Aorto-right pulmonary venous fistula after mitral valve replacement for prosthetic mitral valve infective endocarditis: a case report

BACKGROUND: Aorto-cavitary fistula is a rare condition, and the most common underlying aetiology is infective endocarditis (IE) of the native or the prosthetic aortic valve. We report a case of aorto-right inferior pulmonary venous fistula following redo mitral valve replacement (MVR) for prosthetic mitral valve IE. CASE SUMMARY: A 74-year-old woman underwent urgent redo MVR for prosthetic mitral valve IE. The post-operative course was complicated with heart failure and mediastinal haematoma compressing the left atrium. The haematoma was surgically removed and laceration of the left atrial wall was suture ligated; this was attributed to the surgical trauma dissection of the adhesive tissues. One-week post-operatively, a continuous murmur emerged, which prompted an evaluation of the left to right shunt. Transthoracic echocardiography revealed an echolucent area posterior to the aorta, with continuous flow on colour Doppler. Three-dimensional computed tomography showed a fistula between the aorta and the right inferior pulmonary vein. There was a high risk involved in surgical management; therefore, she was managed medically. Fortunately, the continuous murmur and echolucent space disappeared after 6 months. The fistula was considered to be obstructed by spontaneous thrombus formation in the narrowed segment of the fistula tract. DISCUSSION: The cause of fistula was attributed to possible surgical trauma in the presence of infection. The present case was unique, as it showed spontaneous healing of an aorto-cavitary fistula, which is very rare. The patient was alive with good health status, 6 years after the MVR.