Dynamic aortic stiffness response to exercise as a marker of functional capacity in early-stage heart failure

Aortic stiffness increases ventricular afterload and limits exercise capacity in heart failure (HF), but its dynamic response to exercise remains insufficiently defined. This study aimed to evaluate exercise-induced changes in aortic stiffness and their association with functional capacity in patients with early-stage HF. Heart-rate recovery (HRR) was assessed as secondary parameter.

This prospective study enrolled 42 compensated HF patients (ejection fraction <45%) in sinus rhythm. Aortic diameters were measured 3 cm above the aortic valve using M-mode echocardiography to calculate the Stiffness Index (SI), Peterson's Elastic Modulus (Ep), and Aortic Distensibility (D). All patients underwent a symptom-limited treadmill test using the modified Bruce protocol. HRR was defined as the difference between peak heart rate and heart rate at 1 min of recovery. Echocardiographic measurements were repeated within 60 s after exercise.

Aortic stiffness increased significantly after exercise [SI: 5.05 (4.18-6.30) to 6.03 (4.59-7.79); p < 0.001], while distensibility decreased [2.64 to 1.90 ×10 - 6 cm2·dyn-1; p < 0.001]. Patients with NYHA class II had higher SI and Ep and lower D at rest and post- exercise than NYHA class I patients (all p < 0.001). NYHA class was the only independent predictor of post-exercise stiffness (β = 3.32; 95% CI 1.33-5.30; p = 0.002). Exercise capacity was significantly lower in NYHA II patients (7.0 vs 10.1 METs; p < 0.001). HRR showed no significant association with aortic stiffness or exercise capacity.

In early-stage HF, increased resting and exercise-induced aortic stiffness is strongly associated with reduced functional capacity, indicating early impairment of vascular compliance reserve during physiological stress.