Discussion:
Core-Knot has become popular in valvular surgery since its introduction in 2009. While reducing cardiopulmonary bypass time is its prime benefit, it has also been found to have better holding pressure than manual knot tying.1 Lee et al. evaluated the strength, consistency, and speed of prosthetic attachment sutures secured with Cor-Knot and compared with those of manual knots.1They reported that suture holding pressures for the Cor-Knot fasteners were significantly greater (median, 1008.9 vs 415.8 mm Hg, P < 0.001). Also, there was less variation in attachment pressures with 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). They concluded that mitral annuloplasty ring sutures secured with the Cor-Knot device were stronger, more consistent, and faster than with manually tied knots.1
One of the first reported studies on Cor-Knot system was conducted between 2008-2010. Rodriguez et al. evaluated the clinical outcomes of minimally invasive mitral valve surgery with prosthetic attachment sutures secured by Cor-Knot system.2 No patient had evidence of thrombus formation, hemolysis, or perivalvular leaks.2 One instance of mitral ring dehiscence was noted, but the dehiscence was due to a tear in the mitral annulus and not associated with the titanium fasteners, which all remained intact.2 They concluded that at a minimum of one-year follow-up, Cor-Knot system is safe and effective for securing prosthetic attachment suture.2
Sazzad et al. quantified the incidence of valvular complications related to Cor-Knot device.3 They reported trivial and/or mild paravalvular leak (PVL) in immediate post-operative echocardiography and no reported cases of valvular thrombosis, leaflet perforation, device dislodgement or embolization, moderate and/or severe PVL during hospitalization and follow-up echocardiography within 1 year.3
Lee et al. analyzed prosthetic fixation pressures in prosthetic aortic valves, using Digital Pressure Mapping with 2D and 3D pressure maps generated for all valves. None of the 288 Cor-Knot cases had any decrease in intra-suture pressure, while 12 out of 144 manual-tying cases that had pressure drop to less than 80 mmHg which is considered a risk for paravalvular leaks (PVL) (P < 0.001).4 Therefore, it would be reasonable to use this device at high pressure sites such as the aorta.