Method and apparatus for accessing the wall of a vascular structure or other body lumen while simultaneously providing zone isolation and fluid bypass capability

A method for accessing the wall of a body lumen while simultaneously providing zone isolation and fluid bypass capability, the method comprising:

• providing an access system comprising:
• an erectable proximal isolation barrier capable of making a sealing engagement with the wall of the body lumen;
• an erectable distal isolation barrier capable of making a sealing engagement with the wall of the body lumen;
• a bypass channel secured to, and extending between, the proximal isolation barrier and the distal isolation barrier, the bypass channel comprising a lumen communicating with the region proximal to the proximal isolation barrier and with the region distal to the distal isolation barrier;
• and
• a working catheter passing through the proximal isolation barrier and terminating short of the distal isolation barrier, the working catheter providing a central lumen for providing access to the wall of the body lumen between the proximal isolation barrier and the distal isolation barrier;
• deploying the access system within the body lumen;
• erecting the distal isolation barrier and the proximal isolation barrier so that they make sealing engagements with the wall of the body lumen;
• and
• accessing the wall of the body lumen through the working catheter.