Severity of aortic stenosis predicts early post-operative normalization of left atrial size and function detected by myocardial strain

Background: Aortic stenosis (AS) causes significant disturbances in left ventricular (LV) and left atrial (LA) function irrespective of the extent of myocardial hypertrophy which associates the increased afterload. We hypothesize that aortic valve replacement (AVR) and removal of LV outflow tract obstruction should result in LA size and function recovery, even partial, and were set to study this in a group of patients with AVR for AS.

Methods: Peak atrial longitudinal strain (PALS) was evaluated in 43 patients with severe isolated AS and normal EF (56.6 ± 3.8%) and no obstructive coronary artery disease candidates for AVR, pre-operatively and then 40 days and 3 months after surgery. Results were compared with those from 34 age- and gender-matched healthy controls.

Results: LVEF remained unchanged and LV mass regressed after AVR. Global PALS was reduced pre-operatively and increased 40 days after surgery (p=0.002) and showed only a slight further increase at 3 months follow-up (p<0.0001). Indexed LA volume was increased before surgery, but significantly fell 40 days after surgery (p<0.0001) and showed only a slight further reduction after 3 months (p<0.0001). Trans-aortic mean gradient change after surgery was the only independent predictor of the recovery of LA size and function.

Conclusions: AVR reverses LA abnormalities and regains normal atrial function, a behavior which is directly related to the severity of pre-operative LV outflow tract obstruction. Early identification of LA size enlargement and functional disturbances might contribute to better patient's recruitment for AVR.