An endovascular catheter for vein ablation comprising: an elongated rod (102, 302) having a proximal end and a distal end portion, the elongated rod being sized for insertion into a vein; at least one irritation element coupled to the distal end portion of the elongated rod (102, 302), when the at least one irritation element (104, 304) is an expanded irritation state, it is sized and shaped for contacting an inner wall segment of the vein to irritate the vein segment to trigger spasm of the vein segment, the at least one irritation element is adapted to change iteratively between the expanded irritation state and a non- expanded state; characterized in that: at least one support element (106, 306) is coupled to the distal end portion of the elongated rod (102, 302), the support element constituting at least one of (i) a resilient element arranged to apply a mechanical force to the irritation element from the distal end portion of the elongated rod; (ii) a rigidly arranged shape memory material interwoven with the irritation element (104, 304); wherein the support element (106, 306) is adapted to apply iteratively a mechanical force from the distal end portion, said mechanical force constituting an additional mechanical expansion force over any inherent expansion forces of the irritation element, and thereby return the irritation element to the expanded irritation state, in response to dynamic feedback of vein walls pressing against the irritation element and forcing the irritation element into the non-irritation state, while said at least one irritation element (104, 304) is moved along the vein. an elongated rod (102, 302) having a proximal end and a distal end portion, the elongated rod being sized for insertion into a vein; at least one irritation element coupled to the distal end portion of the elongated rod (102, 302), when the at least one irritation element (104, 304) is an expanded irritation state, it is sized and shaped for contacting an inner wall segment of the vein to irritate the vein segment to trigger spasm of the vein segment, the at least one irritation element is adapted to change iteratively between the expanded irritation state and a non- expanded state; characterized in that: at least one support element (106, 306) is coupled to the distal end portion of the elongated rod (102, 302), the support element constituting at least one of (i) a resilient element arranged to apply a mechanical force to the irritation element from the distal end portion of the elongated rod; (ii) a rigidly arranged shape memory material interwoven with the irritation element (104, 304); wherein the support element (106, 306) is adapted to apply iteratively a mechanical force from the distal end portion, said mechanical force constituting an additional mechanical expansion force over any inherent expansion forces of the irritation element, and thereby return the irritation element to the expanded irritation state, in response to dynamic feedback of vein walls pressing against the irritation element and forcing the irritation element into the non-irritation state, while said at least one irritation element (104, 304) is moved along the vein. at least one support element (106, 306) is coupled to the distal end portion of the elongated rod (102, 302), the support element constituting at least one of (i) a resilient element arranged to apply a mechanical force to the irritation element from the distal end portion of the elongated rod; (ii) a rigidly arranged shape memory material interwoven with the irritation element (104, 304); wherein the support element (106, 306) is adapted to apply iteratively a mechanical force from the distal end portion, said mechanical force constituting an additional mechanical expansion force over any inherent expansion forces of the irritation element, and thereby return the irritation element to the expanded irritation state, in response to dynamic feedback of vein walls pressing against the irritation element and forcing the irritation element into the non-irritation state, while said at least one irritation element (104, 304) is moved along the vein.