VARC Definitions Help TAVR Studies Speak Common Language

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Definitions governing outcomes after transcatheter aortic valve replacement (TAVR) proposed by the Valve Academic Research Consortium (VARC) in January 2011 have been used successfully and are being rapidly adopted as the new standard by the physician community, according to a paper published online, April 11, 2012, ahead of print in the Journal of the American College of Cardiology.

Philippe Généreux, MD, of Columbia University Medical Center (New York, NY), and colleagues conducted a comprehensive search of multiple electronic databases for TAVR studies reporting at least 1 outcome using VARC definitions from January 2011 through October 2011. They identified 16 studies including 3,519 patients.

Consistency in Outcomes

Combining these studies, the investigators calculated pooled estimate rates of VARC-determined outcomes (table 1).

Table 1. Pooled Estimate Rates of VARC-Determined Outcomes

 

Range

Pooled Estimate Rate

Device Success

80%-100%

92.1%

All-Cause 30-Day Mortality

1.7%-14.3%

7.8%

MI

0-5.6%

1.1%

Acute Kidney Injury Stage I

3.2%-24.6%

13.3%

Acute Kidney Injury Stage II/III

3.0%-15.0%

7.5%

Life-Threatening Bleeding

7.0%-25.9%

15.6%

Major Vascular Complications

5.0%-23.3%

11.9%

Major Stroke

0.8%-9.0%

3.2%

New Permanent Pacemaker Implantation

3.4%-50.0%

13.9%


The safety composite endpoint was reported at 30 days in 6 studies and ranged from 17.0% to 61.8%, with a pooled estimate rate of 32.7%. At 1 year, the safety composite was reported in 2 studies, with a pooled estimate rate of 71.1%. One-year all-cause mortality and cardiovascular mortality were reported in 7 and 4 studies, respectively, with associated pooled estimate rates of 22.1% (range 15.3%-30.7%) and 14.4% (range 14.3%-19.6%).

When broken down by device type, CoreValve (Medtronic, Minneapolis, MN) was associated with a higher rate of new permanent pacemaker implantation than Sapien (Edwards Lifesciences, Irvine, CA) at 28.9% vs. 4.9% (P < 0.0001).

Order from Chaos

“This study shows that [VARC definitions] have already been incorporated into clinical trials and in the community,” Dr. Généreux told TCTMD in an interview. “The clinical community has already embraced these definitions, and it seems they have become the new standard.”

In a telephone interview with TCTMD, Ted Feldman, MD, of Evanston Hospital (Evanston, IL), said the guidelines have helped correct the chaos that previously existed among clinical trials.

“Without uniform definitions, even defining mortality will differ from one trial to another so that pooling the results is very difficult, and sometimes impossible,” he said. “Worse, sometimes this is done without much meaning. What this report demonstrates is that the adoption of uniform definitions allows for meaningful pooling of outcome results.”

As a clinician, Dr. Feldman said he found the numbers provided in the study helpful in talking to patients about procedural risks and benefits. “I think this paper makes it clear that there is utility to using uniform definitions,” he commented. “It gets everyone speaking a common language.”

An Evolving VARC

However, Dr. Feldman said the missing piece of the puzzle is finding a way to better understand the study populations. Because the 16 studies analyzed all used different selection criteria, it is challenging to match patients “by simple parameters like age or risk calculator scores when there are other selection biases that are very confounded and difficult,” he said.

“I’m not sure that there is an easy solution to that problem,” Dr. Feldman observed. “Propensity matching is “one of the best things we have [but it] still does not eliminate all of the confounding variables.”

Going forward, Dr. Généreux predicted the definitions “will allow you to see a snapshot and a vision of really what’s happening” across different devices, techniques, operators, and sites. The studies included in the analysis were all conducted with first-generation devices, hence the “high” outcome rates seen, he noted.

“This is the first version,” Dr. Généreux emphasized. “So of course there is some improvement to be made. . . . The main goal was to pool all the data to try to validate VARC, but [we also tried] to find all the issues, pitfalls, or [omissions] of the current VARC to suggest what can be improved.”

Study Details

A total of 1,903 Edwards Sapien devices (54.1%) and 1,186 Medtronic CoreValve devices (33.7%) were implanted. The type of device was not clearly reported by authors in 430 patients (12.2%). The 30-day Society of Thoracic Surgeons score and logistic EuroScore were 8.7% and 22.8%, respectively.

 


Source:
Généreux P, Head SJ, Van Mieghem NM, et al. Clinical outcomes after transcatheter aortic valve replacement using Valve Academic Research Consortium definitions. J Am Coll Cardiol. 2012;Epub ahead of print.

 

 

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VARC Definitions Help TAVR Studies Speak Common Language

Definitions governing outcomes after transcatheter aortic valve replacement (TAVR) proposed by the Valve Academic Research Consortium (VARC) in January 2011 have been used successfully and are being rapidly adopted as the new standard by the physician community, according to a
Disclosures
  • Dr. Généreux reports receiving speaker honoraria, consulting fees, and a research grant from Edwards Lifesciences.
  • Dr. Feldman reports serving as a consultant for Abbott Vascular, Boston Scientific, and Edwards Lifesciences.

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