Left atrial function in the assessment of risk profile of asymptomatic patients with severe aortic stenosis

Purpose: In aortic stenosis (AS), preserved left atrial (LA) function helps in maintaining optimal cardiac output despite the impaired left ventricle (LV) relaxation and reduced compliance. We sought to investigate the possible influence of LA function impairment, as assessed by speckle tracking echocardiography (STE), in symptomatic deterioration of patients with severe AS. Methods: 27 asymptomatic patients (7 males, mean age 73+11 years) with severe AS (aortic valve area= 0.35+0.11 cm2/m2, mean gradient ¼ 55+15 mmHg; indexed stroke volume=37+11 ml/m2), and LV hypertrophy (LV mass index= 135+35 g/m2) but preserved ejection fraction (EF=60+5.5%) were prospectically enrolled. LA volume was evaluated in addition to traditional echo-doppler parameters of LV systolic and diastolic function. With regard to LA strain, both peak of booster pump (negative peak) and reservoir phase (positive peak) were calculated and LV strain, rotations, twist and untwisting rate (recoil) were obtained by STE. Predefined end-points were the occurrence of symtoms (dyspna, angina, syncope) and one major adverse event (death). After a follow-up of 11+7.5 months (range 1–23 months), patients were subdivided into 2 groups: group 0, including 8 steadily asymptomatic patients (mean age 75.5+6.7 years) and group 1, including 19 symptomatic patients (mean age 71.6+12 years). Results: No patient died during follow-up. However, group 1 had lower LVEF (58+5 vs 64+4.3%, p=0.03), AVA (0.19+0.18 vs 0.36+0.15 cm2/m2, p=0.01), LV longitudinal strain (213.6+2.9 vs -19.4+2.7%, p,0.001), higher aortic mean gradient (62+20 vs 48+10 mmHg, p=0.04) and valvulo-arterial impedance (Zva =5.1+2.9 vs 3.5+ 1.5 mmHg/ml/m2, p=0.02) than group 0. Furthemore, all patients had increased LA volume and impaired LA function, but group 1 showed lower reservoir peak than group 0 (8.8+4.5 vs 13.6+4.7%, p=0.01). In contrast, any difference was found regarding LA volume (37.8+15 vs 39+11 ml/m2, p=ns) and atrial booster pump (210.4+2.5 vs 210.3+4.6%, p=ns) between group 1 and 0, respectively. Furthermore, LA reservoir showed a significant correlation with aortic mean gradient (r=0.50, p=0.04), LV radial strain (r=0.88, p=0.009) and LV longitudinal strain (r=0.60, p=0.003) whereas LA booster pump showed a significant correlation with LVEF (r=0.53, p=0.01), LV longitudinal strain (r=0.49, p=0.01) and recoil (r=0.74, p=0.006). Conclusions: Reduction of LA reservoir function may contribute to clinical deterioration of patients with AS. The accurate assessment of LA chamber in addition to common parameters is thus challenging to obtain important prognostic information