A Case of Chronic Limb Threatening Ischaemia with Severely Impaired Pedal Arteries Successfully Treated with Viscosity Intervention and Subsequent Pedal Bypass Surgery.

Introduction: This case report presents a 49 year old man with chronic limb threatening ischaemia (CLTI) and seronegative rheumatoid arthritis who presented with ischaemic foot ulcers, rest pain, and severely impaired pedal circulation. Imaging revealed occlusions of the dorsalis pedis, common plantar, and medial plantar arteries, with no visualised perfusion around the foot wounds, classifying the case as no option CLTI in which conventional revascularisation was deemed unfeasible. Report: The lateral plantar artery was barely visualised and measured 0.4 mm in diameter, initially considered too small for bypass. As a bridging strategy in an initially deemed no option situation, viscosity intervention using Rheocarna (Kaneka Medix Corporation, Osaka, Japan), a selective apheresis system designed to reduce low density lipoprotein cholesterol and fibrinogen via double plasma filtration, was initiated with the expectation that it would improve rest pain and wound condition, and potentially sufficiently enhance pedal microcirculation to enable bypass surgery. Following this intervention, the patient exhibited improvements in wound size, rest pain, and circulatory status. Notably, ultrasound revealed an increase in diameter of the lateral plantar artery to 0.8 mm, after which bypass to this artery became technically feasible. Discussion: The combined approach of pre-operative viscosity intervention and subsequent pedal bypass surgery resulted in marked improvement in pedal perfusion and complete wound healing. The patient regained ambulatory function and returned to daily life. This case highlights the potential of viscosity intervention with Rheocarna as an adjunctive pre-operative strategy to convert no option CLTI into operable cases by optimising pedal circulation status.