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By JOHN BROSKY

Medical Device Daily European Editor

PARIS — Artificial heart valves were invented and first implanted before regulations for such devices were created.

Fifty years later these devices are closely scrutinized, yet surgeons are ignoring prescribed indications not only implanting the newest generation of valves "off-label" but at an alarming rate across Europe.

A registry compiled among 22 German heart centers in 2009 reports a staggering 60% of the procedures for transcatheter aortic valve implantations (TAVI) were performed on patients considered outside the approved indication for high-risk patients.

The registry is selective, including only 697 of the more than 2,500 patients in Germany undergoing TAVI since the procedure was introduced in 2008.

Five European registries presented to date account for just over 4,000 patients or 16% of the 25,000 patients receiving valves using the new percutaneous technique, according to an article in the current issue of EuroIntervention, the journal of the European Association of Percutaneous Cardiovascular Interventions (EAPCI) (Medical Device Daily, May 27, 2010).

At an average reimbursement rate of $30,000 per procedure, the value of the three-year start up for TAVI in Europe would be $750 million.

The number of procedures is expected to double in 2011 in Europe.

"It is out-of-control," acknowledged Alain Cribier, MD, who pioneered the first-in-man TAVI procedure in 2002 at the University Hospital in Rouen.

"There was never an intention that a valve placed by a catheter would replace surgery except among the high risk population denied surgery," he told MDD during a roundtable luncheon here last week sponsored by Edwards Lifesciences (Irvine, California) celebrating the 50th anniversary of the first-in-man implantation of an artificial aortic valve.

This intention was translated into a clinical indication using a Logistic Euroscore of greater than 20, he explained, meaning a patient had a greater than 20% chance of dying as a result of the surgery.

The Euroscore assessment is the result of a consultation between a surgeon and other members of a 'heart team' established at a cardiovascular department.

But the rules have been changed encouraging the surgery among patients considered "frail" by the surgeon, he said, ratcheting the Euroscore down to 15.

"What does frail mean?" he asked, "it is entirely subjective, which leaves the decision to an individual surgeon after what is called in English an 'eyeball exam.'"

"Today it is anything-goes in TAVI surgery," he said.

The looser rules for patient inclusion in TAVI procedures has been adopted in Italy, Germany and the Middle East, according to Cribier.

What Cribier did not say but implied with this comment is that the frailty index is being pushed by Edward's only competitor with an approved TAVI device, CoreValve (Irvine) from Medtronic (Minneapolis), which is the dominant valve used in those markets.

In the German registry, for example, CoreValve accounted for 84% of the implanted devices.

A review of literature shows the advocates for the frailty indication are CoreValve consulting surgeons chafing against the restriction to the Euroscore measure.

CoreValve has also announced it will conduct a multicenter study called SURTAVI to randomized patients with lower surgical risk, defined as less than Euroscore 20, between traditional surgery and TAVI.

The two other guests of honor at the Paris luncheon weighed in to the TAVI debate during the roundtable, Albert Starr, MD, from the Providence Heart and Vascular Institute (Portland, Oregon) and Alain Carpentier from the Hôpital Européen George Pompidou (Paris).

The two surgeons shared the prestigious Albert Lasker Award in 2007 for the development of prosthetic mitral and aortic valves with engineer Lowell Edwards.

Starr led the first-in-man implantation of a mechanical heart valve using a silicone ball-in-cage in 1960 at the University of Oregon Medical School.

Several years later Carpentier invented the first bio-prothesis using porcine flaps for an aortic heart valve.

Carpentier said he believes the shift toward younger patients with low risk for surgery is "inexorable."

The awareness of a therapy for aortic stenosis is leading to more patients being diagnosed with the condition, he said, and then there is the demographic wave of Europe's rapidly aging population that is creating a larger patient population.

In this context, TAVI inevitably will be viewed as alternative to traditional open surgery, "and given a choice between having your chest cut open and a minimally invasive approach, who would want their chest cut?" he said.

"Yet to say that it is a patient decision to have a percutaneous implant is not going to be enough and surgeons need to provide the patient with a more honest assessment of the risks," he said.

Starr said TAVI has significant limitations that require further clinical study and device improvements before being indicated for a wider population.

Issues include the durability of the device, leakage, injury to tissue, and vascular damage from the dominant transfemoral access delivery.

The larger concern, however is the persistently high occurrence of stroke due to calcific embolization that shows up to an alarming degree among TAVI patients than patients in traditional surgery, even up to one year after the procedure.

While surgeons are pushing for wider use of TAVI, Cribier said he believes the clinical issue is now to define the limits for the procedure.

Carpentier agreed saying "the fastest way to kill a new procedure is to learn it is being overused."

The editor of EuroIntervention, Patrick Serruys, has repeatedly called for a large scale trial combined with a registry, similar to the decisive study in coronary stents, the Synergy between PCI with Taxus and Cardiac Surgery (SYNTAX) trial (MDD, Sept. 3, 2008).

"If TAVI is not evidence-based medicine and does not take into account the health economic factors, it will not be considered legitimate or justified in the eyes of the health authorities and therefore not reimbursed," Serruys said.



Published  December 6, 2010

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