Comparing characteristics and clinical and echocardiographic outcomes in low‐flow vs normal‐flow severe aortic stenosis with preserved ejection fraction in an Asian population

Abstract

Background/Objectives In severe aortic stenosis (AS), deterioration of left ventricular ejection fraction (LVEF) to <50% is an AHA/ACC class I indication for valve replacement, regardless of symptoms. Controversy surrounds prognosis of low‐flow AS compared to normal‐flow, and no study has examined LVEF deterioration. We compared factors associated with LVEF deterioration (to <50%) and clinical outcomes. Methods Consecutive subjects with low‐flow (stroke volume index <35 mL/m2, n=56) and normal‐flow (n=72) severe AS (aortic valve area <1 cm2) with preserved LVEF (>50%) and with paired echocardiography were studied. Univariate and multivariate analyses identified factors associated with LVEF deterioration. Clinical outcomes were determined on follow‐up for more than 5 years. Results Significant LVEF deterioration (to <50%) was seen in 18% of low‐flow (initial LVEF 63±8% to 32±9%) and 18% of normal‐flow AS (61±7% to 31±12%). Independent factors in low‐flow AS were hypertension (OR: 30.7, 95% CI: 2.0–467.6, P=.014) and higher end‐systolic wall stress (OR: 1.086, 95% CI: 1.022–1.153, P=.008), compared to normal‐flow, which were hypertension (OR: 15.9, 95% CI: 3.1–81.9, P=.001), higher septal E/E′ ratio (OR: 1.16, 95% CI: 1.01–1.35, P=.043), lower septal S′ velocity (OR: 0.204, 95% CI: 0.061–0.682, P=.010), and higher end‐systolic wall stress (OR: 1.051, 95% CI: 1.001–1.104, P=.047). Overall, a third of the cohort experienced MACE, regardless of flow (log‐rank 0.048, P=.827). However, aortic valve replacement (AVR) rates were lower in low‐flow AS (20% vs 43%, P=.005). Conclusions Low‐flow AS despite normal LVEF appears similar to normal‐flow in terms of LVEF deterioration and clinical outcomes in our Asian population. AVR rate was lower even though low‐flow may not reflect less severe disease.

Differences in Clinical and Echocardiographic Profiles and Outcomes of Patients With Atrial Fibrillation Versus Sinus Rhythm in Medically Managed Severe Aortic Stenosis and Preserved Left Ventricular Ejection Fraction

“…The prevalence of low-flow AS in the SR group was similar and also consistent with previous studies [21,22]. While patients with low-flow AS demonstrated increased mortality in the SR group, this trend was not seen in the AF group [23]. We postulate that while low-flow AS had previously been associated with poorer outcomes due to the increased LV remodelling and subclinical LV dysfunction, similar trends could not be demonstrated in the AF group owing to the already high rates of pathological LV remodelling, which was associated with AF [24][25][26].…”

“…The cross-sectional nature of the study meant that the findings would be subjected to lead time bias as patients were studied at different time points in the natural history of the disease progress of AS. We also did not examine follow-up data in terms of repeated echocardiography for the progression of aortic valve disease, LV dysfunction, and remodelling over time, although we have done so in a paired echocardiographic setting previously [23]. Furthermore, we did not investigate specific biomarkers such as brain natriuretic peptic, which may have important prognostic implications [28].…”

An Asian Perspective on Gender Differences in Clinical Outcomes and Echocardiographic Profiles of Patients With Medically Managed Severe Aortic Stenosis

“…(>50%). The lower-than-expected mean pressure gradients observed were therefore likely related to a significant proportion of our Asian cohort with paradoxical low-flow and low-gradient AS (up to 30%), which has been discussed in a previous study [16]. The prevalence of paradoxical low-flow AS was similar (30%) in our study population.…”

Novel Echocardiography-Derived Left Ventricular Stiffness Index in Low-Flow Versus Normal-Flow Severe Aortic Stenosis with Preserved Left Ventricular Ejection Fraction

“…The main findings of this study were that (1) patients with LF AS had higher LV stiffness than those with normal-flow AS, (2) increasing LV stiffness is related to concentric remodeling and hypertrophy, as well as more advanced diastolic dysfunction; and (3) AS subjects with increased LV stiffness had higher mortality than those with lower LV stiffness. Paradoxical LF AS has been shown to form a significant proportion (up to 30%) of Asian cohorts 13 . Patients with LF AS tended to be older and have increased cardiovascular risk factors such as diabetes mellitus and hyperlipidemia.…”