This invention relates generally to medical devices and more particularly to hemostatic valves.
When access to the vascular system is required, control of bleeding is essential. Thus various connectors or other devices used for intravascular applications make use of a hemostatic valve to enable a catheter or other small diameter instrument to be introduced into the body of a living being while precluding blood from flowing out of the connector. For example, in angioplasty it is a common practice to introduce an angioplasty catheter, e.g., a balloon catheter, through a hemostatic valve located within a connector. The hemostatic valve and its associated connector is used with a conventional guiding catheter to guide a tubular portion of the connector into the interior of the patient's artery. The hemostatic valve ensures that blood does not flow out of the connector, while enabling the angioplasty catheter to be passed therethrough
One common type of hemostatic valve is the so called "Tuohy Borst" valve. That valve comprises an elastomeric, e.g., silicone, membrane having an opening through which the catheter extends and which is closed about the periphery of the catheter by the rotation of a cap to establish hemostasis.
While such a valve is generally suitable for its intended purpose, it nevertheless leaves much to be desired from the standpoints of functionality and ease of use. In this regard connectors employing a "Tuohy Borst" valve require the use of a separate introducer needle or tube to pass through the valve to open its membrane so that the balloon catheter can be safely passed therethrough without damage (conventional balloon angioplasty catheters and angioplasty guidewires are quite delicate and are susceptible to damage if they are attempted to be pushed directly through a Tuohy Borst valve membrane). Thus, after the separate introducer needle or tube is in place in the Tuohy Borst valve a conventional guidewire is passed through the needle or tube. The introducer needle or tube is then removed, the balloon catheter inserted, and the connector's cap tightened to bring its valve membrane tightly into engagement about the periphery of the balloon catheter to effect hemostasis.
During the placement of the introducer needle through the valve, and until the valve is closed about the periphery of the balloon catheter, blood may flow out through the valve. Moreover, since the valve membrane is brought into tight peripheral engagement with the balloon catheter, maneuverability of the catheter by the physician is compromised, if not precluded, e.g., it is difficult if not impossible to move the catheter either longitudinally or rotationally with respect to the hemostatic valve.