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Predictors of LVOT Obstruction After Transcatheter MVR
Study Questions:
What are the predictors of left ventricular outflow tract (LVOT) obstruction after transcatheter mitral valve replacement (TMVR)?
Methods:
The TMVR registry is an international, multicenter, observational registry that enrolled consecutive patients undergoing TMVR for degenerated mitral bioprostheses (valve-in-valve), failed annuloplasty (valve-in-ring), or mitral annular calcification (valve-in-MAC); registry patients with pre-procedural multidetector row computed tomography (MDCT) were included in this study. Echocardiographic and procedural characteristics were recorded, and comprehensive assessment with MDCT was performed to identify the predictors of LVOT obstruction (defined as an increment of mean LVOT gradient ≥10 mm Hg from baseline). The new LVOT (neo-LVOT) area after TMVR was estimated by embedding a virtual valve into the mitral annulus on MDCT, simulating the procedure.
Results:
Among 194 patients with pre-procedural MDCT undergoing TMVR (107 valve-in-valve, 50 valve-in-ring, and 37 valve-in-MAC), LVOT obstruction was observed in 26 patients (13.4%); with a higher rate after valve-in-MAC than after valve-in-ring or valve-in-valve TMVR (54.1% vs. 8.0% vs. 1.9%, p < 0.001). Patients with LVOT obstruction had significantly higher procedural mortality compared with those without LVOT obstruction (34.6% vs. 2.4%, p < 0.001). Receiver-operating characteristic curve analysis showed that an estimated neo-LVOT area ≤1.7 cm2 predicted LVOT obstruction with a sensitivity of 96.2% and specificity of 92.3%.
Conclusions:
LVOT obstruction after TMVR was associated with higher procedural mortality. A small estimated neo-LVOT area was significantly associated with LVOT obstruction after TMVR and may help identify patients at high risk for LVOT obstruction.
Perspective:
This study, using TMVR registry data, suggests that there is a high risk of LVOT obstruction following valve-in-MAC TMVR, with progressively lower rates of occurrence associated with valve-in-ring and valve-in-valve procedures. The high periprocedural mortality associated with LVOT obstruction following valve-in-MAC TMVR might reflect both the hemodynamic burden of LVOT obstruction and patient comorbidities potentially associated with severe MAC. However, with the observed high mortality associated with LVOT obstruction after TMVR, attempts to predict and avoid LVOT obstruction are appropriate, and emphasize the importance of careful patient screening prior to performing TMVR.
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, Computed Tomography, Echocardiography/Ultrasound, Nuclear Imaging
Keywords: Bioprosthesis, Cardiac Surgical Procedures, Cardiac Valve Annuloplasty, Diagnostic Imaging, Echocardiography, Heart Valve Diseases, Heart Valve Prosthesis, Hemodynamics, Mitral Valve, Multidetector Computed Tomography
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