Multi-exchange catheter guide member with improved seal

A catheter and guidewire exchange system, comprising:

• a catheter, comprising:
• an elongate shaft having an exterior surface, a proximal end, and a distal end,
• a first lumen extending through the shaft from the shaft proximal end to the shaft distal end, and sized to receive a guidewire, and
• a longitudinal guideway extending distally from the shaft proximal end, and enabling transverse access from the shaft exterior surface to the first lumen;
• and
• a guide member, comprising:
• a housing having a proximal end and a distal end,
• a catheter passageway extending through the housing from the proximal end to the distal end and adapted to slidably receive the catheter,
• a guidewire passageway extending from the housing proximal end into the catheter passageway, and comprising a tube adapted to merge the guidewire transversely through the guideway and into the first lumen, and
• a user-activated device positioned in the guidewire passageway and comprising a clamping body adapted to clamp the guidewire and thereby secure the guidewire in the guidewire passageway.