PARTNER II Cohort B Demonstrates Safety, Efficacy of Lower Profile TAVR Device

SAN FRANCISCO, CA—New data from the PARTNER II Cohort B study show that a lower profile iteration of a valve widely used in transcatheter aortic valve replacement (TAVR) is at least as safe and effective as an older-generation device. The results were presented March 10, 2013, at the American College of Cardiology/i2 Scientific Session.

For Placement of AoRTic traNscathetER valve II (PARTNER II) Cohort B, Martin B. Leon, MD, of Columbia University Medical Center, (New York, NY), and colleagues enrolled 560 patients with severe aortic stenosis who were judged unsuitable candidates for surgery at 28 US centers. Patients were enrolled from April 2011 through February 2012 and were randomly assigned to undergo TAVR using either the standard Edwards Sapien aortic valve system (n = 276; Edwards Lifesciences, Irvine, CA) or the newer Sapien XT (n = 284).

In comparison with the stainless-steel construction of the original Sapien, the cobalt-chromium XT includes enhancements to the valve support frame, valve leaflet geometry, and delivery system. It also utilizes a smaller sheath size (18Fr vs. 22Fr) to accommodate a smaller minimum vessel diameter.

Similar Low Mortality, Stroke

Patients in both groups had multiple comorbid characteristics including COPD, dementia, liver disease, porcelain aorta, and hostile chest.

Sapien XT was associated with a reduction in anesthesia time compared with the original device (197 ± 60.8 minutes vs. 212 ± 75.7 minutes; P = 0.02). It also was associated with a reduction in need for multiple valves (1.1% vs. 3.7%; P = 0.05), aborted procedures (0.7% vs. 3.0%; P = 0.06) and need for intra-aortic balloon pump during the procedure (0.4% vs. 2.2%; P = 0.06).

At 30 days, the rate of all-cause death was lower in the Sapien XT group, although the difference did not reach statistical significance. Disabling stroke was low in both groups and the rate of rehospitalizations and rates of the combined endpoint (all-cause death, disabling stroke, and rehospitalization) also were similar (table 1).

Table 1. Primary Endpoint Events at 30 Days

 

 
The reintervention rate was 2.9% for Sapien vs. 2.5% for Sapien XT (P = 0.75) and the need for new permanent pacemaker was 5.9% and 6.4%, respectively (P = 0.78).

Compared with the original device, Sapien XT was associated with improved vascular and bleeding events at 30 days, reducing major vascular complications from 15.5% to 9.6% (P = 0.04) and disabling bleeding from 12.6% to 7.8% (P = 0.06). Looking more closely at vascular complication categories, there were significant reductions in perforations (P = 0.003) as well as dissections (P = 0.03) with the XT.

Kaplan-Meier analysis of all-cause mortality at 12 months showed a nonsignificant difference between the Sapien and XT (log-rank P = 0.706). Rates of disabling stroke or rehospitalizations also were similar, but there was a trend toward lower rates of the triple endpoint (death/stroke/rehospitalization) with the XT (P for non-inferiority = 0.0034).

Both devices improved NYHA class, with more than 80% of patients in class I/II at 12 months. Echocardiographic findings indicated a similar increase in aortic valve area, and mean and peak gradients that persisted from 30 days to 1 year. There was a slight difference in the frequency of moderate or severe paravalvular aortic regurgitation with the XT that did not reach statistical significance (P = 0.12).

Learning from Experience

According to Dr. Leon, the new lower-profile device “represents a worthwhile advance with incremental clinical value and is the preferred balloon-expandable [transcatheter heart valve] system.”

Panel co-chair David R. Holmes Jr., MD, of the Mayo Clinic (Rochester, MN), inquired whether the definition of ‘inoperable aortic stenosis’ had changed since the original PARTNER I study.

But in response, Dr. Leon said the demographics between PARTNER I and PARTNER II are “remarkably similar” with the exception of a very slight difference in STS scores and exclusion of patients with extreme comorbidities that have been shown to be futile for TAVR.

“I think it’s more than just a different population,” Dr. Leon replied. “I think there may be a lot of experience [on the part] of operators that may have translated into better overall outcomes.”

Jeffrey J. Popma, MD, of Beth Israel Deaconess Medical Center (Boston, MA), commented that the low stroke rates in both device groups were “reassuring” and questioned what factors may be involved in progressively lowering the stroke rate in the TAVR population.

Dr. Leon said PARTNER II differs from the original trial in that not only are the stroke definitions different, but the oversight/adjudication is as well.

“We do think we’ve learned something with regard to stroke,” Dr. Leon said, adding that a combination of patient selection, device improvement and postprocedural pharmacotherapy have contributed “in aggregate” to the improvement in the stroke rate.

Study Details

Patients had a mean age of 84 years, more than 96% were classified as having NYHA Class III or IV heart failure, and 59% were assessed as clinically frail.

Note: Dr. Leon is a faculty member of the Cardiovascular Research Foundation, which owns and operates TCTMD.

 

 

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Source:Leon MB. A randomized evaluation of the SAPIEN XT transcatheter valve system in patients with aortic stenosis who are not candidates for surgery: PARTNER 2, cohort B outcomes. Presented at: American College of Cardiology Annual Scientific Session; March 10, 2013; San Francisco, CA.

 

 

 

 

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