Comparison of outcomes post Cor-Knot versus Manual tying in valve surgery: our 8-year analysis of over 1000 patients.

Background: In the era of minimally invasive valve surgery (MIVS), automated titanium fasteners such as Cor Knot®, have reduced aortic-cross clamp (AXC) and cardiopulmonary bypass (CPB) times to improve survival outcomes. Whilst, most comparative studies pertain to MIVS, there is a lack of literature comparing Cor-Knot (CT) and manual knot tying (MT) in open valve procedures performed via full median sternotomy, particularly the long-term outcomes. We primarily compare AXC and CPB times, residual valvular regurgitation (RVR), freedom from valve re-intervention (FFI) and secondary post-operative outcomes of CT vs MT.

Methods: Retrospective analysis was performed for all adult patients, undergoing any first-time or redo valve surgery ± concomitant procedure via full median sternotomy, at a single-centre between January 2017 and January 2024). Patients were grouped according to operation type: isolated aortic valve replacement (AVR), isolated mitral valve replacement (MVR), isolated mitral valve repair (MVr), double valve, valve and concomitant CABG, major aortic surgery and redo valve surgery. Patients within each procedural group were further subdivided into either CT or MT groups. RVR and FFT between CT and MT in each subgroup were analysed using the Kaplan-Meier method.

Results: N = 1010 (CT: N = 492, MT: N = 518). Mean age was 67.7 years. AXC and CPB times were lower in the CT group (62.9 and 86.4 min) vs the MT group (74.9 and 100.1 min) in isolated aortic valve replacements (AVR)(p < 0.001). AXC and CPB times were also lower in the CT group (83.6 and 120.9 min) vs the MT group (103.7 and 143.3 min) in valve + CABG procedures (p < 0.001). The CT group had no RVR in isolated AVR or valve & CABG procedures, however a higher RVR in mitral valve surgery (p = 0.28), double valves (p = 0.49) and redo valves (p > 0.99) compared to the MT group. FFI at 7 years was 98.8% (MT) vs 94.1% (CT) (p = 0.02) in isolated AVR.

Conclusion: Cor-knot can safely and easily be used in all valve procedures. Intra-operative and cinical outcomes with CorKnot can be correlated better in AVR however the short and long-term benefits of CorKnot following mitral surgery are limited. Further larger studies, particularly in more complex procedural groups and long-term analyses are warranted to further validate our results.