Invasive versus echocardiographic gradients in degenerated surgical aortic valve prostheses: A multicenter study

OBJECTIVES: To compare echocardiographic and invasive mean gradients obtained concomitantly in degenerated bioprosthetic surgical aortic valves (SAVRs). METHODS: In a multicenter study, we compared concomitant echocardiographic and invasive mean gradients of SAVR, obtained before valve-in-valve transcatheter aortic valve replacement in all patients, patients with primary stenosis (AS), primary aortic regurgitation (AR), and mixed aortic valve disease (MAVD), and in small versus large valves (≤ or >23 mm). Dimensionless index (DI) was calculated in all groups. RESULTS: In total, 74 patients were included and data presented as median (interquartile range). Echocardiography-catheterization mean gradient discordance was observed in all patients (invasive = 22 mm Hg [11-34] vs echocardiographic = 32 mm Hg [21-42], P = .013), small valves (invasive = 15 mm Hg [8-34] vs echocardiographic = 28 mm Hg [21-41], P = .013), and large valves (invasive = 20 mm Hg [8.5-27.13] vs echocardiographic = 32 mm Hg [25.5 – 41.5], P < .0001), with a bias of 8 ± 15 mm Hg and wide limits of agreement (–22 to 39 mm Hg) on Bland–Altman plots, indicating these modalities may not be interchangeable. Discordance occurred in AR (invasive = 3 mm Hg [1-6] vs echocardiographic = 12 mm Hg [7-22], P = .017) and in MAVD (invasive = 19 mm Hg [12-29] vs echocardiographic = 31 mm Hg [23-39], P < .0001) but not in AS (invasive = 35 mm Hg [24-45] vs echocardiographic = 41 mm Hg [30-50], P = .45). A lower DI (0.21 [0.14-0.25]) occurred in AS compared with MAVD (0.31 [0.19-0.39]) and AR (0.55 [0.51-0.69]), P < .0001. CONCLUSIONS: Discordance between echocardiography and invasive mean gradients exists in degenerated SAVR, regardless of valve size, but depends on mechanism of failure and DI helps stratify these patients. With a discrepancy between echocardiographic mean gradients AND the patient's symptoms OR the valve leaflet structure and/or mobility on imaging, especially before redo-SAVR or valve-in-valve transcatheter aortic valve replacement, invasive gradients may adjudicate the true valvular hemodynamics.