Pathologic aspects of polytetrafluoroethylene sutures in human heart

doi:10.1016/0003-4975(95)01138-2

The Annals of Thoracic Surgery

Volume 61, Issue 3, March 1996, Pages 883-887

https://doi.org/10.1016/0003-4975(95)01138-2 Get rights and content

Background.

Polytetrafluoroethylene (PTFE) sutures have been widely used as a mitral chord substitute. We present the cases of 4 patients who underwent mitral valve repair with chordal replacement by PTFE sutures and these required another operation. This gave us the chance to examine the PTFE sutures.

Methods.

Structural analysis of the PTFE sutures was performed 26 to 378 days postoperatively. The specimens were examined grossly, microscopically, and by scanning or transmission electron microscopy or both.

Results.

The PTFE suture in 1 patient was found to be completely covered with endothelial cells 154 days post-operatively. There was no calcification, and the flexibility and pliability of the PTFE sutures was preserved. Even though the PTFE sutures seemed uncovered on visual inspection, there was a thin lining of collagen and fibrin on the surface. Endothelial cells were seen in areas that looked clear in one specimen 26 days postoperatively.

Conclusions.

We think that the new layer of collagen could be promising in terms of durability and that the endothelial layer will resemble normal tissue in its anticoagulant properties.

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Cited by (17)

Post-mortem evaluation of expanded polytetrafluoroethylene (ePTFE) used in mitral valve repair in dogs
2012, Journal of Veterinary Cardiology
Citation Excerpt :
PTFE has been used to simulate chordae in a sheep model, and the PTFE was found to be completely covered by a tissue sheath with a collagen matrix and endothelial surface. Some reports have studied the long-term histological features of ePTFE in human medicine.11–14 Similar pathological findings are found in the human heart.
Mitral valve repair is one of the treatment options for mitral regurgitation. Expanded polytetrafluoroethylene (ePTFE) is a polymer that has been widely used in cardiovascular surgery. In this case series, we report the autopsy and histological findings in 6 dogs that underwent cardiopulmonary bypass for mitral annuloplasty using ePTFE sheets and chordoplasty using ePTFE sutures.
From May 2005 to October 2009, 3 female and 3 male dogs with severe mitral regurgitation underwent mitral valve repair. This case series included 3 Cavalier King Charles spaniels, 2 Maltese, and 1 Shih Tzu. The survival period after surgery was 19–72 (35 ± 19) months.
In all the cases, autopsy revealed that the ePTFE sheets and sutures were not damaged and well integrated into the surrounding highly differentiated, connective tissues. Low-power microscopy revealed that in all cases, the tissues surrounding the ePTFE sheet in the mitral valve annulus had almost completely been covered by granulation tissue. No inflammatory infiltrate or thrombogenesis was observed around the ePTFE in any of the cases.
There was no evidence of reactive changes in the region surrounding the ePTFE. These results suggest that ePTFE has excellent tissue compatibility and durability and can be effectively used for canine mitral valve repair.
Calcification of synthetic polymers functionalized with negatively ionizable groups: A critical review
2007, Reactive and Functional Polymers
The functionalization of polymers with ionizable carboxyl and oxyphosphorus (phosphate, phosphonate, etc.) groups has been frequently advocated as a method of enhancing their calcification capacity as a prerequisite in certain biomedical applications. However, the existing literature regarding in vitro and in vivo experimental calcification of functionalized polymers is rather a collection of contradictory reports. Some investigators found that carboxyl or oxyphosphorus substituents increased the calcification capacity of polymers, while others could not notice any effect, and in some instances an inhibitory effect was unambiguously demonstrated. Although this problem is of immediate relevance to the field of orthopaedic and dental biomaterials, no study of the results published to date is available. This work presents a thorough overview of the subject and analyzes critically the extant reports.
Seven years' experience with suture annuloplasty for mitral valve repair
2006, Journal of Thoracic and Cardiovascular Surgery
Our early experience with the mural annulus shortening suture procedure for mitral valve repair showed superior hemodynamic performance over ring annuloplasty. The aim of this study was to assess the durability of the mural annulus shortening suture procedure and evaluate our 7-year experience regarding valve function, hemodynamic performance, and clinical outcome.
Between 1996 and 2003, 222 elective consecutive patients (58.1% males; age, 59 ± 14 years) underwent simple or complex mitral valve repair. Minimal invasive reconstruction was performed in 150 patients. For correction of annular dilatation, we used double-running 2-0 polytetrafluoroethylene sutures to reinforce the posterior circumference of the annulus. Patients were investigated prospectively by means of transthoracic echocardiography before discharge and 1 and 5 years after the operation. The mean follow up was 32 ± 21 months (range 1-77 months).
The operative mortality was 3.1%. Hemodynamic performance at 1 and 5 years showed low mean transvalvular gradients (2.1 ± 0.9 and 2.0 ± 0.8 mm Hg, respectively) and a calculated mitral valve orifice area of 3.3 ± 0.9 cm² and 3.1 ± 0.6 cm², respectively, with progressive annular dilatation from 31.2 ± 3 mm to 33.9 ± 4 mm at 1 year and 35.7 ± 4 mm at 5 years (P < .01). Clinical status improved from New York Heart Association class 3.0 ± 0.4 to 0.6 ± 0.8 at 1 year and 0.8 ± 0.8 at 5 years. Freedom form nontrivial residual mitral regurgitation was 82.3%, freedom from reoperation was 95.1% and actuarial survival was 87.2%, all at 77 months.
The midterm results show satisfactory hemodynamic performance and clinical improvement. Valve competence and reoperation rates are comparable with those of other reports. Durability of the mural annulus shortening suture procedure for mitral valve repair is questioned because progressive annular redilatation occurs.
Structural characterization of the chordae tendineae in native porcine mitral valves
2005, Annals of Thoracic Surgery
Citation Excerpt :
Mitral valve repair is becoming a more attractive option instead of replacement to correct regurgitation. Currently silk, nylon, and e-polytetrafluoroethylene (Gortex) sutures are used for chordae replacement [16–22]. If these synthetic materials are used to replace the native chordae, it is possible that the leaflet tissue where the native chordae inserts may become necrotic due to lack of a nutrient supply.
This study was aimed to characterize the different mitral valve chordae tendineae to provide additional understanding of their function.
Mitral valve chordae tendineae from fresh porcine hearts were stained for collagen and elastin using either a Verhoeff and van Gieson stain or Verhoeff light green stain. Cellular distribution was determined using a hematoxylin and eosin stain. Immunohistochemistry was used to verify the findings of vasculature. Biochemical assays were performed to quantify DNA, collagen, and elastin content of each of the six different types of chordae tendineae.
Blood vessels were observed in the longitudinal and circumferential directions of the chordae. The strut chordae on the anterior leaflet of the mitral valve showed an increased degree of vascularization compared with the other chordae. All chordae had an inner layer characterized by a high concentration of collagen and an outer layer that was mostly elastin with interwoven collagen fibers. The collagen microstructure was characterized by directional crimping. Hematoxylin and eosin staining showed fibroblasts evenly distributed throughout the inner and outer layer of the chordae tendineae. Quantitative analysis showed significantly higher levels of DNA and collagen content in the anterior and posterior marginal chordae compared with the other chordae.
The chordae tendineae were seen to have different microstructures according to chordal type. The presence of vessels characterized the chordae tendineae as complex living components that work in coordination with the papillary muscles and mitral valve leaflets to prevent mitral valve prolapse and regurgitation. They may also function to supply nutrients to the valve leaflets.
Repair of congenital tricuspid valve abnormalities with artificial chordae tendineae
1998, Annals of Thoracic Surgery
Background. Congenital abnormalities of the tricuspid valve, including Ebstein’s malformation, dysplasia, straddling, and those found in pulmonary atresia with intact septum and congenitally corrected transposition, are an uncommon cause of tricuspid regurgitation. Congenital tricuspid valve anomalies are found as a spectrum of disease in which both the leaflets and the subvalvar apparatus are often involved. Tricuspid valve repair is complicated in such patients because the chordae tendineae are often abnormally short and thick. Replacement or augmentation of chordae tendineae has proved to be a useful component of mitral valve repair. In the present report, we describe the techniques and results of chordal augmentation in the repair of congenital tricuspid valve abnormalities.
Methods. Since July 1992, tricuspid valve repair has been performed in 5 children with severe tricuspid regurgitation secondary to congenital abnormalities of the tricuspid valve with significant chordal pathology. As a component of the repair, chordal replacement or augmentation was performed using expanded polytetrafluoroethylene suture.
Results. Intraoperative and postoperative echocardiographic assessment showed good mobility of the tricuspid valve leaflets and trivial to mild tricuspid regurgitation. There were no complications and no early or late mortality. At follow-up of 34 to 60 months (median, 49 months), tricuspid valve function has remained excellent in 4 of the 5 patients. In the remaining patient, progressive regurgitation of the right ventricle to pulmonary artery allograft conduit has led to right ventricular dilatation, with a secondary increase in tricuspid regurgitation from trivial to moderate.
Conclusions. Chordal replacement or augmentation with expanded polytetrafluoroethylene suture is a useful technique in the repair of congenitally dysplastic tricuspid valves with abnormal chordal structures.
Mitral-valve repair without annuloplasty rings: Results after repair of anterior leaflet versus posterior-leaflet defects using polytetrafluoroethylene sutures for chordal replacement
2000, European Journal of Cardio-thoracic Surgery

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Original article: CardiovascularPathologic aspects of polytetrafluoroethylene sutures in human heart

Background.

Methods.

Results.

Conclusions.

J Thorac Cardiovasc Surg

J Thorac Cardiovasc Surg

J Thorac Cardiovasc Surg

Ann Thorac Surg

J Thorac Cardiovasc Surg

J Thorac Cardiovasc Surg

Ann Thorac Surg

Original article: Cardiovascular
Pathologic aspects of polytetrafluoroethylene sutures in human heart