What follows is an outsider's report on the next big phase of cardiology—the percutaneous treatment of valvular heart disease.
I have little doubt that in 5 to 10 years, transcutaneous valves will be normal. It's hard not to see similarities to the coronary angioplasty and stent developments of decades past.
"In the beginning, [transcatheter aortic-valve implantation] TAVIwas a niche procedure; it made sense to restrict it to those patients with extreme operative risk," said Dr Martin Leon (Columbia University, New York) at the outset of the pro-con debate session here at the European Society of Cardiology 2015 Congress entitled "Intermediate-risk patients: The answer is TAVI."
We were clearly no longer at the beginning. Leon told the packed conference room that more than 200,000 implants have been done in 65 countries. TAVI is a common procedure with reduced complications, better case selection, and refined tools.
His defense of less restricted TAVI began with the premise that it now makes no sense to restrict TAVI based on an imprecise, arbitrary, and nonvalidated algorithm. (I learned after referring a patient for TAVI that there are indeed severe restrictions at my hospital.)
To accept his premise, Leon said we must suspend our past beliefs. This meant an uncoupling of old thinking in which we were conditioned to put patients with aortic stenosis into silos of low, intermediate, and high risk. Silos are so out these days, aren't they?
Did you know (I did not) there are eight class I or IIa indications for surgical aortic-valve replacement (SAVR), and although these indications are reasonable, they are not supported by evidenced-based clinical trials. Most important from Leon's perspective is the fact that surgical indications for AVR are not based on risk strata of the patient. Why then should TAVI be so confined?
Leon then noted the complex mesh of risk algorithms before TAVI. "Risk is on a continuum; it is not meant to be easily partitioned." These strict criteria have been invented by experts," he said.
After establishing the eminence-based nature of risk-based guidelines, Leon launched into a skillful description of the immense data available for TAVI. For the balloon-expandable device, "we have now treated more than 9000 patients in FDA studies with three generations of the device. That's more than 10 times the total number of patients mentioned in the guidelines for SAVR."
In elderly high-risk patients, more than 80% of surviving patients have good functional capacity. "There is now strong evidence showing superiority—not equivalence—of TAVI vs SAVR."
Another reason to extend TAVI to lower-risk patients is that it's already being done. He listed seven studies, mostly from Germany, in which lower-risk patients are being treated by TAVI. In the US, it's the same trend. Clinical practice is changing ahead of guidelines. Little surprise there.
Citing smaller studies, propensity-matched comparisons, and registry data, Leon told the audience that the evidence is there for TAVI benefit in lower-risk patients.
For instance, results of the prospective multicenter randomized Nordic Aortic Valve Intervention Trial (NOTION) were surprising[1]. NOTION compared TAVI and SAVR in an all-comers population (nonselected patient group). These were patients with low-risk scores. Although underpowered for mortality benefits, the results showed numerically better results with TAVI than with SAVR.
Leon concluded his case with comments on complications and valve durability. Complications from TAVI are vastly lower. He showed numerous data-intensive sides that documented the steady decline in complications over time. And his take on durability was that TAVI looked good at 5 years. In the rebuttal section, he emphasized that new surgical valves are approved without any sense of 10-year durability.
And the finale: "The conversation needs to change. We have checked the boxes for low-risk patients. We used to ask: who does poorly with SAVR? That question should change to: who does well with TAVI?"
Intermediate-Risk Patients: The Answer Is Not TAVI
Cardiac surgeon Dr Thomas Walther (Kerckhoff Clinic, Bad Neuheim, Germany) began the contra side of the debate by saying that he agreed with much of Leon's case. He likes TAVI; he does TAVI.
Four slides into his case, however, Walther presented the major issues surrounding less-restrictive TAVI:
There are no long-term results. "We must wait for valve-durability data."
Aortic regurgitation is still a problem.
High rates of AV block and pacer dependence with TAVI play a larger role in younger patients.
There remains some unpredictability with device landing and function.
Native valve calcifications are a problem.
Costs must not be ignored.
"SAVR is safe and good. It offers multiple options, including other surgical procedures, such as mitral-valve repair, aortic repair, and other concomitant procedures," said Walther.
He then showed his favorite slide. It depicted survival curves, demonstrating that a group of patients they operated on in Leipzig (mean age 72) had the same 10-year survival as an age- and gender-matched population of Germans. His point: other than a small scar, patients who have surgical AVR do beautifully. My translation: If it ain't broke, don't fix it.
Walther broke down AS patients into three categories:
Straightforward patients with moderate and symmetric calcifications with good landing points. These patients can be done with TAVI.
Variable intermediate patients who present a difficult choice.
And a hostile group with heavy calcifications and eccentric distribution that extends through the annulus. These patients can be operated on with low risk and good outcomes.
Walther took a different view of complications. "Complications [with TAVI] may be coming down, but they are still significant." He focused on the importance of talking with patients about the absolute risks of each of the TAVI complications compared with SAVR.
Walther, like Leon, used the wealth of data on TAVI to make the case that most of the trials showing TAVI benefit over SAVR used a selected patient population, which does not represent the all-comers' reality of clinical practice.
The German surgeon gently urged caution in overextending the procedure to patients well-suited for SAVR.
Comments
In the second half of the session, Dr Nicolas Van Mieghem (Thorax Center, Rotterdam, Netherlands) and Dr Francesco Saia (University of Bologna, Italy) debated the topic of denying (or not denying) TAVI to very high-risk patients. The speakers were excellent, but it was a less compelling debate. They basically agreed. Both urged doctors to look at their patient and ask: was she sick because of aortic stenosis or with aortic stenosis?
The struggle to stop fighting the natural order of life and aging isn't specific to TAVI procedures. It's endemic in cardiology—and I don't see an easy answer.
One notable aspect of these debates was that it took 88 minutes (of a 90-minute session) to make the clear statement that costs to the healthcare system from these procedures must be faced by all involved.
To me, healthcare costs of TAVI are a disruptive notion. I've taken to relating much of what we do in cardiology to "TAVI units." An ablation catheter, a stent, or a new drug all look like bargains compared with TAVI in a 90-year-old.
I learned a lot. I'm glad I went to the session.
JMM
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Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: TAVI: A Solution for All Patients: A Pro-Con Debate at ESC 2015 - Medscape - Aug 30, 2015.
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