Abstract
BackgroundPre- and post-procedural hemodynamic changes which could affect adverse outcomes in aortic stenosis (AS) patients who undergo transcatheter aortic valve replacement (TAVR) have not been well investigated. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) enables accurate analysis of blood flow dynamics such as flow velocity, flow pattern, wall shear stress (WSS), and energy loss (EL). We sought to examine the changes in blood flow dynamics of patients with severe AS who underwent TAVR.MethodsWe examined 32 consecutive severe AS patients who underwent TAVR between May 2018 and June 2019 (17 men, 82 ± 5 years, median left ventricular ejection fraction 61%, 6 self-expanding valve), after excluding those without CMR because of a contraindication or inadequate imaging from the analyses. We analyzed blood flow patterns, WSS and EL in the ascending aorta (AAo), and those changes before and after TAVR using 4D flow CMR.ResultsAfter TAVR, semi-quantified helical flow in the AAo was significantly decreased (1.4 ± 0.6 vs. 1.9 ± 0.8, P = 0.002), whereas vortical flow and eccentricity showed no significant changes. WSS along the ascending aortic circumference was significantly decreased in the left (P = 0.038) and left anterior (P = 0.033) wall at the basal level, right posterior (P = 0.011) and left (P = 0.010) wall at the middle level, and right (P = 0.012), left posterior (P = 0.019) and left anterior (P = 0.028) wall at the upper level. EL in the AAo was significantly decreased (15.6 [10.8–25.1 vs. 25.8 [18.6–36.2]] mW, P = 0.012). Furthermore, a significant negative correlation was observed between EL and effective orifice area index after TAVR (r = − 0.38, P = 0.034).ConclusionsIn severe AS patients undergoing TAVR, 4D flow CMR demonstrates that TAVR improves blood flow dynamics, especially when a larger effective orifice area index is obtained.
Highlights
Pre- and post-procedural hemodynamic changes which could affect adverse outcomes in aortic steno‐ sis (AS) patients who undergo transcatheter aortic valve replacement (TAVR) have not been well investigated
They met any of the following criteria on transthoracic echocardiography: a peak aortic velocity (Vmax) ≥ 4.0 m/s, a mean transaortic pressure gradient ≥ 40 mmHg, an aortic valve area (AVA) ≤ 1.0 cm2, or an aortic valve area index (AVAI) ≤ 0.6 cm2/m2
There was no significant difference in hemodynamic changes between severe AS and very severe AS groups (Additional file 5: Table S1)
Summary
Pre- and post-procedural hemodynamic changes which could affect adverse outcomes in aortic steno‐ sis (AS) patients who undergo transcatheter aortic valve replacement (TAVR) have not been well investigated. We sought to examine the changes in blood flow dynamics of patients with severe AS who underwent TAVR. Transcatheter aortic valve replacement (TAVR) has emerged as a minimally invasive treatment option for patients with severe symptomatic aortic stenosis (AS) who cannot tolerate surgical aortic valve replacement (SAVR) and those at intermediate–high surgical risk, and is expanding to younger, lower-surgical-risk patients [1,2,3]. Increased arterial stiffness and hemodynamic abnormalities in the AAo increase LV oxygen demand and cardiac work, leading to exacerbation of heart failure (HF) [8, 9]. Non-invasive pre- and post-procedural hemodynamic assessment in the AAo may help evaluate the effects of TAVR
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