[Show abstract][Hide abstract] ABSTRACT: The safety and effectiveness of the MitraClip device (Abbott Vascular, Menlo Park, CA) is being evaluated in the Endovascular Valve Edge-to-Edge Repair Study (EVEREST) clinical studies. The healing response after device implantation has not previously been characterized in humans.
A total of 67 explanted devices (implantation duration, 1 to 1878 days) from 50 patients were submitted for histological evaluation. Explants were analyzed in 4 implantation intervals: acute (≤30 days; n=7), subacute (31 to 90 days; n=23), chronic (91 to 300 days; n=18), and long term (>300 days; n=19). The acute healing response consisted of platelet/fibrin deposition. The subacute response exhibited granulation tissue with early fibrous encapsulation (pannus). The chronic response was characterized by various degrees of tissue bridging between the device arms. The long-term healing response demonstrated collagen-rich matrix (by type I collagen), incorporating the device components with complete encapsulation by organized, fibrous growth. In long-term devices with minimal surgical disruption, a fibrous tissue bridge (mean area, 7.39±4.3 mm(2)) was observed over and between the device arms, resulting in atrial tissue continuity between the 2 valve leaflets. Devices demonstrated no evidence of endocarditis, mechanical wear, component fracture, or corrosion up to the time of explantation (median, 119 days; first and third quartiles, 42 and 365 days).
In all patients, device mechanical integrity was maintained up to the time of explantation. Four phases of physiological healing were observed: platelet and fibrin deposition, inflammation, granulation tissue, and finally, fibrous encapsulation. Long-term device fibrous encapsulation with extension over adjacent mitral leaflets and tissue bridge formation adds structural stability. Clinical Trial Registration- URL: http://clinicaltrials.gov/show/NCT00209274. Unique identifiers: NCT00209339 and NCT00209274.
[Show abstract][Hide abstract] ABSTRACT: Mitral valve surgery is the standard of care for patients with symptomatic mitral regurgitation (MR) or asymptomatic MR with evidence of left ventricular dysfunction or dilation. Whether an endovascular approach to repair can offer comparable effectiveness with improved safety remains to be determined in randomized trials.
The EVEREST II Trial is a multicenter, randomized controlled trial to evaluate the benefits and risks of endovascular mitral valve repair using the MitraClip device compared with open mitral valve surgery (control) in patients with moderate or severe MR. Using a 2:1 randomization ratio, the trial is enrolling up to 186 MitraClip-treated subjects and 93 control subjects. Trial end points include a primary efficacy end point: the proportion of patients free from death, surgery for valve dysfunction, and with moderate-severe (3+) or severe (4+) MR at 12 months; the primary safety end point includes the proportion of patients with death, myocardial infarction, reoperation, nonelective cardiovascular surgery, stroke, renal failure, deep would infection, ventilation >48 hours, gastrointestinal complication, new permanent atrial fibrillation, septicemia, or transfusion of >or=2 U at 30 days or hospital discharge, whichever is longer.
This randomized controlled trial is designed to evaluate the performance of endovascular mitral repair in comparison to open mitral valve surgery in patients with significant MR.
American heart journal 07/2010; 160(1):23-9. DOI:10.1016/j.ahj.2010.04.009 · 4.46 Impact Factor