Paradoxical Normal-Flow Aortic Stenosis Despite Reduced Left Ventricular Ejection Fraction: Insights From the...

Area of Science:

• Cardiology
• Cardiac Surgery
• Medical Imaging

Background:

• Severe aortic stenosis (AS) typically presents with low flow and low gradient, but a subset exhibits normal flow with reduced ejection fraction (NF-LEF).
• This NF-LEF phenotype is associated with eccentric left ventricular remodeling and enlarged cavities.
• Understanding the characteristics and outcomes of NF-LEF is crucial for effective treatment strategies.

Purpose of the Study:

• To determine the prevalence and hemodynamic characteristics of the NF-LEF phenotype in severe aortic stenosis.
• To evaluate the outcomes of transcatheter aortic valve implantation (TAVI) in patients with NF-LEF compared to other AS phenotypes.
• To identify factors associated with the NF-LEF phenotype.

Main Methods:

• A substudy of the COMPARE-TAVI 1 trial included 979 patients undergoing transfemoral TAVI.
• Patients were stratified into four groups based on left ventricular ejection fraction (LVEF) and stroke volume index (SVI): normal flow/normal LVEF, NF-LEF, low flow/normal ejection fraction, and low flow/low ejection fraction.
• Clinical data, echocardiographic parameters, and long-term follow-up outcomes were analyzed.

Main Results:

• The NF-LEF phenotype was identified in 10.7% of patients.
• NF-LEF was associated with higher rates of moderate or worse aortic regurgitation, eccentric hypertrophy, and larger left ventricular cavities.
• Despite higher comorbidity burdens, NF-LEF patients showed comparable survival and functional improvements post-TAVI to the normal flow/normal LVEF group.

Conclusions:

• NF-LEF represents a distinct and prevalent severe aortic stenosis phenotype characterized by preserved flow despite reduced LVEF, often linked to eccentric remodeling and aortic regurgitation.
• Transcatheter aortic valve implantation in NF-LEF patients yields favorable long-term survival and functional outcomes, similar to those with normal flow and normal LVEF.
• The NF-LEF phenotype warrants recognition as a significant subgroup within severe aortic stenosis, demonstrating substantial clinical improvement after TAVI.