Dilatation catheter with varied stiffness

A dilation catheter comprising:

• a balloon inflation shaft defining a balloon inflation lumen and having a distal end and a proximal end;
• a balloon affixed to the balloon inflation shaft distal end and in fluid communication with said balloon inflation lumen;
• a stiffening wire having a distal end and a proximal end extending through said balloon inflation lumen from said balloon inflation shaft distal end to a predetermined location near said balloon inflation shaft proximal end;
• a manifold connected to said balloon inflation shaft proximal end for directing fluid and said stiffening wire into said balloon inflation lumen;
• said manifold having a substantially straight longitudinal channel therethrough having a distal channel end receiving the proximal end of said balloon inflation shaft and bonded thereto and having a proximal channel end through which said stiffening wire proximal end extends;
• a seal surrounding said stiffening wire adjacent to said proximal channel end for preventing fluid egress while permitting said stiffening wire proximal end to be moved between a first advanced position and a second retracted position relative to said proximal channel end within a predetermined range;
• a cap over said proximal channel end for increasing and decreasing pressure of said seal against said wire;
• a handle over said cap means secured to the proximal end of said stiffening wire for moving said stiffening wire over said predetermined range;
• a stop on said stiffening wire within said manifold for limiting movement of said handle away from said cap;
• and
• said handle including a tubular flange sized to fit over said cap in tight friction engagement therewith;
• whereby said movement of said stiffening wire over said predetermined range is limited in one direction by said stop means and in the opposite direction by said handle engagement with said cap and inadvertent movement of said handle away from said cap is restricted.