Primary structural failure of mechanical valve prosthesis in the form of leaflet fracture and embolization with the modern mechanical valve prosthesis is infrequent [1,2,3]. The On-X valve is a new generation mechanical valve with a design supposedly optimized for better hemodynamic performance. There are only three cases reported in the literature of On-X valve leaflet escape, which makes it improbable that a leaflet escape could be an initial diagnosis. We suspect that the valve fractured first and then embolized as it was in 2 pieces. However, the report did not conclusively support this theory. Gobel et al. reported the first fatal case of leaflet escape with the On-X valve in the aortic position. Kayegama et al. and Amoros Riviera et al. reported two cases of On-X mechanical mitral valve leaflet fracture and embolization [3, 4, 6]. The site of embolization reported was the left iliac artery, abdominal aorta and aortoiliac bifurcation. Two patients had fatal outcomes in the three cases reported with On-X mechanical valve leaflet escape [3, 4, 6]. Amoros Riviera et al. observed that one of the hinges had ruptured in the explanted valve; however, the mechanism of failure in the other two reported cases is not reported.
In patients presenting in cardiogenic shock or with pulmonary oedema with severe regurgitation on a background history of a previous valve replacement, a mechanical valve failure in the form of thromboembolism or pannus formation is usually the cause [1,2,3,4,5,6]. However, we would like to highlight leaflet embolization as another possible cause and the need for prompt diagnosis and surgical treatment as this may be lethal.
Transthoracic or transoesophageal echocardiography can be used to diagnose a missing leaflet. Fluoroscopy screening of the valve is also an alternative. However, both transthoracic echocardiography and fluoroscopy could not clearly identify the missing leaflet. In cases where the embolized leaflet is not found inside the heart intraoperatively or fragmentation is suspected, a full-body CT is reliable for localizing escaped leaflets [2,3,4]. The common sites for leaflet embolization have been the abdominal aorta, and iliac arteries [1,2,3,4,5,6]. After the diagnosis, patients should undergo emergency surgery for valve replacement.
There is no consensus regarding removing the embolized leaflets if there is no threatened limb or ischemic complications. We decided to remove the fractured leaflets as we feared the risk of the fragments lacerating the aorta or eroding into the vessel wall. Catheter removal was considered but not undertaken due to the possible risk of the fractured ends of the leaflets lacerating the vessel. We removed the embolized leaflets surgically.
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