Clinical application and market capacity analysis of artificial blood vessels

Clinical application and market capacity analysis of artificial blood vessels – Cheersonic

The clinical application of artificial blood vessels is currently mainly concentrated in two departments, vascular surgery and cardiovascular surgery. Among them, cardiovascular surgery is mainly used in coronary artery bypass grafting; vascular surgery is mainly used in three directions:
1) Peripheral vascular bypass grafting;
2) Vascular trauma (defect ≥2cm);
3) Hemodialysis vascular access.

01. Coronary artery bypass grafting (CABG)

Coronary artery bypass grafting (commonly known as coronary artery bypass grafting) is a procedure used to repair or replace an blocked coronary artery to improve the blood supply to the heart muscle. The surgical approach involves the use of grafted blood vessels (usually the saphenous vein and internal mammary artery) to create a vascular access distal to the aorta and obstructed coronary arteries. According to the actual lesion, the doctor decides the number of grafts.

Coronary artery bypass grafting and percutaneous coronary intervention (PCI) are currently the two main treatments for coronary artery stenosis.

The current source of blood vessel donors for coronary artery bypass surgery is mainly the patient’s own blood vessels, mainly from the following three materials:

Internal mammary artery: The left internal mammary artery is anastomosed to the anterior descending branch. The patency rate in 1 year is 95.7%, and the patency rate in 10 years is over 90%. There are many branches, easy bleeding, and limited length, which requires high anastomotic technique;

Great saphenous vein: the most commonly used and easily obtained blood vessel, with a large diameter and sufficient length. The saphenous vein is prone to intimal thickening and vascular sclerosis due to intimal injury, excessive stretching and other reasons. Proximal venous anastomotic stenosis and thrombosis may occur within one year. The patency rate in 10 years is about 50%, and the long-term effect is not as good. internal mammary artery;

Radial artery: From a surgical point of view, the radial artery is an ideal bridging vessel, with a diameter that matches the coronary artery, moderate length, and easy access. However, the artery was abandoned due to its tendency to spasm. With the advancement of technology, it has gradually received attention in recent years.

Due to the limited source of own vascular donors, the matching degree of vascular caliber, and the restenosis of grafted vessels after CABG, the clinical demand for small-caliber artificial blood vessels has increased, but there is currently no corresponding small-caliber vascular product on the market.

We define the application of small-caliber artificial blood vessels in CABG surgery as a potential incremental market. It is estimated that the CABG market in China will have an annual capacity of 50,000 surgical cases in the future, and the annual growth rate is expected to be around 2%. Based on the average price of artificial blood vessel terminals of 30,000 yuan, the potential market size is 1.5 billion yuan per year.

02. Arteriovenous dialysis fistula (AVG)

The vascular access of long-term dialysis patients is particularly important to maintain the basic life of patients. Basically, patients need 2-3 dialysis per week. Repeated puncture is a great challenge to the physiological state of blood vessels.

More than 60% of hemodialysis patients currently use a central venous catheter (CVC) for their first dialysis. Expert consensus recommends that both physicians and patients should understand and follow the “fistula first” principle to reduce unnecessary CVC use.

At present, there is no absolute ideal type of vascular access. Referring to the recommendations of some international guidelines, the expert group believes that long-term vascular access should:

1) The first choice is the autologous arteriovenous fistula (AVF): that is, the arterial blood vessel is inserted into the vein to make the vein thicker, and the blood in the vein is taken for dialysis. For the first autologous arteriovenous fistula angioplasty, the minimum arterial diameter should be ≥1.5 mm, and the vein diameter should be ≥2 mm (behind the bundle arm).

The most common surgical option is the radial artery and cephalic vein anastomosis of the forearm, which allows the development of the superficial veins of the patient’s forearm. The operation itself is less traumatic and less bleeding, so it is not a major operation, but the operation is more delicate and requires vascular anastomosis skills. Many patients in my country have small blood vessels and poor conditions, and the success rate of the first internal fistula is generally about 90%.

Advantages of autologous arteriovenous fistula:
Autovascular anastomosis without foreign body rejection;
After the own vein is dilated, the flow is larger;
Vascular compression is easy to stop bleeding, and it is not easy to ooze blood at the needle orifice or difficult to stop bleeding.

Disadvantages of autologous arteriovenous fistula:
It cannot be used directly, and requires a process of venous arterialization: it takes at least 4 weeks for the internal fistula to mature, and it is best to wait 8 to 12 weeks before starting the puncture. If the veins are not fully dilated and the dialysis blood flow is insufficient 8 weeks after the operation, the internal fistula is poorly matured or hypoplastic. It is not yet mature 3 months after the operation, and it is necessary to consider making a new internal fistula;
Patients with diabetes, hypertension and obesity have relatively poor vascular conditions and a higher risk of poor maturation of autologous arteriovenous fistulas;
Complications such as: vascular stenosis, thrombosis, infection and so on.

2) When AVF cannot be established, the second choice should be graft arteriovenous fistula (AVG). The usual order of selection is forearm graft fistula, upper arm AVG. AVG can be established 3 to 6 weeks before the start of dialysis, and if a ready-to-wear graft is used, it can be delayed until hours to days before dialysis is required.

Prosthetic vascular fistula surgery suitable population:
The condition of the autologous superficial veins in both upper extremities is not good, and it is expected that the autologous fistula will be difficult to mature;
The autologous veins of both upper extremities are tortuous;
Depletion of superficial autologous veins in both upper extremities after multiple autologous fistulas;
In severe obesity, the specific surface of autologous veins is too deep.

3) Central venous catheter (CVC): the product is divided into dialysis catheter with tunnel and polyester sleeve (TCC): can be referred to as tunnel catheter or long-term dialysis catheter; dialysis catheter without tunnel and polyester sleeve (NCC): can be referred to as Non-tunneled catheters or temporary dialysis catheters.

When a patient does not have a mature AVF and needs to enter dialysis, a transitional pathway should be established. Using TCC or NCC, direct arterial puncture is not recommended. When the transitional access is expected to be indwelling for more than 4 weeks, a catheter with a tunnel and a Dacron sheath is preferred. In the Chinese expert consensus, the recommended indications for NCC and TCC are as follows:

Status of use:

At present, statistics from most areas of my country show that AVF is the main vascular access type for maintenance hemodialysis patients in my country, but the second vascular access type is TCC, and AVG has the lowest proportion. Judging from the current status of vascular access in my country, maintenance hemodialysis patients who cannot establish AVF use too much TCC. For the above patients, it is recommended to use AVG as much as possible, and increase the proportion of AVG use to 10% to further reduce the use rate of TCC.

03. Peripheral Arterial Disease (PAD)

Peripheral arterial disease (PAD) refers to ischemic disease caused by stenosis and reduction or interruption of forward blood flow in other major blood vessels other than central blood vessels and coronary arteries. The main cause is atherosclerosis. Globally, the prevalence of PAD in the elderly is as high as 10%-20%. In the treatment of PAD, lifestyle modification and risk factor control (eg, smoking cessation, blood sugar control, lipid regulation, antihypertensive therapy), drug therapy (eg, antiplatelet, anticoagulant therapy,), and revascularization can be used.

Revascularization is suitable for patients with severe intermittent claudication affecting quality of life, ineffective drug therapy, with pain at rest, skin ulcers, and gangrene. Revascularization methods include endovascular interventional therapy and surgical treatment. The former includes percutaneous balloon dilatation, stent placement and laser angioplasty. Surgical procedures include artificial vascular and autologous vascular bypass grafting. In peripheral vascular artery disease, the number of patients with lower extremity is the largest, accounting for about 80% of all PAD cases in China. The following content will illustrate the example of lower extremity artery disease.

Also with the development of minimally invasive interventional procedures, the indications for surgical revascularization have gradually narrowed. The total number of reference surgery cases is unknown, and no market capacity assessment will be made for this.

04. Vascular trauma

Vascular injuries are mainly caused by car accident injuries, fall fracture injuries, firearm bullet injuries and severe crush injuries, among which car accident injuries and fall fracture injuries are the most common. For those with vascular defects longer than 2 cm, the principle of tension-free vascular anastomosis in microsurgery should be strictly followed, and vascular transplantation should be used to repair them.

Autologous vein transplantation is preferred. Generally, the great saphenous vein or cephalic vein is transplanted. The superficial autologous vein has the advantages of no antigenicity, convenient material extraction, high patency rate, strong anti-infection ability, good flexibility and extensibility, etc. The great saphenous vein and cephalic vein are larger blood vessels. Graft material that is often excised from the defect. The disadvantage of autologous vein transplantation is that the material is limited, the donor site is damaged, the caliber of the blood vessel may not match, etc. In addition, wound infection can also easily lead to thrombosis. The total number of reference surgery cases is unknown, and no market capacity assessment will be made for this.

Summarize the current directions of various clinical needs:
Coronary artery bypass grafting: limited sources of autologous arterial blood vessels, secondary surgery, low caliber matching; low long-term patency rate of autologous venous blood vessels; no small-caliber artificial blood vessels yet on the market;
Hemodialysis venous access: the ePTFE artificial blood vessel wall cannot repair the eye of the needle by itself, and can only rely on the surrounding tissue to compress and stop the bleeding; after local puncture, the intimal tissue of the artificial blood vessel is proliferated and narrowed; repeated puncture is easy to form pseudoaneurysm;
Peripheral arterial disease: ePTFE for small diameter vessels (<6mm) has low patency rates; patency rates are 40% after 6 months and 25% after 3 years;
Vascular defect: unable to reconstruct the vascular system in time; limited access to native blood vessels;
Existing synthetic materials are not degradable, and tissues cannot grow and remodel.

The article comes from Heyi Guangye Innovation Platform, author Du Fuchong

Cheersonic is the leading developer and manufacturer of ultrasonic coating systems for applying precise, thin film coatings to protect, strengthen or smooth surfaces on parts and components for the microelectronics/electronics, alternative energy, medical and industrial markets, including specialized glass applications in construction and automotive.