By JOHN BROSKY
Medical Device Daily European Editor
PARIS Champagne was served all around, even for journalists, to celebrate the tenth anniversary of the first transcatheter valve implantation (TAVI) in May, 2002 in Rouen, France.
The pioneer and guest of honor, Alain Cribier, MD, noted that 50,000 valves have been implanted to date, primarily in European centers, since the first device was approved just five years ago.
In November, 2011 Edwards Lifesciences (Irvine, California) finally won approval for its Sapien valve from the FDA (Medical Device Daily, Nov. 4, 2011).
And just two weeks ago the Centers for Medicare & Medicaid Services released its final decision approving reimbursement for TAVI. (Medical Device Daily May 2, 2012)
Cribier also highlighted the new generation of 15 TAVI devices that are being promoted this year here at EuroPCR, the annual meeting of the European Association of Percutaneous Cardiovascular Interventions (EAPCI; Sophia Antipolis, France).
"The field is still expanding and there are new indications being considered including the valve-in-valve procedure," he said, with a nod to the presentation delivered during the session he chaired "From Late-Breaking Trails to Clinical Practice."
Compared to the heady excitement, flowing champagne and rising market valuations surrounding the success of TAVI, the presentation of the Global Valve-in-Valve Registry was little noticed.
Yet it opens a door to a vast new field of opportunity for TAVI, and rekindles the tense competition between heart surgeons and the 18,000 interventional cardiologists gathered here.
Danny Dvir, MD, from the Washington Hospital Center (Washington) and the Rabin Medical Center (Petah Tikva, Israel) outlined the opportunity.
Bioprosthetic valves are increasingly implanted in aortic-valve replacement open-heart surgeries, he explained.
These valves commonly fail within 10 years, resulting in a need for a high-risk, open-heart revalving operation.
Using the TAVI approach to place a replacement valve inside the original, failing valve, or "degenerated bioprosthetic valve," as the cardiologists prefer to say, offers a less-invasive, alternative approach.
To date, these valve-in-valve (VIV) procedures have been reported in only small case series, and the safety and efficacy of this technique is largely unknown until the compilation of a global registry.
Translating this last statement reveals that the small studies to date have been conducted by Edwards and Medtronic's Corevalve (Irvine, California) and suggests these two leaders in TAVI are already at work on VIV.
Also, the fact that Dvir and fellow authors of the study of 416 patients presented at EuroPCR reveals that VIV is already being practiced by 54 TAVI centers in Europe, North-America, Australia, New Zealand and the Middle-East.
The Global Valve-in-Valve Registry reviewed cases completed using 225 Edwards Sapien valves, 190 CoreValve devices, and one Melody transcathether pulmonary valve therapy from Medtronic (Minneapolis).
The failure of the degenerative bioprosthetic valve was classified in one of three conditions for the registry study: stenosis for 168 patients, regurgitation for 125 patients, and a condition called combined for 123 patients, which is defined as a moderate degree of both stenosis and regurgitation where both mechanisms are comparable in severity.
Dvir reported the VIV procedure was clinically effective in the majority of patients with 87.5% having a New-York Heart Association (NYHA) score of I or II early after the procedure.
One-year survival rates after VIV procedures were considered "comparable to most native-valve TAVR registries," which means that roughly one out of four patients died.
The devil is in the details, especially for Edwards' Sapien valve, which was found to pose a high risk of 2-to-1 when used inside a bioprosthesis valve with an internal diameter of less than 20 millimeters.
Surprisingly, but fortunately for Edwards, John Webb, MD, was invited to comment on the presentation in a new feature at this year's congress called "How and why this study may change my practice."
A prestigious expert in valvular heart disease, Webb is the pioneering leader of TAVI for Edwards, having trained and proctored many of the surgeons using the Sapien valve.
"This is an extremely important study," he said, suggesting that a key take-home message is that interventional cardiologists need to better understand surgical valves before attempting to replace them.
"Know your valve," he said, showing multiple examples where the interior diameter of the target valve varies significantly from the stated manufacturer's specifications.
This helps to explain why malpositioning of the replacement TAVI valve occurred in 11% of cases.
He also noted pointedly that the registry only included the first-generation Sapien valve and not the new Sapien XT, and that the majority of cases using Edwards valves were performed with the riskier transapical access.
"This registry has limitations, but at the same time it is probably real," in reflecting actual conditions," he concluded.
Presenting his conclusions, Divr suggested the registry shows the procedure is feasible, but "technically demanding, includes several safety concerns, and should probably be reserved for highly experienced centers."
He also suggested new TAVI devices dedicated for VIV procedures need to be developed to enable treatment of small bioprosthetic valves with improved efficacy and safety.
In addition to the high rate of initial device malposition, safety hazards included cases of clinically evident ostial coronary obstruction and a need for an emergent surgery, both at 2% of cases.
Dvir told MDD that he is confident new valves specific for this procedure will now be developed.
"The population of patients who have or soon will have bioprostethtic valves is growing significantly, he said.
"There will be a flood of these patients in a few years," he said. "Some will have surgery. Others will have simply become older or develop co-morbidities and will not be candidates for another surgery.
"We are going to face a dilemma where either we do nothing, relying on optimal medical treatment, or this," he said.
Another expert invited to say how VIV might change his practice was more direct.
José Luis Pomar, Chief of Cardiovascular Surgery at the Hospital Clinic of Barcelona said, "This study tells us there is a promising future for this procedure, and it may encourage utilization of the technique on patients who are less severe."
Published May 16, 2012