The Mysterious Case of Dyspnea.

BACKGROUND

Dehiscence of a mitral valve annuloplasty ring is a rare occurrence that often manifests as mitral regurgitation and heart failure. We present a case of mitral ring dehiscence which was initially unrecognized by standard 2-dimensional transthoracic echocardiography (2D TTE); and 2-dimensional transesophageal echocardiography (2D TEE);.

METHODS

A 65-year-old woman was referred to Cardiology clinic for evaluation of dyspnea. Her history included tobacco abuse, atrial fibrillation status post pulmonary vein isolation, nonischemic cardiomyopathy, and prior mitral valve repair with annuloplasty ring for rheumatic valvular disease. She had been asymptomatic post-surgery. Physical examination, cardiac rhythm and initial ischemic workup were unremarkable. Pulmonary function tests revealed moderate emphysematous type obstructive lung disease. A 2D TTE demonstrated moderate mitral regurgitation with normal left ventricular function. In right heart catheterization, large v waves were noted and 2D TEE also revealed severe mitral regurgitation. On 2D TEE, the mitral valve annuloplasty ring was visible above the native anterior mitral valve leaflet. Color Doppler flow estimated the effective regurgitation orifice area of 0.4cm2 using the proximal isovelocity surface area method and regurgitant volume of 58 cc, consistent with severe mitral regurgitation. A "floating mitral ring" and dehiscence measuring 1 cm in diameter were seen on high resolution three-dimensional reconstruction resulting from the detachment of the ring from the weakened posterior annulus. Based on these findings patient was referred to cardiothoracic surgeon for re-do mitral valve surgery.

CONCLUSIONS

This was a perplexing case as the patient's dyspnea could be explained by many disease processes including atrial fibrillation, mitral regurgitation and chronic obstructive lung disease. The standard imaging modalities did not help us to formulate a diagnosis. 3D TEE provided invaluable and unparalleled information of mitral valve pathology. Annuloplasty ring dehiscence is a well described complication of mitral valve repair and should always be considered in symptomatic patients.