Abstract 15474: Acute Increase in Systemic Arterial Load Blunts Afterload Release after Transcatheter Aortic Valve Implantation. Frequency-Domain and Wave-Intensity Analyses
The interaction between ventricular, valvular and vascular components determines the hemodynamic consequences of aortic stenosis (AS). Acute valvular relief is an excellent scenario to assess the effects of ventricular, valvular and vascular coupling in AS.
Methods: High-fidelity aortic pressure (P) and flow (Volcano Combowire) recordings were obtained in 10 patients (77±10 years old, 4 female) with severe AS at baseline and after CoreValve transcatheter aortic valve implantation (TAVI). Doppler-echocardiography and thermodilution studies were performed immediately prior to the procedure. Signals were processed using frequency-domain (FD) and wave-intensity (WIA) analyses using custom-built software. Systemic vascular resistance, aortic input impedance spectrum (Z), total arterial compliance (C), FD-derived arterial elastance (Ea), and LV endsystolic elastance (Ees) were calculated.
Results: After TAVI mean and peak systolic aortic P increased, partially blunting the release in peak LVP (TABLE). Stroke volume remained unchanged, accompanied by a significant increase in Ea as well as in the first three harmonics of Z, and a parallel decrease in C. Because Ees acutely increased, arterial-ventricular coupling (Ees/Ea) remained unchanged. Individual SV response closely correlated to the change in Ea (R=0.92). WIA showed an increase in the forward compression wave and pulse wave speed after TAVI. Valvuloarterial impedance (Zva) derived from Doppler parameters did not correlate with vascular indices and failed to identify changes in vascular load.
Conclusion: Assessment of vascular function in patients with AS, even using gold-standard methods, is heavily conditioned by outflow obstruction. An increase in the steady and pulsatile components of vascular load acutely blunt the hemodynamic benefits of TAVI. Because this effect is compensated by an improvement of global systolic chamber function overall arterial-ventricular coupling is unchanged.
- © 2012 by American Heart Association, Inc.