Abstract 3110: Prevalence and Covariates of Low Left Ventricular Midwall Shortening in Patients with Asymptomatic Aortic Valve Stenosis. A SEAS Substudy
Background: Low left ventricular (LV) ejection fraction (EF) usually indicates need of aortic valve replacement in severe asymptomatic aortic stenosis (AS). Midwall shortening (MWS) may be a better measure of LV systolic function in patients with LV hypertrophy.
Methods: We used baseline echocardiography in 1732 patients (mean age 67±10, 39% women, 51% hypertensive) recruited in the Simvastatin Ezetimibe in Aortic Stenosis (SEAS) study to assess prevalence and covariates of low MWS in patients with asymptomatic AS. MWS was considered low when < 14.2%, stress-corrected MWS when < 89.2%, and ejection fraction when < 50%. LV hypertrophy was considered present if LV mass/body surface area >116 g/m2 in men or >104 g/m2 in women and concentric LV geometry if relative wall thickness >0.43. Severity of AS was assessed by aortic valve area/ body surface area (AVAI). Mild, moderate and severe AS were defined as AVAI > 0.9 cm2/m2, ≤ 0.9cm2/m2 and > 0.6 cm2/m2, and > 0.6cm2/m2, respectively.
Results: Prevalence of low MWS and stress-corrected MWS increased with severity of AS (15% and 28% in mild, 22% and 34% in moderate and 25% and 36% in severe AS, all p < 0.05). Low ejection fraction was present in 2% of patients irrespective of severity of AS. Only 6% and 3% of patients with low MSW and stress-corrected MWS had low EF (both p < 0.001). Patients with low MWS and stress-corrected MWS had higher peak and mean transaortic velocities and gradients, smaller AVAI, and included more men and hypertensive patients (all p < 0.05), while these relationships were absent for low EF. In logistic regression analysis, low MWS was associated with concentric geometry, LV hypertrophy, lower AVAI, male gender, and concomitant hypertension (Table⇓).
Conclusions: LV systolic function assessed by MWS is impaired in 25% of patients with severe asymptomatic AS. Of these, only 8% can be diagnosed by EF. In particular, low MWS is more common in patients with concentric LV geometry or concomitant hypertension.