Clinical Impact of Midframe Underexpansion Following TAVR Using a Self-Expanding Transcatheter Heart Valve

The occurrence and clinical impact of transcatheter heart valve midframe underexpansion following transcatheter aortic valve replacement are not well understood.

The aim of this study was to evaluate midframe underexpansion among patients treated with the self-expanding ACURATE neo2 device.

This retrospective analysis included 604 patients (median age 82 years; Q1-Q3: 78-85 years; 61.4% women) from 2 European high-volume centers. Midframe underexpansion was assessed on postimplantation fluoroscopic images and defined as nonparallelism of commissure posts. The primary endpoint was a composite of all-cause mortality, stroke, or rehospitalization at 1 year.

Midframe underexpansion was identified in 13.9% of patients (84 of 604) and was associated with higher rates of the primary endpoint (33 of 84 [39.3%; 95% CI: 28.8%-50.5%] vs 54 of 520 [10.4%; 95% CI: 7.9%-13.3%]; P < 0.001) and each of its components. Furthermore, midframe underexpansion was independently associated with 1-year all-cause mortality (adjusted HR: 4.07; 95% CI: 2.26-7.33; P < 0.001). The only independent predictor of midframe underexpansion was the absence of postdilatation (adjusted OR: 5.76; 95% CI: 2.60-12.77; P < 0.001). Postdilatation significantly decreased the rate and extent of midframe underexpansion.

In this European cohort of ACURATE neo2 recipients, midframe underexpansion occurred in a minor proportion and was associated with poorer clinical outcomes through 1 year. Postdilatation effectively reduced the rate and extent of midframe underexpansion.