title: Hypotheses, rationale, design, and methods for evaluation of ischemic preconditioning assessed by sequential exercise tests in diabetic and non-diabetic patients with stable coronary artery disease--a prospective study.
abstract: BACKGROUND
  Ischemic preconditioning is a powerful mechanism of myocardial protection and in humans it can be evaluated by sequential exercise tests. Coronary Artery Disease in the presence of diabetes mellitus may be associated with worse outcomes. In addition, some studies have shown that diabetes interferes negatively with the development of ischemic preconditioning. However, it is still unknown whether diabetes may influence the expression of ischemic preconditioning in patients with stable multivessel coronary artery disease.
  
  
  METHODS
  This study will include 140 diabetic and non-diabetic patients with chronic, stable coronary artery disease and preserved left ventricular systolic function. The patients will be submitted to two sequential exercise tests with 30-minutes interval between them. Ischemic parameters will be compared between diabetic and non-diabetic patients. Ischemic preconditioning will be considered present when time to 1.0 mm ST-segment deviation is greater in the second of two sequential exercise tests. Exercise tests will be analyzed by two independent cardiologists.
  
  
  CONCLUSIONS
  Ischemic preconditioning was first demonstrated by Murry et al. in dog's hearts. Its work was reproduced by other authors, clearly demonstrating that brief periods of myocardial ischemia followed by reperfusion triggers cardioprotective mechanisms against subsequent and severe ischemia. On the other hand, the demonstration of ischemic preconditioning in humans requires the presence of clinical symptoms or physiological changes difficult to be measured. One methodology largely accepted are the sequential exercise tests, in which, the improvement in the time to 1.0 mm ST depression in the second of two sequential tests is considered manifestation of ischemic preconditioning.Diabetes is an important and independent determinant of clinical prognosis. It's a major risk factor for coronary artery disease. Furthermore, the association of diabetes with stable coronary artery disease imposes worse prognosis, irrespective of treatment strategy. It's still not clearly known the mechanisms responsible by these worse outcomes. Impairment in the mechanisms of ischemic preconditioning may be one major cause of this worse prognosis, but, in the clinical setting, this is not known. The present study aims to evaluate how diabetes mellitus interferes with ischemic preconditioning in patients with stable, multivessel coronary artery disease and preserved systolic ventricular function.
authors: Paulo Cury
authors: PC
authors: Rezende
authors: Rosa Maria Rahmi
authors: RM
authors: Garcia
authors: Augusto Hiroshi
authors: AH
authors: Uchida
authors: Leandro Menezes Alves
authors: LM
authors: Costa
authors: Thiago Luis
authors: TL
authors: Scudeler
authors: Rodrigo Morel Vieira
authors: RM
authors: Melo
authors: Fernando Teiichi Costa
authors: FT
authors: Oikawa
authors: Cibele Larrosa
authors: CL
authors: Garzillo
authors: Eduardo Gomes
authors: EG
authors: Lima
authors: Carlos Alexandre Wainrober
authors: CA
authors: Segre
authors: Desiderio
authors: D
authors: Favarato
authors: Priscyla
authors: P
authors: Girardi
authors: Myrthes
authors: M
authors: Takiuti
authors: Celia Cassaro
authors: CC
authors: Strunz
authors: Department of Atherosclerosis, Heart Institute of the University of Sao Paulo, Sao Paulo, Brazil. whady.hueb@incor.usp.br.
authors: Whady
authors: W
authors: Hueb
authors: José Antonio Franchini
authors: JA
authors: Ramires
authors: Roberto
authors: R
authors: Kalil Filho
mesh_terms: D015331:Cohort Studies; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D003920:Diabetes Mellitus / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D005069:Evaluation Studies as Topic; D005080:Exercise Test / Q000379:methods*; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D011446:Prospective Studies