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.

TAVR in Low-Risk Patients: 1-Year Results From the LRT Trial.

OBJECTIVES: This study sought to evaluate clinical outcomes and transcatheter heart valve hemodynamics at 1 year after transcatheter aortic valve replacement (TAVR) in low-risk patients. BACKGROUND: Early results from the LRT (Low Risk TAVR) trial demonstrated that TAVR is safe in patients with symptomatic severe aortic stenosis who are at low risk for surgical valve replacement. METHODS: The LRT trial was an investigator-initiated, prospective, multicenter study and was the first Food and Drug Administration-approved Investigational Device Exemption trial to evaluate feasibility of TAVR in low-risk patients. The primary endpoint was all-cause mortality at 30 days. Secondary endpoints included clinical outcomes and valve hemodynamics at 1 year. RESULTS: The LRT trial enrolled 200 low-risk patients with symptomatic severe AS to undergo TAVR at 11 centers. Mean age was 73.6 years and 61.5% were men. At 30 days, there was zero mortality, zero disabling stroke, and low permanent pacemaker implantation rate (5.0%). At 1-year follow-up, mortality was 3.0%, stroke rate was 2.1%, and permanent pacemaker implantation rate was 7.3%. Two (1.0%) subjects underwent surgical reintervention for endocarditis. Of the 14% of TAVR subjects who had evidence of hypoattenuated leaflet thickening at 30 days, there was no impact on valve hemodynamics at 1 year, but the stroke rate was numerically higher (3.8% vs. 1.9%; p = 0.53). CONCLUSIONS: TAVR in low-risk patients with symptomatic severe aortic stenosis appears to be safe at 1 year. Hypoattenuated leaflet thickening, observed in a minority of TAVR patients at 30 days, did not have an impact on valve hemodynamics in the longer term.

Transcatheter Aortic Valve Replacement in Low-Risk Patients With Symptomatic Severe Aortic Stenosis.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) is now the standard of care for patients with symptomatic severe aortic stenosis who are extreme, high, or intermediate risk for surgical aortic valve replacement (SAVR). OBJECTIVES: The authors sought to evaluate TAVR in a prospective multicenter trial involving low-risk patients. METHODS: The Low Risk TAVR (Feasibility of Transcatheter Aortic Valve Replacement in Low-Risk Patients With Symptomatic, Severe Aortic Stenosis) trial was the first U.S. Food and Drug Administration-approved Investigational Device Exemption trial to enroll in the United States. This investigator-led trial was a prospective, multicenter, unblinded, comparison to historical controls from the Society of Thoracic Surgeons (STS) database. The primary endpoint was all-cause mortality at 30 days. RESULTS: The authors enrolled 200 low-risk patients with symptomatic severe aortic stenosis at 11 centers to undergo TAVR. The authors compared outcomes with an inverse probability weighting-adjusted control cohort of 719 patients who underwent SAVR at the same institutions using the STS database. At 30 days, there was zero all-cause mortality in the TAVR group versus 1.7% mortality in the SAVR group. There was zero in-hospital stroke rate in the TAVR group versus 0.6% stroke in the SAVR group. Permanent pacemaker implantation rates were similar between TAVR and SAVR (5.0% vs. 4.5%). The rates of new-onset atrial fibrillation (3.0%) and length of stay (2.0 ± 1.1 days) were low in the TAVR group. One patient (0.5%) in the TAVR group had >mild paravalvular leak at 30 days. Fourteen percent of TAVR patients had evidence of subclinical leaflet thrombosis at 30 days. CONCLUSIONS: TAVR is safe in low-risk patients with symptomatic severe aortic stenosis, with low procedural complication rates, short hospital length of stay, zero mortality, and zero disabling stroke at 30 days. Subclinical leaflet thrombosis was observed in a minority of TAVR patients at 30 days. (Feasibility of Transcatheter Aortic Valve Replacement in Low-Risk Patients With Symptomatic, Severe Aortic Stenosis [Low Risk TAVR; NCT02628899).

Polymer-free Biolimus A9-coated stents in the treatment of de novo coronary lesions with short DAPT: 9-month angiographic and clinical follow-up of the prospective, multicenter BioFreedom USA clinical trial.

BACKGROUND: BioFreedom is a polymer- and carrier-free drug-coated stent that delivers Biolimus A9 to the vessel wall. Our purpose was to evaluate the efficacy and safety of this DCS in patients with short-duration dual antiplatelet therapy. METHODS: The BioFreedom US IDE feasibility trial was a single-arm, open-label, prospective study of patients requiring stenting of de novo lesions. Patients received 3 months of DAPT, repeat angiography at 9 months, and clinical follow-up at multiple intervals. A subgroup also underwent intravascular ultrasound (IVUS) interrogation. The primary safety end point was major adverse cardiac events, defined as a composite of cardiac death, myocardial infarction, target lesion revascularization, or stent thrombosis. The primary efficacy end point, in-stent late lumen loss at 9 months, was compared with a historical control from a first-generation paclitaxel-eluting stent. RESULTS: A total of 72 patients from 10 sites received BioFreedom DCS implanted in 83 de novo lesions. At 9 months, the incidence of composite MACE was 8.4%, and TLR was 1.5%. Short DAPT was safe without occurrence of stent thrombosis. The primary end point of LLL was 0.32±0.53 mm. Paired IVUS analyses comparing postprocedural with 9-month measurements showed low in-stent neointimal volume obstruction (5.39±5.28%) and low neointimal hyperplasia (7.43±8.04 mm3). CONCLUSIONS: This study's angiography and IVUS assessments demonstrated that the BioFreedom DCS has anti-restenotic efficacy similar to first-generation DES. In the absence of concerning safety signals, this DCS should be considered effective and safe for patients who require a shorter duration of DAPT.