Figure 20-11 Renal revascularization in a patient with renovascular hypertension and renal insufficiency admitted to the intensive care unit for preoperative monitoring and stabilization. Bilateral renal revascularization was performed, and after return from the operating room, a substantial decline in renal function was noted. These changes were tracked equally well by creatinine clearance derived from a 2-hour (CC02) and a 22-hour (CC22) collection.