TCT Course Director Outlines Current TAVR Controversies

In a didactic session on Saturday at TCT, Martin B. Leon, MD, outlined five major controversies in transcatheter aortic valve replacement (TAVR) facing clinicians in 2014.

Inclusion of low-risk patients

sun.leon.headLeon, of Columbia University Medical Center, New York, and TCT course director, highlighted data from the PARTNER and CoreValve studies, along with findings from the STS/ACC Transcatheter Valve Therapy (TVT) Registry indicating that lower-risk patients are being included more frequently in trials as well as in clinical practice. Outcomes are also improving in this patient group, according to Leon. “There is clearly no evidence that TAVR is performing less well than surgery in lower-risk patients,” he said.

Leon added that the question of whether the evolution of TAVR use is uncontrolled or ill advised — or a thoughtful consequence of better case selection — is valid. It may be beneficial to wait until results of the PARTNER II and SURTAVI studies emerge before indications are adjusted, he added, and raised the question of when a true low-risk study should be considered.

Device vs. device comparisons

Leon noted that while 95% of TAVR patients around the world have been treated with the Sapien (Edwards Lifesciences) or the CoreValve (Medtronic) devices, clinical trials are not helping to elucidate whether one is preferable over the other. “In the absence of definitive randomized trials and no obvious differences in major clinical endpoints, such as death and stroke, the debate often deteriorates into a subjective diatribe claiming technology advantages, deferring to user preferences, and focusing on softer secondary endpoints,” he said, citing a small sample size and indefinite endpoints in the CHOICE study.

The solution may come in the form of new TAVR systems that broaden the device landscape. Self-expanding systems such as the Portico (St. Jude), the Engager and Evolut R (Medtronic) and the Acurate (Symetis) are forthcoming, as are non-expanding systems such as Direct Flow (Direct Flow Medical), Lotus Valve System (Boston Scientific), JenaValve (JenaValve Technology) and Sapien 3 (Edwards Lifesciences).

Paravalvular regurgitation and strokes

Leon also cited recent data from a meta-analysis demonstrating a nearly two-fold mortality increase with mild aortic regurgitation. “There is no question in my mind that this is not a good thing,” he added.

While the causes of paravalvular regurgitation after TAVR are multifactorial, Leon suggested that screening techniques such as valve-sizing algorithms based on multislice CT may be helpful, but he noted that 3D measurements can be confusing.

“The striking variability in both the assessment techniques of post-procedure paravalvular regurgitation and the application of post-dilatation thresholds remains unresolved,” he observed. “But maybe all of this will just go away [with the advent of] new devices.”

Leon stressed that strokes remain the one complication that the clinical community needs to work to resolve, noting that they increase mortality by a factor of anywhere from three to five.

However, findings from PARTNER suggest that stroke-related mortality has been decreasing. “Over time, it appeared that stroke frequency after TAVR was declining with improved case selection, device and procedural refinements, and increased operator experience,” he said. “So are strokes still a vexing dilemma after TAVR or is the problem stabilized and acceptable?”

Procedural considerations

Finally, Leon suggested that transfemoral access has become the default approach for TAVR, and that many European clinicians are moving to simplify the procedure. “However, overly aggressive transfemoral first-and-only access may be exposing patients to unnecessary vascular complications,” he said.

Lower profile and safer transapical systems may be the answer.

The minimalist approach, including the virtual elimination of procedural TEE, may yield suboptimal results in some patients, according to Leon. “Combined procedures also clearly require further careful evaluation,” he said. “I would argue that in some cases IVUS is a good thing.” However, he added that the management of patients with aortic stenosis, CAD and other CV conditions remains unresolved.

 

Disclosures:

 

  • Leon reports relationships with multiple pharmaceutical and device companies.

 

Comments