Left atrial dynamics in the hemodynamic response during exercise in patients with asymptomatic severe aortic stenosis

Abstract

Abstract Background The hemodynamic impact of left atrial (LA) dynamics in aortic stenosis (AS) in relation to cardiopulmonary response to exercise has never been studied. We aimed at investigating the link between LA function vs hemodynamics and prognosis in asymptomatic severe AS patients. Methods A total of 106 patients: 76 asymptomatic severe AS patients (aortic valve area (AVA) <1.0 cm2 or AVA index <0.6 cm2/m2) and 30 gender-matched control subjects underwent cardiopulmonary exercise testing combined with Echo-Doppler with assessment of LA strain. AS patients were divided into 4 groups according to peak aortic jet velocity (PV), mean pressure gradient (MPG), stroke volume index (SVI), and left ventricular ejection fraction (LVEF). Results Normal-flow low-gradient AS (NFLG: PV <4 m/s and MPG <40 mmHg, SVI >35ml/m2, LVEF ≥50%, N=23), High-gradient AS (HG: PV ≥4 m/s or MPG ≥40 mmHg, LVEF ≥50%, N=23), Paradoxical low-flow low-gradient AS (PLFLG: PV <4 m/s and MPG <40 mmHg, SVI ≤35ml/m2, LVEF ≥50%, N=18), and Classical low-flow AS (CLF: LVEF <50%, N=12) had a higher LA volume index than Control (Control 22±6, NFLG 38±12*, HG 33±9*, PLFLG 33±11*, and CLF 49±15* ml/m2, *P<0.05 vs Control). In PLFLG and NFLG AS, LA strain at rest (21±9 and 26±13%) and during exercise (26±12 and 31±14%) were decreased compared to Control (37±8% at rest, 43±11% during exercise) but LA strain was increased from rest to exercise (P<0.001). HG and CLF AS had no increase in LA strain (31±15 and 19±10% at rest, 28±15 and 18±9% during exercise) (figure). In Cox proportional hazards analysis, age and gender adjusted hazard ratio for the composite end point (aortic valve replacement, hospitalization for heart failure, and all-cause mortality) of changes in LA-strain from rest to exercise (1% increase) was 1.05 (95% CI 1.00 to 1.09, P=0.044) among AS patients. Conclusions In asymptomatic severe AS, the study of LA functional adaptation to exercise plays a key role in the hemodynamic unfavorable cascade signaling major adaptive differences in dynamics during physical challenge. Overall, LA dynamics provides prognostic information also in AS patients. Funding Acknowledgement Type of funding sources: None.