A catheter having an elongated shaft with an inflation lumen and a guidewire lumen, a balloon on a distal shaft section, and a proximal intermediate port proximal to the balloon and a distal intermediate port distal to the balloon, the intermediate ports being in communication with the guidewire lumen and being configured to slidably receive a guidewire therethrough so that the guidewire extends into or out of a proximal section of the guidewire lumen through the proximal intermediate port, extends along an outer surface of the balloon, and extends into or out of a distal section of the guidewire lumen through the distal intermediate port. The balloon is inflated in a patient's blood vessel to perform a medical procedure, with the section of the guidewire extending along an outer surface of the balloon providing improved balloon retention at the desired location in the blood vessel during inflation of the balloon.