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Comparison of Strength, Consistency, and Speed of COR-KNOT Versus Manually Hand-Tied Knots in an Ex Vivo Minimally Invasive Model

Lee, Candice Y. MD*; Sauer, Jude S. MD; Gorea, Heather R. BSME; Martellaro, Angelo J. AAS; Knight, Peter A. MD*

Innovations:Technology and Techniques in Cardiothoracic and Vascular Surgery: March/April 2014 - Volume 9 - Issue 2 - p 111–116
doi: 10.1097/IMI.0000000000000051
Original Articles

Objective This study compared the strength, consistency, and speed of prosthetic attachment sutures secured with automated fasteners with those of manual knots using an ex vivo porcine mitral valve annuloplasty model. A novel miniature pressure transducer system was developed to quantify pressures between sutured prosthetic rings and underlying cardiac tissue.

Methods Sixteen mitral annuloplasty rings were sewn into ex vivo pig hearts. Eight rings were secured with the COR-KNOT device; and eight rings, with hand-tied knots using a knot pusher. A cardiac surgeon and a surgery resident each completed four manually tied rings and four COR-KNOT rings via a thoracotomy trainer. The total time to knot and cut each ring’s sutures was recorded. Suture attachment pressures were measured within (intrasuture) and between (extrasuture) each suture loop using a 0.5 × 2.0-mm microtransducer probe system.

Results The suture holding pressures for the COR-KNOT fasteners were significantly greater than for the manually tied knots (median, 1008.9 vs 415.8 mm Hg, P < 0.001). All automated fasteners measured greater than 500 mm Hg, whereas 56% of the hand-tied knots were less than 500 mm Hg, and 14% were less than 75 mm Hg. There was less variation in attachment pressures for the COR-KNOT fasteners than for the hand-tied knots (SD, 401.6 vs 499.3 mm Hg, P = 0.04). Significant time savings occurred with the use of the COR-KNOT compared with manual tying (12.4 vs 71.1 seconds per knot, P = 0.001).

Conclusions The novel microtransducer technology provided an innovative means of evaluating cardiac prosthetic anchoring sutures. In this model, mitral annuloplasty ring sutures secured with the COR-KNOT device were stronger, more consistent, and faster than with manually tied knots.

From the *University of Rochester Medical Center, Rochester, NY USA; and †LSI SOLUTIONS, Victor, NY USA.

Accepted for publication December 29, 2013.

All technical and financial support for this research was provided by LSI SOLUTIONS, Victor, NY USA.

Presented at the Annual Scientific Meeting of the International Society for Minimally Invasive Cardiothoracic Surgery, June 12–15, 2013, Prague, Czech Republic.

Disclosures: Candice Y. Lee, MD, received funding through the Peter A. Knight Research Fellowship, which is supported by LSI SOLUTIONS, Victor, NY USA. Jude S. Sauer, MD; Heather R. Gorea, BSME; and Angelo J. Martellaro are full-time employees of LSI SOLUTIONS. Dr Sauer is the president and chief executive officer, Ms Gorea is a clinical research manager, and Mr Martellaro is a designer for LSI SOLUTIONS. Peter A. Knight, MD, receives funding from LSI SOLUTIONS for the Peter A. Knight, MD, Research Fellow.

Address correspondence and reprint requests to Candice Y. Lee, MD, Department of Cardiothoracic Surgery, University of Rochester Medical Center, 601 Elmwood Ave, Box surg, Rochester, NY 14642 USA. E-mail:

©2014 by the International Society for Minimally Invasive Cardiothoracic Surgery