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Expanding the largest Sapien 3 (S3) transcatheter aortic valve replacement (TAVR) valve beyond the recommended range in patients with extra large aortic annuli appeared safe in a multicenter report.

Overexpansion of the device frame in 74 patients had 100% procedural success without annular rupture or coronary obstruction, reported a group led by Gilbert Tang, MD, MBA, of Mount Sinai Medical Center in New York City, online in.

At 30 days, rates of mild, moderate, and severe paravalvular leak were 22.3%, 6.9%, and 0%, respectively.

The investigators called these "acceptable" paravalvular leak rates for a population with annular areas averaging 721 mm² (average diameter therefore exceeding 30 mm). The largest S3 valve, at 29 mm, maxes out a recommended annular area of 683 mm².

Although another option is the even-larger 34-mm CoreValve Evolut R device approved for mean annular diameters up to 30 mm, the authors pointed out that 88% of their study group would have still been outside manufacturer recommendations for that valve.

Mild-or-greater paravalvular leak was associated with larger maximum annular and left ventricular outflow tract (LVOT) diameters, a larger LVOT area and perimeter, an LVOT exceeding the annular area, and high annular eccentricity.

New left bundle branch block was seen in 17% of patients, 6.3% requiring a new permanent pacemaker. By 30 days, there were two deaths, one stroke, and two major vascular complications.

"Our overall permanent pacemaker rate of 6.3% was lower than those reported in the S3 clinical trials," Tang's group also commented. "This could be due to valve undersizing to annulus and LVOT in our patients, reducing the contact between the S3 frame and interventricular septum, with lower risk of new conduction abnormalities."

Their experience consisted of 74 patients at intermediate-or-greater surgical risk getting TAVR with the S3 valve despite their extremely large annuli. Data were sourced from the U.S. Transcatheter Valve Therapy registry from the American College of Cardiology and Society of Thoracic Surgeons.

Procedures took place at 16 centers in 2013-2017. All patients underwent transthoracic echocardiography. Aortic root dimensions were determined at end-systole by multidetector CT in 68, transesophageal echocardiography in four, and cardiac MRI in two patients.

Operators by and large opted for the transfemoral TAVR with a 32% rate of post-dilatation (mostly with final balloon overfilling).

Even though there are "only few" patients with anatomy that is too large for TAVR, "[t]here are many reasons why the results of the current study are so important for the community," according to an by Julinda Mehilli, MD, and David Jochheim, MD, both of Munich University Clinic in Germany.

"Tang and colleagues should be congratulated for highlighting the technological possibilities of the third generation balloon-expandable prosthesis in larger annuli beyond manufacturers recommendations. It offers us as operators more certainty in these challenging subset of patients and gives us some important insights of the prosthesis performance under these exceptional conditions."

However, the study was too short to place the results in the context of prosthetic valve deterioration and longer-term hemodynamic performance, the editorialists said. Moreover, the study couldn't clarify the true prevalence of patients with extra large annuli.

Other limitations are that they had a small sample to work with and that annular dimensions and paravalvular leakage were not assessed with core lab adjudication, Tang's group acknowledged.