title: Impact of chronic kidney disease on myocardial blood flow regulation in dogs.
abstract: OBJECTIVE
  Chronic kidney disease (CKD) increases cardiovascular risk possibly due to coronary microvessel dysfunction and impaired myocardial flow reserve. This study investigated the effects of CKD on the regulation and transmural distribution of myocardial blood flow along with oxygen demand during intravenous dobutamine-induced increases in cardiac work.
  
  
  METHODS
  CKD was produced in dogs by a two-stage subtotal nephrectomy (kidney ablation-infarction model). Serum creatinine and blood urea nitrogen were evaluated during the development of CKD along with systemic blood pressure (tail-cuff plethysmography). After 5 weeks, the CKD dogs were staged according to the International Renal Interest Society staging system; all dogs were anesthetized and surgically prepared for blood flow studies. Data analyses were performed between sham control (CTR) and stage 1 and 2 CKD dogs.
  
  
  RESULTS
  At baseline, myocardial blood flow and diastolic aortic pressure were similar for all groups. During intravenous dobutamine, myocardial blood flow was markedly higher than CTR even though hematocrit levels declined with the severity of CKD. In the CTR dogs, myocardial blood flow increased in direct relation to cardiac work. However, in the CKD dogs (stage 1 and 2), maximum blood flow was achieved with low-dose dobutamine, indicating that coronary autoregulation is more readily exhausted with minimal increases in cardiac work during CKD.
  
  
  CONCLUSIONS
  We report that CKD markedly impairs coronary vascular reserve and myocardial blood flow regulation which could contribute to greater cardiovascular risk and poor clinical outcomes in CKD patients.
authors.affiliation: Department of Medicine, Faculty of Medicine, Laval University, Quebec, Que., Canada.
authors.forename: John G
authors.initials: JG
authors.lastname: Kingma
authors.forename: Denys
authors.initials: D
authors.lastname: Simard
authors.forename: Pierre
authors.initials: P
authors.lastname: Voisine
authors.forename: Jacques R
authors.initials: JR
authors.lastname: Rouleau
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D003326:Coronary Circulation; D003404:Creatinine / Q000097:blood; D004285:Dogs; D008297:Male; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000503:physiopathology*
chemical_list: D003404:Creatinine