Acute kidney injury in cardiac surgery

Anne Ristikankare

Research output: ThesisDoctoral ThesisCollection of Articles

Abstract

Acute kidney injury in cardiac surgery Acute kidney injury (AKI) is a serious complication in cardiac surgery. It occurs in up to 40 % of procedures according to the latest consensus definition of AKI. It has been associated independently with increased mortality, morbidity, and hospital costs. Even a small increase in serum creatinine is associated with mortality, and in severe AKI requiring renal replacement therapy mortality has increased over 50 %. Serum creatinine remains the benchmark of kidney function, even its lack of sensitivity and late increase in acute kidney injury. A novel biomarker of kidney function, cystatin C, has been claimed to be less affected than creatinine by patients age, sex, and muscle mass. We studied cystatin C in elderly cardiac surgery patients and in heart transplant patients to find out if cystatin C can detect AKI earlier than creatinine after surgery. There was no significant difference between these markers, and these results are in accordance with majority of other studies of cystatin C in cardiac surgery patients. Creatinine is still the primary marker of kidney function in AKI. The pathophysiology of AKI in cardiac surgery is multifactorial and injury to kidneys can occur during pre-, intra-, and postoperative period. The main risk factors are other comorbidities of the patient, especially preoperative chronic kidney failure, and hypoperfusion of the kidneys during perioperative period. The possible causes of hypoperfusion are hypotension, cardiac low output syndrome, and the use of the cardiopulmonary bypass. N-acetylcysteine is a drug, which has antioxidant and vasodilatory properties. We conducted a randomized, double blind study to find out if it can protect kidneys in cardiac surgery patients with preoperative renal dysfunction. N-acetylcysteine was administered intravenously during intra- and postoperative period, but had no effect on postoperative renal function. Meta-analyses on this subject published after our study has come to same conclusions. A novel inotrope, levosimendan, was studied in 60 coronary bypass grafting patients with left ventricle dysfunction to discover its effect on the kidneys. In this randomized, double blind study there was no significant difference in creatinine or cystatin C concentrations between the patients in the control or levosimendan groups, but there was a tendency towards preserved renal function in the levosimendan group. Larger randomized trials are needed to prove the renoprotective effects of levosimendan in cardiac surgery. There are no drugs that have proved to prevent AKI in cardiac surgery at the present time. The methods to prevent AKI are to avoid interventions known to be harmful to the kidneys and to optimize hemodynamics and hydration. A better understanding of the pathology of human acute kidney injury may produce more protective strategies in the future.
Original languageEnglish
Place of PublicationHelsinki
Publisher
Print ISBNs978-951-51-1812-7
Electronic ISBNs978-951-51-1813-4
Publication statusPublished - 2015
MoE publication typeG5 Doctoral dissertation (article)

Fields of Science

  • Acetylglucosaminidase
  • Acetylcysteine
  • +therapeutic use
  • Acute Kidney Injury
  • +diagnosis
  • +etiology
  • +prevention & control
  • Biomarkers
  • Cardiac Surgical Procedures
  • +adverse effects
  • Cardiopulmonary Bypass
  • Cardiotonic Agents
  • +pharmacology
  • Coronary Artery Bypass
  • Creatinine
  • +blood
  • +urine
  • Cystatin C
  • Free Radical Scavengers
  • Glomerular Filtration Rate
  • +drug effects
  • Hydrazones
  • Kidney
  • Kidney Failure, Chronic
  • +complications
  • Kidney Function Tests
  • Postoperative Complications
  • Preanesthetic Medication
  • Pyridazines
  • 3126 Surgery, anesthesiology, intensive care, radiology

Cite this

Ristikankare, A. (2015). Acute kidney injury in cardiac surgery. Helsinki: University of Helsinki.