Paradoxical low-flow aortic stenosis – baseline characteristics, impact on mortality

Introduction
Paradoxical low-flow, low-gradient aortic stenosis (pLF-LGAS) constitutes an important part of the population undergoing transcatheter aortic valve implantation (TAVI). However, it remains the least defined subtype of aortic stenosis (AS).

Aim
To investigate baseline characteristics and impact on mortality of pLF-LGAS in patients treated with TAVI.

Material and methods
Two-hundred and thirty-one consecutive patients (mean aortic valve area: 0.76 ±0.41 cm²) who underwent TAVI in our centre during the period of 6 years were included in the study. Based on echocardiographic examination, patients with pLF-LGAS were identified, analysed and compared to a population with high-gradient AS (HGAS) and low-flow, low-gradient AS with reduced ejection fraction (classical, cLF-LGAS). The primary endpoints of the study were all-cause mortality after 30 days and 1 year.

Results
pLF-LGAS was diagnosed in 42 (18.2%) patients, whereas 40 (17.3%) had cLF-LGAS and 149 (64.5%) had HGAS. The pLF-LGAS population was younger, had higher prevalence of hypertension, and had higher ejection fraction (EF) than the HGAS population, and had a smaller proportion of heavily symptomatic patients than the cLF-LGAS population. Overall, 46 (19.9%) patients died within 12 months after TAVI. The 30-day and 1-year survival was comparable between AS subtypes. Multivariate analysis identified severe renal failure as an independent predictor of mortality among all patients.

Conclusions
pLF-LGAS is common among subjects undergoing TAVI. Patients with paradoxical AS are younger, more often burdened with hypertension and have higher EF than the HGAS population, while being less symptomatic than the cLF-LGAS group. Presence of pLF-LGAS does not seem to affect short- and mid-term survival. Severe renal failure is an independent predictor of mortality after TAVI.