Assessment of acute changes in biventricular volumes, systolic function and strain after MitraClipTM-implantation using magnetic resonance imaging and feature tracking

Abstract

MitraClipTM-implantation has been shown to significantly reduce mitral regurgitation (MR) in patients with high surgical risk. Whereas hemodynamic and echocardiographic studies suggest a reduction in left ventricular (LV) volumes and an increase in cardiac output following the intervention, there is very limited data on assessment of volumetric and functional changes after MitraClipTM-implantation using cardiac magnetic resonance (CMR) imaging, the considered method of choice in such a scenario. Methods Patients with moderate to severe MR, high surgical risk and absence of contraindications to CMR imaging underwent MitraClipTM-implantation and CMR imaging on a 1.5 Tesla scanner (Intera, CV, Philips Medical Systems) before and within seven days after the procedure. In addition to volumetric and flow studies, myocardial feature tracking (FT) technology for quantification of myocardial wall mechanics was applied. From steady-state free precession images of short axis views LV maximal circumferential (ECCSAX) and radial (ERRSAX) and of the 4-chamber view LV longitudinal (ELL4CH) and radial (ERR4CH) strain was calculated using dedicated prototype software (TomTec, Germany). Results Twenty patients (age: 76 ± 8 years) with functional MR (n = 15) or degenerative MR (n = 5) with a median Euroscore of 33 (range 17-62) underwent the MitraClipprocedure and CMR imaging. Detailed results of volumetric assessment of the LV and right ventricle (RV) as well as calculated mitral and tricuspid regurgitation fraction are summarized within the table. There was a 44% relative reduction in MR fraction after MitraClipTMimplantation. In this severely compromised patient population (mean pre-implant cardiac index of 1.7 L/min/m2), there were smaller LV enddiastolic volumes after the intervention, but reduced total stroke volume at unchanged effective LV stroke volume (=net aortic forward flow) and