Here's a common question we get from patients with previous surgical valves: "Doctor, I heard you can implant valves now using catheter techniques without open heart surgery. Is that true?"

If you have a mechanical valve, whether it is in the aortic or mitral position, the answer is no. Or, at least, we are not there yet.

This short article focuses on the mitral valve. If a patient has a degenerated bioprosthetic mitral valve, there is a transcatheter mitral valve replacement (TMVR) option for some patients. Who can get TMVR valve-in-valve? You first need to have a degenerated bioprosthetic mitral valve with regurgitation or stenosis. The gold standard is still a redo surgery; however, many patients are considered inoperable or high risk. Therefore, TMVR can be considered. The most commonly used commercially available valve is Edwards SAPIEN valve (Edwards Lifesciences; Irvine, CA), which is designed for transcatheter aortic valve replacement; its use in the mitral position is on a compassionate-use basis. The procedure is mostly done by a transseptal approach and less commonly by a transapical approach. It is guided by transesophageal echocardiography (TEE) and fluoroscopy.

Pre-procedure planning includes a dedicated cardiac computed tomography image to measure the following:

1. Valve size (can also be done with TEE along with the measured actual internal dimension, which is correlated with the true internal dimension of the failed bioprosthetic valve)
2. Aorto-mitral angle (favorable angle is >105 degrees)
3. Neo-left ventricular outflow tract (LVOT) area measured after a virtual implantation of the SAPIEN valve (needs to be >200 mm² to prevent LVOT obstruction) (Figure 1)

If the septum is thick, alcohol septal ablation can be done ahead of time to decrease the risk of LVOT obstruction in cases where the predicted neo-LVOT area is <200 mm². Another novel strategy, balloon assisted translocation of the mitral anterior leaflet, can be used to prevent LVOT obstruction, which is one of the main concerns of TMVR. Success rate is about 94-97%, with 91-95% 30-day survival and 86% 1-year survival.

Figure 1: Three-Dimensional Cardiac Computed Tomography Image With a Virtually Embedded SAPIEN Valve in the Mitral Position to Guide in Predicting LVOT Obstruction

References

1. Eleid MF, Cabalka AK, Williams MR, et al. Percutaneous Transvenous Transseptal Transcatheter Valve Implantation in Failed Bioprosthetic Mitral Valves, Ring Annuloplasty, and Severe Mitral Annular Calcification. JACC Cardiovasc Interv 2016;9:1161-74.
2. Eleid MF, Whisenant BK, Cabalka AK, et al. Early Outcomes of Percutaneous Transvenous Transseptal Transcatheter Valve Implantation in Failed Bioprosthetic Mitral Valves, Ring Annuloplasty, and Severe Mitral Annular Calcification. JACC Cardiovasc Interv 2017;10:1932-42.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Cardiac Surgery and VHD, Interventions and Imaging, Interventions and Structural Heart Disease, Angiography, Echocardiography/Ultrasound, Nuclear Imaging

Keywords: Coronary Angiography, Mitral Valve, Echocardiography, Transesophageal, Transcatheter Aortic Valve Replacement, Constriction, Pathologic, Compassionate Use Trials, Heart Valve Diseases, Fluoroscopy, Surgical Instruments, Tomography

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