Best Degree of Oversizing Varies by TAVR Device

Different degrees of oversizing result in varying outcomes between balloon-expandable and self-expanding TAVR devices, shows an observational study published online April 2, 2015, ahead of print in Catheterization and Cardiovascular Interventions.

Although the findings are “simply hypothesis generating,” study coauthor Jonathon Leipsic, MD, of St. Paul’s Hospital (Vancouver, Canada), told TCTMD in an email, they “should at least make operators pause and think about which device may be suited for a given patient’s anatomy and annular geometry.”

Dr. Leipsic and colleagues looked at 368 patients treated at 3 experienced TAVR centers who had undergone 3-dimensional multidetector CT to evaluate annulus geometry, including short and long diameter, annulus perimeter, and area. One-year follow-up was available for 78% of patients.

Patients were assigned to 2 groups based on whether their annular size would only allow for:

• Moderate oversizing (n = 190): 5%-20% by area or 2.5%-9.5% by perimeter, described by the researchers as the favorable Sapien XT (Edwards Lifesciences) zone
• Large oversizing (n = 178): 20.1%-35% by area or 9.6%-16.2% by perimeter, described as the favorable CoreValve (Medtronic) zone

Within the moderate group, 78 patients received Sapien XT and 112 CoreValve. All those implanted with Sapien XT had devices that were oversized moderately, but among the CoreValve recipients, only 15.2% had moderate oversizing and 84.8% had severe oversizing (> 35% by area or > 16.2% by perimeter).

Within the large group, 88 received Sapien XT and 90 CoreValve. All those implanted with CoreValve had large device oversizing, whereas among Sapien XT recipients, only 46.6% had devices that were largely oversized and 53.4% were mildly oversized (< 5% by area or < 2.5% by perimeter).

Differences in Dilatation, Annular Rupture, Major Stroke

Patients in the moderate oversizing group had similar baseline characteristics, irrespective of whether they received Sapien XT or CoreValve. Those in the large oversizing group had a higher mean Society of Thoracic Surgeon score with Sapien XT than with CoreValve (6.7 vs 5.0; P = .002) as well as greater prevalence of chronic renal insufficiency (44.3% vs 18.9%; P < .001).

Most procedural characteristics and clinical outcomes were similar between the 2 device types within the moderate and large oversizing groups. Notably, there were no differences related to the degree of paravalvular leakage.

However, with moderate oversizing, CoreValve procedures were more likely to involve postballoon dilatation and resulted in higher rates of major stroke and the need for pacemaker implantation by 30 days. With large oversizing, Sapien XT cases carried higher risks of annular rupture, conversion to surgery, and acute kidney injury but—as in the moderate group—had a reduced need for pacemaker implantation at 30 days (tables 1 and 2).

 

 

 

“Optimal clinical performance of CoreValve and Sapien XT appears to be reached with different degrees of oversizing,” the researchers conclude. “Certain annular sizes that allow for only moderate or large oversizing, but not both, appear to benefit from a device-specific approach.”

Finding the Best Fit

Dr. Leipsic said the current study is just a starting point. “We need to continue to investigate and learn how to optimally treat each patient now with TAVR,” he noted. “With more devices available and growing experience, we have the opportunity to potentially individualize and optimize device selection.”

Appropriate oversizing, Dr. Leipsic added, can “help ensure the best clinical outcomes possible.”

Today’s clinicians have many resources at their disposal but also face challenges, he explained. “In the early days of TAVR, there were limited devices and limited sizes, thereby limiting the importance of preprocedural imaging. Now, with more [transcatheter heart valve] sizes and next-generation devices, the decisions are much more complicated and need to be taken in the context of many patient-specific factors.”

Study Provides Clarity While Reinforcing Current Practice

In an email with TCTMD, Isaac George, MD, of Columbia University Medical Center (New York, NY), praised the study as being “very informative.

“The sizing algorithms have been proposed before in the past but [their validation] is an important step in achieving better procedural outcomes,” he continued. “[The current study] reinforces our current practice for oversizing but also provides key information about how the performance of the Sapien XT and CoreValve valves [changes] at different sizing. This information could potentially be useful for patients who possess anatomic limitations for oversizing, which can thus guide the choice of valve.”

As the array of devices expands, it will be important to understand advantages and disadvantages, the ramifications of sizing, and the profile for each valve, Dr. George said, adding, “Having the ability to use multiple valves will only enhance our experience.”

While these data are a “good start,” he noted, more rigorous study of sizing will be provided by the PARTNER II and SURTAVI trials.

 

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Source:
Dvir D, Webb JG, Piazza N, et al. Multicenter evaluation of transcatheter aortic valve replacement using either Sapien XT or CoreValve: degree of device oversizing by computed-tomography and clinical outcomes. Catheter Cardiovasc Interv. 2015;Epub ahead of print.

Disclosures:

• Dr. Leipsic reports consulting for and serving on the advisory board of Edwards Lifesciences.
• Dr. George reports no relevant conflicts of interest. 

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