[Rare complication of extracorporeal circulation: diffuse coronary fibrosis; giant cell myocarditis]

A 38 year old woman developed severe coronary stenosis several months after double valve replacement. Aorto-coronary bypass surgery was performed but the patient died of a peroperative myocardial infarction. Histological studies showed not only fibrous thickening of the intima of the whole coronary arterial tree, but also variable medial changes with inflammatory infiltration. In addition, inflammatory granulomata with giant cells were found in the myocardium. These coronary lesions and their association with a giant cell myocarditis cannot be satisfactorily explained by known pathological conditions. The usual mechanisms of coronary disease were not operative in this case. There remains the hypothesis of a primary change of the coronary wall related to either cannulation, anoxic arrest or perfusion fluid, or a combination of these factors. The coronary lesions could have developed by an immunological process which would also explain the giant cell myocarditis.