Acute aortic dissection can be complicated by malperfusion syndromes, including ischemia of the lower limbs. In some cases, delayed correction of leg ischemia leads to reperfusion injury, potentially resulting in renal failure. We describe the case of a 64-year-old woman who presented with acute aortic dissection manifesting itself as lower-limb ischemia. During and after aortic surgery with cardiopulmonary bypass, the patient developed myonephropathic metabolic syndrome. Hyperkalemia was corrected and acute kidney injury was prevented by infusing large volumes of intravenous fluids and administering human atrial natriuretic peptide. Peripheral bypass surgery was unnecessary. This case suggests that restoring blood flow to an ischemic leg by means of adjunctive perfusion during aortic repair with cardiopulmonary bypass is a viable way to overcome the biochemical instability associated with prolonged ischemia, especially hyperkalemia in the early phase of reperfusion.