Improving risk assessment for post-surgical low cardiac output syndrome in patients without severely reduced ejection fraction undergoing open aortic valve replacement. The role of global longitudinal strain and right ventricular free wall strain

Low cardiac output syndrome (LCOS) after surgical aortic valve replacement (SAVR) is related to increased mortality and treatment related costs. We aimed to evaluate whether echocardiography-derived left ventricular global longitudinal strain (LV-GLS) relates to the occurrence of postoperative LCOS in patients undergoing SAVR. We prospectively enrolled 75 patients with symptomatic severe aortic stenosis, left ventricular ejection fraction (LVEF) > 40%, NYHA Class <IV, without other significant valve disease. Echocardiographic examination, including LV-GLS assessment was performed before SAVR. In a subgroup of patients right ventricular free wall strain (RVFWS) was also measured. The main outcome was the occurrence of LCOS. Secondary outcome was 30-day mortality. Patients were divided according to LCOS occurrence, which was found in 41% of the population. Baseline clinical characteristics were similar between groups except for LVEF, and LV-GLS. We found LV-GLS to be related to 30-day mortality (OR 1.3, p <0.041, 95% CI 1.02-1.69). After multivariate analysis for variables related to LCOS, only age (p = 0.034), LVEF (p = 0.037) and LV-GLS (p = 0.040) independently predicted LCOS. Mean RVFWS was lower in patients in whom the primary outcome occurred (-12.8 +/- 4.3 vs. -17.1 +/- 3.9, p = 0.0081). In ROC curves analysis a RVFWS of -15% yielded a sensitivity of 81.2% and specificity of 71.4% for the occurrence of LCOS. LV-GLS is a useful parameter for risk stratification in patients with severe aortic stenosis without severely depressed LVEF, and is independently associated with LCOS occurrence. RVFWS wall strain may be useful for risk stratification in patients undergoing AVR.