Is relative aortic valve load determinant of left ventricular remodeling in patients with severe aortic stenosis referred for surgical valve replacement?

Abstract Introduction Relative Valve Load (RVL) is a novel echocardiographic index based on the ratio of transaortic mean pressure gradient (MG) to the global valvuloarterial impedance (Zva) in order to estimate the contribution of the valvular afterload to the global left ventricular (LV) load. In patients with severe aortic stenosis (AS) referred for intervention, LV reverse remodeling (LVRR) is expected to occur following afterload relief. We aimed to evaluate whether pre-operative RVL influences LVRR in a cohort of patients with severe AS who underwent surgical aortic valve replacement (SAVR). Methods Single-centre prospective cohort study of 158 patients with severe symptomatic AS and no previous history of ischemic cardiomyopathy (median age 73 68-77 years, 47% male; MG 61±17mmHg, mean indexed aortic valve area 0.4±0.09cm2/m2, mean LV ejection fraction LVEF 59±9%) referred for SAVR between 2019-2022. Both pre- and post-operative transthoracic echocardiographic (TTE) and cardiac magnetic resonance (CMR) study (at the 3rd to 6th month after SAVR) were performed. LV RR was defined when in presence of at least one of the imaging criteria: 15% decrease in end-diastolic volume (EDV) by CMR; 15% decrease in LV indexed mass (LVMi) by CMR; 10% decrease in geometric remodeling (LV mass/EDV ratio) by CMR; 10% increase in LVEF by CMR; 50% increase on global longitudinal strain by TTE. Patients were divided into high and low RVL based on optimised cut-off values determined by Youden Index. The primary endpoint was defined as death or heart failure hospitalization. Results From an initial cohort of 158 patients, a total of 116 (median age 72 68-77, 48% male) had complete pre- and post-SARV imaging study, of whom 108 had data to calculate RVL (all patients with high gradient and preserved LVEF). At baseline, patients with higher RVL (≥14.3mL/m2, 53%) more frequently had chronic kidney disease (p=0.046), higher LVMi (90±30 vs. 69 55-80g/m2, p=0.002), higher LVEF (60±7 vs. 57±9%, p=0.031) and higher EDV (167±46 vs. 131 117-160mL, p=0.002). Overall, 101 (87%) met at least one LVRR criterion (Figure 1A). The most common criterion was a reduction in LVMi (65%, n=75). The number of LVRR criterion did not differ according to RVL cut-off (p=0.957). LV remodeling criteria did not differ according to preoperative RVL except for higher prevalence of EDV regression in patients with lower RVL (45 vs. 43%, p=0.030). At a mean follow-up of 41±17months, the primary endpoint occurred in 28 patients (24%, which included 4 deaths), with RVL cut-off showing no predictive value for survival or HF hospitalization (log-rank p=0.840) (Figure 1B). Conclusion In a cohort of patients with classical severe symptomatic AS referred for surgery, distinct pre-operative RVL was unrelated to LVRR and did not predict the outcome after intervention. This index may be expected to be of value in patients with low-gradient/paradoxical severe AS.