Large, sustained cardiac lipid peroxidation and reduced antioxidant capacity in the coronary circulation after brief episodes of myocardial ischemia

Abstract

OBJECTIVES

We sought to investigate whether a brief episode of myocardial ischemia produces a detectable cardiac oxidative stress in patients undergoing elective coronary angioplasty (PTCA).

BACKGROUND

Although cardiac oxidative stress has been clearly demonstrated in experimental models of ischemia-reperfusion, its presence in patients after transient myocardial ischemia is still unclear.

METHODS

In order to evaluate oxidative stress in ischemic cardiac regions, plasma conjugated dienes (CD), lipid hydroperoxides (ROOHs) and total antioxidant capacity (TRAP), independent indexes of oxidative stress, were measured in the aorta and great cardiac vein (GCV) before (t₀), 1, (t₁), 5 (t₅) and 15 min (t₁₅) after first balloon inflation in 15 patients undergoing PTCA on left anterior descending coronary artery (Group 1); six patients with right coronary artery stenosis (Group 2), which is not drained by the GCV, were studied as controls.

RESULTS

In Group 1 at baseline, CD and ROOHs levels were higher in GCV than in aorta (p < 0.01 for both), and TRAP levels were lower (p < 0.01). Aortic levels of CD, ROOHs and TRAP did not change at any time after t₀; venous levels of CD and ROOHs levels markedly increased at t₁, at t₅and remained elevated at t₁₅(p < 0.01 for all comparisons vs. t₀); venous levels of TRAP decreased at t₁and t₅(p < 0.01 vs. t₀) and returned to normal at t₁₅. In Group 2, CD, ROOHs and TRAP levels were similar in the aorta and GCV and did not change throughout the study.

CONCLUSIONS

Short episodes of myocardial ischemia during PTCA induce a sustained oxidative stress, which is detectable in the venous effluent of reperfused myocardium.