Cardiac magnetic resonance imaging in patients undergoing percutaneous mitral valve repair with the MitraClip system.

Background: Percutaneous mitral valve repair (MVR) with the MitraClip(®) system in patients with mitral regurgitation (MR) is known to reduce symptoms and to improve cardiac morphology and function. MitraClip has been approved for cardiac magnetic resonance imaging (MRI). To date, however, no systematic analysis exists on cardiac MRI in patients undergoing the MitraClip procedure.

Objective: The aim of this study was to (1) prove feasibility and robustness of cardiac MRI and (2) visualize effects of the procedure on cardiac morphology and function by cardiac MRI.

Methods: 27 consecutive patients (age 77.5 ± 7.6 years) with symptomatic moderate to severe MR undergoing the MitraClip(®) procedure were prospectively included. Cardiac MRI at 1.5 T was performed before and at 3 months after intervention. Cardiac morphology and function were evaluated using steady-state free precession (SSFP) cine sequences by assessment of left ventricular enddiastolic and endsystolic diameters (LVEDD, LVESD) and volumes (EDV, ESV), ejection fraction (LVEF) and stroke volume (SV), diameter of mitral annulus, and myocardial mass (MM). Planimetry of the left atrium (LA) was performed in identical slices in a four-chamber view.

Results: Around the clip an extinction artifact was observed which did not disturb the evaluation of cardiac morphology and function. At follow-up, we observed significant decreases of LVEDD (58.0 to 53.3 mm, p < 0.0001), EDV (167 to 159 mL, p = 0.0006) and ESV (101 to 89 mL, p < 0.0001), diameter of mitral annulus (41.4 to 37.9 mm, p < 0.0001), myocardial mass (148.4 to 144.5 g, p = 0.0004) and LA size (40.2 to 37.6 cm(2), p < 0.0001). LVEF improved (43.3 to 46.7 %, p = 0.0041).

Conclusions: Cardiac MRI is feasible and robust in patients with MitraClips. The clinical benefit of a successful MitraClip intervention is paralleled by significant improvements of cardiac morphology and function which can be monitored and validated using MRI in clinical follow-up examinations.