Case Study: Antiphospholipid syndrome (APS) typically manifests as acute thromboembolic events or thrombotic microangiopathy, leading to acute kidney injury. However, in this case, long-standing undiagnosed APS caused extensive thrombosis of major arteris including the renal arteries, but renal perfusion was preserved through compensatory collateral development. Consequently, the kidney evolved into a chronic ischemic phenotype, presenting as chronic kidney disease (CKD). A 47-year old woman with no prior medical or pregnancy history was transferred to our emergency department following tracheostomy for acute dyspnea after a failed intubation. Chest computed tomography (CT) demonstrated pneumonia and bilateral pleural effusions, and abdominopelvic CT revealed long-segment thrombotic obliteration extending from the abdominal aorta to both proximal external iliac arteries. Given the patient’s relatively young age and extensive arterial thrombosis, APS was suspected. Serologic testing showed triple positivity for antiphospholipid antibodies; lupus anticoagulant, anti-cardiolipin (IgG), and anti-β2 glycoprotein I (IgG), satisfying the diagnostic criteria for APS. Anticoagulation therapy with warfarin was initiated. Two weeks later, the patient developed seizures secondary to an acute ischemic stroke. Follow-up abdominopelvic CT angiography demonstrated persistent extensive occlusion of the abdominal aorta and renal arteries. Nevertheless, distal perfusion to the lower extremities and abdominal viscera was preserved through prominent collateral circulation via the Winslow pathway. With subsequent decline in renal function, hemodialysis was initiated for volume control, and the patient progressed to chronic maintenance hemodialysis. This case highlights a rare presentation in which prolonged and insidious large-vessel arterial occlusion manifests as CKD. It emphasizes the necessity of screening for APS in young patients with extensive arterial thrombosis, even when renal dysfunction appears chronic and already established at initial presentation.