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J Chest Surg 2024; 57(1): 96-98

Published online January 5, 2024 https://doi.org/10.5090/jcs.23.076

Copyright © Journal of Chest Surgery.

COR-KNOT-Induced Leaflet Perforation: How It Happens and How to Prevent It: A Case Report

Michael Salna , M.D., M.B.A.1, Jack Shanewise , M.D.2, Alex D’Angelo, M.D.1, Isaac George , M.D.1

1Division of Cardiac, Thoracic, and Vascular Surgery, Department of Surgery and 2Division of Cardiac Anesthesiology, Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY, USA

Correspondence to:Isaac George
Tel 1-212-305-4134
Fax 1-212-305-4134
E-mail ig2006@cumc.columbia.edu
ORCID
https://orcid.org/0000-0001-7770-4450

Received: June 21, 2023; Revised: August 11, 2023; Accepted: August 14, 2023

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

The COR-KNOT suture fastening device has dramatically improved the efficiency of valve suture fixation. Despite its relative ease of use, there are important considerations in deployment to limit the risk of prosthetic valve injury. Herein, we report a case of iatrogenic aortic bioprosthetic insufficiency caused by poorly positioned COR-KNOTs and outline technical strategies to ensure success.

Keywords: Valve replacement, COR-KNOT, Sutures, Aortic valve, Case report

The COR-KNOT (LSI Solutions, Victor, NY, USA) is an automated suture fastening system that, with a squeeze of the device, crimps a metal fastener to secure and then trim sutures. It is designed to expedite suture fixation of valves and reduce operative time, particularly in minimally invasive surgery where the limited working space can make knot-tying challenging. The ease of this device, however, cannot be taken for granted. If the metal fasteners are improperly oriented, they may damage valve leaflets. Herein, we report a case of re-operative aortic valve replacement due to severe aortic insufficiency from multiple presumed COR-KNOT-induced leaflet injuries.

The patient was a 64-year-old with hypertension, hyperlipidemia, type 2 diabetes (hemoglobin A1c 7.1%), heart failure with reduced ejection fraction (ejection fraction 40%), coronary artery disease (multiple angioplasties without stenting), and bicuspid aortic stenosis who underwent a prior tissue aortic valve replacement (27-mm Carpentier-Edwards) and ascending aortic replacement (30-mm graft) at an outside hospital in 2018. Though asymptomatic on follow-up, echocardiography revealed severe eccentric aortic insufficiency, paravalvular leak (PVL), a left ventricular end-diastolic diameter of 5.8 cm, and an ejection fraction of 32%. Cardiac catheterization also showed a mid-left anterior descending coronary lesion. Therefore, re-operative aortic valve replacement and coronary artery bypass grafting were planned.

He underwent an uneventful re-operative sternotomy and left internal mammary artery (LIMA) harvest. The heart was dissected out and central cannulation was performed. A retrograde cardioplegia cannula was inserted into the coronary sinus and, upon aortic cross-clamping, retrograde cardioplegia was given and a left ventricular vent was inserted into the superior pulmonary vein. The aorta was opened and ostial cardioplegia was given down the right and left coronary ostia.

The LIMA was grafted to the left anterior descending artery, and attention returned to the aortic valve. Upon inspection, there appeared to be 3 distinct holes—1 in the center of the right sinus leaflet and 2 in the non-coronary sinus leaflet (Fig. 1). Immediately adjacent to each of these holes was a COR-KNOT that was inwardly bent, such that when the leaflets extended to the open position, those corresponding COR-KNOTs were located exactly adjacent to the holes (Supplementary Video 1). We surmised that the inward orientation of these core-knots caused friction-induced holes to form on the non-calcified leaflets. The site of PVL was also identified at the level of the left coronary ostia.

Figure 1.Intraoperative pictures showing COR-KNOT-induced leaflet perforations. (A) Perforation of the right leaflet. Arrow marks COR-KNOT. (B) Two perforations in the non-coronary leaflet. (C) Explanted valve demonstrating perforations (circled). R, right sinus; L, left sinus; N, non- coronary sinus.

The valve and pledgets were explanted and a 29-mm Inspiris valve (Edwards Lifesciences, Irvine, CA, USA) was seated and secured with COR-KNOTs, remaining vigilant to ensure that their orientation was perpendicular to the annulus. The aorta was closed in 2 layers. After confirmation of good valvular function with absence of PVL, the patient was weaned from cardiopulmonary bypass, hemostasis was achieved, and the patient was closed and transported to the intensive care unit in stable condition.

The patient provided written informed consent for publication of the case details and clinical images.

The COR-KNOT device has revolutionized efficiency in cardiac surgery. Valves can be seated more quickly, reducing the cross-clamp time, and perhaps more securely in minimally invasive surgery where knot tying in deep holes can be cumbersome [1].

Several case studies have reported late-stage leaflet perforation resulting in severe aortic insufficiency with the COR-KNOT device [2-4]. In all these reports, there appeared to be a medially directed COR-KNOT, which, through presumed constant abrasion on the leaflet, led to eventual perforation.

We have used the COR-KNOT in thousands of valve operations, including both rigid and flexible mitral annuloplasty rings, without any reports of leaflet perforation. We believe that this complication can be prevented by meticulous attention to several steps when firing the device. Specifically, the 3 most important tenets are: (1) Ensuring that the device is secured on the outer ring of the valve. The Inspiris valve, for example, has an inner ring that supports the valve leaflets, and an outer ring for the aortic sewing cuff. (2) Holding the device perpendicular to the annulus, and remaining conscientious to never cant the device inwards, which would result in a medially directed fastener. (3) Holding tension on the sutures and the thumb plate of the device for 3 seconds before firing the device. This ensures the fastener has adequate time to seat and properly engage at the base of the outer sewing ring and prevents a loose COR-KNOT from interacting with a leaflet.

Finally, in the current case, the originally implanted valve appeared undersized, which resulted in a more intra-annular position (and may have contributed to PVL as well). With an undersized valve, the COR-KNOT may also tend to face inwards. We believe that by following these 3 steps, the issue of COR-KNOT-induced leaflet perforation can all but be eliminated.

Author contributions

Conceptualization: all authors. Project administration: all authors. Writing–original draft: MS. Final approval of the manuscript: all authors.

Conflict of interest

No potential conflict of interest relevant to this article was reported.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Supplementary materials

Supplementary materials can be found via https://doi.org/10.5090/jcs.23.076. Supplementary Video 1. Intraoperative inspection of damaged prosthesis leaflets.

jcs-57-1-96-supple.mp4
  1. Beute TJ, Oram MD, Schiller TM, et al. Use of an automated suture fastening device in minimally invasive aortic valve replacement. Ann Thorac Surg 2018;106:58-62. https://doi.org/10.1016/j.athoracsur.2018.01.073.
    Pubmed CrossRef
  2. Baciewicz FA Jr. Cor-Knot perforation of aortic valve leaflet. Ann Thorac Surg 2018;106:936-7. https://doi.org/10.1016/j.athoracsur.2018.03.038.
    Pubmed CrossRef
  3. Rodriguez Cetina Biefer H, Weber A, Maisano F, Benussi S. Leaflet perforation by Cor-Knot automated fasteners: more usual than you think. Ann Thorac Surg 2018;105:664-5. https://doi.org/10.1016/j.athoracsur.2017.04.014.
    Pubmed CrossRef
  4. Patel SP, Cubeddu RJ, D'Orazio SE, Solomon BJ. Prosthetic valve leaflet perforation resulting in critical aortic insufficiency: a rare late complication after use of Cor-knot(R). J Card Surg 2022;37:5490-2. https://doi.org/10.1111/jocs.16983.
    Pubmed CrossRef

Article

Case Report

J Chest Surg 2024; 57(1): 96-98

Published online January 5, 2024 https://doi.org/10.5090/jcs.23.076

Copyright © Journal of Chest Surgery.

COR-KNOT-Induced Leaflet Perforation: How It Happens and How to Prevent It: A Case Report

Michael Salna , M.D., M.B.A.1, Jack Shanewise , M.D.2, Alex D’Angelo, M.D.1, Isaac George , M.D.1

1Division of Cardiac, Thoracic, and Vascular Surgery, Department of Surgery and 2Division of Cardiac Anesthesiology, Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY, USA

Correspondence to:Isaac George
Tel 1-212-305-4134
Fax 1-212-305-4134
E-mail ig2006@cumc.columbia.edu
ORCID
https://orcid.org/0000-0001-7770-4450

Received: June 21, 2023; Revised: August 11, 2023; Accepted: August 14, 2023

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The COR-KNOT suture fastening device has dramatically improved the efficiency of valve suture fixation. Despite its relative ease of use, there are important considerations in deployment to limit the risk of prosthetic valve injury. Herein, we report a case of iatrogenic aortic bioprosthetic insufficiency caused by poorly positioned COR-KNOTs and outline technical strategies to ensure success.

Keywords: Valve replacement, COR-KNOT, Sutures, Aortic valve, Case report

Case report

The COR-KNOT (LSI Solutions, Victor, NY, USA) is an automated suture fastening system that, with a squeeze of the device, crimps a metal fastener to secure and then trim sutures. It is designed to expedite suture fixation of valves and reduce operative time, particularly in minimally invasive surgery where the limited working space can make knot-tying challenging. The ease of this device, however, cannot be taken for granted. If the metal fasteners are improperly oriented, they may damage valve leaflets. Herein, we report a case of re-operative aortic valve replacement due to severe aortic insufficiency from multiple presumed COR-KNOT-induced leaflet injuries.

The patient was a 64-year-old with hypertension, hyperlipidemia, type 2 diabetes (hemoglobin A1c 7.1%), heart failure with reduced ejection fraction (ejection fraction 40%), coronary artery disease (multiple angioplasties without stenting), and bicuspid aortic stenosis who underwent a prior tissue aortic valve replacement (27-mm Carpentier-Edwards) and ascending aortic replacement (30-mm graft) at an outside hospital in 2018. Though asymptomatic on follow-up, echocardiography revealed severe eccentric aortic insufficiency, paravalvular leak (PVL), a left ventricular end-diastolic diameter of 5.8 cm, and an ejection fraction of 32%. Cardiac catheterization also showed a mid-left anterior descending coronary lesion. Therefore, re-operative aortic valve replacement and coronary artery bypass grafting were planned.

He underwent an uneventful re-operative sternotomy and left internal mammary artery (LIMA) harvest. The heart was dissected out and central cannulation was performed. A retrograde cardioplegia cannula was inserted into the coronary sinus and, upon aortic cross-clamping, retrograde cardioplegia was given and a left ventricular vent was inserted into the superior pulmonary vein. The aorta was opened and ostial cardioplegia was given down the right and left coronary ostia.

The LIMA was grafted to the left anterior descending artery, and attention returned to the aortic valve. Upon inspection, there appeared to be 3 distinct holes—1 in the center of the right sinus leaflet and 2 in the non-coronary sinus leaflet (Fig. 1). Immediately adjacent to each of these holes was a COR-KNOT that was inwardly bent, such that when the leaflets extended to the open position, those corresponding COR-KNOTs were located exactly adjacent to the holes (Supplementary Video 1). We surmised that the inward orientation of these core-knots caused friction-induced holes to form on the non-calcified leaflets. The site of PVL was also identified at the level of the left coronary ostia.

Figure 1. Intraoperative pictures showing COR-KNOT-induced leaflet perforations. (A) Perforation of the right leaflet. Arrow marks COR-KNOT. (B) Two perforations in the non-coronary leaflet. (C) Explanted valve demonstrating perforations (circled). R, right sinus; L, left sinus; N, non- coronary sinus.

The valve and pledgets were explanted and a 29-mm Inspiris valve (Edwards Lifesciences, Irvine, CA, USA) was seated and secured with COR-KNOTs, remaining vigilant to ensure that their orientation was perpendicular to the annulus. The aorta was closed in 2 layers. After confirmation of good valvular function with absence of PVL, the patient was weaned from cardiopulmonary bypass, hemostasis was achieved, and the patient was closed and transported to the intensive care unit in stable condition.

The patient provided written informed consent for publication of the case details and clinical images.

Discussion

The COR-KNOT device has revolutionized efficiency in cardiac surgery. Valves can be seated more quickly, reducing the cross-clamp time, and perhaps more securely in minimally invasive surgery where knot tying in deep holes can be cumbersome [1].

Several case studies have reported late-stage leaflet perforation resulting in severe aortic insufficiency with the COR-KNOT device [2-4]. In all these reports, there appeared to be a medially directed COR-KNOT, which, through presumed constant abrasion on the leaflet, led to eventual perforation.

We have used the COR-KNOT in thousands of valve operations, including both rigid and flexible mitral annuloplasty rings, without any reports of leaflet perforation. We believe that this complication can be prevented by meticulous attention to several steps when firing the device. Specifically, the 3 most important tenets are: (1) Ensuring that the device is secured on the outer ring of the valve. The Inspiris valve, for example, has an inner ring that supports the valve leaflets, and an outer ring for the aortic sewing cuff. (2) Holding the device perpendicular to the annulus, and remaining conscientious to never cant the device inwards, which would result in a medially directed fastener. (3) Holding tension on the sutures and the thumb plate of the device for 3 seconds before firing the device. This ensures the fastener has adequate time to seat and properly engage at the base of the outer sewing ring and prevents a loose COR-KNOT from interacting with a leaflet.

Finally, in the current case, the originally implanted valve appeared undersized, which resulted in a more intra-annular position (and may have contributed to PVL as well). With an undersized valve, the COR-KNOT may also tend to face inwards. We believe that by following these 3 steps, the issue of COR-KNOT-induced leaflet perforation can all but be eliminated.

Article information

Author contributions

Conceptualization: all authors. Project administration: all authors. Writing–original draft: MS. Final approval of the manuscript: all authors.

Conflict of interest

No potential conflict of interest relevant to this article was reported.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Supplementary materials

Supplementary materials can be found via https://doi.org/10.5090/jcs.23.076. Supplementary Video 1. Intraoperative inspection of damaged prosthesis leaflets.

jcs-57-1-96-supple.mp4

Fig 1.

Figure 1.Intraoperative pictures showing COR-KNOT-induced leaflet perforations. (A) Perforation of the right leaflet. Arrow marks COR-KNOT. (B) Two perforations in the non-coronary leaflet. (C) Explanted valve demonstrating perforations (circled). R, right sinus; L, left sinus; N, non- coronary sinus.
Journal of Chest Surgery 2024; 57: 96-98https://doi.org/10.5090/jcs.23.076

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References

  1. Beute TJ, Oram MD, Schiller TM, et al. Use of an automated suture fastening device in minimally invasive aortic valve replacement. Ann Thorac Surg 2018;106:58-62. https://doi.org/10.1016/j.athoracsur.2018.01.073.
    Pubmed CrossRef
  2. Baciewicz FA Jr. Cor-Knot perforation of aortic valve leaflet. Ann Thorac Surg 2018;106:936-7. https://doi.org/10.1016/j.athoracsur.2018.03.038.
    Pubmed CrossRef
  3. Rodriguez Cetina Biefer H, Weber A, Maisano F, Benussi S. Leaflet perforation by Cor-Knot automated fasteners: more usual than you think. Ann Thorac Surg 2018;105:664-5. https://doi.org/10.1016/j.athoracsur.2017.04.014.
    Pubmed CrossRef
  4. Patel SP, Cubeddu RJ, D'Orazio SE, Solomon BJ. Prosthetic valve leaflet perforation resulting in critical aortic insufficiency: a rare late complication after use of Cor-knot(R). J Card Surg 2022;37:5490-2. https://doi.org/10.1111/jocs.16983.
    Pubmed CrossRef

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