As many readers know, I advise caution to patients prior to pursuing TAVI (or transcatheter aortic valve implantation, primarily because there is no long-term data on durability or long-term effects.

One of these days, I may have to eat my words – and when that day comes; I will be happy to do so (and will do it with a 14-point font).  But that day is not today.

As reported by Reed Miller over at Heartwire, there are the first results of a very small Canadian study with average follow-up 3.7 years after implantation..  Unfortunately, its way too small of a sample – and mean follow-up falls short of the five-year mark.

But given the rate of implantation in Europe (Germany, in particular) and the fact that these valves are used in younger patients over there – we should have some large (thousands of patients enrolled) studies with five-year data in just a year or two.. One of two well designed studies with a large study population would sure make a lot of us over here (in the USA) feel a lot more comfortable about the safety and efficacy of these devices in our patients.

Now, I bet most of you have gotten pretty good at picking through these Heartwire articles to get to the bit of truth inside – and the experts quoted here do a much better job at providing straight forward answers (unlike the cast of characters quoted for many of the articles regarding the stent scandals.)

(I’ll re-post below so you can see for yourself.)  I’ve also included links to our little collection of TAVI articles here – or the ‘TAVI library” for first-time readers to catch up.

1.  Aortic Stenosis – more patients need surgery  – for some background on the issue (more articles on Aortic stenosis under cardiology)

2.  TAVI  – ‘a new stent scenario’ – discussing concerns with the widespread adoption of this therapy

3.  TAVI recommendations and guidelines –  the most recent established US guidelines for therapy

4.  TAVI – an overview – getting back to the basics

5.  TAVI – mortality data – this had some pretty frightening results, another reason for caution.

6. TAVI and FDA approval: what does it mean? – talking about the implications of FDA approval, and the history of FDA approval of medical devices.

CoreValve TAVI maintains durability out to four years in small study

(Reed Miller)

[Bold type from original article]

Paris, France – The longest follow-up of patients implanted with the CoreValve (Medtronic) transcatheter aortic-valve implantation (TAVI) device presented so far suggests that it is reliable and durable in high-risk patients, according to the study investigators [1].

“In due time, I’m sure we will see a gradual decrease in the average patient age, treating patients with less comorbidity than was done in the beginning, strengthened by these types of results showing the durability of the implants,” study lead-investigator Dr Peter den Heijer (Amphia Hospital, Breda, the Netherlands) told heartwire.

Here at the European Society of Cardiology 2011 Congress, den Heijer presented long-term follow-up results from 52 patients implanted with the second-generation version of CoreValve in 2005 and 2006 in Europe and Canada. All of the patients in the study were at least 80 years old with a logistic EuroSCORE over 20 or over 65 years old with at least one high-risk comorbidity. All of the patients had severe aortic stenosis and an aortic-valve annulus diameter between 20 mm and 24 mm. Two-thirds of the patients had NYHA class 3 heart failure and almost 20% had class 4 heart failure.

Four-year follow-up data was collected on 20 patients, but 26 patients died, including 13 cardiac deaths. Overall survival was 58.5% at two years and 45.1% at four years. At four years, the surviving patients showed significant improvement in heart-failure symptoms, with 61% in class 1 heart failure and 22% in class 2. Nearly a third of patients showed grade 2 or 3 aortic regurgitation at baseline, but after four years 57% showed no regurgitation and 43% showed grade 1 regurgitation. The mean valve gradient decreased from 41 mm Hg at baseline to 12 mm Hg at 30 days and 10 mm Hg at four years.

There were no strokes reported in the study population between three months and four years and no frame fractures, valve migrations, valve endocarditis, or structural valve deteriorations leading to stenosis or regurgitation. “That’s important, because the goal of this treatment is to provide patients with severe aortic stenosis, a severely life-limiting disease, with a better prognosis, and it appears to be not at all hampered by the structure of the valve,” den Heijer told heartwire.

In a 70-patient study by Dr Ronen Gurvitch (University of British Columbia, Vancouver) colleagues, the Sapien (Edwards Lifesciences) transcatheter aortic valve showed no structural valvular deterioration, stent fracture, deformation, or valve migration over a mean follow-up of 3.7 years [2].

CoreValve is available in Europe and is being tested in a major US clinical trial that Medtronic says will be completed in 2012. The FDA is expected to approve Edward’s Sapien TAVI device soon, following a positive appraisal by its advisory committee.

Still much too early to assess long-term TAVI results

Surgeon Dr Craig Miller (Stanford University, CA), one of the investigators of the pivotal PARTNER trial of Sapien, told heartwire that while the four-year results with CoreValve are “decent,” the clinical community will “need much larger numbers of patients followed at two, three, and four years for the hemodynamics to mean much.”

PARTNER investigator Dr Michael Mack (Medical City Dallas Hospital, TX) told heartwire, “Although it’s reassuring that there are now results out to four years and there’s no sign of structural valve deterioration, it really adds minimal information to what we know already.

“There’s only 20 patients alive at four years, so how do you know what happened to the other 30 patients [in the trial]? Some died of cardiac death and some died of unknown causes. How do you know they didn’t die of structural valve deterioration?” he said. “A better way of doing this study for all aspects is that all the information should be on matched patients.”

Mack said that the real long-term durability of transcatheter valves will become more clear with more data from the SOURCE registry and the long-term follow-up of PARTNER trial, which will include annual core-lab-adjudicated echocardiography follow-up out to five years.

In an email to heartwire, Dr Grayson Wheatley (Arizona Heart Institute, Phoenix) pointed out that although the study had a high percentage of cardiac-related deaths, the arrhythmia-related deaths were a smaller proportion than in some other recent studies. But Mack and Wheatley also pointed out that because there was no echocardiographic core lab in this study, the functional assessments of the valve may not have been always accurate.

Wheatley also pointed out that this study used an older version of the CoreValve, so “this study doesn’t relate too well to real-world use of the CoreValve due to new design changes in the valve system, but it does show that, in general, TAVI procedures can be used in high-risk cardiac patients and that there will be long-term survivors.”

TAVI overseas –

As mentioned above, TAVI has rapidly been implemented in Europe.  Latin American medicine has begun to embrace this emerging technology as well.  In fact, US physicians are travelling outside the country to perform this procedure on their patients (since it’s not FDA approved.)

From a statement by the University of Miami Medical School – International Medicine Institute: [verbatim]

“New Technology Treats Aortic Heart Valve Disease Without Surgery

 At 86, Dr. Isaac Hariton is back to walking three miles a day since getting a new aortic valve this past June. To avoid surgery, this retired surgeon traveled to Cali, Columbia, for his procedure.  Hariton’s doctor is Eduardo de Marchena from UHealth – University of Miami Health System, who traveled with him to implant a valve not FDA approved for use in this country.”