The general use of catheters as medical devices is very well-developed by now. U.S. Pat. No. 4,581,017 to Sahota, for example, shows the use of a guide catheter for insertion into an artery to assist with treating the artery (e.g. with a stenosis); and it further shows the use of another catheter for telescoping insertion into the first catheter to extend beyond the first catheter to treat or access portions of the artery that the first catheter cannot reach because of its larger diameter or lack of flexibility, trackability or support. Subsequent patents show further developments of such telescoping or extension catheter systems. For example, U.S. Pat. No. 5,385,562 to Adams et al., U.S. Pat. No. 5,439,445 to Kontos, and U.S. Pat. No. 5,290,247 to Crittendon all show the use of a catheter having a tubular portion that extends or telescopes beyond the guiding catheter, and an elongated manipulation/insertion wire or shaft attached to the tubular portion to manipulate the tubular portion axially—in push/pull fashion—within the guiding catheter after it has been inserted through the hemostasis valve and into the guiding catheter. The Adams '562 patent suggests that the proximal manipulation/insertion wire may actually be a low-diameter tubular shaft for conducting air to inflate and deflate a restriction balloon that restricts movement of the tubular portion.
According to conventional practice with these types of devices, doctors or technicians often introduce a contrast solution, flushing agent, or therapeutic agent into and through the guiding catheter in order to assist in the viewing of arteries, veins, and other tissues in the body (e.g. by x-ray or fluoroscopy) or for other procedural or therapeutic reasons. In some cases, though, it is desirable to limit the use of such solutions because too much of the solution can harm the patient. Introducing the solution through the guiding catheter may result in either too much solution entering the body or the solution not being injected at the correct target location. The diameter of the guiding catheter must be large enough to conduct a variety of tools and devices during the procedure, and so it is not practical to decrease the diameter of the guiding catheter in order to limit the usage of contrast solution.
Accordingly, there has been a need in the art for improved boosting catheters and related methods and system.