Registry Study Explores Potential for TAVR in Low-, Intermediate-Risk Patients

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Key Points:
  • TAVR a potential option in low- to intermediate-risk patients with severe aortic stenosis
  • Careful heart team assessment crucial to determining appropriate candidates
  • Clinicians awaiting randomized clinical trial results on lower-risk groups

By Heather Lindsey
Monday, April 01, 2013

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With the input of a heart team, patients with severe aortic stenosis who are deemed to be at low or intermediate surgical risk may still be candidates for transcatheter aortic valve replacement (TAVR), according to a study published online March 13, 2013, ahead of print in the European Heart Journal. The procedure is currently approved in the United States for inoperable or high-risk patients.

Peter Wenaweser, MD, of Bern University Hospital (Bern, Switzerland), and colleagues prospectively analyzed outcomes of 389 consecutive subjects with symptomatic severe aortic stenosis enrolled in the Bern TAVI Registry between August 2007 and October 2011. The mean patient age was 82.5 ± 5.8 years, and 42% were men.

Key Role for Heart Team

A ‘heart team’ consisting of interventional cardiologists and cardiovascular surgeons evaluated potential candidates based on their clinical history and status, as well as a dedicated geriatric assessment. Accepted patients were stratified into 3 surgical risk groups based on the Society of Thoracic Surgeons (STS) score: low (<3; n = 41); intermediate (3 to 8; n = 254); and high (>8; n = 94).

At 30 days, all-cause mortality was highest in the high-risk group compared with the intermediate- and low-risk groups (14.9% vs. 3.9% vs. 2.4%; P = 0.001), driven mainly by increased cardiovascular mortality (12.9% vs. 3.2% vs. 0; P = 0.003). Major adverse events including acute renal failure (8.5% vs. 2.8% vs. 0; P = 0.03) and major access site complications (12.8% vs. 7.1% vs. 0; P = 0.03) were also more frequent in high-risk patients. No differences were seen among groups with respect to cerebrovascular accident, MI, and bleeding complications.

At 1 year, between-group differences in risk were seen for all-cause death, cardiovascular death, and the composite of all-cause death, stroke, or MI, whereas risks were similar for major stroke and MI (table 1).

Table 1. Outcomes at 1 Year: Comparison by Risk Group

 

Low vs. Intermediate Risk
RR (95% CI)

Intermediate vs. High Risk
RR (95% CI)

Overall P Value

All-Cause Death

0.27 (0.09-0.77)

0.41 (0.24-0.67)

0.0003

Cardiovascular Death

0.16 (0.04-0.70)

0.35 (0.19-0.62)

0.0001

Major Stroke

2.00 (0.36-11.11)

1.07 (0.29-3.99)

0.42

MI

0.56 (0.05-6.31)

0.12 (0.01-1.04)

0.023

All-Cause Death, Stroke, or MI

0.48 (0.22-1.06)

0.43 (0.27-0.69)

0.0041


In an analysis of 308 patients who underwent TAVR via transfemoral access, those considered low-risk (n = 33) had no instances of death and experienced no cases of cerebrovascular accident, MI, or acute renal failure at 30 days. Intermediate-risk patients had a 30-day all-cause mortality rate of 3.5%. At 1 year, there was a linear increase in all-cause and cardiovascular death from lower to higher risk (9.3% vs. 14.8% vs. 32.3%; P = 0.0013).

TAVR “is not limited to inoperable or STS-defined high-risk patients and should be guided by the decision of an interdisciplinary heart team,” the study authors conclude. “Compared with patients at calculated risk, well-selected patients with STS-defined intermediate or low risk appear to have favorable clinical outcomes.”

When to Consider TAVR

In an e-mail communication with TCTMD, Dr. Wenaweser said that TAVR should first be considered in patients usuitable for surgery due to high-risk factors not reflected in the usually applied risk scores.

Patients deemed at intermediate risk based on their STS score and heart team assessment are candidates for randomized clinical trials evaluating surgery vs. TAVR, explained Dr. Wenaweser. The SURTAVI and the PARTNER 2 trials are currently recruiting patients to address the question of the range of risk appropriate for TAVR, he reported.

William M. Suh, MD of the David Geffen School of Medicine at UCLA (Los Angeles, CA), told TCTMD in an e-mail communication that US physicians “are eagerly awaiting completion of these trials so that we might be able to expand TAVR to intermediate-risk patients, assuming that these trials will show similar positive results as [the current] study.”

In the meantime, said Philippe Généreux, MD, of Columbia University Medical Center (New York, NY), “it’s encouraging to see a lower rate of complications in lower-risk patients with this new treatment option.” With upcoming TAVR devices being even smaller and designed specifically to address issues such as stroke and paravalvular leakage, he noted to TCTMD in a telephone interview, “we are expecting significantly [lower] complication rates.”

STS Score Has Limitations

Because all patients in the study were judged to be at increased risk for surgery in particular, “patient selection for [TAVR] should not only be based upon surgical risk scores,” said Dr. Wenaweser. Meticulous patient screening by the heart team is crucial to obtaining the best possible clinical result in the individual patient, he observed.

Several important factors contributing to an increased risk for surgery are not reflected in the EuroScore, he noted, adding that the STS score seems most appropriately geared toward TAVR candidates.

Nonetheless, Dr. Généreux said, the STS score does not capture all the needed variables for risk stratification. “We are in need of a new tool to assess [patient] risk, but it still needs to always be used [in conjunction] with the clinical judgment of the heart team,” he concluded.

Study Details

High-risk patients were older and had a lower BMI compared with those in the intermediate- and low-risk groups. High-risk patients were also more likely to have diabetes, arterial hypertension, peripheral vascular disease, chronic obstructive pulmonary disease, and renal failure. In addition, LVEF was lower in the high-risk group.

 


Source:
Wenaweser P, Strortecky S, Schwander S, et al. Clinical outcomes of patients with estimated low or intermediate surgical risk undergoing transcatheter aortic valve implantation. Eur Heart J. 2013;Epub ahead of print

 

Disclosures:

  • Dr. Wenaweser reports receiving honoraria from Edwards Lifesciences and Medtronic.
  • Drs. Suh and Généreux report no relevant conflicts of interest.

 

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