Original Investigation
Systemic Vascular Load in Calcific Degenerative Aortic Valve Stenosis: Insight From Percutaneous Valve Replacement

This work was presented in part at the Scientific Sessions of the American Heart Association, 2012, Los Angeles, California, November 4 to 7; abstract A15474.
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Abstract

Background

Systemic arterial load impacts the symptomatic status and outcome of patients with calcific degenerative aortic stenosis (AS). However, assessing vascular properties is challenging because the arterial tree’s behavior could be influenced by the valvular obstruction.

Objectives

This study sought to characterize the interaction between valvular and vascular functions in patients with AS by using transcatheter aortic valve replacement (TAVR) as a clinical model of isolated intervention.

Methods

Aortic pressure and flow were measured simultaneously using high-fidelity sensors in 23 patients (mean 79 ± 7 years of age) before and after TAVR. Blood pressure and clinical response were registered at 6-month follow-up.

Results

Systolic and pulse arterial pressures, as well as indices of vascular function (vascular resistance, aortic input impedance, compliance, and arterial elastance), were significantly modified by TAVR, exhibiting stiffer vascular behavior post-intervention (all, p < 0.05). Peak left ventricular pressure decreased after TAVR (186 ± 36 mm Hg vs. 162 ± 23 mm Hg, respectively; p = 0.003) but remained at >140 mm Hg in 70% of patients. Wave intensity analysis showed abnormally low forward and backward compression waves at baseline, increasing significantly after TAVR. Stroke volume decreased (−21 ± 19%; p < 0.001) and correlated with continuous and pulsatile indices of arterial load. In the 48 h following TAVR, a hypertensive response was observed in 12 patients (52%), and after 6-month follow-up, 5 patients required further intensification of discharge antihypertensive therapy.

Conclusions

Vascular function in calcific degenerative AS is conditioned by the upstream valvular obstruction that dampens forward and backward compression waves in the arterial tree. An increase in vascular load after TAVR limits the procedure’s acute afterload relief.

Key Words

aortic valve stenosis
hemodynamics
vascular function

Abbreviations and Acronyms

AS
aortic stenosis
BCW
backward compression wave
C
compliance
Ea
systemic arterial elastance
FCW
forward compression wave
SVI
stroke volume index
TAVR
transcatheter aortic valve replacement
WIA
wave intensity analysis
Z
impedance
Zc
characteristic impedance

Cited by (0)

This study was supported by Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, Spain, grants PIS09/02602, PIS012/02878, RD12/0042, CM12/00273 (to Dr. Perez del Villar), and CM11/00221 (to Dr. Mombiela). Drs. Mombiela, González-Mansilla, and del Villar were partially supported by grants from the Fundación para Investigación Biomédica Gregorio Marañón, Spain. Dr. Martínez-Legazpi was supported by U.S. National Institutes of Health grant 1R21 HL108268-01. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

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