Advice

The technology

The technology

Cor‑Knot (LSI Solutions) is a single-use device to replace hand-tied surgical knots in valve surgery, including open and minimally invasive mitral valve repair, and aortic valve replacement. The Cor‑Knot device consists of a handle, lever and shaft.

There are 2 sizes of device: Cor‑Knot MIS (31 cm length, 5 mm diameter shaft) and Cor‑Knot Mini (17 cm length, 4 mm diameter shaft). The Cor‑Knot Mini device also contains a rotational knob with an indicator fin which is intended to help the user with suture orientation.

Add-ons include the Cor‑Knot quick load unit, which is used to load a single, sterile titanium fastener (Cor‑Knot fastener) into the Cor‑Knot device. Squeezing the applicator lever secures the suture (by crimping the fastener) and trims the suture tails at the same time. Cor‑Knot devices must be used with the Cor‑Knot fastener. The company states that Cor‑Knot is designed to be used with the company's specified suture (LSI 2‑0 polyester sutures) but other 2‑0 polyester sutures can be used.

Innovations

The innovative aspects according to the company are that the device provides a quicker, more consistent and secure knot than hand-tied knots. The company claims that Cor‑Knot reduces cardiopulmonary bypass time, reduces aortic cross-clamp time and reduces the risk of paravalvular leak.

Current care pathway

Aortic valve replacement with an artificial prosthesis (biological or mechanical) is the conventional treatment for people with severe aortic valve dysfunction. Valves may be placed using open heart surgery or transcatheter aortic valve implantation (TAVI).

If someone is referred for surgery, a cardiac surgeon determines whether open or minimally invasive surgery is more appropriate for them. Currently cardiac surgeons use hand-tied knots in minimally invasive and open valve surgery procedures. Endoscopic knot pushers can be used in minimally invasive valve surgery.

Other options for aortic valve replacement are:

  • Sutureless aortic valve replacement for aortic stenosis, which involves removing the narrowed aortic valve and replacing it with an artificial valve that keeps itself in place. The procedure may be quicker than conventional surgical aortic valve replacement, because the valve does not need to be sewn in, which reduces cardiopulmonary and aortic cross‑clamp times.

  • TAVI for aortic stenosis is a less invasive alternative to open cardiac surgery for treating aortic stenosis, avoiding the need for sternotomy and cardiopulmonary bypass.

  • Valve-in-valve TAVI (for treating failed bioprosthetic aortic valves originally placed by either open heart surgery or TAVI) is a less invasive alternative treatment that avoids the need for cardiopulmonary bypass.

Degenerative mitral regurgitation is treated by surgery to repair or replace the mitral valve. The mitral valve can be repaired by thoracoscopically assisted mitral valve surgery. People who cannot have open surgery can have percutaneous mitral valve leaflet repair for mitral regurgitation.

The following NICE interventional procedures guidance has been identified as relevant to this care pathway:

Population, setting and intended user

Cor‑Knot is for use in people who need valve surgery, including conventional and minimally invasive mitral valve repair, and aortic valve replacement. If surgery is appropriate, a cardiac surgeon determines whether it should be open or minimally invasive.

Cor‑Knot is likely to be used in secondary care by cardiac surgeons. The company states that it could be used in around 2,500 heart valve procedures each year in the UK. Training is provided by the company and included in the cost of the device. It involves teaching the theatre team to unpack, handle and load the device, and then practise in a dry laboratory demonstration. Education and training is ongoing. The company also provides clinical specialists to support cases and training.

Costs

The cost of a single heart valve replacement or repair procedure ranges from £8,025 to £14,813 (HRG codes ED24A-C and ED25A-C) for elective procedures.

Technology costs

The cost per patient of Cor‑Knot varies according to the number of knots tied. A mitral valve procedure using 15 fasteners costs £787.50. An aortic procedure using 12 fasteners costs £632.00. The list prices for Cor‑Knot are:

  • standard Cor‑Knot Device £315.00 for a pack of 2 (maximum 12 sutures each)

  • Cor‑Knot Mini device £254.00 for a pack of 2

  • Cor‑Knot Quick Load Fastener £378.00

  • Cor‑Knot Quick Load Fastener £2,266.00 for 6 pouches.

Costs of standard care

Non-absorbable sterile 2‑0 sutures cost from £1.07 to £1.93 per suture (NHS Drug Tariff, accessed December 2019). A patient who has valve surgery would typically need 9 to 18 sutures, depending on the surgery. A reusable knot pusher costs between £500 and £2,000, according to the company. Additional instruments would also be needed, such as laparoscopic scissors.

Resource consequences

Cor‑Knot has been launched in the UK, and according to the company is currently being used in 32 trusts.

The resource impact is in addition to standard care, but this could be offset if using Cor‑Knot has benefits over hand knotting, such as reducing adverse events, length of hospital stay or procedure time. But there is limited evidence to support this.