Thoughtful Insights at TCT: Many Questions Remain Around Treatment of Valvular Disease

Washington, DC—Uncertainty surrounding the treatment of high-risk patients with aortic stenosis and mitral regurgitation (MR) formed the basis of an “Aortic and Mitral Valve Disease” session on the last day of TCT 2014.

Case presentations, “thoughtful insights” reactions, and panel discussions covered 3 broad areas: high-risk aortic stenosis with concomitant CAD, low-flow aortic stenosis with MR, and functional MR in high-risk patients with low ejection fraction.

Major questions about appropriate patient management remain in each area. “You should be congratulated on picking 3 topics for which there are no answers to anything,” Martyn R. Thomas, MD, of St. Thomas’ Hospital (London, England), quipped to TCT Course Director Martin B. Leon, MD, of Columbia University Medical Center (New York, NY).

High-Risk Aortic Stenosis With Concomitant CAD

The first case was a 90-year-old woman who had multivessel CAD, severe aortic stenosis, and normal left ventricular (LV) function. After undergoing balloon aortic valvuloplasty to get her through surgery for colon cancer, she underwent PCI of the LAD, with other lesions deferred. After that, she underwent transfemoral TAVR.

James B. Hermiller Jr., MD, of St. Vincent Heart Center of Indiana (Indianapolis, IN), noted in his “thoughtful insights” presentation that about two-thirds of those with aortic stenosis also have obstructive coronary disease. In these patients, he said, the standard treatment has been surgical aortic valve replacement (SAVR) plus CABG.

Numerous questions remain regarding the use of TAVR in these patients, Dr. Hermiller said, including the impact of CAD on TAVR outcomes, the optimal timing of PCI relative to TAVR, stent choice, which lesions to treat, and whether fractional flow reserve can guide revascularization.

Some of the panel discussion revolved around the completeness of revascularization. Allan Schwartz, MD, of Columbia University Medical Center, said it is a judgment call: “The more angina plays a role, the more you want to revascularize completely. However, if you have someone with critical [aortic stenosis] and you relieve [it], often angina changes from a severe problem to something that’s easily manageable.”

For that reason, several of the panelists reported such patients would not typically undergo PCI in addition to TAVR at their centers. Dr. Thomas added that PCI generally would be performed if the goal was to ease angina or improve LV function.

Dr. Hermiller said that if TAVR is selected over SAVR at the advice of the heart team, other factors need to be considered when choosing the approach to CAD. TAVR alone may be reasonable in patients with small-vessel or distal disease, a chronic total occlusion (CTO), or disease requiring complex PCI that may induce renal failure, he said. On the other hand, he continued, TAVR plus PCI can be considered in patients with LM or proximal disease, large areas perfused, ACS, or clinical evidence of ischemia.

Some answers about the appropriate approach to these patients might come from the ACTIVATION trial, which is randomizing patients to TAVR without coronary revascularization or to PCI followed by TAVR.

Low-Flow Aortic Stenosis With MR

Two cases of patients who had paradoxical low-flow, low-gradient severe aortic stenosis with normal ejection fraction preceded the “thoughtful insights” presentation by Philippe Pibarot, DVM, PhD, of Quebec Heart and Lung Institute (Quebec, Canada). In both cases—one accompanied by moderate-to-severe degenerative MR—TAVR resulted in increased stroke volume and improvement in symptoms.

Dr. Pibarot highlighted the importance of making sure these patients actually have “severe” aortic stenosis as opposed to pseudo-severe disease before deciding on treatment, a process that is not always straightforward in practice. Multiple techniques can be used, including dobutamine stress echocardiography and calcium scoring using multidetector computed tomography.

Dobutamine stress echocardiography “is still the gold standard for figuring that out,” said panelist Howard C. Herrmann, MD, of the Hospital of the University of Pennsylvania (Philadelphia, PA), who added that an anatomic assessment of the valve using transesophageal echocardiography can also be particularly helpful.

The next question would be whether intervention is beneficial, Dr. Pibarot said, and an analysis of the PARTNER trial showed better survival following TAVR compared with SAVR or medical therapy—at least through 18 months. In addition, studies have shown a recovery of flow after TAVR, with faster recovery with transfemoral vs transapical procedures, but more data are needed, Dr. Pibarot said.

As to how to treat patients with both severe aortic stenosis and MR, Dr. Schwartz said, the more structural the mitral valve disease is, the less likely intervention will resolve heart failure symptoms. So in general, one would focus on treating the more serious problem of aortic stenosis, he explained, particularly in an elderly patient. “But in a younger patient you hate to leave severe structural MR behind,” he stated.

TCT Course Director Gregg W. Stone, MD, of Columbia University Medical Center, noted that in prior series, TAVR improved MR about one-third of the time when the origin was functional and less than 20% of the time when degenerative.

Dr. Herrmann pointed out that previous studies have shown pretreatment gradient to also predict the change in MR after TAVR, with greater improvements in those with the largest gradients. Thus, a patient with low-flow, low-gradient aortic stenosis would have less improvement in MR.

Functional MR in High-Risk Patients With Low Ejection Fraction

In his “thoughtful insights” presentation, Michael J. Mack, MD, of the Heart Hospital Baylor Plano (Plano, TX), raised 2 major questions: how should functional MR be treated and does such treatment improve patient outcomes?

There are 3 options to treat functional MR—restrictive undersized mitral valve annuloplasty, mitral valve replacement, and the MitraClip (Abbott Vascular)—all of which should be preceded with guideline-directed medical therapy, he said. “One of the major lessons that we’ve learned in the COAPT trial so far is how undertreated ischemic mitral regurgitation is and, when these patients get on appropriate guideline-directed medical therapy, how much of the time the mitral regurgitation improves.”

Although annuloplasty can correct MR, the problem will return in about one-third of cases as the ventricular disease progresses, Dr. Mack said. That issue led to the CTSN SMR trial, which compared surgical mitral valve repair and replacement for severe ischemic MR. The result showed that replacement was a more durable fix than repair, with MR recurring in 2.3% and 32.6%, respectively, at 1 year.

The other option is the MitraClip. In the ongoing COAPT trial, patients with significant functional MR who are taking guideline-directed medical therapy are being randomized to continue on medical therapy alone or undergo a MitraClip procedure. The trial, Dr. Mack and other panelists agreed, will help clarify the unanswered question of whether treating MR has clinical benefits.

In the very early stages of development are devices for transcatheter mitral valve replacement (TMVR), which might turn out to be the best option of them all if it is determined that treating MR is worthwhile, Dr. Mack said.

When asked to speculate about the ideal patient for TMVR, Dr. Herrmann said that the procedure would likely be more appropriate for a patient at high surgical risk rather than an inoperable patient in whom there are no other options.

 

 

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Disclosures:

 

• Dr. Thomas reports receiving consultant fees/honoraria/speaker’s bureau payments from Edwards Lifesciences.
• Dr. Hermiller reports receiving consultant fees/honoraria/speaker’s bureau payments from Abbott Vascular, AstraZeneca, Boston Scientific, Daiichi Sankyo/Eli Lilly, and St. Jude Medical.
• Dr. Pibarot reports receiving grant funding from the Canadian Institutes of Health Research and the Heart and Stroke Foundation of Canada and research grants from Edwards Lifesciences and V-Wave Ltd.
• Dr. Stone reports receiving consultant fees/honoraria/speaker’s bureau fees from Reva and TherOx and having equity in Artasis, Biostar Funds, Caliber, Guided Delivery Systems, MedFocus Funds, Micardia, and VNT.

Dr. Mack reports being the co-principal investigator of the COAPT trial of MitraClip, which is sponsored by Abbott Vascular.

• Dr. Leon reports relationships with multiple device companies.
• Dr. Herrmann reports relationships with multiple pharmaceutical and device companies.
• Dr. Schwartz reports no relevant conflicts of interest.

Related Stories:

• Incomplete Revascularization Linked to Poorer Outcomes in TAVR Patients With CAD
• Low-Flow, Low-Gradient AS: An Important Clinical Target for TAVR
• Randomized Trials of the MitraClip in FMR: From COAPT to RESHAPE