Transfusion requirements after cardiac surgery: the TRACS randomized controlled trial.

CONTEXT: Perioperative red blood cell transfusion is commonly used to address anemia, an independent risk factor for morbidity and mortality after cardiac operations; however, evidence regarding optimal blood transfusion practice in patients undergoing cardiac surgery is lacking. OBJECTIVE: To define whether a restrictive perioperative red blood cell transfusion strategy is as safe as a liberal strategy in patients undergoing elective cardiac surgery. DESIGN, SETTING, AND PATIENTS: The Transfusion Requirements After Cardiac Surgery (TRACS) study, a prospective, randomized, controlled clinical noninferiority trial conducted between February 2009 and February 2010 in an intensive care unit at a university hospital cardiac surgery referral center in Brazil. Consecutive adult patients (n = 502) who underwent cardiac surgery with cardiopulmonary bypass were eligible; analysis was by intention-to-treat. INTERVENTION: Patients were randomly assigned to a liberal strategy of blood transfusion (to maintain a hematocrit ≥30%) or to a restrictive strategy (hematocrit ≥24%). MAIN OUTCOME MEASURE: Composite end point of 30-day all-cause mortality and severe morbidity (cardiogenic shock, acute respiratory distress syndrome, or acute renal injury requiring dialysis or hemofiltration) occurring during the hospital stay. The noninferiority margin was predefined at -8% (ie, 8% minimal clinically important increase in occurrence of the composite end point). RESULTS: Hemoglobin concentrations were maintained at a mean of 10.5 g/dL (95% confidence interval [CI], 10.4-10.6) in the liberal-strategy group and 9.1 g/dL (95% CI, 9.0-9.2) in the restrictive-strategy group (P < .001). A total of 198 of 253 patients (78%) in the liberal-strategy group and 118 of 249 (47%) in the restrictive-strategy group received a blood transfusion (P < .001). Occurrence of the primary end point was similar between groups (10% liberal vs 11% restrictive; between-group difference, 1% [95% CI, -6% to 4%]; P = .85). Independent of transfusion strategy, the number of transfused red blood cell units was an independent risk factor for clinical complications or death at 30 days (hazard ratio for each additional unit transfused, 1.2 [95% CI, 1.1-1.4]; P = .002). CONCLUSION: Among patients undergoing cardiac surgery, the use of a restrictive perioperative transfusion strategy compared with a more liberal strategy resulted in noninferior rates of the combined outcome of 30-day all-cause mortality and severe morbidity. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01021631.

Investigação dos polimorfismos maternos C677T e A1298C dogene MTHFR e A66G do gene MTRR como fatores de risco para a síndrome de Down / Investigation of the MTHFR C677T and A1298 and MTRR A66G gene polymorphisms as maternal risk factors for Down Syndrome

A Síndrome de Down (SD) é causada pela presença de três cópias do cromossomo 21 e ocorre em 95 por cento dos casos como um modelo de não-disjunção cromossômica, geralmente durante a meiose materna. Estudos indicam que alterações no metabolismo do folato, e pode levar à hipometilação do DNA e à não-disjunção cromossômica. Nesse sentido, polimorfismos genéticos que alteram enzimas envolvidas neste metabolismo como as enzimas Metilenotetrahidrofolato redutase (MTHFR) e Metionina sintase redutase (MTRR), podem aumentar o risco de não-disjunção cromossômica e, conseqüentemente, da SD. O objetivo deste estudo foi investigar os polimorfismos MTHFR C677T e A1298C e o polimorfismo MTRR A66G como fatores de risco maternos para a SD. Foram avaliadas 50 mães de indivíduos com SD, portadores de trissomia livre do cromossomo 21, e 30 mães de indivíduos sem a síndrome. A análise molecular dos polimorfismos MTRRA66G e MTHFR C677T foi realizada pela técnica de PCR-RFLP. O polimorfismo MTHFR A1298C foi investigadopor meio da técnica de PCR alelo-específico. As freqüências dos alelos polimórficos MTHFR 677T e 1298Cforam, respectivamente, de 0,31 e 0,27 no grupo caso e 0,38 e 0,35 no grupo controle. A freqüência do aleloMTRR 66G foi de 0,59 e 0,47 nos grupos caso e controle, respectivamente. Desse modo, não houve diferença nas freqüências alélicas dos polimorfismos entre os grupos. Não houve também diferença significativa na distribuição genotípica entre os grupos. Neste estudo não foi possível estabelecer uma correlação entre os polimorfismos C677T e A1298C do gene MTHFR e A66G do gene MTRR e o risco materno para a síndrome de Down.