Advanced cardiac imaging in percutaneous transvenous mitral annuloplasty

Abstract

Functional mitral regurgitation is a consequence of ventricular enlargement and annular dilatation. Current treatment options include medical and surgical therapy. Reduction of functional mitral regurgitation has a significant impact on patient prognosis [1]. Percutaneous transvenous mitral annuloplasty (PTMA) systems have been suggested for interventional treatment of functional mitral regurgitation in heart failure patients [2, 3]. These devices are inserted into the coronary sinus. They use the close proximity of the coronary sinus, great and anterior interventricular vein to the mitral annulus to enable remodeling of the mitral annulus. Reduction of mitral regurgitation is based on a reduction of the anterior–posterior mitral annulus dimension resulting in improved leaflet coaptation. Advanced imaging modalities allowing a 3-dimensional display of the complex mitral valve apparatus may allow improved understanding of treatment effects [4]. This report describes the use of 3D transesophageal echocardiography and CT–angiographic fusion imaging to visualize the treatment effect of a PTMA system. The Viacor PTMA system (Viacor, Inc. Wilmington, MA, USA) consisting of a multi-lumen PTFE catheter and Nitinol (nickel–titanium alloy) treatment rods as described recently, was implanted in a 66-year-old male patient. The patient had severe mitral insufficiency due to ischemic cardiomyopathy with dilated mitral annulus. Mitral valve surgery was denied to the patient due to severe comorbidities including pulmonary hypertension and silicosis. Figure 1, panel a demonstrates a hybrid image combining a CT scan of the coronary sinus with the fluoroscopic image before PTMA. Figure 1, panel b is a hybrid image showing the coronary sinus configuration (blue vessel) from the CT scan before PTMA combined with a fluoroscopic image showing the PTMA in place. The PTMA device indicates the new coronary sinus position after force induction by the PTMA device. The green area is obtained from the coronary sinus position before PTMA and with the PTMA device in place (white arrows). It indicates the effect of the device on the area encompassed by the coronary sinus and indirectly reflects also the change in mitral annulus area induced by the device. Figure 1, panels c and d are 3D stop frame images before and with PTMA obtained by 3D real-time TEE demonstrating the deformation of the mitral annulus induced by the device (black arrows). To demonstrate the effect of the annuloplasty procedure on the mitral valve, rendered 3D images were obtained by a dedicated software (Qlab 7.0 , Philips Healthcare, Andover, MA, USA). With this technique the mitral valve including the annulus and leaflets can be characterized with regard to the width of the annulus, the anterior-to-posterior and the anterolateral-to-posteromedial diameter as well as the mitral regurgitant orifice area. A significant reduction of the mitral anterior-to-posterior diameter from 40 to 33 mm and of the mitral regurgitant orifice area from 0.56 cm before the procedure to 0.12 cm after the procedure could be visualized (Figs. 2, panels a, b). Color Doppler echocardiography demonstrates reduction of mitral regurgitation from before PTMA (Fig. 2, panel c) to with PTMA (Fig. 2, panel d). By proximal convergence method a reduction of regurgitant flow was confirmed. This report demonstrates that a combination of different imaging modalities allows improved understanding of R. Hoffmann (&) P. Schauerte M. Kelm J. Balzer Medical Clinic I, University Clinic Aachen, University Aachen, Pauwelsstrasse, 52074 Aachen, Germany e-mail: wilma.hoffmann@t-online.de