EXPAND: Transcatheter mitral valve repair cuts mitral regurgitation in real-world population
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In a real-world study of newer-generation transcatheter mitral valve repair devices, patients who underwent transcatheter mitral valve repair, even those with complex mitral anatomy, had significantly reduced mitral regurgitation compared with those treated with previous-generation devices.
For the global EXPAND study, researchers implanted 1,041 patients with the devices (MitraClip NTR or XTR, Abbott); 835 had adequate imaging to undergo analysis by an echocardiography core lab.
D. Scott Lim, MD, professor of medicine at the University of Virginia, presented an analysis of 422 patients with primary mitral regurgitation or mixed etiology (mean age, 80 years; 52% men) at the virtual American College of Cardiology Scientific Session.
“The MitraClip has been in evolution over time, and this study evaluated the current generation of MitraClip NTR and XTR devices, which have improved delivery systems, and for the XTR variant, longer clip arms,” Lim said during a presentation. “Therefore, the primary objective of this report is to detail the real-world, echo core lab- and clinical events committee-adjudicated outcomes in primary mitral regurgitation treated by the NTR and XTR systems from the more than 1,000-patient global EXPAND registry.”
Major adverse event rates at 30 days were low, Lim said during the presentation, noting that the rate of death was 2.4%, the rate of stroke was 1.2%, the rate of nonelective CV surgery for device-related complications was 0.9% and there were no cases of MI.
Among device-related leaflet adverse events, single leaflet device attachment occurred in 1.9% of patients and leaflet injury occurred in 0.2%, he said.
Less mitral regurgitation
Mitral regurgitation severity dropped greatly in the cohort between baseline and 30 days, according to the researchers. Lim said at 30 days, 27.7% of patients had no or trace mitral regurgitation, 86.9% had severity of 1+ or less and 97.3% had severity of 2+ or less.
In addition, he said, among patients with primary mitral regurgitation, severity of 1+ or less at 30 days was greater in the EXPAND cohort than in the prohibitive risk cohort from the EVEREST clinical trials (82.1% vs. 53.6%).
Patients from EXPAND also showed signs of positive left ventricular remodeling, with reductions from baseline to 30 days in LV end-systolic diameter (P < .0001), LV end-diastolic diameter (P < .0001), LV end-systolic volume (P = .01) and LV end-diastolic volume (P < .0001), Lim said.
The cohort also improved in NYHA class (P < .001) and Kansas City Cardiomyopathy Questionnaire score (50.2 to 70; P < .001) from baseline to 30 days, he said.
Mitral regurgitation severity reduction occurred both in patients with complex anatomy (1+ or lower at 30 days, 79.4%) and in those without complex anatomy (1+ or lower at 30 days, 88.9%), according to the researchers.
Lim noted, however, that in those with complex anatomy, reduction in mitral regurgitation severity was greater with use of the XTR clip compared with the NTR clip (P = .0383), whereas choice of clip did not affect reduction in mitral regurgitation severity in those without complex anatomy (P = .6802).
“The EXPAND study represents the first contemporary report of echo core lab- and clinical events committee-adjudicated outcomes in patients with primary mitral regurgitation treated with the next-generation NTR and XTR MitraClips,” Lim said. “The EXPAND study confirms the safety and efficacy of the MitraClip NTR and XTR systems in primary MR subjects in a contemporary real-world setting.”
Improvement in technology
The data demonstrate “the improvement of the MitraClip technology and the knowledge that operators have gained with experience over the last decade,” Alan Zajarias, MD, MSc, FACC, professor of medicine at Washington University School of Medicine in St. Louis, said during a discussion after the presentation. “The results are going to be generalizable to the general population, as the study included the types of patients that are being treated commercially. The results also demonstrate that the procedure is very successful, with an up to 94.5% success rate with decreased procedural times compared with previous data sets.” – by Erik Swain
Reference:
Lim DS, et al. Featured Clinical Research III. Presented at: American College of Cardiology Scientific Session; March 28-30, 2020 (virtual meeting).
Disclosures: The study was funded by Abbott. Lim reports he consults for Abbott, Edwards Lifesciences, Pipeline and Venus, holds equity in 510Kardiac and Venus and received institutional research grants from Abbott, Boston Scientific, Corvia, Edwards Lifesciences, Keystone Heart, LivaNova, Medtronic and W.L Gore and Associates. Zajarias reports he has financial ties with Abbott, Boston Scientific, C.R. Bard and Edwards Lifesciences.
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