Cardiologist Raj Makkar, MD, vice president of cardiovascular innovation and intervention and chair of interventional cardiology at Cedars-Sinai in Los Angeles, spoke to Cardiovascular Business at ACC.23 about the safety and efficacy of transcatheter edge-to-edge repair (TEER) of the mitral valve in patients with degenerative mitral regurgitation (MR). His analysis was based on STS/ACC TVT Registry data from 2014 to 2022.
The study looked at 60,883 patients who underwent TEER between 2014 and June 30, 2022. Of those, 19,088 had undergone TEER for moderate-severe or severe MR due to degenerative pathology. MR success was defined as post-repair residual MR at or below moderate and the absence of sever stenosis with a mean gradient at or below 10mmHg. The study also looked at overall procedure success rates, mortality, reintervention rates and heart failure readmissions.
"We found 89% of patient were able to achieve success," Makkar said. "The second thing was, the safety of the procedure was excellent."
In-hospital mortality was about 1%, all-cause strokes was about 0.6%, and unplanned surgery or interventions were also around 1%. Looking at 30-day outcomes, mortality was 2.66% and the risk of any other negative outcomes was also around 1%, Makkar explained.
TEER helps reduce death rates by 50%
The researchers also compared outcomes of patients with successful versus unsuccessful procedures. Makkar said this was done as a similar comparison of patients with the procedure and a sham procedure or receiving a placebo, which would normally be done in a randomized controlled trial.
"We found patients who had a successful procedure had a death rate that was half as much of patients who did not have a successful procedure. And the same was true for heart failure readmissions, which were cut by half. And for mitral reinterventions, patients who had a successful procedure, the rate was cut by 85%," Makkar said. "This is not a randomized trial, but it is a form of indirect evidence that repairing the mitral valve does impact clinical differences."
He said the landmark COAPT study showed a major difference between heart failure patients with functional MR being treated with TEER compared to this treated with drugs along. However, Makkar said there is not a similar comparison study in degenerative MR, so he feels this study offers that type of evidence showing the efficacy of TEER in a real-world population for the first time.
Are more MitraClips to reduce MR better or worse for patient outcomes?
This study also looked at patient outcomes based on the level of residual MR after the procedure compared to unsuccessful procedure patients. Makkar said reducing MR but not completely eliminating it does help patients. However, the study shows there might be a point where a procedure is good enough and it is best to not completely eliminate all the regurgitation with additional clips. Procedurally, extra clips may eliminate or further reduce MR, but this also can increase pressure gradients that can lead to poorer outcomes.
"We also looked at gradients in these patients. So when we talk about any transcatheter mitral valve therapy, it is important to not only pay attention to mitral regurgitation or reduction in MR, but also to the gradients. This is because you can eliminate the MR leakage by putting in several clips, but the gradients will go up and that effects clinical outcomes," Makkar explained.
The best category of patients where those with mild residual MR and a low gradient of less than 5mmHg. But patients had poorer outcomes if they had mild residual MR and higher gradients of between 5-10.
This raised the question if one clip is good enough or if more clips are better if considering the gradient information.
"It gives me pause. It is not about eliminating mitral regurgitation and color [on the Doppler echo] in these patients, it is about creating a balance. It is about reducing mitral regurgitation and making sure you are not significantly increasing the gradients and causing stenosis. So you will have to deal with each procedure individually."
Makkar said this was a big takeaway for him. "We need to be as mindful of the gradients as we are of reducing mitral regurgitation in the patient," he said.
Higher levels of operator experience with TEER led to improved outcomes
The study also broke out data for each year between 2014-2022 to track overall performance. It was clear that, as operators gained more experience with MitraClip, there were fewer complications and improved outcomes. A similar treat was also seen in transcatheter aortic valve replacement (TAVR) over the past decade. As TAVR operators gained more experience the rates of stroke and the need for permanent pacemakers saw marked reductions.
Overall, TEER procedural success rates increased from 81.5% in 2014, to 92.2% in 2022 because operators had gained a lot of experience over eight years, Makkar explained. In addition to operator and the overall collective experience in the structural heart field with TEER, he said 3D transesophageal echo (TEE) also greatly improved the ability to visualize the clip device and surrounding anatomy in real time as it is moving, greatly enhancing the ability to grasp the rapidly moving mitral valve leaflets. The MitraClip itself also went through several design iterations to its present generation, making it easier to use.
Dave Fornell has covered healthcare for more than 17 years, with a focus in cardiology and radiology. Fornell is a 5-time winner of a Jesse H. Neal Award, the most prestigious editorial honors in the field of specialized journalism. The wins included best technical content, best use of social media and best COVID-19 coverage. Fornell was also a three-time Neal finalist for best range of work by a single author. He produces more than 100 editorial videos each year, most of them interviews with key opinion leaders in medicine. He also writes technical articles, covers key trends, conducts video hospital site visits, and is very involved with social media. E-mail: dfornell@innovatehealthcare.com