Apparatus for use with a suction source, the apparatus comprising a cleaning catheter, which comprises: an elongate, tubular catheter body, which is shaped so as to define (a) a distal-most suction orifice, (b) a suction lumen, which (i) is arranged along the catheter body at least partially within the catheter body, and (ii) includes a proximal longitudinal portion that is coupleable in fluid communication with the suction source, and (c) an outer lateral wall, which is shaped so as to define a lateral opening therethrough into the suction lumen, wherein the lateral opening is disposed distal to the proximal longitudinal portion of the suction lumen; an inflatable element, which comprises an inflatable-element outer wall, and is mounted to the catheter body; and an inner membrane, which: is at least partially positioned within an interior of the inflatable element and is mounted to the catheter body around the lateral opening along an air-tight seal perimeter that surrounds the lateral opening, so as to define a collapsible membrane portion that covers the lateral opening, and, together with the inflatable-element outer wall, defines an inflatable chamber between the inflatable-element outer wall and the collapsible membrane portion, characterised in that the inner membrane entirely surrounds the catheter body, and is arranged such that at least when the inflatable chamber is at ambient pressure, the proximal longitudinal portion of the suction lumen is in fluid communication with the distal-most suction orifice, and the collapsible membrane portion is biased to assume a bulged state. an elongate, tubular catheter body, which is shaped so as to define (a) a distal-most suction orifice, (b) a suction lumen, which (i) is arranged along the catheter body at least partially within the catheter body, and (ii) includes a proximal longitudinal portion that is coupleable in fluid communication with the suction source, and (c) an outer lateral wall, which is shaped so as to define a lateral opening therethrough into the suction lumen, wherein the lateral opening is disposed distal to the proximal longitudinal portion of the suction lumen; an inflatable element, which comprises an inflatable-element outer wall, and is mounted to the catheter body; and an inner membrane, which: is at least partially positioned within an interior of the inflatable element and is mounted to the catheter body around the lateral opening along an air-tight seal perimeter that surrounds the lateral opening, so as to define a collapsible membrane portion that covers the lateral opening, and, together with the inflatable-element outer wall, defines an inflatable chamber between the inflatable-element outer wall and the collapsible membrane portion, characterised in that the inner membrane entirely surrounds the catheter body, and is arranged such that at least when the inflatable chamber is at ambient pressure, the proximal longitudinal portion of the suction lumen is in fluid communication with the distal-most suction orifice, and the collapsible membrane portion is biased to assume a bulged state. is at least partially positioned within an interior of the inflatable element and is mounted to the catheter body around the lateral opening along an air-tight seal perimeter that surrounds the lateral opening, so as to define a collapsible membrane portion that covers the lateral opening, and, together with the inflatable-element outer wall, defines an inflatable chamber between the inflatable-element outer wall and the collapsible membrane portion, characterised in that the inner membrane entirely surrounds the catheter body, and is arranged such that at least when the inflatable chamber is at ambient pressure, the proximal longitudinal portion of the suction lumen is in fluid communication with the distal-most suction orifice, and the collapsible membrane portion is biased to assume a bulged state.