Studies Show Efficacy, Relative Safety of Valve-in-Valve Technique

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Early data on valve-in-valve procedures for failing aortic bioprostheses indicate that the procedure is clinically effective in the majority of patients, although safety and efficacy concerns persist. These include high postprocedural gradients, coronary occlusion, and valve malpositioning, according to a study published online October 10, 2012, ahead of print in Circulation and another study published online October 9, 2012, ahead of print in Circulation: Cardiovascular Interventions.

For the first study, researchers led by Danny Dvir, MD, of Washington Hospital Center (Washington, DC), examined data from 202 patients in the Global Valve-in-Valve Registry, which began in December 2010 and includes 38 centers from Europe, North America, Australia, New Zealand, and the Middle East.

Patients were categorized by primary mechanism of valve failure:

  • Stenosis (42%)
  • Regurgitation (34%)
  • Combined stenosis-regurgitation (24%)

Of these, 124 underwent the valve-in-valve procedure using the CoreValve system (Medtronic, Minneapolis, MN), while 78 received the Sapien or Sapien XT devices (Edwards Lifesciences, Irvine, CA).

Patients included in the trial had between 1 and 4 previous surgical aortic valve replacements (85.6% had 1 surgery). A higher proportion of the Sapien-treated valves were stented devices (as opposed to stentless) compared with CoreValve-treated bioprostheses (87.2% vs. 70.2%; P = 0.005).

High Success, Similar Mortality

Procedural success was achieved in 93.1%. Among the failures, 14 met the registry definition for procedural failure and 83 met the Valve Academic Research Consortium (VARC) definition for device failure. The majority of failures were secondary to elevated postprocedure gradients of moderate degree (mean gradients 20-39 mm Hg). Procedural success according to the registry definition was higher in the CoreValve group than in the Sapien group (96.8% vs. 87.2%; P = 0.009), as was device success according to the VARC definition (64.5% vs. 50%; P = 0.04, respectively).

Median duration of hospital stay was 8 days. Adverse procedural outcomes included initial device malposition in 15.3% and ostial coronary obstruction in 3.5%. Post-procedural valve maximum and mean gradients were 28.4 ± 14.1 mm Hg and 15.9 ± 8.6 mm Hg, respectively, and 95% of patients had less than +1 degree of aortic regurgitation. Overall, the prevalence of elevated post-procedural gradients was higher after Sapien implantation than after CoreValve (40% vs. 21.3%, respectively; P < 0.0001).

At 30 days, the rate of death for the entire cohort was 8.4%, while the rate of major stroke was 2%. There were no differences between the 2 device types for the outcomes of death, major vascular complication, or major stroke (table 1).

Table 1. Thirty-Day Outcomes

 

CoreValve
(n = 124)

Sapien
(n = 78)

P Value

Death

7.3%

10.3%

0.45

Major Vascular Complications

1.6%

6.4%

0.11

Major Stroke

1.6%

2.6%

0.64


The majority of patients (83.7%) had achieved New York Heart Association functional class I/II at 30 days. Significant aortic regurgitation was present in 10 cases (5%). Left ventricular ejection fraction was 51.3 ± 11.8%, a level similar to that measured before the procedure (50.5 ± 12.2; P = 0.62). There was no difference between device groups in the need for a permanent pacemaker implantation (8.9% vs. 5.1%, respectively; P = 0.31).

At 1-year follow-up, the estimated survival rate was 85.8% (95% CI 79.9%-91.6%). Survival did not differ between patients undergoing valve-in-valve procedures with either device.

Promising, But Challenges Remain

In an editorial accompanying the study, E. Murat Tuzcu, MD, Samir R. Kapadia, MD, and Lars G. Svensson, MD, PhD, all of the Cleveland Clinic (Cleveland, OH), say the study “provides us a reality check” by showing both efficacy and ongoing challenges of the new technique.

They point out that since the study does not have a control group, the relative risk and efficacy compared with conventional surgery remains undefined. Additionally, since 28% of patients had a mean transvalvular gradient of greater than 20 mm Hg following TAVR—a proportion that doubled in those with small surgical prostheses (internal diameter < 20 mm)—and high gradients were more common with the Sapien, the findings “represent less than ideal hemodynamic results,” they write. This highlights the challenges operators face in determining the true internal diameter of a given valve when performing valve-in-valve procedures.

According to Dr. Tuzcu and colleagues, the internal diameter of bioprosthetic valves ranges from 17 to 20 mm for a 21-mm device and from 15 to 19 mm for a 19-mm valve when assessed intraoperatively. “This measurement not only depends on the valve type, but also on whether the bioprosthetic valve is placed surpra- or intra-annularly and whether valve pledgets are placed above or below the annulus,” the editorial states. “The issue of internal diameter size of the diseased valve is more important for the Edwards Sapien valve because of its ‘intra-annular’ positioning unlike for the CoreValve which has functioning leaflets above the minimum internal diameter.”

They also point to coronary artery occlusions carrying a high rate of mortality, which occurred more frequently in the stentless valves and valves with leaflet mounted on the outside of the frames.

“To prevent this frequently lethal complication, we need to examine the relationships between the coronary artery ostia, the bioprosthetic valve sewing ring, the leaflets, the sinotubular junction, and Sinuses of Valsalva,” the authors write. “For the time being we should either avoid or use extreme caution in using [valve-in-valve] technique in [stentless valves and valves with leaflet mounted on the outside of the frames], which leaves little space between the prosthetic leaflets and coronary ostia.”

Yet another issue raised by the editorial is the malposition rate of 15.3% and the need for a second TAVR valve in 8.4% of patients, which they refer to as “surprisingly high.” Dr. Tuzcu and colleagues note that these complications “can potentially be prevented by clear understanding of the anatomy of different valves, pre-procedural planning with CT scan and use of guiding intraprocedural radioscopic software for positioning.”

More CoreValve Data

In the second study, Axel Linke, MD, of University of Leipzig-Heart Center (Leipzig, Germany), and colleagues report on results from 27 symptomatic patients with failing aortic valve bioprostheses who were aged at least 65 years and had a logistic EuroSCORE of at least 10%. All were treated with valve-in-valve procedures using exclusively CoreValve devices.

In those with aortic stenosis and combined aortic stenosis/aortic regurgitation (n = 25), the mean gradient declined from 42 ± 16 mm Hg before to 18 ± 8 mm Hg after CoreValve implantation (P < 0.001); in those with aortic regurgitation alone, the level declined by 2. There were no intraprocedural deaths and no procedural MIs.

At 30 days, the mortality rate was 7.4%. Likewise, the rates of life-threatening bleeding and kidney failure stage III also were each 7.4%, and major access site complication occurred in 11.1%.

According to the study authors, the data demonstrate the efficacy of the CoreValve device for valve-in-valve procedures irrespective of the failure mode and the type of bio­prosthetic valve. In addition, they say, the study shows that “valve-in-valve implantation results in marked, instantaneous improvement in hemodynamics, which remains evident at long-term follow-up.”

 


Sources:
1. Dvir D, Webb J, Brecker S, et al. Transcatheter aortic valve replacement for degenerative bioprosthetic surgical valves: Results from the global valve-in-valve registry. Circulation. 2012;Epub ahead of print.

2. Tuzcu EM, Kapadia SR, Svensson LG. Valve in valve: Another milestone for transcatheter valve therapy. Circulation. 2012;Epub ahead of print.

3. Linke A, Woitek F, Merx MW, et al. Valve-in-valve implantation of Medtronic CoreValve prosthesis in patients with failing bioprosthetic aortic valves. Circ Cardiovasc Interv. 2012;Epub ahead of print.

 

 

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Disclosures
  • Dr. Dvir reports no relevant conflicts of interest.
  • Dr. Linke reports serving as a consultant for Medtronic.
  • Drs. Tuzcu and Svensson report serving as unpaid members of the executive committee and investigators of the PARTNER trial.
  • Dr. Kapadia reports serving as an unpaid member of the steering committee and investigator of the PARTNER trial.

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