Incidence, Mechanisms, and Predictors of Mean Systolic Gradients ≥20 mm Hg after Transcatheter Aortic Valve Implantation

Abstract

There is a significant increase in transvalvular gradients after transcatheter aortic valve implantation (TAVI) in some patients; however, mechanisms underlying the greater than expected gradients are unknown. We sought to determine the incidence and mechanisms of greater than expected gradients post-TAVI. A total of 424 patients who underwent TAVI at our institution between November 2008 and August 2015 and had at least 1 follow-up echocardiogram were included in the study. Greater than expected gradients were defined as mean systolic Doppler gradients ≥20 mm Hg. The primary end-point was incidence and mechanisms of mean systolic Doppler gradients ≥20 mm Hg. A total of 36 (8%) patients had mean systolic Doppler gradients ≥20 mm Hg. The mechanisms of mean systolic Doppler gradients ≥20 mm Hg were: patient prosthesis mismatch in 15 (42%) patients, high cardiac output in 13 (36%), prosthetic and periprosthetic regurgitation in 11 (31%), stenosis in 5 (14%), and multiple mechanisms in 8 (22%). Patients with mean systolic Doppler gradients ≥20 mm Hg had higher cardiac re-hospitalization rate, but no difference in mortality or major cardiovascular events when compared with the normal gradient group. Smaller prosthetic valve size (p <0.0001) and larger body mass index (p = 0.02) were associated with mean systolic Doppler gradients ≥20 mm Hg; warfarin therapy at discharge had no effect on gradients. In conclusion, about 8% patients had mean systolic Doppler gradients ≥20 mm Hg following TAVI, and patient-prosthesis mismatch was the most common mechanism. The mean systolic Doppler gradients ≥20 mm Hg after TAVI are not benign and warrant careful surveillance.