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

OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.