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CT-Based Annulus Sizing Reduces Regurgitation After TAVR

By Yael L. Maxwell

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Use of a multidetector computed tomography (CT) to select the optimal prosthesis size for transcatheter aortic valve replacement (TAVR) reduces paravalvular regurgitation, according to a prospective study published online May 22, 2013, ahead of print in the Journal of the American College of Cardiology.

Researchers led by Jonathon Leipsic, MD, of St. Paul’s Hospital (Vancouver, Canada), looked at 266 consecutive patients with high-risk or inoperable severe aortic stenosis being evaluated for TAVR at 3 Canadian hospitals and 1 European center. Half of the cohort (n = 133) underwent preprocedural multidetector CT imaging; an algorithm using the CT results was used to recommend balloon-expandable valve size, with the goal of modest annulus area oversizing between 5% and 10%. In the control group (n = 133), valve sizing was based solely on integration of echocardiographic and angiographic measurements.

CT Makes a Difference

More than mild paravalvular regurgitation (primary endpoint) was less common in the CT group as in the control group. The CT arm also fared better with regard to the secondary combined endpoint (in-hospital mortality, aortic annular rupture, and severe paravalvular regurgitation), driven by a lower incidence of severe regurgitation. No difference was seen between the groups in rates of in-hospital mortality or aortic annular rupture (table 1).

Table 1. Procedural Outcomes

 

CT
(n = 133)

No CT
(n = 133)

P Value

> Mild Paravalvular Regurgitation

5.3%

12.8%

0.032

Secondary Combined Endpoint

3.8%

11.3%

0.02

In-Hospital Mortality

3.8%

6.8%

0.272

Aortic Annular Rupture

0.8%

0.8%

1.0

Severe Paravalvular Regurgitation

0

4.5%

0.032


Overall, the higher the degree of annulus area oversizing, the lower the level of paravalvular regurgitation: 16.4% oversizing was associated with no regurgitation, 10.4% with mild regurgitation, and 0.5% with more than mild regurgitation (P = 0.001).

As-treated analysis showed that, in the control group, rates of both the primary endpoint (9.4% vs. 5.6%; P = 0.111) and secondary combined endpoint (9.4% vs. 4.7%; P = 0.149) were nearly twice as high as in the CT cohort.

Common Definitions Needed

As TAVR becomes more widely used in lower-risk patients, complications like paravalvular regurgitation and aortic root injury are bound to be more common, Dr. Leipsic and colleagues observe. “The strength of our study manifests in a clear, reproducible, and readily available sizing algorithm,” they write, adding that 3-D aortic assessment and annular area sizing should be considered in all TAVR patients.

Ted Feldman, MD, of Evanston Hospital (Evanston, IL), told TCTMD in a telephone interview, “There’s a rapidly growing consensus that echo is a much less 3-D way to assess annular size or [select] prosthesis size, and the improved clinical outcomes [shown in the study] in terms of both paravalvular leak and total events are very impressive.”

He pointed out, however, that the operator did not follow the CT recommendations in 20% of the cases where there were no paravalvular leaks and no annular ruptures. “That reinforces the conclusion . . . that you don’t just take 1 measurement. CT is an important supplement to the judgment of valve size,” Dr. Feldman stressed.

Other elements including the left ventricular outflow tract and sinus of Valsalva dimensions “have to be integrated into the . . . decision-making process,” he continued.

In the future, “we will see more comprehensive imaging analyses” that go hand-in-hand with the more complex software packages being used and developed, Dr. Feldman added. For this to happen, “we need [to do] a lot of work to understand better what the ideal methods are, and we should probably have common definitions so that the various software vendors and different types of workstations can all report the same measurement. We’ve got decades of definitions in echo so that the measurements are widely understood, [but] we’re just at the beginning of this journey with CT.”

Study Details

All patients were implanted with the Sapien XT device (Edwards Lifesciences, Irvine, CA); available valve sizes were 20, 23, 26, and 29 mm in diameter. Patients in the control group had higher Society of Thoracic Surgeons scores, while patients in the study arm more often received underfilled deployment balloons and were implanted with the largest available prosthesis.

 

Source:
Binder RK, Webb JG, Wilson AB, et al. The impact of integration of a multidetector computed tomography annulus area sizing algorithm on outcomes of transcatheter aortic valve replacement: A prospective, multicenter, controlled trial. J Am Coll Cardiol. 2013;Epub ahead of print.

 

 

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Disclosures
  • Dr. Leipsic reports serving as a consultant to Edwards Lifesciences.
  • Dr. Feldman reports serving as a consultant to Abbott, Boston Scientific, and Edwards Lifesciences.

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