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Early rupture of an expanded polytetrafluoroethylene neochord after complex mitral valve repair: An electron microscopic analysis
CASE REPORTS
Early rupture of an expanded polytetrafluoroethylene neochord after complex mitral valve repair: An electron microscopic analysis Javier G. Castillo, MD,a Anelechi C. Anyanwu, MD,a Ahmed El-Eshmawi, MD,a Ronald E. Gordon, PhD,b and David H. Adams, MD,a New York, NY Mitral valve repair is currently accepted as the gold standard procedure for patients who require surgery for mitral valve regurgitation, particularly in the setting of degenerative mitral valve disease.1 Repair techniques including posterior leaflet resection, sliding valvuloplasty, and complete remodeling annuloplasty are now widely and routinely applied in most centers. During the past decade, in addition to more tailored resections techniques, many centers have emphasized nonresection mitral repair strategies whenever possible, particularly in minimally invasive settings.2 In the ‘‘respect rather than resect’’ approach, chordal replacement with polytetrafluoroethylene (PTFE) (Gore-Tex; W. L. Gore & Associates, Inc, Newark, Del) sutures is used in preference to classic Carpentier techniques such as leaflet resection, chordal transposition, or the posterior leaflet flip technique. Several technical variants have been introduced including a single PTFE suture, premeasured PTFE loops, and the loop-in-loop technique, which allows functional adjustment of the final loop length.3 Mitral valve repair with PTFE neochordoplasty has been recognized to be stable and durable,4 and only a few isolated cases of ruptured PTFE neochords have been described.5 We report a case of early failure of an expanded PTFE neochord loop owing to complete rupture 4 months after implantation.
CLINICAL SUMMARY The patient was a 55-year-old man with severe mitral valve regurgitation secondary to a congenital anomaly with shortened chordeae tendineae and lateral displacement of both papillary muscles leading to type IIIb dysfunction. In addition, myxomatous changes with leaflet thickening and anterior leaflet pseudoprolapse were observed. After a limited sternotomy incision, inspection of the mitral valve revealed very complex disease with restrictive changes in the subvalvular apparatus but with relatively preserved From the Department of Cardiothoracic Surgerya and the Department of Pathology (Electron Microscopy Core Facility),b The Mount Sinai School of Medicine, New York, NY. Disclosures: Authors have nothing to disclose with regard to commercial support. Received for publication Oct 8, 2012; revisions received Nov 7, 2012; accepted for publication Dec 5, 2012; available ahead of print Jan 14, 2013. Address for reprints: David H. Adams, MD, Department of Cardiothoracic Surgery, The Mount Sinai Medical Center, 1190 Fifth Ave, New York, NY 10029-6500 (E-mail: [email protected]). J Thorac Cardiovasc Surg 2013;145:e29-31 0022-5223/$36.00 Copyright Ó 2013 by The American Association for Thoracic Surgery http://dx.doi.org/10.1016/j.jtcvs.2012.12.011
commissures (Figure 1, A). Annuloplasty sutures were placed around the annulus and several frozen chords were then cut to further free the anterior commissure. Additionally, a large chord was fenestrated to mobilize the anterior leaflet. The posterior leaflet was mobilized and a glutaraldehyde-fixed pericardial patch was used to augment the posterior leaflet (Figure 1, B). A premeasured set of pledget-supported 13-mm PTFE (Gore-Tex CV-5) loops were attached to the anterior papillary muscle head. Subsequently, 2 secondary loops (Gore-Tex CV-3) were attached to the anterior leaflet margin (loop-in-loop technique). Furthermore, a single neochord (Gore-Tex CV-3) was attached to P2 to resuspend the posterior leaflet (Figure 1, C). Finally, a true size 28-mm Carpentier-Edwards Classic annuloplasty ring (Edwards Lifesciences LLC, Irvine, Calif) was implanted (Figure 1, D). The valve had a very symmetric line of coaptation and a normal saline test. Intraoperative transesophageal and predischarge transthoracic echocardiography demonstrated trace mitral regurgitation. The patient was discharged home on postoperative day 6. Four months later, the patient had acute dyspnea and peripheral edema. Transthoracic echocardiography showed recurrent severe mitral regurgitation and anterior leaflet prolapse secondary to chordal rupture. Valve analysis revealed anterior leaflet prolapse (Figure 2, A) owing to the fracture of 1 of the premeasured loops (Figure 2, B) and a partial fracture of a second premeasured loop (Figure 2, C and D). Moreover, there was severe fibrosis and early calcification of A3 (not present at the initial operation) and a tear in the anterior leaflet along the free calcified margin. The valve was deemed irreparable and valve replacement was performed with a size 25-mm Hancock II porcine valve (Hancock Jaffe Laboratories, Inc, Irvine, Calif). Intraoperative and predischarge echocardiography confirmed good function of the bioprosthesis and the patient was discharged home on postoperative day 7. The specimen was sent for electron microscopic analysis (Figure 3, A). In addition, new CV-5 PTFE sutures were subjected to traction and friction forces to be compared with the surgical specimen. Electron microscopy confirmed complete host covering with deposition of platelets over the PTFE suture as well as the ingrowth of fibroblasts and collagen formation (Figure 3, B). Under the microscope, the area of fracture showed signs of deterioration owing to both traction and friction forces. This was clearly depicted after comparison with the images of new CV-5 PTFE sutures subjected to only friction (Figure 3, C) or only traction forces (Figure 3, D).
The Journal of Thoracic and Cardiovascular Surgery c Volume 145, Number 3
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Case Reports
FIGURE 1. Initial repair. The mitral valve presents complex rheumatic changes (A) requiring advanced repair techniques including a glutaraldehyde-fixed pericardial patch augmentation of the posterior leaflet (B), a single neochord for posterior leaflet resuspension, and a loop-in-loop technique to the anterior leaflet (C). Saline test shows a very symmetric line of coaptation (D).
DISCUSSION Chordal replacement with PTFE neochords for mitral valve reconstruction has been proven to be stable and
durable up to 20 years after surgery.4 Additionally, their relative ease of use has led to a current trend toward favoring the application of PTFE neochords in preference to leaflet
FIGURE 2. Four months after surgery, intraoperative valve analysis reveals complete anterior leaflet prolapse (A), the fracture of 1 of the premeasured loops (B), and a partial fracture of a second premeasured loop (C and D).
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Case Reports
FIGURE 3. Electron microscopic analysis of the surgical specimen shows signs of deterioration owing to traction and friction forces (A, 390,500 mcm). Complete host covering with deposition of platelets over the polytetrafluoroethylene (PTFE) suture as well as the ingrowth of fibroblasts and collagen formation were confirmed (B, 3180,250 mcm). The analysis of a new CV-5 PTFE suture subjected to only friction (C, 3120,250 mcm) or only traction (D, 390,500 mcm) forces.
resection or more complex techniques in many circumstances. Only a few isolated cases of PTFE failure have been reported, most of them in the setting of late rupture up to 14 years after surgery.6-8 Recently, Yamashita and Skarsgard5 described an unusual failure of a PTFE neochord (running suture technique) as early as 2 months after surgery. The authors alluded to intracardiac forces that potentially exceeded the strength of the CV-5 PTFE suture (failure load > 830 g) as the most likely cause, but unfortunately, no histopathologic analysis was obtained. We now report a case of early fracture of a CV-5 PTFE neochord only 4 months after the initial surgical procedure. We prefer the loop-in-loop technique, which allows functional adjustment with saline testing of the ‘‘second loop’’ as opposed to geometric measurement of a single loop to correct segmental prolapse. Although other mechanisms of failure of PTFE loops, such as instrument damage, clip damage, damage by energy sources, or native tissue or knot disruption, have all been described, none was the case in this patient. We are confident the loop ruptured from excise force and friction of the 2 loops interacting during systole. Tying the 2 loops together after height adjustment might decrease the risk of friction and loop disruption. Another possibility is to consider using a stronger PTFE suture for the anchoring loops in the loop-to-loop approach, particularly if a large
segmental prolapse is being treated and there are no native secondary chords. Application of more than 2 loops to a prolapsing segment may also be warranted if the entire support is dependent on loops. Our case serves as a reminder that all repair techniques have an intrinsic technical failure rate and that techniques and applications of PTFE neochords in mitral valve repair need continued study and possible refinement in certain circumstances. References 1. Castillo JG, Anyanwu AC, Fuster V, Adams DH. A near 100% repair rate for mitral valve prolapse is achievable in a reference center: implications for future guidelines. J Thorac Cardiovasc Surg. 2012;144:308-12. 2. Falk V, Seeburger J, Czesla M, Borger MA, Willige J, Kuntze T, et al. How does the use of polytetrafluoroethylene neochordae for posterior mitral valve prolapse (loop technique) compare with leaflet resection? A prospective randomized trial. J Thorac Cardiovasc Surg. 2008;136:1205; discussion 1205-6. 3. Okamoto K, Yozu R, Kudo M. Loop-in-loop technique in mitral valve repair via minithoracotomy. Ann Thorac Surg. 2012;93:1329-30. 4. David TE, Armstrong S, Ivanov J. Chordal replacement with polytetrafluoroethylene sutures for mitral valve repair: a 25-year experience. J Thorac Cardiovasc Surg. June 17, 2012. [Epub ahead of print]. 5. Yamashita MH, Skarsgard PL. Intermediate and early rupture of expanded polytetrafluoroethylene neochordae after mitral valve repair. Ann Thorac Surg. 2011;92:341-3. 6. Butany J, Collins MJ, David TE. Ruptured synthetic expanded polytetrafluoroethylene chordae tendinae. Cardiovasc Pathol. 2004;13:182-4. 7. Coutinho GF, Carvalho L, Antunes MJ. Acute mitral regurgitation due to ruptured ePTFE neo-chordae. J Heart Valve Dis. 2007;16:278-81. 8. Farivar RS, Shernan SK, Cohn LH. Late rupture of polytetrafluoroethylene neochordae after mitral valve repair. J Thorac Cardiovasc Surg. 2009;137:504-6.
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Early rupture of an expanded polytetrafluoroethylene neochord after complex mitral valve repair: An electron microscopic analysis Javier G. Castillo, MD,a Anelechi C. Anyanwu, MD,a Ahmed El-Eshmawi, MD,a Ronald E. Gordon, PhD,b and David H. Adams, MD,a New York, NY Mitral valve repair is currently accepted as the gold standard procedure for patients who require surgery for mitral valve regurgitation, particularly in the setting of degenerative mitral valve disease.1 Repair techniques including posterior leaflet resection, sliding valvuloplasty, and complete remodeling annuloplasty are now widely and routinely applied in most centers. During the past decade, in addition to more tailored resections techniques, many centers have emphasized nonresection mitral repair strategies whenever possible, particularly in minimally invasive settings.2 In the ‘‘respect rather than resect’’ approach, chordal replacement with polytetrafluoroethylene (PTFE) (Gore-Tex; W. L. Gore & Associates, Inc, Newark, Del) sutures is used in preference to classic Carpentier techniques such as leaflet resection, chordal transposition, or the posterior leaflet flip technique. Several technical variants have been introduced including a single PTFE suture, premeasured PTFE loops, and the loop-in-loop technique, which allows functional adjustment of the final loop length.3 Mitral valve repair with PTFE neochordoplasty has been recognized to be stable and durable,4 and only a few isolated cases of ruptured PTFE neochords have been described.5 We report a case of early failure of an expanded PTFE neochord loop owing to complete rupture 4 months after implantation.
CLINICAL SUMMARY The patient was a 55-year-old man with severe mitral valve regurgitation secondary to a congenital anomaly with shortened chordeae tendineae and lateral displacement of both papillary muscles leading to type IIIb dysfunction. In addition, myxomatous changes with leaflet thickening and anterior leaflet pseudoprolapse were observed. After a limited sternotomy incision, inspection of the mitral valve revealed very complex disease with restrictive changes in the subvalvular apparatus but with relatively preserved From the Department of Cardiothoracic Surgerya and the Department of Pathology (Electron Microscopy Core Facility),b The Mount Sinai School of Medicine, New York, NY. Disclosures: Authors have nothing to disclose with regard to commercial support. Received for publication Oct 8, 2012; revisions received Nov 7, 2012; accepted for publication Dec 5, 2012; available ahead of print Jan 14, 2013. Address for reprints: David H. Adams, MD, Department of Cardiothoracic Surgery, The Mount Sinai Medical Center, 1190 Fifth Ave, New York, NY 10029-6500 (E-mail: [email protected]). J Thorac Cardiovasc Surg 2013;145:e29-31 0022-5223/$36.00 Copyright Ó 2013 by The American Association for Thoracic Surgery http://dx.doi.org/10.1016/j.jtcvs.2012.12.011
commissures (Figure 1, A). Annuloplasty sutures were placed around the annulus and several frozen chords were then cut to further free the anterior commissure. Additionally, a large chord was fenestrated to mobilize the anterior leaflet. The posterior leaflet was mobilized and a glutaraldehyde-fixed pericardial patch was used to augment the posterior leaflet (Figure 1, B). A premeasured set of pledget-supported 13-mm PTFE (Gore-Tex CV-5) loops were attached to the anterior papillary muscle head. Subsequently, 2 secondary loops (Gore-Tex CV-3) were attached to the anterior leaflet margin (loop-in-loop technique). Furthermore, a single neochord (Gore-Tex CV-3) was attached to P2 to resuspend the posterior leaflet (Figure 1, C). Finally, a true size 28-mm Carpentier-Edwards Classic annuloplasty ring (Edwards Lifesciences LLC, Irvine, Calif) was implanted (Figure 1, D). The valve had a very symmetric line of coaptation and a normal saline test. Intraoperative transesophageal and predischarge transthoracic echocardiography demonstrated trace mitral regurgitation. The patient was discharged home on postoperative day 6. Four months later, the patient had acute dyspnea and peripheral edema. Transthoracic echocardiography showed recurrent severe mitral regurgitation and anterior leaflet prolapse secondary to chordal rupture. Valve analysis revealed anterior leaflet prolapse (Figure 2, A) owing to the fracture of 1 of the premeasured loops (Figure 2, B) and a partial fracture of a second premeasured loop (Figure 2, C and D). Moreover, there was severe fibrosis and early calcification of A3 (not present at the initial operation) and a tear in the anterior leaflet along the free calcified margin. The valve was deemed irreparable and valve replacement was performed with a size 25-mm Hancock II porcine valve (Hancock Jaffe Laboratories, Inc, Irvine, Calif). Intraoperative and predischarge echocardiography confirmed good function of the bioprosthesis and the patient was discharged home on postoperative day 7. The specimen was sent for electron microscopic analysis (Figure 3, A). In addition, new CV-5 PTFE sutures were subjected to traction and friction forces to be compared with the surgical specimen. Electron microscopy confirmed complete host covering with deposition of platelets over the PTFE suture as well as the ingrowth of fibroblasts and collagen formation (Figure 3, B). Under the microscope, the area of fracture showed signs of deterioration owing to both traction and friction forces. This was clearly depicted after comparison with the images of new CV-5 PTFE sutures subjected to only friction (Figure 3, C) or only traction forces (Figure 3, D).
The Journal of Thoracic and Cardiovascular Surgery c Volume 145, Number 3
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Case Reports
FIGURE 1. Initial repair. The mitral valve presents complex rheumatic changes (A) requiring advanced repair techniques including a glutaraldehyde-fixed pericardial patch augmentation of the posterior leaflet (B), a single neochord for posterior leaflet resuspension, and a loop-in-loop technique to the anterior leaflet (C). Saline test shows a very symmetric line of coaptation (D).
DISCUSSION Chordal replacement with PTFE neochords for mitral valve reconstruction has been proven to be stable and
durable up to 20 years after surgery.4 Additionally, their relative ease of use has led to a current trend toward favoring the application of PTFE neochords in preference to leaflet
FIGURE 2. Four months after surgery, intraoperative valve analysis reveals complete anterior leaflet prolapse (A), the fracture of 1 of the premeasured loops (B), and a partial fracture of a second premeasured loop (C and D).
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Case Reports
FIGURE 3. Electron microscopic analysis of the surgical specimen shows signs of deterioration owing to traction and friction forces (A, 390,500 mcm). Complete host covering with deposition of platelets over the polytetrafluoroethylene (PTFE) suture as well as the ingrowth of fibroblasts and collagen formation were confirmed (B, 3180,250 mcm). The analysis of a new CV-5 PTFE suture subjected to only friction (C, 3120,250 mcm) or only traction (D, 390,500 mcm) forces.
resection or more complex techniques in many circumstances. Only a few isolated cases of PTFE failure have been reported, most of them in the setting of late rupture up to 14 years after surgery.6-8 Recently, Yamashita and Skarsgard5 described an unusual failure of a PTFE neochord (running suture technique) as early as 2 months after surgery. The authors alluded to intracardiac forces that potentially exceeded the strength of the CV-5 PTFE suture (failure load > 830 g) as the most likely cause, but unfortunately, no histopathologic analysis was obtained. We now report a case of early fracture of a CV-5 PTFE neochord only 4 months after the initial surgical procedure. We prefer the loop-in-loop technique, which allows functional adjustment with saline testing of the ‘‘second loop’’ as opposed to geometric measurement of a single loop to correct segmental prolapse. Although other mechanisms of failure of PTFE loops, such as instrument damage, clip damage, damage by energy sources, or native tissue or knot disruption, have all been described, none was the case in this patient. We are confident the loop ruptured from excise force and friction of the 2 loops interacting during systole. Tying the 2 loops together after height adjustment might decrease the risk of friction and loop disruption. Another possibility is to consider using a stronger PTFE suture for the anchoring loops in the loop-to-loop approach, particularly if a large
segmental prolapse is being treated and there are no native secondary chords. Application of more than 2 loops to a prolapsing segment may also be warranted if the entire support is dependent on loops. Our case serves as a reminder that all repair techniques have an intrinsic technical failure rate and that techniques and applications of PTFE neochords in mitral valve repair need continued study and possible refinement in certain circumstances. References 1. Castillo JG, Anyanwu AC, Fuster V, Adams DH. A near 100% repair rate for mitral valve prolapse is achievable in a reference center: implications for future guidelines. J Thorac Cardiovasc Surg. 2012;144:308-12. 2. Falk V, Seeburger J, Czesla M, Borger MA, Willige J, Kuntze T, et al. How does the use of polytetrafluoroethylene neochordae for posterior mitral valve prolapse (loop technique) compare with leaflet resection? A prospective randomized trial. J Thorac Cardiovasc Surg. 2008;136:1205; discussion 1205-6. 3. Okamoto K, Yozu R, Kudo M. Loop-in-loop technique in mitral valve repair via minithoracotomy. Ann Thorac Surg. 2012;93:1329-30. 4. David TE, Armstrong S, Ivanov J. Chordal replacement with polytetrafluoroethylene sutures for mitral valve repair: a 25-year experience. J Thorac Cardiovasc Surg. June 17, 2012. [Epub ahead of print]. 5. Yamashita MH, Skarsgard PL. Intermediate and early rupture of expanded polytetrafluoroethylene neochordae after mitral valve repair. Ann Thorac Surg. 2011;92:341-3. 6. Butany J, Collins MJ, David TE. Ruptured synthetic expanded polytetrafluoroethylene chordae tendinae. Cardiovasc Pathol. 2004;13:182-4. 7. Coutinho GF, Carvalho L, Antunes MJ. Acute mitral regurgitation due to ruptured ePTFE neo-chordae. J Heart Valve Dis. 2007;16:278-81. 8. Farivar RS, Shernan SK, Cohn LH. Late rupture of polytetrafluoroethylene neochordae after mitral valve repair. J Thorac Cardiovasc Surg. 2009;137:504-6.
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