At present, whether it is the possibility of drug-coated balloon (DCB) as a substitute for stent or its use method is still controversial. There is still room for improvement in the use of DCB. If the drug coating of DCB only acts on the target lesions, the amount of drug lost into the circulation of the body can be reduced, or the side effects of human body can be reduced.
Application of DCB
In the treatment of peripheral artery disease, DCB is allowed to be used for short and local lesions, but it cannot replace the stent implantation for long-term and calcified lesions.
Throughout the development of endovascular surgery, from balloon dilation/percutaneous transluminal angioplasty (PTA) to stent implantation, and then to remove the original lesions while reducing the number of implants, which reflects the continuous pursuit of people from restoring the vascular lumen patency to maintaining the patency of the lumen, and then to maintain the patency of the lumen and restore the vascular function at the same time It is not only the improvement of anatomical structure but also the restoration of vascular function.
Therefore, the general trend of the development of lower extremity arterial occlusive disease is to restore the anatomical structure before the disease, that is, to open the true lumen of endovascular surgery; the other is not to interfere with the physiological function of the blood vessel itself, that is, to maintain the vasomotor function. It is from the treatment of primary lesions, the removal of proliferative lesions (volume reduction) to the reduction of stent placement requirements, the emergence of DCB, biodegradable stents and other new devices.
In terms of clinical evidence, a systematic review of 2406 subjects from 13 studies in the United States and Germany shows that the incidence of target lesion revascularization (TLR) of DCB and DES is lower than that of bare metal stents and PTA, and it can save medical costs in the long run.
Causes of Unstable Concentration of Coating Drugs Reaching Target Lesion
However, DCB also has limitations, including ineffective treatment of severe calcification; the use of drugs to inhibit intimal hyperplasia is cytotoxic; and the concentration of coated drugs reaching the target lesion is unstable. There may be two reasons for the instability of drug concentration reaching the target lesion: one is that the bare delivery of drug balloon varies with the route (length and twist) of host vessel and blood flow velocity; the other is affected by the operation technology of the operator. If the drug coating can be reduced in vitro operation and delivery process, and the effective drug can be delivered to the target lesion, the concentration of drug coating can be appropriately reduced, to reduce the toxic reaction of patients.
Proposed Solutions
Professor Xu Xin of Fudan University Central Hospital proposed three methods to make DCB drug coating only act on target lesions: 1. Establish a reasonable surgical pathway; 2. At present, the working distance of balloon is 135 cm, which is delivered to the target lesion under the protection of 90 cm long sheath, and the longest drug coating is 30 cm after subtracting 45 cm naked operation distance. This method makes transportation smoother and reduces the drug coating falling off. It is feasible in the current practical operation, but it has little effect on the distal embolization. 3. Making the external protection system of the balloon, that is, retracting the protective sleeve when the balloon reaches the target lesion, and then opening the balloon. However, the three-layer structure has strict requirements for existing engineering technology.
