Ventilator-assisted transcatheter edge-to-edge mitral valve repair for severe atrial functional mitral regurgitation: a case report

BACKGROUND: Atrial functional mitral regurgitation (AFMR) is an entity of mitral regurgitation (MR) in atrial fibrillation (AF) with dilated left atrium (LA) and/or normal left ventricular function. Transcatheter edge-to-edge mitral valve repair with MitraClip is reportedly an effective therapy for AFMR. However, performing MitraClip for patients with such condition is challenging because of its characteristic morphology. CASE SUMMARY: An 80-year-old man with permanent AF and severe MR was hospitalized for heart failure with preserved ejection fraction. On echocardiography, a marked dilation of the LA caused the anterior mitral leaflet to flatten along the mitral annulus (MA) plane. The posterior mitral leaflet was tethered towards the posterior left ventricle, thus producing a coaptation gap of 6.5 mm between the leaflets. Given his high surgical risk, MitraClip therapy was performed, but leaflet grasping was difficult because of the notable coaptation gap. When positive end-expiratory pressure (PEEP) was applied by mechanical ventilation, the MA gradually decreased in diameter. Under 20 cm H(2)O of PEEP, the coaptation gap decreased to 0 mm, which finally enabled the grasping of the leaflets. The clip was deployed, thus leaving only mild MR. Thereafter, the patient had an uneventful clinical course. DISCUSSION: In patients with AFMR, the sagittal dilation of the MA and asymmetry in the tethering angles of the leaflets often produce a marked coaptation gap, which poses a challenge in MitraClip therapy. In our patient, the ventilator-assisted technique effectively reduced the coaptation gap between the leaflets, thus leading to successful results.