Comparison of strength, consistency, and speed of COR-KNOT versus manually hand-tied knots in an ex vivo minimally invasive model

Innovations (Phila). Mar-Apr 2014;9(2):111-6; discussion 116. doi: 10.1097/IMI.0000000000000051.


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.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Automation / instrumentation*
  • Computer Simulation
  • Disease Models, Animal
  • Education, Medical, Continuing / methods*
  • Equipment Design
  • Humans
  • Minimally Invasive Surgical Procedures / education*
  • Mitral Valve Annuloplasty / methods*
  • Suture Techniques / education*
  • Suture Techniques / instrumentation*
  • Sutures*
  • Swine