The present invention generally relates to a rapid exchange configuration that reduces the profile of a catheter riding on a guidewire and minimizes guidewire resistance. According to certain embodiments, a body of the catheter includes a distal portion and a proximal portion. The distal portion defines a guidewire lumen and includes a guidewire exit port being open in a proximal direction and leading to the guidewire lumen. A proximal section of the guidewire lumen is straight.