Invited Commentary

Abstract

This study by Kelley and colleagues [1Kelley Jr., T.M. Kashem M. Wang He et al.Anterior leaflet augmentation with CorMatrix porcine extracellular matrix in twenty-five patients: unexpected patch failures and histologic analysis.Ann Thorac Surg. 2017; 103: 114-121Abstract Full Text Full Text PDF PubMed Scopus (31) Google Scholar] conveys several messages on the surgical management of patients with mitral regurgitation (MR) with Carpentier types IIIa and IIIb lesions, but what all 44 patients had in common was augmentation of the anterior leaflet of the mitral valve with a large patch of CorMatrix (CorMatrix, Roswell, GA) in 25 patients or glutaraldehyde-fixed autologous pericardium in 19. One operative death and two late deaths occurred during the first year of follow-up. The CorMatrix patch failed in 8 patients and caused severe MR that prompted reoperation in 7 patients. The failures occurred from 71 to 327 days after operation (mean, 192 days), suggesting that the remaining patients may be at high risk for patch failure, but this information is not available because the follow-up was closed at 1 year. Only 2 patients with autologous pericardial patches experienced moderate MR. Numerous important issues are worth discussing in this study, ranging from the appropriateness of patch enlargement of the anterior leaflet, to repair of the mitral valve in patients with functional or postinflammatory MR, to the size of the patch used, the type of annuloplasty, and how the operations were conducted, but the main focus here is that the CorMatrix patch of the anterior leaflet of the mitral valve was associated with an unacceptably high failure rate in the first year of follow-up. My personal experience with CorMatrix as a patch material for heart valve reconstruction is limited, and the results have been less than satisfactory. I used it to replace parts of the mitral valve leaflets in 4 patients with active infective endocarditis: in 1 patient the patch disintegrated, and 10 months later mitral valve replacement was necessary [2Luk A. Rao V. Cusimano R.J. David T.E. Butany J. CorMatrix extracellular matrix used for valve repair in the adult: is there de novo valvular tissue seen?.Ann Thorac Surg. 2015; 99: 220-227Abstract Full Text Full Text PDF Scopus (17) Google Scholar]; 2 patients experienced moderate MR likely related to the patch, and 1 patient remains without MR up to 2 to 3 years since the operation. We also used CorMatrix to reconstruct the mitral annulus in 8 patients and the mitral annulus and intervalvular fibrous body in 6 patients with extensive dystrophic calcification and severe mitral valve dysfunction. Of 13 operative survivors, 7 have required reoperation because of disintegration of the patch, and 3 have had paravalvular dehiscence during the first 4 years of follow-up. Luckily, all patients survived their reoperations and remain well. In our hands, every bioprosthetic valve secured to the CorMatrix patch became detached within 6 months and 2 years from operation. We have concluded that prosthetic heart valves should not be secured on a CorMatrix patch. The biologic behavior of this material has been highly variable. In one case report it was used as a pericardial substitute and at reoperation was found to have “remodeled into viable, fully cellularized, vascularized, nonfibrotic connective tissue similar to native pericardium” [3Stelly M. Stelly T.C. Histology of CorMatrix bioscaffold 5 years after pericardial closure.Ann Thorac Surg. 2013; 96: 127-129Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar]. Most reports have failed to confirm that CorMatrix behaves as a bioscaffold for the growth of native tissue [4Zaidi A.H. Nathan M. Emani S. Baird C. del Nido P.J. Gauvreau K. et al.Preliminary experience with porcine intestinal submucosa (CorMatrix) for valve reconstruction in congenital heart disease: histologic evaluation of explanted valves.J Thorac Cardiovasc Surg. 2014; 148: 2216-2225Abstract Full Text Full Text PDF PubMed Scopus (90) Google Scholar, 5Nelson J.S. Heider A. Si M.S. Ohye R.G. Evaluation of explanted CorMatrix intracardiac patches in children with congenital heart disease.Ann Thorac Surg. 2016 May 27; Abstract Full Text Full Text PDF Scopus (36) Google Scholar]. Our experience with 11 explants have shown no evidence that the extracellular membrane is replaced by living tissues from the host. The anastomotic site showed leukocytes, macrophages, fibroblasts, and new blood vessels. These are disappointing findings because heart valve surgeons badly need a patch material that functions as a bioscaffold where native tissue can grow and renew itself. Glutaraldehyde-fixed autologous pericardium and glutaraldehyde-fixed xenograft pericardium calcifies and fractures when used to replace parts of leaflets and cusps. Anterior Leaflet Augmentation With CorMatrix Porcine Extracellular Matrix in Twenty-Five Patients: Unexpected Patch Failures and Histologic AnalysisThe Annals of Thoracic SurgeryVol. 103Issue 1PreviewThis study reported on the treatment of Carpentier type IIIa and type IIIb mitral regurgitation (MR) with a large patch anterior mitral valve leaflet augmentation technique using CorMatrix (CorMatrix Cardiovascular Inc, Alpharetta, GA) extracellular matrix (ECM). Full-Text PDF