Exercise Mildly Increases Transaortic Gradients in Aortic Stenosis With Preserved Ejection Fraction: An Invasive Hemodynamic Study

Abstract

Background

The assessment of aortic stenosis (AS) severity remains a challenge in some patients, and hemodynamic exercise testing has been proposed as a diagnostic tool in this population. However, the current understanding of exercise hemodynamics in AS is limited.

Methods

Retrospective review of 34 adults (aged ≥ 18 years) with ≥ moderate AS and preserved left ventricular ejection fraction (LVEF) undergoing exercise invasive hemodynamics (supine cycle protocol) with simultaneous measurement of aortic and left ventricular pressures.

Results

Age was 77.1 (IQR 68.6; 84.1) years, and 50% were female. LVEF was 62.1 ± 6.6%. All patients were symptomatic. Resting aortic valve area (AVA) was 1.0 ± 0.2 cm² and aortic valve (AV) systolic mean gradient 22.0 ± 7.3 mmHg. At peak exercise (40 [IQR 30; 60] W), AV systolic mean gradient (Δ3 [0.6; 7] mmHg, p < 0.001) and AVA (Δ0.2 [0; 0.6] cm², p = 0.002) significantly increased, while stroke volume (SV) did not (Δ6.8 ± 19.4 ml; p = 0.07). Exercise-induced changes in AV systolic mean gradient were directly related to changes in cardiac output (r = 0.53, p = 0.003), being inversely related to exercise systemic vascular resistance (r = −0.60, p = 0.002). Elevated pulmonary artery wedge pressure was present in 41.2% at rest (≥ 15 mmHg) and 69.7% during exercise (≥ 25 mmHg).

Conclusions

Symptomatic patients with ≥ moderate AS and preserved LVEF experience small increases in AV mean gradient with exercise, and unlike the normal physiological response to exercise, there was no significant increase in SV. In most patients, AVA rose during exercise. Exercise-induced elevation in filling pressures was highly prevalent.