Acipimox does not augment thallium-201 redistribution in the fasting state

Area of Science:

• Cardiology
• Nuclear Medicine
• Pharmacology

Background:

• Myocardial uptake of thallium-201 (TI-201) can be enhanced by oral glucose or insulin infusion.
• Acipimox, a nicotinic-acid derivative, reduces serum free fatty acid (FFA) levels and increases myocardial glucose uptake.
• This study investigated acipimox's effect on TI-201 redistribution in patients with coronary artery disease.

Purpose of the Study:

• To assess the impact of acipimox on TI-201 redistribution in patients with coronary artery disease.
• To determine if acipimox, by enhancing myocardial glucose uptake, improves TI-201 uptake and redistribution.

Main Methods:

• Fourteen patients with coronary artery disease underwent two sequential TI-201 perfusion studies.
• Stress was induced by adenosine and ergometer exercise, followed by administration of either acipimox or placebo.
• Redistribution imaging was performed after 4 hours, with patients crossing over to the alternate treatment on a subsequent visit.
• Quantitative image analysis included polar plots and segmental uptake assessment.

Main Results:

• No significant differences were observed in hemodynamic parameters between acipimox and placebo groups.
• Quantitative analysis (polar plots and segmental uptake) showed no significant differences in defect extent, severity, or reversibility between the two arms.
• The proportion of segments classified as normal, fixed defect, reversible defect, or reverse redistribution did not differ significantly.

Conclusions:

• Acipimox does not enhance TI-201 redistribution in the fasting state in patients with coronary artery disease.
• The lack of enhancement may be attributed to acipimox not significantly increasing serum insulin levels.
• Insulin appears crucial for the combined transport of glucose and TI-201 into myocytes, which is essential for improved myocardial uptake and redistribution.