Views Differ on Future of Percutaneous Mitral Valve Therapies

In a session at TCT 2014, two surgeons squared off over the proposal that catheter-based mitral valve therapies for mitral regurgitation (MR) will have an important clinical role in the future.

Evidence-based optimism 

tues.maisano.headFrancesco Maisano, MD, of University Hospital of Zurich, Switzerland, took an optimistic view, but one based on addressing skeptics’ challenges. These include that the mitral valve anatomy is far more complex than that of the aortic valve; intervention requires guidance with sophisticated imaging; mitral disease is highly variable, requiring multiple devices and techniques; and surgical standards for the procedure are high.

He questioned the notion that percutaneous therapy remains ‘experimental,’ noting that almost 16,000 patients have been treated worldwide. In the real-world ACCESS EU study, MitraClip (Abbott Vascular) proved safe and significantly reduced MR grade and improved NYHA functional class.   

Maisano also challenged the idea that percutaneous mitral intervention is good only for palliation; rather, he said in his experience it can achieve “surgical-like” outcomes, with no residual MR. He added that percutaneous therapy and surgery should be viewed as complementary.

Transcatheter mitral interventions are difficult but learnable, he said. For example, over a 5-year period at MitraClip centers of excellence, procedure time declined from 180 to 55 minutes, while acute procedural success rose from 80% to 92%.

He pointed to several emerging technologies for direct annuloplasty or transapical delivery while foreseeing advances in imaging, such as a fusion of echocardiography and fluoroscopy.

Maisano predicted that ultimately percutaneous intervention may overtake surgery as the standard procedure for mitral disease.

Mitral complexity favors surgery 

tues.bolling.headSteven F. Bolling, MD, of the University of Michigan, Ann Arbor, Mich., likewise stressed that the mitral valve is incredibly complex compared with the aortic valve. Most important, he said, degenerative MR and functional MR are two very different diseases. If degenerative MR is repaired, the patient is cured, and that sets an extremely high bar for percutaneous therapies. On the other hand, functional MR signals congestive HF, and survival is poor.

MitraClip has several challenges, Bolling said. For degenerative MR, it is used only in extremely high-risk patients because it is not as effective as surgery and carries complications. And in functional MR patients, a small study showed 17% periprocedural mortality with the MitraClip. Moreover, the procedure did not achieve left ventricular remodeling, a key outcome for congestive HF. In the only study comparing surgery vs. percutaneous repair in functional MR, surgery produced lower recurrence rates at 6 months.  

Mitral valve repair is complex, and one technique does not fit all situations, Bolling emphasized, adding that surgeons perform a variety of repairs, and the Alfieri stitch — the surgical equivalent of MitraClip repair — is least effective among them.

Lack of annuloplasty may be holding back the percutaneous approach, some have suggested, but that strategy may be no more than reinventing a lesser surgical technique, Bolling contended. Moreover, nonsurgical coronary annuloplasty is often not feasible. Although a number of new technologies have been introduced to address it, a major drawback is that fluoroscopic guidance is inadequate and advanced imaging is years away, Bolling said. 

With regard to percutaneous mitral valve replacement, there are several new contenders, Bolling noted, but all are plagued by paravalvular leak and produce left ventricular distortion.

Finally, MitraClip does not meet the standard of cost/quality effectiveness, he said.

  

Disclosures: 

  • Bolling reports receiving consultant fees/honoraria/serving on the speaker’s bureau for Abbott Vascular and Medtronic and royalties from Edwards Lifesciences. 
  • Maisano reports receiving grant support/research contracts from Medtronic, consulting fees/honoraria/serving on the speaker’s bureau for Abbott Vascular, St. Jude Medical and Valtech Cardio, having equity in 4tech and receiving royalties from Edwards Lifesciences.

 

Comments