Researchers analyzed outcomes of 362 patients with only one kidney who underwent surgery between 1990 and 2008 at Mayo Clinic and Cleveland Clinic for renal cortical tumors. Using a technique called warm ischemia, surgeons kept the patient’s kidneys body temperature during the partial nephrectomy. Ischemia involves cutting off the blood supply to the kidney with clamps in order to control bleeding and to keep blood from obscuring the surgeon’s view of the kidney. Ischemia can cause tissue damage from a lack of oxygen and nutrients.
Researchers found that each additional minute of warm ischemia is associated with a five-to-six-percent increase in the odds of developing acute renal failure or reduced kidney functioning and is associated with a six percent increased risk of new onset Stage IV chronic kidney disease during long-term follow-up.
“This is the largest evaluation of warm ischemia time in patients with a single kidney who are undergoing a partial nephrectomy,” says R. Houston Thompson, M.D., a urologist at Mayo Clinic and study primary investigator. “These results suggest that every minute counts when the renal arteries and veins are clamped. When planning for the surgery, surgeons should make efforts to minimize ischemia time, especially in situations where a person only has one kidney,” says Dr. Thompson.