On January 16th, 1964, Dotter and Judkins performed the world's first lower limb vascular angioplasty on an elderly female patient using a balloon catheter. Thirteen years later, Gruentzig performed the world's first coronary angioplasty using a balloon catheter. Today, balloon dilation catheters are widely used for the diagnosis and treatment of cardiovascular diseases. Reviewing the development of balloon dilation catheter technology provides many insights for our current and future work. Next, let's take a look at the types of balloon catheters.
The rapid exchange balloon dilation catheter is currently the most widely used type of balloon dilation catheter in percutaneous coronary intervention (PCI). The catheter has a side hole 25cm from the tip of the balloon, through which the guide wire is inserted and emerges from the side hole when it is inserted through the top of the balloon. This design greatly facilitates the operation of the operator and saves time. The structure of the rapid exchange balloon is also different from other types of balloons in that it includes a connection segment between the balloon and the push rod, occasionally leading to rupture. Both the balloon and guide wire are operated by one person, resulting in an ideal imaging effect. The disadvantage of this type of balloon catheter is that if the entire balloon system is not removed, the guide wire cannot be replaced. If an extension guide wire is not used, the OTW balloon cannot be replaced, and the push force is slightly reduced, and the tracking is slightly worse.
The over-the-wire balloon dilation catheter (OTW) was first used in PTCA in 1982. It can be used for CTO lesions or when guide wire exchange is required, as well as for interventricular septal chemical ablation and central cavity pressure measurement and blood sampling. Currently, OTW balloons are rarely used clinically. The advantages of the OTW balloon dilation catheter include easy exchange of guide wires and good tracking. When the guide wire is difficult to pass through the occlusive lesion, the OTW balloon can provide additional support, similar to the role of a microcatheter. If the guide wire still cannot pass through the lesion, the OTW balloon dilation catheter can be used as a transmission catheter to exchange other guide wires. After the guide wire passes through the lesion, the OTW balloon dilation catheter can also be used for distal angiography to facilitate judging whether the guide wire is located in the true cavity. Therefore, the OTW balloon dilation catheter still has certain advantages in handling CTO lesions. The disadvantage of this type of balloon catheter is that the balloon size is slightly larger and the length of the steel wire is 300 cm, requiring cooperation between two operators.
The balloon dilation catheter has a flexible plastic guide wire fixed at the top of the catheter that is 2 cm long. Among the commonly used balloon dilation catheters, it has the smallest outer shape, which increases the rate of crossing the lesion and results in an ideal imaging effect, and only requires one person to operate it. However, when the catheter enters the target blood vessel, it needs to be pushed forward while rotating in both directions, making the catheter prone to breakage. It cannot move independently, and cannot exchange guide wires. It is basically no longer used clinically.
The perfusion balloon dilation catheter has multiple side holes at its proximal and distal ends, so when the balloon is inflated, blood flow can still enter the diseased distal end.
When the average aortic pressure is 80 mmHg, the distal blood flow can still reach 40-60 ml/min. When continuous balloon pressure is needed to treat complications such as coronary artery perforation, the use of perfusion balloon dilation catheters has certain advantages. The main disadvantage is that the catheter is relatively thick and has poor ability to cross lesions.
The special types of balloons currently used in clinical practice mainly include double wire balloons, cutting balloons, drug-eluting balloons, etc. Essentially, these three types of balloons belong to rapid exchange balloon dilation catheters, but they have special functions that differ from conventional rapid exchange balloons.
The outer diameter of the double wire balloon is similar to that of a regular balloon, and there is an inner lumen at the end of the balloon for guiding the wire shape. In addition, there is a fixed wire on the surface of the balloon, located at the position of 180° on either side of the balloon from the guide wire.
The double wire balloon can cut plaque tissue in a regular manner, with minimal damage to the endothelium and ensuring that the balloon does not shift. The cutting balloon is a product that combines micro-cutting technology with balloon dilation. The currently clinically used cutting balloons are third-generation products, which have better passability, can achieve full dilation with lower pressure, and have low rates of irregular tearing of the vascular intima and low rates of re-narrowing in the long term.
The drug-eluting balloon is a product that combines traditional balloon dilation technology with drug-eluting technology, and is gradually showing its superiority as an effective supplement to stenting. The drug-eluting balloon can avoid side effects caused by metal stents and polymer carriers, and can apply drugs to specific areas of the diseased blood vessel wall to control re-narrowing.