title: Absence of circadian variation of acute coronary syndrome onset in chronic kidney disease patients.
abstract: BACKGROUND
  Several studies have reported on the circadian variation in acute coronary syndrome (ACS) onset. The influence of morning blood pressure surge, platelet aggregation and sympathetic activity is believed to cause this circadian variation. At the same time, a high frequency of ACS and sympathetic nerve hyperactivity has been reported in chronic kidney disease (CKD). Therefore, we investigated the relationship between CKD and the circadian variation in ACS.
  
  
  METHODS
  This study included 460 consecutive patients undergoing primary percutaneous coronary intervention for ACS between 2003 and 2009. Patients undergoing hemodialysis were excluded. The subjects were divided into two groups according to the value of estimated glomerular filtration rate (eGFR): CKD group [eGFR ≤ 60 ml/min/1.73 m2 by Modification of Diet in Renal Disease (MDRD) equation] and No CKD group (eGFR > 60 ml/min/1.73 m2 by MDRD equation). Clinical and angiographic characteristics, as well as the time distribution of ACS, were compared between the two groups.
  
  
  RESULTS
  There were no significant differences in clinical and angiographic characteristics between the two groups. A significant increase in morning coronary events was observed in the No CKD group. This increase was absent in the CKD group.
  
  
  CONCLUSIONS
  The existence of CKD affected the circadian variation associated with the more frequent ACS onset observed in the No CKD group patients. Probably, these data may suggest the cause of frequent cardiovascular events in CKD patients.
authors.affiliation: Department of Cardiovascular Medicine, Toho University Ohashi Medical Center, 2-17-6, Ohashi, Meguro-Ku, Tokyo, Japan 153-8515. qqs86gt@athena.ocn.ne.jp
authors.forename: Hideki
authors.initials: H
authors.lastname: Itaya
authors.forename: Takuro
authors.initials: T
authors.lastname: Takagi
authors.forename: Kaoru
authors.initials: K
authors.lastname: Sugi
authors.forename: Masato
authors.initials: M
authors.lastname: Nakamura
mesh_terms: D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy; D000368:Aged; D000704:Analysis of Variance; D015906:Angioplasty, Balloon, Coronary; D002908:Chronic Disease; D002940:Circadian Rhythm; D017023:Coronary Angiography; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007564:Japan; D007668:Kidney / Q000503:physiopathology*; D007674:Kidney Diseases / Q000150:complications* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors