In some examples, a vessel closure system includes a catheter configured to be introduced into a vessel of a patient, the catheter defining a catheter lumen, and a closure device configured to be received within the catheter lumen. In some instances, the closure device may include an elongated flexible member and one or more anchors attached to the elongated flexible member. The anchors may be distributed along a length of the elongated flexible member, and each anchor may include an anchor head configured to be introduced into a wall of the vessel and engage with the wall of the vessel to cause the wall to move radially inward in response to a proximal pulling force applied to the elongated flexible member.