An apparatus includes an inner catheter that is coupled to a handle and defines a lumen configured to receive a guidewire. An outer catheter is movably coupled to the handle and defines a first lumen in fluid communication with a distal opening and that is configured to introduce a therapeutic agent through the distal opening and into a target pancreatic artery(ies). The outer catheter defines a second lumen configured to receive at least a portion of the inner catheter. An actuator is coupled to the handle and configured to move the outer catheter relative to the handle. A first occlusion element is coupled to the inner catheter and a second occlusion element is coupled to the outer catheter and disposed proximal to the first occlusion element. A distance between the first occlusion element and the second occlusion element is adjustable when the outer catheter is moved relative to the handle.
