Papillary muscle tissue embolism causing myocardial infarction after minimally invasive mitral valve repair: a case report

Abstract Background Perioperative myocardial infarction after minimally invasive mitral valve surgery is uncommon. Recognized mechanisms include iatrogenic circumflex coronary injury and coronary embolism, but embolization of papillary muscle tissue has not been well described. Case summary A 76-year-old woman underwent minimally invasive mitral valve repair for severe mitral regurgitation caused by P3 prolapse. Inferior ST-segment elevation developed after aortic unclamping and persisted despite repeated de-airing. Because the patient remained haemodynamically stable and transoesophageal echocardiography did not show a definite new regional wall-motion abnormality, she was initially observed closely. Persistent ST-segment elevation and mild lateral wall hypokinesis two hours after intensive care unit admission prompted emergency coronary angiography, which demonstrated complete occlusion of the posterolateral branch of the left circumflex coronary artery. Aspiration thrombectomy restored Thrombolysis In Myocardial Infarction grade 3 flow. Histopathological examination of the retrieved material showed that all identifiable tissue fragments consisted of striated cardiac muscle, supporting papillary muscle tissue embolism. The patient recovered without residual regional wall-motion abnormality. Discussion Papillary muscle tissue can be disrupted during subvalvular manipulation and embolize to a coronary artery after restoration of forward flow. Persistent or recurrent ST-segment elevation after mitral valve surgery should prompt early coronary angiography even when air embolism is initially suspected and haemodynamics remain stable.