SCMR 22nd Annual Scientific Sessions
Description of Clinical Presentation:
A 71 year old man was referred to our institution for evaluation of prosthetic mitral valve regurgitation. He underwent coronary artery bypass surgery and mitral valve replacement with a bioprosthetic valve (29 mm St Jude Epic) at another institution in September 2017. The patient had persistent heart failure symptoms, with further workup by transesophageal echocardiogram demonstrating a paravalvular (PVL) defect at 5 O’clock position resulting in eccentric paravalvular mitral regurgitation (MR). The native leaflets were left intact surrounding the bioprosthetic valve. The patient was deemed high risk for re-operation and a percutaneous closure was pursued. CMR was performed for accurate MR quantitation and pre-procedural planning.
Diagnostic Techniques and Their Most Important Findings:
We utilized a CMR fusion imaging technique to circumvent the challenges in visualizing the PVL on 2D fluoroscopy. We typically use gated cardiac computed tomography but CMR was preferred in this case due to renal insufficiency and for more accurate quantitation of the MR. The technique of CMR fusion imaging is illustrated in the following steps: 1) Data import and procedural planning: 3D multi-planar gated subtracted MRA sequence was imported into the 3D workstation and targets such as the PVL site, prosthetic mitral valve, trans-septal access site and aortic annulus were electronically marked. 2) Image co-registration: Non-contrast cone beam CT images (syngoDynaCT®, Siemens Medical Solutions USA Inc.) were acquired in the cardiac cath lab after rapid-pacing. Mitral valve ring from cone-beam CT was aligned with signal void of the mitral prosthesis from T1-VIBE/MRA images using semi‐automated image co-registration (syngo 3D3D fusion®, Siemens) (Figure 1). 3) Overlay of targets from CMR on fluoroscopy: After image fusion, the anatomical targets including PVL site were overlaid on fluoroscopy, tracked automatically with C-arm and table movements. These targets then served as a 3D roadmap for the interventionalist enhancing fluoroscopy with information from CMR datasets. The PVL was crossed with a wire and a VSD occluder was then deployed. Unfortunately, the defect was too large and various sized occluder devices were attempted but did not hold. Then, the patient underwent surgical removal of the prosthetic valve with repair of the native mitral leaflets. There was good correlation between Cardiac CTA performed preoperatively to evaluate CABG graft patency and CMR regarding the PVL defect (figure 2). Patient did well other than needing a pacemaker post operatively and was discharged home a week later.
Learning Points from this Case: We demonstrate the utility of CMR-fusion imaging in transcatheter procedural guidance for closure of mitral PVL. Most reports on the use of this technology were done with CTA or 3D echocardiography. In this case, CMR provided accurate anatomic (defect sizing for trans-catheter PVL closure) and functional assessment (quantification of mitral regurgitation) without ionizing radiation or iodinated contrast.