麻豆传媒

WASHINGTON -- Transcatheter aortic valve replacement (TAVR) can be safe for low-risk patients with severe aortic stenosis, according to interim results of a study presented here.

None of the first 125 enrolled patients in the Low Risk TAVR study died within 30 days of the procedure, reported Ron Waksman, MD, of MedStar Heart & Vascular Institute in Washington, D.C., at the annual conference.

Notably, these patients went into TAVR with a Society of Thoracic Surgeons (STS) score averaging just 1.9% and had a mean age of 74.6 years -- the youngest and lowest-risk TAVR cohort yet in a reported study, Waksman said. The guidelines suggest surgical aortic valve replacement (SAVR) for this group.

During their stays in the hospital, 3.2% of patients had major bleeds, 0.8% moderate-to-severe paravalvular leaks, and 4.0% a need for a new pacemaker. None suffered a stroke.

Even so, subclinical leaflet thrombosis was present in this cohort by just 30 days: 9.3% had hypo-attenuating leaflet thickening that reduced leaflet motion. Taking oral anticoagulation instead of antiplatelet therapy was tied to fewer cases of subclinical leaflet thrombosis.

Session panelist Neil Moat, MBBS, of Royal Brompton Hospital in London, said he found it worrying that there was a signal of structural valve failure at a time when TAVR is moving toward younger, lower-risk patients.

"This is one of the first descriptions of a prospective study of TAVR in low-risk patients," commented David Cohen, MD, of Beth Israel Deaconess Medical Center and Harvard Medical School in Boston. "It is important to remember that the clinical significance of these findings remains completely unknown at present."

"That said, the results are not particularly surprising since we already knew from Sapien 3 intermediate risk trials that TAVR with current generation devices can be done at very low risk even in intermediate-risk patients. The fact that the results are at least as good in low risk patients is therefore not unexpected," Cohen told 麻豆传媒.

Before TAVR becomes widely adopted for lower and lower risk patients, clinicians have to understand the long-term durability of these valves, he said, noting that most of the low-risk studies that are currently underway are planned to continue to follow the patients for at least 10 years.

The Low Risk TAVR study is a propensity-matched study, but only one arm was presented in the interim analysis at CRT.

Participating sites were mostly low-volume centers with little TAVR experience. They generally performed fewer than 150 cases a year, according to Waksman.

In this study, operators exclusively used Sapien 3 and CoreValve devices. During these procedures, TAVR recipients largely got conscious sedation. Transfemoral access accounted for all cases.

Craig Smith, MD, of New York-Presbyterian/Columbia University Medical Center, suggested that the sample size is not large enough to draw any meaningful conclusions.

The study's full dataset including a propensity-matched comparison with SAVR is to be reported within the year, Waksman said.

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