibitorio foi dose dependente em concentracoes de 50-500 µg/mL. Utilizando-se a quantificacao de ATP como um indice da capacidade de secrecao plaquetaria, foi observado diminuicao da liberacao das plaquetas tratadas com GP. Por outro lado, o GP nao promoveu efeito inibidor no tempo de protrombina (TP), tempo de tromboplastina parcial ativada (ATTP) e tempo de trombina (TT). Em conclusao, os resultados demonstram que o GP promove mudancas no metabolismo plaquetario com efeito inibitorio na hemostasia primaria.