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ResumoFundamento: A injúria de isquemia e reperfusão constitui um mecanismo fisiopatológico frequente e de difícil controle durante a Cirurgia de Revascularização do Miocárdio (CRVM) com circulação extracorpórea, sendo o momento crítico o término da cirurgia, quando ocorre o desclampeamento da aorta e a liberação dos radicais hiperóxidos causadores da injúria.Objetivo: Avaliar, em estudo prospectivo, duplo-cego randomizado, controlado com placebo, os efeitos da Trimetazidina (Tmz) sobre a injúria de isquemia e reperfusão miocárdica, identificando a variação dos marcadores plasmáticos de agressão miocárdica (troponina T e CPK-Mb), e as alterações ecocardiográficas da função ventricular.Métodos: Foram estudados 60 pacientes, divididos em dois grupos (Placebo e Tmz) com, no máximo, disfunção ventricular leve, estratificados por ecocardiografia e recebendo medicação/placebo na dose -no pré-operatório sem medicação, 12 a 15 dias de medicação/placebo colhida cinco minutos após o desclampeamento aórtico, e nas 12, 24 e 48 horas seguintes. Resultados: Tanto a troponina T como a CPK-Mb atingiram valores altamente significativos (p = 0,0001) no grupo tratado em relação ao grupo controle nos quatro momentos analisados − 5 min, 12 h, 24 h e 48 h. As variáveis ecocardiográficas não evidenciaram mudanças evolutivas em cada grupo isoladamente e quando comparados em conjunto. Conclusão AbstractBackground: The ischemia and reperfusion ischemia is a common physiopathological mechanisms, which has difficult control during Coronary Artery Bypass Grafting (CABG) with cardiopulmonary bypass, the critical moment of which happening by the end of surgery, when there is declamping of aorta and release of hyperoxic radicals causing the injury.

Arterial hypoxemia was common in 53 patients following acute myocardial infarction. It was most marked in patients with evidence of left ventricular failure. Arterial oxygen tension, however, was reduced in many of the patients who were without evidence of failure. An increase in arterial oxygen tension following three deep breaths suggested maldistribution of ventilation. Right-to-left shunting of blood was demonstrated by 100% oxygen studies. There was a significant correlation between reduced arterial oxygen tension and low pulmonary diffusing capacity, but a poor correlation between the former and a low cardiac index. We suggest that the hypoxemia following acute myocardial infarction is the result of abnormalities in small airways as well as of vascular congestion in the lungs. The patients with the lowest arterial oxygen tension at the time of study subsequently had more marked arrhythmias and a higher mortality rate.

Background: Organic inflammatory response is a pathophysiological mechanism present at every coronary artery bypass grafting with extracorporeal circulation (CABG-ECC), the release of inflammatory mediators being one of its defense mechanisms.