Feasibility of transcatheter aortic valve replacement in low-risk patients with symptomatic severe aortic stenosis: Rationale and design of the Low Risk TAVR (LRT) study.

BACKGROUND

Safety and effectiveness of transcatheter aortic valve replacement (TAVR) in low-risk patients with symptomatic severe aortic stenosis have not yet been established.

HYPOTHESIS

Transcatheter aortic valve replacement is feasible in patients with symptomatic severe aortic stenosis and low risk for surgical aortic valve replacement.

DESIGN

The LRT study is the first US Food and Drug Administration-approved Investigational Device Exemption prospective multicenter feasibility trial of TAVR in low-risk patients. Patients determined to be low risk by the Heart Team will be enrolled to undergo TAVR with a commercially available balloon-expandable or self-expandable device. A propensity score-matched, site-specific cohort of historical surgical aortic valve replacement patients will serve as a control group treated during the site's enrollment period or within the prior 3 years. Low-risk patients with symptomatic bicuspid aortic stenosis undergoing TAVR will be enrolled into a separate registry arm. All TAVR patients will undergo 4-dimensional contrast-enhanced cardiac computed tomography 4-6 weeks after implantation to assess for subclinical leaflet thrombosis and will be followed up clinically for 5 years with yearly echocardiography to monitor prosthesis function.

SUMMARY

The LRT study will test feasibility of TAVR in low-risk patients with symptomatic severe aortic stenosis in the United States with either tricuspid or bicuspid native aortic valves. Enrollment commenced in 2016 and results are expected in 2018.