An abbreviated hyperinsulinemic-euglycemic clamp results in similar myocardial glucose utilization in both diabetic and non-diabetic patients with ischemic cardiomyopathy

Positron emission tomography (PET) with insulin-stimulated ¹⁸F-2-deoxyglucose (FDG) uptake is the gold standard for myocardial viability. However, insulin stimulation is infrequently performed due to time and inconvenience. We therefore assessed the clinical applicability of an abbreviated hyperinsulinemic-euglycemic clamp.

Dynamic FDG PET was performed in 50 patients with ischemic cardiomyopathy (ejection fraction: .30 ± .10) using an abbreviated hyperinsulinemic-euglycemic clamp with separate Non-Diabetic (n = 26) and Diabetic (n = 24) protocols (American Society of Nuclear Cardiology guidelines), and supplemental potassium. In regions with normal resting perfusion (¹³N-ammonia uptake ≥80% maximal segment), there were no differences in either maximal (Non-Diabetic: .60 ± .20 vs Diabetic: .60 ± .17 μmol/min/g, P = .93) or mean rates of myocardial glucose uptake (MGU) (Non-Diabetic: .52 ± .18 vs Diabetic: .52 ± .14 μmol/min/g, P = .63) between the protocols. Multivariate analysis showed that diastolic blood pressure alone (maximal MGU, r ² = .20, P = .001) or with NYHA Heart Failure Class (mean MGU, r ² = .25, P = .003) could account for some of the variability in normal-region MGU. Potassium supplementation safely attenuated the decline in plasma levels.

This abbreviated hyperinsulinemic-euglycemic clamp produced similar MGU values in normal resting myocardium in non-diabetic and diabetic subjects, which are no different than published rates with a standard insulin clamp. Thus, this abbreviated approach is sufficient to overcome myocardial insulin resistance.