AIM: Percutaneous valve replacement may trump SAVR techniques
SAVR is the "only treatment known to improve symptoms and survival in patients with severe, symptomatic aortic stenosis,” the authors wrote. “Perioperative mortality, however, is high among many patients for whom SAVR may be indicated.”
To evaluate the evolving treatment method of PHV replacement as an option for treatment of aortic stenosis, Remy R. Coeytaux, MD, PhD, of Duke University Medical Center in Durham, N.C., and colleagues performed a review of articles published between Jan. 1, 1990 and Oct. 15, 2009, which illustrated studies that looked at the use of PHV replacement as a method to repair aortic stenosis.
Eligible articles reported at least one clinical outcome (mortality, successful implementation rates or hemodynamic measurements). Coeytaux and colleagues evaluated device implantation success rates and 30-day mortality.
The researchers identified 84 articles that evaluated 76 separate studies assessing the efficacy of PHV replacement—50 were single or multiple case reports and 34 were case series representing 2,311 patients with severe aortic stenosis.
The authors noted that 76 percent of the procedures were delivered by the femoral artery and 22 percent were performed using the transapical approach. Two percent of patients had prostheses delivered through the femoral vein, subclavian artery, axillary artery or ascending aorta.
After review, the researchers concluded that procedural success rates of PHV replacement procedures had increased over the report period and were estimated at 97 percent.
Across all studies, 30-day survival was 89 percent (1,996 patients of 2,197). The researchers found that 30-day mortality rates were 11 percent across the board and these rates were higher for conventional SAVR. Thirty-day outcomes with endpoints of major adverse cardiovascular and cerebral events from any cause were 8 percent.
Of studies that evaluated the effect PHV had on other organ function, Coeytaux and colleagues found that acute kidney injury occurred in 11.7 percent of cases—1.4 percent required hemodialysis. Additionally, acute kidney injury occurred in 9.2 percent of PHV patients compared with 25.9 percent of SAVR patients.
“Specific characteristics, such as age, functional status, cardiac status and medical comorbidity, have been shown to be associated with mortality in conventional heart valve surgery,” the authors wrote. “It is unknown, however, if these same factors also affect outcomes for PHV replacement, and, if they do, whether their effect is directly related to the PHV device or procedure.”
Of the devices used during PHV replacement, the majority were Edwards Lifesciences' Sapien (1,040 patients) or Medtronic's CoreValve (1,316 patients).
Thirty-day success and survival rates were 93 percent and 88 percent for patients undergoing replacement with the Sapien device and 95 percent and 91 percent with the CoreValve device.
Procedural complications occurred in 339 patients who underwent PHV replacements with the Edwards device and 646 patients with Medtronic device. Thirteen percent of these complications were major access site complications, 8.1 percent were life-threatening arrhythmias, 4.1 percent required hemodynamic support, 1.9 percent were vascular access site complications and 1.7 percent involved ventricular perforation.
“The existing published literature on PHV replacement consists of case reports and series that focus almost exclusively on the Edwards Sapien transcatheter heart valve and Medtronic CoreValve ReValving Systems,” the authors wrote. “This literature demonstrates the feasibility of PHV replacement in the treatment of aortic stenosis among patients whose high perioperative risk profile places them at significantly higher risk for poor outcome from SAVR.”
The researchers said that limitations of the study stemmed from the absence of prospective, randomized, controlled clinical trials that assessed PHV replacement. “Although case series demonstrate technical feasibility, they do not evaluate efficacy,” the authors noted.
While currently no PHV devices are approved for U.S. use by the FDA, the Sapien and CoreValve systems have received a CE mark for use throughout Europe.
Additionally, the researchers said that the randomized, controlled PARTNER (Placement of AoRtic TraNscathetEr) trial recently completed its testing of the Edwards device at 26 sites throughout the U.S., Canada and Germany. The study is assessing the efficacy and safety of PHV replacement and has enrolled 1,040 patients with aortic stenosis.
“In summary, PHV replacement for severe aortic stenosis remains an investigational procedure in the U.S. but is a promising therapeutic option for patients with severe, symptomatic aortic stenosis who have a higher risk for poor outcome with SAVR,” the authors wrote.
“The rapid adoption of PHV in Europe supports its role in fulfilling an unmet clinical need," Coeytaux and colleagues concluded. "Further studies are needed to evaluate factors related to improved long-term results, particularly those that assess the effect of noncardiac conditions on outcomes, and the effectiveness and cost effectiveness of the various PHVs compared with conventional heart valves and other PHVs.”
The report was funded by the Department of Health and Human Services’ Agency for Healthcare Research and Quality.