LRT Trial: Transcatheter Aortic Valve Replacement In Low Risk Patients with Symptomatic Severe Aortic Stenosis Appears To Be Safe At 1 Year

Fahad Alkhalfan, M.D.
By Fahad Alkhalfan, M.D. on

A study led by Dr. Ronald Waksman showed that in low-risk patients with symptomatic severe aortic stenosis, transcatheter aortic valve replacement (TAVR) appears to be safe at 1 year. This study, which was published in JACC Cardiovascular Interventions, provides evidence to support the use of TAVR in low-risk patients.

TAVR is an established treatment option for patients with severe aortic stenosis who are at intermediate or high risk for complications as a result of surgical aortic valve replacement (SAVR). While there have been many trials that assessed the safety and efficacy of TAVR in low-risk patients, the Low Risk TAVR (LRT) trial was one of the first FDA approved trials in the United States. The investigators aimed to present both the 1-year clinical outcomes and hemodynamics un the TAVR cohort of the LRT trial.

“LRT is the first prospective trial to report 1-year outcomes of TAVR in low-risk patients in the United States. It is to be expected that procedural outcomes in low-risk patients with symptomatic severe AS should be better than in intermediate- or high-risk patients. The LRT trial confirmed this with excellent in-hospital and 30-day TAVR results that were maintained at 1 year, with low mortality and stroke rates.” – Dr. Ronald Waksman, M.D.

The LRT trial was a prospective multicenter center trial that evaluated the feasibility of TAVR in low-risk patients. The primary endpoint was all-cause mortality at 30 days. Secondary endpoints included both clinical outcomes and hemodynamics at 1 year. Secondary outcomes included stroke, paravalvular regurgitation, permanent pacemaker implantation, and need for intervention at 1 year.

A total of 200 patients were enrolled in the LRT trial. As compared to other trials, patients in the LRT trial were younger, had a lower predicted risk of mortality due to surgery, and had fewer comorbidities. There were no deaths or disabling strokes by 30 days. At 1 year follow up, mortality was 3.0%, stroke rate was 2.1%, and permanent pacemaker implantation rate was 7.3%. Two patients (1.0%) underwent surgical reintervention for endocarditis. Transcatheter heart valve hemodynamics were deemed to be excellent at 30 days and the results were consistent at 1 year. Mean left ventricular ejection fraction was 63.1 ± 8.3%. Hypoattenuated leaflet thickening (HALT) was noted in 14% of patients by 30 days. However, this was only noted in the patients who received the balloon expandable valves. While there was a higher rate of stroke in patients with HALT by 1 year, this was not significant (3.8% vs 1.9%, p = 0.53).

LRT was the first prospective trial to report 1 year outcomes in low risk patients who received TAVR. The trial showed that there were excellent outcomes at 30 days and 1 year. The excellent results of TAVR in low-risk patients is consistent with other previously published studies. When discussing why TAVR has yet to be implemented in low-risk patients, Dr. Waksman wrote, “With these excellent results, the argument against dissemination of TAVR to low-risk patients is primarily based on the lack of long-term durability data of transcatheter heart valves. All bioprostheses—surgical and transcatheter—have a finite lifespan before their leaflets inevitably degenerate, leading to stenosis or regurgitation. From the PARTNER 1 trial, 5year echocardiography data in surviving subjects have revealed no signal for premature structural valve deterioration. The paucity of data regarding durability of transcatheter heart valves is often underscored as a weakness of TAVR, but the data for surgical bioprostheses are also sparse.” However, the investigators noted that more data is required to determine whether HALT, which occurred in this study, is associated with an increased risk of stroke.

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