Percutaneous transluminal coronary angioplasty (PTCA) was first described by Andreas Gruentzig in 1976, when he reported the successful application of the new technique in canine coronary experiments. Dr. Gruentzig designed and assembled balloon dilation catheters in his own kitchen. He performed the first coronary angioplasty in a conscious human patient in September 1977 in Zurich, Switzerland. The dilation catheter consisted of a balloon attached to a long shaft and a short wire attached to its tip. Soon after, balloon catheters were designed with a central guidewire lumen. Since the introduction of balloon angioplasty, major advancements have taken place in the field of percutaneous coronary interventions, but the majority of cases still require dilatation of the lesion with a balloon catheter even when a stent or other devices are used. In many instances, lesion preparation is crucial prior to stent deployment.
Coronary Balloon Material
Challenging lesions require a balloon with optimal performance in terms of:
Catheter pushability in order to transmit the force applied by the interventionalist’s hand to the distal end of the catheter, especially when guiding support is not adequate;
Catheter trackability over the guidewire through tortuous segments; and
Lesion crossability, especially in cases of calcified lesions with severe stenosis.
Therefore, despite the fact that standalone “plain old balloon angioplasty” (POBA) is mostly a thing of the past, there is an ongoing effort to manufacture more user-friendly balloon catheters that can address preparation of complex lesions to complement newer percutaneous technology. Several balloon catheter characteristics are considered in the manufacturing process.
Over-the-Wire and Rapid Exchange Systems
In an over-the-wire (OTW) system, the balloon catheter has a central lumen permitting free guidewire movement. This system is helpful when crossing difficult anatomy such as a chronic total occlusion, where balloon support is helpful and wire exchange is anticipated. On the other hand, the rapid exchange (RX) balloon catheter system is preferred by most single operators. The lesion is crossed with a standard-length guidewire. The wire is then fixed with one hand while the balloon catheter is advanced with the other. The wire exits a few centimeters from the distal end of the balloon catheter rather than its proximal end. The main disadvantage is that the wire cannot be pulled out for reshaping and cannot be exchanged for another wire without taking the entire system out. Balloon support may not be as good as with a full-length OTW system, since the balloon catheter is tracking over a relatively short distance of the wire. Therefore, the shaft design plays a fundamental role in balancing several characteristics for optimal catheter performance. These include pushability of the proximal shaft and flexibility as well as trackability of the distal shaft. Other important characteristics are lubricity, torque transmission and kink resistance. Factors that improve crossability include a smooth transition from the distal shaft ...