Download this article's Factoid (PDF & PPT for Gold Subscribers)

Transcatheter aortic valve replacement (TAVR) provides good 1-year survival for selected patients with degenerated surgical bioprosthetic valves, according to a registry study published in the July 9, 2014, issue of the Journal of the American Medical Association. However, prognosis is less positive in those with stenosed or small surgical valves.

The report updates earlier datasets from the Global Valve-in-Valve Registry, which were published in Circulation in November 2012 and presented at EuroPCR in May 2012.

The main access route in the self-expandable group was transfemoral (92.5%), while the majority of the balloon-expandable group received valves via transapical access (69.5%; P < .001). A second transcatheter device was implanted in 7.5% of the self-expandable group and 4.1% of the balloon-expandable group. Ostial coronary obstruction after valve-in-valve implantation occurred in 2% and was more frequent in the stenosis group (3.9%; P = .02).

Mortality Highest in Stenosis Group

Median hospital stay was 8 days and was unaffected by the mechanism of bioprosthesis failure or type of transcatheter device. At 30 days, mortality and mean residual gradient were highest in the stenosis group. At least moderate regurgitation, meanwhile, was more common in the regurgitation group. Improvement in NYHA functional class was similar regardless of the type of bioprosthesis failure. One-year outcomes followed similar patterns (table 1).

Table 1. Outcomes at 30 Days and 1 Year

Severe prosthesis-patient mismatch (defined as a postprocedure effective aortic orifice area divided by body surface area < 0.65 cm²/m²) occurred in 31.8% of patients but did not affect 1-year survival. Additionally, there were no differences between self-expandable and balloon-expandable devices with regard to mortality or stroke.

Survival Lower for Small Bioprostheses  

Overall, 1-year Kaplan-Meier survival was 83.2%. Patients in the stenosis group had worse outcomes than those in the regurgitant or combined groups (76.6% vs 91.2% and 83.9%, respectively; P = .01). Likewise, patients with small surgical valves had worse 1-year survival than those with intermediate or large valves (74.8% vs 81.8% and 93.3%, respectively; P = .001).

Independent predictors of 1-year mortality on multivariable analysis were:

• Small surgical bioprosthesis (HR 2.04; 95% CI 1.14-3.67)
• Baseline surgical bioprosthesis stenosis (HR 3.07; 95% CI 1.33-7.08)
• Transapical access (HR 2.25; 95% CI 1.26-4.02)
• Higher STS score (HR 1.01; 95% CI 1.03-4.93)

In particular, small surgical bioprosthesis was correlated with early (≤ 30 days) mortality, while baseline bioprosthesis stenosis was correlated with late (>30 days) mortality.  

The authors say that “[v]alve-in-valve implantation should be considered a heterogeneous group of procedures, performed in widely diverse surgical valves with different degeneration modes.

“The current analysis highlights the need for meticulous evaluation of bioprosthesis mechanism of failure before attempting a valve-in-valve procedure,” Dr. Dvir and colleagues observe. “Patients who are diagnosed as having failed surgical valves secondary to stenosis should be further separated into those with degenerated valves and those who have elevated gradients and small effective orifice area as a result of severe [prosthesis-patient mismatch] with their surgical valve.” 

The valve-in-valve approach “should only be rarely offered to patients after implantation of small surgical valves without signs of valve degeneration, for which gradients are relatively stable over time,” they conclude.

Overall, however, the positive findings may have implications for surgical practice, the authors suggest. They note that surgeons may now perform surgical valve replacement in patients at an earlier age knowing that a less invasive—and potentially repeatable—strategy is available to rescue the surgical valve when it eventually fails.

Determining Size of the Surgical Bioprosthesis Key   

“The decision about [how to handle] a failed surgical bioprosthesis has to remain a very individual one for each patient,” Peter C. Block, MD, of Emory University School of Medicine (Atlanta, GA), told TCTMD in a telephone interview. 

Why TAVR should have a worse outcome in a stenotic surgical bioprosthesis than a regurgitant one is not clear, he said, but the size of the failed surgical valve and the potential for prosthesis-patient mismatch is crucial. “We want to put in the largest transcatheter device possible,” he explained. 

Unfortunately, determining the size of the surgical bioprosthesis can be tricky, Dr. Block said. Because CT imaging is not reliable and bioprosthesis manufacturers typically provide only the outside dimensions, he reported that he asks the company to send a copy or mockup of the valve so the inside dimensions can be measured directly prior to TAVR. Another technical challenge, he said, is visualizing the landing zone in stentless surgical bioprostheses.

In addition, if significant paravalvular leak is present, it must be plugged before the transcatheter valve is implanted, he advised.

Still, Dr. Block concluded, “For elderly patients who are not good surgical candidates, this is a wonderful way to deal with a failed surgical bioprosthesis where mismatch is not an issue.”

 Note: Co-authors Susheel Kodali, MD, and Martin B. Leon, MD, are faculty members of the Cardiovascular Research Foundation, which owns and operates TCTMD. 

Source: 
Dvir D, Webb JG, Bleiziffer S, et al. Transcatheter aortic valve implantation in failed bioprosthetic surgical valves. JAMA. 2014;312:162-170.

Related Stories:

•  Global Valve-in-Valve Registry: Procedure Technically Challenging, but Highly Feasible
•  Studies Show Valve-in-Valve TAVR Successful for Failed Surgical Bioprostheses
•  Early Results of ‘Valve-in-Valve’ Implantation for Failed Bioprostheses Encouraging