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The effect of cholesterol-lowering and antioxidant therapy on endothelium-dependent coronary vasomotion
T J Anderson1, I T Meredith, A C Yeung
1Cardiovascular Division, Brigham and Women's Hospital, Boston.
Insights
Cholesterol-lowering and antioxidant therapy improved coronary artery vasodilation in patients with coronary artery disease. This combined treatment enhanced endothelial function, potentially reducing ischemic cardiac events.
Area of Science:
- Cardiology
- Vascular Biology
- Pharmacology
Background:
- Coronary artery disease (CAD) patients with lipid abnormalities often exhibit endothelial vasodilator dysfunction.
- This dysfunction may contribute to ischemic cardiac events.
- The potential for cholesterol-lowering or antioxidant therapy to restore endothelium-dependent coronary vasodilation remains unclear.
Purpose of the Study:
- To investigate the effects of cholesterol-lowering and antioxidant therapy on endothelium-dependent coronary vasodilation in patients with CAD.
- To compare the efficacy of diet, LDL-lowering therapy, and combined LDL-lowering and antioxidant therapy.
Main Methods:
- Randomized assignment of 49 CAD patients to three groups: diet, LDL-lowering (lovastatin and cholestyramine), or LDL-lowering-antioxidant (lovastatin and probucol).
- Assessment of endothelium-dependent coronary artery vasomotion using intracoronary acetylcholine infusion at baseline and after one year.
- Evaluation of vasoconstrictor responses to acetylcholine, considered abnormal in this patient population.
Main Results:
- Both LDL-lowering and LDL-lowering-antioxidant therapies significantly reduced LDL cholesterol levels compared to diet alone.
- The LDL-lowering-antioxidant group showed the greatest improvement in acetylcholine-induced coronary artery vasomotion (from -19% to -2% change).
- The LDL-lowering group also demonstrated improvement, though less pronounced than the combined therapy group.
Conclusions:
- Combined cholesterol-lowering and antioxidant therapy significantly improved endothelium-dependent vasomotion in CAD patients.
- This enhancement in endothelial function may have implications for myocardial ischemia activity.
- The findings suggest a potential mechanism explaining the reduced incidence of adverse coronary events associated with cholesterol-lowering therapies.
Background:
Patients with coronary artery disease and abnormalities of serum lipids often have endothelial vasodilator dysfunction, which may contribute to ischemic cardiac events. Whether cholesterol-lowering or antioxidant therapy can restore endothelium-dependent coronary vasodilation is unknown.
Methods:
We randomly assigned 49 patients (mean serum cholesterol level, 209 +/- 33 mg per deciliter [5.40 +/- 0.85 mmol per liter]) to receive one of three treatments: an American Heart Association Step 1 diet (the diet group, 11 patients); lovastatin and cholestyramine (the low-density lipoprotein [LDL]-lowering group, 21 patients); or lovastatin and probucol (the LDL-lowering-antioxidant group, 17 patients). Endothelium-dependent coronary-artery vasomotion in response to an intracoronary infusion of acetylcholine (10(-8) to 10(-6) M) was assessed at base line and after one year of therapy. Vasoconstrictor responses to these doses of acetylcholine are considered to be abnormal.
Results:
Treatment resulted in significant reductions in LDL cholesterol levels of 41 +/- 22 percent in the LDL-lowering-antioxidant group and 38 +/- 20 percent in the LDL-lowering group (P < 0.001 vs. the diet group). The maximal changes in coronary-artery diameter with acetylcholine at base line and at follow-up were -19 and -2 percent, respectively, in the LDL-lowering-antioxidant group, -15 and -6 percent in the LDL-lowering group, and -14 and -19 percent in the diet group (P < 0.01 for the LDL-lowering-antioxidant group vs. the diet group; P = 0.08 for the LDL-lowering group vs. the diet group). (The negative numbers indicate vasoconstriction). Thus, the greatest improvement in the vasoconstrictor response was seen in the LDL-lowering-antioxidant group.
Conclusions:
The improvement in endothelium-dependent vasomotion with cholesterol-lowering and antioxidant therapy may have important implications for the activity of myocardial ischemia and may explain in part the reduced incidence of adverse coronary events that is known to result from cholesterol-lowering therapy.