Apparatus and methods are described including inserting a catheter into a subject's body via a vein of the subject's groin. The catheter is advanced distally such that a distal end of the catheter is disposed inside the subject's renal vein. Respective stabilizing portions of the catheter stabilize the catheter by being in contact with inner walls of, respectively, an iliac vein of the subject, and a vena cava of the subject. Subsequently, a medical device is deployed inside the renal vein by retracting the distal end of the catheter, such that the distal end of the catheter is in a retracted state, in which the respective stabilizing portions of the catheter still stabilize the catheter by being in contact with the inner walls of, respectively, the subject's iliac vein and the subject's vena cava. Other applications are also described.