Introduction: Afterload conferred by aortic stiffness contributes to heart failure (HF) pathogenesis. Hypothesis: Patients with HF have a greater rise in aortic stiffness with physical exertion compared to individuals without HF. Methods: Outpatients with HF (n=21) and without HF (n=26) underwent cardiovascular magnetic resonance (1.5T CMR) at rest and following submaximal supine bicycle ergometry. Short axis cine steady-state free precession (SSFP) images were obtained to quantify left ventricular volumes and ejection fraction. Cross-sectional aortic SSFP imaging at the level of the pulmonary artery bifurcation was obtained to measure descending aorta (DA) distensibility at rest and immediately after exercise. We compared least squares (LS) means of DA distensibility between HF and control groups, adjusting for age, sex, and metabolic equivalents (METs) achieved. Results: Characteristics of controls and HF patients are presented in the TABLE . There was no difference of DA distensibility between control and HF groups either at rest or after exercise (p=0.77 and p=0.13, respectively). However, compared to controls with no significant change in aortic stiffness with exercise, individuals with HF had a reduction in DA distensibility post-exercise in analyses adjusted for age, sex, and METs achieved ( TABLE ). In subgroup analyses, patients with HF with reduced ejection fraction (n=14) had lower post-exercise DA distensibility vs. rest (adjusted-LS means 3.06 x10 -3 mm Hg -1 , 95% CI 2.35x10 -3 —3.76x10 -3 mm Hg -1 , vs. 4.55 x10 -3 mm Hg -1 , 95% CI 3.84 x10 -3 —5.26 x10 -3 mm Hg - 1, respectively, p=0.020). DA distensibility at rest vs. exercise in patients with HF with preserved ejection fraction was similar (p=0.38). Conclusions: Patients with HF have exercise-induced aortic stiffness not seen in individuals without HF. This may result in less favorable ventricular-vascular coupling with exertion in HF patients. Character count: 1653 (limit=1700)
Read full abstract