A balloon catheter system, comprising: a balloon that extends in an axial direction, surrounds a balloon interior of the balloon and has an outer side facing away from the balloon interior, and a catheter connected to the balloon and extending in the axial direction (x), the catheter having a lumen by way of which the balloon interior can be filled with a fluid medium for expanding the balloon in a radial direction of the balloon, wherein the balloon comprises a first and a second annular electrode (5, 6), the two electrodes (5, 6) being disposed on the outer side of the balloon, each extending in a circumferential direction of the balloon and being located opposite one another in the axial direction (x), the first electrode being configured to measure strain of the balloon in the circumferential direction and/or in the radial direction of the balloon, and/or the two electrodes (5, 6) being configured to measure an impedance of tissue of a patient resting against the electrodes (5, 6), and/or the two electrodes (5, 6) being configured to measure a redox potential of tissue of the patient contacting the second electrode, characterized in that the first electrode includes a first section extending in the circumferential direction, the first electrode furthermore including a second section, which extends along the circumferential direction, runs along the first section and is located opposite the first section in the axial direction (x), and the first section has a first end section and a second end section, and the second section has a first end section and a second end section, the two second end sections (51b, 52b) of the first electrode being joined to one another by a joining section that extends in the axial direction (x). a balloon that extends in an axial direction, surrounds a balloon interior of the balloon and has an outer side facing away from the balloon interior, and a catheter connected to the balloon and extending in the axial direction (x), the catheter having a lumen by way of which the balloon interior can be filled with a fluid medium for expanding the balloon in a radial direction of the balloon, wherein the balloon comprises a first and a second annular electrode (5, 6), the two electrodes (5, 6) being disposed on the outer side of the balloon, each extending in a circumferential direction of the balloon and being located opposite one another in the axial direction (x), the first electrode being configured to measure strain of the balloon in the circumferential direction and/or in the radial direction of the balloon, and/or the two electrodes (5, 6) being configured to measure an impedance of tissue of a patient resting against the electrodes (5, 6), and/or the two electrodes (5, 6) being configured to measure a redox potential of tissue of the patient contacting the second electrode, characterized in that the first electrode includes a first section extending in the circumferential direction, the first electrode furthermore including a second section, which extends along the circumferential direction, runs along the first section and is located opposite the first section in the axial direction (x), and the first section has a first end section and a second end section, and the second section has a first end section and a second end section, the two second end sections (51b, 52b) of the first electrode being joined to one another by a joining section that extends in the axial direction (x).