Contractile Reserve as A Predictor of Improvement in Ejection Fraction in Low-Flow, Low-Gradient Severe Aortic Stenosis Following Transcatheter Aortic Valve Replacement

Hawatmeh, Amer

Background
Patient with low flow, low-gradient aortic stenosis (LFLG-AS) have greater perioperative risk and worse outcomes. Dobutamine stress echocardiography (DSE) is recommended for diagnostic and prognostic implications in this population. The aim of this study was to examine the improvement in left ventricular ejection fraction (LVEF) in patients with LFLG-AS with and without contractile reserve following transcatheter aortic valve replacement (TAVR).

Methods
A retrospective study of patients with LFLG-AS who had DSE as part of pre-operative evaluation protocol before TAVR at a single center. Patients were included in the analysis if baseline aortic valve area (AVA) was ≤1.0 cm2 (or AVA index≤0.6 cm2), LVEF was < 50%, and mean transaortic pressure gradient (MPG) was <40 mmHg. Contractile reserve (CR) was defined as an increase in baseline stroke volume > 20%. Patients were divided into two groups according to the presence or absence of CR. LVEF was assessed at 30 days and 12 months post TAVR.

Results
A total of 38 patients were included. CR was present in 18 patients (47%) and absent in 20 (53%). Mean age was 81 years, 25 (65%) were males, mean LVEF 38.2%, mean aortic valve gradient was 28.7 mmHg. Patients with CR displayed an increase in LVEF at 30 days (mean absolute increase, 4.9% [95% CI, 1.2%-10.3%]), and 1-year (mean absolute increase, 6.2% [95% CI, 1.9%-11.2%]) compared to patients without CR who displayed a mean absolute increase of 5% ([95% CI, 0.8%-12.1%]) at 30 days, and 5.7% [95% CI, 2.1%-13.3%]) at 1 year. There was no statistically significant difference between the two groups (P=0.43) and the presence or absence of CR didn’t not predict postoperative improvement in LVEF at 30 days or 1 year.

Conclusions
In patients with LFLG severe AS undergoing TAVR, the presence or absence of CR didn’t not predict postoperative improvement in LVEF at 30 days or 1 year.