Ischaemic stroke due to thrombus formation on the ventricular side of the mitral valve more than one year after MitraClip implantation: a case report

OBJECTIVES: Edge-to-edge mitral valve repair with MitraClip leads to a differed flow pattern and a decreased flow velocity at the left ventricle apex. This combination may lead to initiation of thrombus formation, especially in patients with severely reduced ejection fraction. The prevalence and mechanism of left ventricular thrombus formation after MitraClip implantation is still unknown. METHODS: We describe a case of a 74 year old women with a non-ischaemic cardiomyopathy and chronic heart failure with a severely reduced ejection fraction who was treated with a MitraClip for a severe secondary mitral valve insufficiency. One and a half year later she suffered from an ischaemic stroke due to a large thrombus at the ventricular side of the posterior mitral leaflet. Oral anticoagulation was started with complete resolution of the thrombus. We performed a literature review. RESULTS: There are just a few case reports of this complication and two single centre observational retrospective studies on the prevalence of thrombus formation after MitraClip. They reported a divergent prevalence of 4.4% and 21%. Multiple hypotheses have been described such as the correction of the regurgitating blood that might be leading to more stasis of blood in the left ventricle. Another hypothesis states that the 2 divergent jets after the MitraClip can lead to an increase of shear stress, which might initiate thrombus formation. CONCLUSION: Thrombus formation in the left ventricle after MitraClip implantation in patients with severely reduced ejection fraction is a rare complication. This case reports shows that it may occur even more than one year after the intervention. Permanent vigilance is warranted, especially in patients who are not chronically treated with oral anticoagulation.