A Novel Imaging Approach to Assess Paravalvular Leak for Transcatheter Valve Replacement

Background/Rationale

There are currently no objective, validated measures of paravalvular leak (PVL) by echocardiogram (Lerakis et al). The PARTNER 2 year outcomes demonstrated that even mild PVL is associated with poor prognosis (Kodali et al) and decreased survival after transaortic valve replacement (TAVR). It has been proposed that the severity of PVL could be measured based on a comparison of jet arc length and pressure half-time on color Doppler transthoracic echocardiogram (TTE) to the circumference of the valve annulus in the parasternal short-axis view. Accordingly, a jet arc corresponding to <10% of the annulus circumference indicates mild PVL, 10-20% moderate PVL, and >20% severe PVL. However, this grading method still needs to be validated against an independent reference standard such as Cardiac MRI (cMRI).

Cardiac MRI (cMRI) is a reliable way to measure PVL post-TAVR. It enables measurement of both regurgitant volume and regurgitant fraction using gradient echo-based phase-contrast sequence velocity flow mapping, accurately measuring forward stroke volume and backward regurgitant flow across the valve. Being independent of jet morphology, cMRI may be a superior way to follow patients post-TAVR. cMRI provides a quantitative assessment of the regurgitant fraction and can therefore serve as the reference standard for validation of TTE-based grading schemes.

Study Procedures

Patients seen at The Heart Hospital Baylor Plano (THHBP) will be enrolled into the study if they are eligible and provide written consent. Upon enrollment, demographic and clinical risk factors data will be collected for each patient. All patients will receive TTE and cMRI, within 1 week of each other, at their 30 days ± 14 days, 6 months ± 30 days, or 1 year ± 60 days follow up visit post-TAVR. TTE is usually performed at these follow-up visits as part of the routine clinical work up. All females of childbearing age will have a urine pregnancy test prior to cMRI. Patients will be assigned PVL severity grades according to the two diagnostic methods by Dr. Grayburn (TTEs), and Dr. Gopal (cMRIs). Both investigators will be blinded to each other grading results.