title: Reduced functional measure of cardiovascular reserve predicts admission to critical care unit following kidney transplantation.
abstract: BACKGROUND
  There is currently no effective preoperative assessment for patients undergoing kidney transplantation that is able to identify those at high perioperative risk requiring admission to critical care unit (CCU). We sought to determine if functional measures of cardiovascular reserve, in particular the anaerobic threshold (VO₂AT) could identify these patients.
  
  
  METHODS
  Adult patients were assessed within 4 weeks prior to kidney transplantation in a University hospital with a 37-bed CCU, between April 2010 and June 2012. Cardiopulmonary exercise testing (CPET), echocardiography and arterial applanation tonometry were performed.
  
  
  RESULTS
  There were 70 participants (age 41.7±14.5 years, 60% male, 91.4% living donor kidney recipients, 23.4% were desensitized). 14 patients (20%) required escalation of care from the ward to CCU following transplantation. Reduced anaerobic threshold (VO₂AT) was the most significant predictor, independently (OR = 0.43; 95% CI 0.27-0.68; p<0.001) and in the multivariate logistic regression analysis (adjusted OR = 0.26; 95% CI 0.12-0.59; p = 0.001). The area under the receiver-operating-characteristic curve was 0.93, based on a risk prediction model that incorporated VO₂AT, body mass index and desensitization status. Neither echocardiographic nor measures of aortic compliance were significantly associated with CCU admission.
  
  
  CONCLUSIONS
  To our knowledge, this is the first prospective observational study to demonstrate the usefulness of CPET as a preoperative risk stratification tool for patients undergoing kidney transplantation. The study suggests that VO₂AT has the potential to predict perioperative morbidity in kidney transplant recipients.
authors.affiliation: Department of Renal Medicine and Transplantation, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, United Kingdom. stephen_ting@yahoo.com
authors.forename: Stephen M S
authors.initials: SM
authors.lastname: Ting
authors.forename: Hasan
authors.initials: H
authors.lastname: Iqbal
authors.forename: Thomas
authors.initials: T
authors.lastname: Hamborg
authors.forename: Chris H E
authors.initials: CH
authors.lastname: Imray
authors.forename: Susan
authors.initials: S
authors.lastname: Hewins
authors.forename: Prithwish
authors.initials: P
authors.lastname: Banerjee
authors.forename: Rosemary
authors.initials: R
authors.lastname: Bland
authors.forename: Robert
authors.initials: R
authors.lastname: Higgins
authors.forename: Daniel
authors.initials: D
authors.lastname: Zehnder
mesh_terms: D000328:Adult; D015308:Anaerobic Threshold; D005080:Exercise Test; D005260:Female; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D007362:Intensive Care Units; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010343:Patient Admission; D011379:Prognosis; D012372:ROC Curve