TAVI Specialists Expect Surgical Valves to Survive, as More Surgeons Also Do TAVI

Reed Miller

March 02, 2011

March 2, 2011 (Washington, DC) — Transcatheter-valve experts anticipate the emergence of a group of moderate-risk patients who will be able to choose either transcatheter aortic-valve implants (TAVI) or surgery, as well as an increasing number of surgeons skilled at both techniques, according to a panel discussion held at CRT 2011, the Cardiovascular Research Technologies conference, this week [1].

"Surgery has so many times been pronounced dead, and yet it has life, and this will certainly be the case with TAVI," said Dr Eberhard Grube (International Heart Center, Essen, Germany). "I don't think that surgery will be obsolete, but if I can look forward, in a couple of years [TAVI] will go into a lower-risk population. But for the most part surgery will remain, at least for the next four or five years, the gold standard."

Currently, TAVI is mostly restricted to the patients for whom surgery carries high risks, but the panelists are apparently confident that the Placement of Aortic Transcatheter Valve Trial (PARTNER) cohort A, which has randomized patients between the Edwards Sapien TAVI device or surgery, will show that TAVI is a good alternative to surgery in high-risk patients when the data are released at the ACC 2011 meeting/i2 Summit in April. The Sapien valve already showed superiority to best medical management in patients not eligible for surgery in the PARTNER cohort B results, released at last year's TCT meeting. Medtronic is a few years behind with a similar trial program for its CoreValve system.

"As we gain more experience, there's no reason to believe that once we have more durability data and clinical data, that we won't be able to push it further down [into a lower-risk population]," Grube said.

Dr John Lasala (Washington University, St Louis, MO) agreed. "Twenty years ago we were led to believe that PCI would eliminate coronary bypass grafting, and clearly that's not happened. In this case it's the reverse scenario--in PCI we started with the easiest ones and worked up. In TAVI we've started with the most difficult ones and worked down--but it's unlikely that surgery will become obsolete."

Lasala observed, "It's clear that all the surgeons, those particularly in a TAVI center right now, are trying to acquire the skills along with us to perform TAVI by themselves." Lasala said that surgeons can bring important skills to this field, noting that some of the transapical and subclavian procedures are more like minimally invasive surgeries than fully percutaneous interventions.  "The surgeons do not want to pass up an honest opportunity. [Surgical valve replacement] will be viable for the foreseeable future, but they are also preparing for adaptation to TAVI.""

Dr Ganesh Manoharan (Royal Victoria Hospital, Belfast, Northern Ireland) added that TAVI adoption will be driven by patient choice. "Eventually when the data come in and our experience gets better, we'll see patients choosing TAVI. I can't understand why you'd want your chest opened up if you [see] a comparable technology or technique." He said that this shift has begun in Europe. "We're now getting numerous referrals directly from our surgical colleagues who were referred to them from other cardiologists. If surgeons trust what you do and trust your data and they see patients improving, they will see the benefit of patients going home in five days."

Despite this shift, Manoharan predicts the population undergoing surgical valve replacement will also continue to grow, because the total number of patients needing new valves is growing as the population ages.

Dr Maurice Buchbinder (Foundation for Cardiovascular Medicine, San Diego, CA) pointed out that because TAVI has been used only in older patients, the long-term durability of the devices has not been an issue. But it will become an important consideration if the valves are put in younger patients who expect to live a long time with the valve.

Lasala agreed, and added that the durability issue will eventually push the manufacturers to create mechanical TAVI devices. The Sapien valve is made primarily of bovine tissue, and CoreValve uses porcine tissue.

But the panelists agreed that the true durability of these new devices will end up being established in real-world, less ill patients and not fully demonstrated beforehand in clinical studies. Grube said, "There are bound to be some disappointments" with the devices failing and needing to be replaced, just as there were with the earliest tissue and mechanical valves until their durability could be more precisely predicted. "I don't think we will have these long-term data before we can decide when to do this. It will be driven by clinical needs and physician and patient acceptance."

But he believes this will not be a major problem, since it is usually possible to put a new valve inside a failing valve and it's unlikely that many patients would ever need their valve replaced more than once. "We're not talking about a 50-year-old, but a 75- or 80-year-old. And there's a good chance that it's not going to be an emergency, and so you can see [the implanted device is starting to fail] and decide what to do and in many cases reimplant a second valve in eight or nine years."

Manoharan said that the best way to test durability of the devices is to make that an end point in a trial of TAVI in moderate-risk patients. Buchbinder agreed with that proposal, adding, "The surgical valves that are implanted in surgery did not have [special] durability trials [before being implanted in younger patients]. They had mechanical bench testing, but the first [long-term] implant was just implant number one." Manoharan reports that he is a consultant/advisory board member for Medtronic, St Jude Medical, Radi Medical, Boston Scientific, and Guided Delivery Systems and a proctor for Medtronic's CoreValve. Buchbinder reports that he has no conflicts of interest.