State-of-the-Art Review
Emerging Approaches to Management of Left Ventricular Outflow Obstruction Risk in Transcatheter Mitral Valve Replacement

https://doi.org/10.1016/j.jcin.2023.01.357Get rights and content

Highlights

  • LVOT obstruction is a predictor of poor outcome after transcatheter mitral valve replacement (TMVR) and is a common reason for exclusion from TMVR therapy.

  • Several novel therapeutic strategies have shown efficacy at reducing risk of LVOT obstruction to facilitate TMVR. This review introduces a new algorithm for approach to avoidance of LVOT obstruction before TMVR with septal reduction strategies that include alcohol septal ablation and radiofrequency ablation, as well as anterior mitral leaflet electrosurgical laceration.

  • Several forthcoming therapies under study will further characterize the optimal management of LVOT obstruction risk before TMVR, including novel techniques to reduce septal thickness, dedicated anterior leaflet modification devices, and dedicated TMVR devices designed to prevent anterior leaflet displacement toward the LVOT.

Abstract

An increasing number of patients with mitral valve disease are high risk for surgery and in need of less invasive treatments including transcatheter mitral valve replacement (TMVR). Left ventricular outflow tract (LVOT) obstruction is a predictor of poor outcome after TMVR, and its risk can be accurately predicted using cardiac computed tomography analysis. Novel treatment strategies that have shown efficacy in reducing risk of LVOT obstruction after TMVR include pre-emptive alcohol septal ablation, radiofrequency ablation, and anterior leaflet electrosurgical laceration. This review describes recent advances in the management of LVOT obstruction risk after TMVR, provides a new management algorithm, and explores forthcoming studies that will further advance the field.

Section snippets

Assessment of LVOT Obstruction Risk Before TMVR

The gold standard method for assessment of the LVOT anatomy and procedural TMVR planning is gated cardiac CT angiography, which provides excellent spatial resolution and clear definition of left ventricular structure. All patients being considered for TMVR require a gated cardiac CT assessment for determination of procedural candidacy. An exception to this is patients who have a degenerated mitral bioprosthesis being considered for mitral valve-in-valve therapy, in which case CT may be

Impact of TMVR Design on LVOT Obstruction Risk

The self-expanding double-framed nitinol Tendyne device (Abbott) has a tapered shape in the left ventricular cavity that allows for less protrusion into the LVOT compared with cylindrical-shaped devices.16 The Intrepid device (Medtronic) similarly has a low profile with minimal protrusion into the LVOT, thus lowering LVOT obstruction risk. As a result, the neoLVOT for Tendyne or Intrepid in a given patient will typically be slightly larger than with a cylindrical-shaped valve such as SAPIEN 3

Alcohol Septal Ablation

Alcohol septal ablation was originally developed for treatment of hypertrophic cardiomyopathy (HCM) in the 1980s19 and is recommended as a Class I indication for treatment of severely symptomatic LVOT obstruction refractory to medical therapy.20 The technique involves percutaneous cannulation of the coronary artery in the cardiac catheterization laboratory using a guiding catheter, advancing a 0.014-inch wire and over-the-wire balloon into the septal perforator branch supplying the basal

TMVR Patient Management Algorithm

The approach we use consists of positioning the virtual transcatheter valve in the anticipated implantation location and measuring the virtual THV frame neoLVOT and skirt neoLVOT (Figure 7). When the frame neoLVOT is <200 mm2 and the skirt neoLVOT is <200 mm2, the interventricular septum is assessed to determine whether hypertrophy is present and whether ablation of the basal septum is feasible. We use a diastolic septal thickness cutoff of 10 mm or more to determine whether ablation can be

Future Directions

The neoLVOT management algorithm proposed in this review is currently being used in the prospective MITRAL 2 (MITRAL II Pivotal Trial [Mitral Implantation of TRAnscatheter vaLves]; NCT04408430) and outcomes of this approach will be forthcoming. As experience with LVOT modification techniques in TMVR grows, more data regarding patient selection and efficacy of these approaches will become available. Future study of clinical and anatomical predictors of optimal response to ASA, LAMPOON, and other

Conclusions

Several new and effective techniques are available to help reduce the risk of LVOT obstruction in TMVR.

Funding Support and Author Disclosures

Dr Mahoney has served as a consultant for Edwards Lifesciences and Medtronic. Dr Killu has served as a consultant for Boston Scientific; and has received honoraria from Biosense Webster. Dr. Guerrero has received institutional research grant support from Edwards Lifesciences; and has served as consultant for Abbott Structural Heart and Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

References (30)

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