The ornamental design for a ballooncatheter, as shown and described.
1.1: a first perspective view of the balloon catheter with a balloon portion thereof in an inflated state.
1.2: a second perspective view thereof.
1.3: a front elevational view thereof.
1.4: a rear elevational view thereof.
1.5: a top plan view thereof.
1.6: a bottom plan view thereof.
1.7: a left elevational view thereof.
1.8: a right elevational view thereof.
1.9: a first enlarged perspective view of the balloon portion of the balloon catheter in the inflated state.
1.10: a second enlarged perspective view of a balloon portion of the balloon catheter in the inflated state.
1.11: a front elevational view of the balloon portion of the balloon catheter in the inflated state.
1.12: a perspective view of the balloon catheter with the balloon portion thereof in a deflated state.
The parallel thin lines on the surfaces of the balloon catheter represent only shading and do not illustrate ornamentation or decoration. The curly brackets and the breaks in the drawings indicate indeterminate length of the balloon catheter and form no part of the claimed design.