title: Serum oxidizability potential of ischemic heart disease patients is associated with exercise test results and disease severity.
abstract: OBJECTIVE
  To find out whether serum oxidizability potential correlates with exercise test (EXT) parameters and predicts their results in chronic ischemic heart disease (IHD) patients.
  
  
  METHODS
  Oxidizability potential was determined in a group of chronic IHD patients who underwent a symptom limited EXT upon initiation of a cardiac rehabilitation program. The thermo-chemiluminescence (TCL) assay was used to assess serum oxidizability potential. This assay is based on heat-induced oxidation of serum, leading to the formation of electronically excited species in the form of unstable carbonyls, which further decompose into stable carbonyls and light energy (low chemiluminescence). Measured photons emission is represented by a kinetic curve which is described by its amplitude and slope (= ratio). We assessed the correlations of TCL ratio with exercise duration, metabolic equivalents (METS), maximal heart rate (mHR), maximal systolic BP, > 1 mm S-T depression, diabetes, hypertension, smoking, left ventricular ejection fraction (LVEF) > or < 40%, previous myocardial infarction, and aorto-coronary by-pass surgery and compared to the TCL ratio measured in a group of healthy controls.
  
  
  RESULTS
  A high TCL ratio (%) correlated well with METS (r = 0.84), with mHR (r = 0.79) and with exercise induced S-T segment shift (r = 0.87, P < 0.05). A lower serum oxidizability potential, expressed as a low TCL ratio, thus suggestive of a previous high oxidative stress, was found in IHD patients compared to healthy controls, and, in particular, in patients with low LVEF%. The TCL ratio (%) in IHD patients was 193 ± 21, compared to 215 ± 13 in controls (P < 0.05), and was 188 ± 14.7 in patients with LVEF < 40% as compared to 200 ± 11.9 in those with LVEF > 40% (P < 0.01). A trend for lower TCL ratio (%) was found in diabetic, hypertensive, and post-coronary bypass surgery patients. A paradoxically low TCL ratio (low oxidizability potential) was observed in patients without S-T depression compared to patients with S-T depression (189 ± 22 vs 201 ± 15, P = NS), due to the fact these patients had a much lower LVEF% and a lower exercise capacity.
  
  
  CONCLUSIONS
  Serum oxidizability potential is associated with EXT parameters, results, and IHD severity. TCL ratio is an "easy-to-measure marker" that might be incorporated into risk assessment and prediction in chronic IHD patients.
authors.affiliation: Allah Shanati, Yelena Rivlin, Sergei Shnizer, Uri Rosenschein, Ehud Goldhammer, Department of Cardiology and Cardiac Rehabilitation, Bnai Zion Medical Center, and the Faculty of Medicine, Technion, Haifa 31048, Israel.
authors.forename: Allah
authors.initials: A
authors.lastname: Shanati
authors.forename: Yelena
authors.initials: Y
authors.lastname: Rivlin
authors.forename: Sergei
authors.initials: S
authors.lastname: Shnizer
authors.forename: Uri
authors.initials: U
authors.lastname: Rosenschein
authors.forename: Ehud
authors.initials: E
authors.lastname: Goldhammer