How low is "low-flow" in aortic stenosis? A retrospective analysis of patients with true low-flow/low-gradient aortic stenosis undergoing TAVI.

Background: Transcatheter aortic valve implantation (TAVI) is a valuable treatment option for patients with reduced left ventricular ejection fraction (LVEF) and low-flow/low-gradient (LF/LG) aortic stenosis (AS). According to current literature, the presence of severe AS is unlikely in case of severely reduced LVEF and mean pressure gradient (meanPG) below 30 mmHg. However, a considerable number of patients presenting with typical clinical symptoms of severe AS, show gradients below 30 mmHg. We hypothesized, that these patients undergoing TAVI do have a measurable clinical benefit and an improved LVEF.

Methods: In this single center retrospective cohort study, data from 1199 patients undergoing TAVI between 2013 and 2017 was analyzed. A 6-month follow-up was performed to assess changes in NT-proBNP, NYHA-class, and LVEF.

Results: Thirty patients presented with LVEF<35%, an aortic valve area (AVA<1 cm2), and a meanPG below 30 mmHg. Mean logistic EuroSCORE II was 24.05±10.9. Most patients (56%) showed improved NYHA-class upon follow-up. NT-proBNP-levels decreased from 3.901 pg/mL IQR 10.880 to 1.491 pg/mL IQR 2.245 (P<0.001). LVEF increased from 30% IQR 6.25 to 40% IQR 15 (P<0.001).

Conclusions: Based on our findings TAVI represents a valuable treatment option even in patients with LF/LG AS and PGmean below 30mmHg.