MitraClip Performs Well Even in Patients with Degenerative Regurgitation

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Percutaneous repair of mitral regurgitation (MR) in high-risk patients has a high rate of success and is equally effective for both functional and degenerative disease, according to registry results published online February 22, 2013, ahead of print in the American Journal of Cardiology.

Davide Capodanno, MD, PhD, of Ferrarotto Hospital (Catania, Italy), and colleagues looked at data from 117 patients with functional (n = 89) or organic (n = 28) MR who were treated at their institution between August 2008 and October 2012. All patients received implantation with the MitraClip System (Abbott Vascular, Santa Clara, CA) and were enrolled in the Getting Reduction of Mitral Insufficiency by Percutaneous Clip Implantation (GRASP) registry.

Few Differences in Safety or Efficacy by Etiology

Acute device success was 100%. Reduction of MR to grades 1+ and 2+ was achieved in 61% and 39% of patients with degenerative MR and 64% and 36% of patients with functional MR, respectively (P = 0.75). At 30 days, the rates of death and major adverse events were 0.9% and 3.4%, respectively, indicating reasonable safety; interestingly, all events occurred in patients with functional disease. The primary efficacy endpoint (composite of freedom from death, surgery for mitral valve dysfunction, or grade 3+ or 4+ MR) was 96.4%.

The mortality rate at 1-year follow-up was 14.0%, with most of those deaths from cardiovascular causes (45%). The primary efficacy endpoint at 1-year was 75.8%, with no difference between patients with functional or degenerative MR (log-rank P = 0.78).

No patients required surgery for mitral valve dysfunction within the first year after clip implantation, nor were there any cases of clip detachment or embolization.

The majority of patients received 1 clip (n = 69), with the remainder receiving 2 (n = 47) and 1 patient requiring 3 clips. Patients with degenerative disease were more likely than patients with functional disease to require more than 1 clip (64% vs. 34%; P = 0.005).

Device implantation time, defined as the time from guide insertion until clip delivery system removal, decreased with experience from 71 minutes in the first third of the study to 58 minutes in the last third. Times varied between patients with 1 vs. 2 or more clips (55 minutes vs. 90 minutes; P < 0.001).

Careful Selection, Operator Experience Paramount

In an e-mail communication with TCTMD, Dr. Capodanno said registries such as GRASP are important because they serve to document current practice with the MitraClip. They also expand on the generalizability of the procedure beyond the clinical and echocardiographic criteria of the EVEREST II trial, the largest so far to look at high-risk MR patients. Patients in GRASP were higher risk than the EVEREST II cohort in that they were older (72 ± 10 years vs. 67 ± 13 years), more symptomatic (NYHA class ≥ III in 80% vs. 51%), and had lower LVEF (38 ± 13% vs. 60 ± 10 %).

Although grasping a valve with degenerative disease is more difficult and time-consuming than grasping a valve with functional disease—and often requires more than 1 clip—the GRASP data “suggest that careful anatomic selection and technical dedication during the procedure may achieve satisfactory acute and mid-term clinical results even in patients with degenerative etiology,” Dr. Capodanno said.

However, the registry also brings up the issue of the learning curve associated with using the percutaneous device. According to Dr. Capodanno, proficiency in clip implantation can be achieved relatively fast after about 10 to 15 simple cases of MR.

“The learning curve should begin with functional cases and gradually incorporate more complex cases, including degenerative MR,” he said. “After about 40 cases, an operator should be able to master all the possible presentations. The learning process goes faster when operators and echocardiograph[ers] collaborate [as] a whole.”

But in a telephone interview with TCTMD, Ted Feldman, MD, of Evanston Hospital (Evanston, IL), countered, “I don’t think you can write a battle plan that’s that clear.

“Etiology is less important in some sense than just doing those early cases, regardless of what the anatomy is, because the procedure is more novel than anything we have done historically in the cath lab,” he explained, adding that the skill set also includes better communication between the imaging technician and operator. “Then you have [all] that comes with becoming facile in the procedure and that encompasses probably the first 30 to 50 cases. But the other part of the learning curve that is continuous and evolving is patient selection. So, to talk about the learning curve as only cases, or as only what goes on the in cath lab, understates the challenge.”

Registry Data Crucial to Ongoing Understanding

Dr. Feldman said the GRASP data “serve as reference points for our ongoing experience,” adding that the strength of the registry is that the procedures are all being performed by a small team that has developed both procedural and patient-selection expertise.

“It adds a perspective that’s important,” Dr. Feldman said, “because the limitation we have in the United States is that very few operators have had enough regular procedural experience [with the MitraClip] to develop the level of technical expertise that the Catania group has.” By looking at a broader patient population than EVEREST and US trial experience, the GRASP data also show that patients who have no other option due to their extreme degenerative anatomy “will do fairly well with this procedure,” he noted.

Dr. Capodanno concluded that while the results seem promising, “large series with follow-up longer than 1 year are needed to address the issue of the efficacy and duration of MitraClip results in patients with functional or degenerative mitral regurgitation.”

Study Details

Patients with functional MR presented more commonly with diabetes, hypertension, history of CAD, previous PCI, and low LVEF compared with degenerative MR patients.

Source:

Grasso C, Capodanno D, Scandura S, et al. One- and twelve-month safety and efficacy outcomes of patients undergoing edge-to-edge percutaneous mitral valve repair (from the GRASP Registry). Am J Cardiol. 2013;Epub ahead of print.

Related Stories:

• EVEREST II Registry Looks at MitraClip in High-Risk Patients
• Extended EVEREST II Data Examine Safety, Efficacy of MitraClip as Well as Cost Effectiveness
• Clip Device Effective for Both Functional, Degenerative Mitral Regurgitation