Serum oxidizability potential of ischemic heart disease patients predicts exercise test results and disease severity.

Abstract

Background: Little is known about the relationship between exercise test indices and serum oxidizability potential in chronic ischemic heart disease (IHD) patients. Aim: to find out whether serum oxidizability potential correlates with exercise test parameters and predicts its result in chronic IHD patients. Methods: 54 chronic IHD patients and 11 normal controls underwent a symptom limited exercise test (EXT) upon initiation of a cardiac rehabilitation program; prior to the test a thermo-chemiluminiscence (TCL) assay of serum oxidizability potential was performed. This assay is based on heat-induced oxidation of the serum which leads to the formation electronically excited species in the form of unstable carbonyls, which further decompose into stable carbonyls and light energy (low chemiluminiscence). Measured photons emission is represented by a kinetic curve which is described by its amplitude and slope (= ratio). Correlations of TCL ratio with exercise duration (ED), metabolic equivalents (METS), maximal heart rate (mHR), maximal systolic BP (mSBP), >1mm S-T depression, Diabetes, Hypertension, Smoking, LV ejection fraction (LVEF) > or 40%, p<.01. A trend for lower TCL ratio (%) was found in diabetic, hypertensive, and postCABG patients. A paradoxically low TCL ratio (low oxidizablity potential) was observed in patients without S-T depression compared to patients with S-T depression (189+/-22 vs 201+/-15, p= ns) which is due to the fact these patients had a much lower LVEF% as well as a lower exercise capacity. Conclusion: Serum oxidizability potential is associated with exercise test parameters, results, and IHD severity. TCL ratio is an easy to measure marker that might be incorporated into risk assessment and prediction in chronic ischemic heart disease patients.