title: Changes in renal function over time in patients with cardiac resynchronisation therapy.
abstract: OBJECTIVE
  Cardiac resynchronisation therapy (CRT) with defibrillator back-up (CRT-D) is widely used in selected patients with moderate/severe heart failure. Renal failure is common in these patients. Data on the impact of CRT on renal function are controversial and limited by short follow-up. The aim of this study was to describe changes in glomerular filtration rate (GFR) from baseline compared with 1 and 2 years after CRT implantation.
  
  
  METHODS
  A total of 284 CRT-D patients with creatinine levels at baseline and after 1 year were identified in two prospective registries. In 149 patients, levels after 2 years were available. GFR in ml/min/1.73 m2 was estimated with the Modification Diet in Renal Disease equation and patients stratified into GFR stages 1 to 4.
  
  
  RESULTS
  The population was predominantly male (75%), mean (± standard deviation) age was 61 ± 7 years and ejection fraction 24% ± 8 %. GFR was 63 ± 24 ml/min/1.73 m2 at implantation and 60 ± 24 ml/min/1.73 m2 after 1 year (p = 0.26). At the 2-year follow-up, GFR had decreased from 60 ± 21 to 56 ± 21 ml/min/1.73 m2 (p = 0.04). Mean GFR decreased in stages 1 and 2, remained stable in stage 3 and improved in stage 4 patients. After 2 years, GFR had decreased ≥10 ml/min/1.73 m2 in 42%, but improved in only 15% (p = 0.04).
  
  
  CONCLUSIONS
  Overall, mean GFR in CRT-D patients decreases at 1 and 2 years after implantation, depending in part on the initial degree of renal function. However, the chance of further substantial deterioration (≥10 ml/min/1.73 m2) is considerable.
authors.affiliation: University of Basel Hospital, Department of Cardiology, Basel, SWITZERLAND; bschaer@uhbs.ch.
authors.forename: Beat A
authors.initials: BA
authors.lastname: Schaer
authors.forename: Lara
authors.initials: L
authors.lastname: Hitz
authors.forename: Christian
authors.initials: C
authors.lastname: Sticherling
authors.forename: Mischa
authors.initials: M
authors.lastname: Kühne
authors.forename: Michael
authors.initials: M
authors.lastname: Dickenmann
authors.forename: Luc
authors.initials: L
authors.lastname: Jordaens
authors.forename: Stefan
authors.initials: S
authors.lastname: Osswald
authors.forename: Dominic A
authors.initials: DA
authors.lastname: Theuns
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D058406:Cardiac Resynchronization Therapy; D058409:Cardiac Resynchronization Therapy Devices; D002648:Child; D017147:Defibrillators, Implantable; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006333:Heart Failure / Q000150:complications / Q000628:therapy*; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012042:Registries; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000503:physiopathology*; D055815:Young Adult