¹²³I-β-methyl-iodophenyl-pentadecanoic acid myocardial scintigraphy in diabetic patients without overt ischemic heart disease

Fatty acid metabolism in the myocardium is affected by metabolic disorders such as diabetes mellitus. We evaluated ¹²³I-,β-methyl-iodophenyl- pentadecanoic acid (BMIPP) myocardial scintigraphy in 15 diabetes mellitus patients without overt coronary heart disease. Patients with overt coronary heart disease were excluded by careful history taking, resting electrocardiography, treadmill exercise testing, echocardiography and resting ²⁰¹TI scintigraphy. Patients with remarkably impaired left ventricular (LV) systolic function (%FS<30%) were also excluded. BMIPP uptake scores as the ratio of heart/mediastinum (H/M) and liver/mediastinum (L/M) at 20 minutes after injection were analyzed and compared with clinical profile, serum parameters, and LV parameters obtained from echocardiography. Five of the 15 patients showed abnormal BMIPP images; two patients showed a decreased uptake in the inferior segments, while three showed a diffuse decrease in BMIPP uptake. Body mass index (BMI), fasting blood sugar (FBS), HbAIC, IRI, and LV end-diastolic diameter (LVEDD) were higher in these five patients with abnormal BMIPP findings (abnormal BMIPP group vs normal BMIPP group, BMI: 29 vs 23 kg/m², p< 0.05; FBS; 178 vs 114 mg/dl, p<0.01; HbAIC; 7.6 vs 6.2%, p<0.01; IRI: 18.5 vs 9.5 μU/ml, p< 0.01; LVEDD: 52 vs 44 mm, p<0.05). ¹²³I-metaiodobenzyl-guanidine (MIBG) scintigraphy in the five patients with abnormal BMIPP uptake showed more severe defects than in the 10 patients with normal BMIPP imaging. BMIPP scintigraphy demonstrated a significant correlation between H/M and L/M by BMIPP (r = 0.74, p<0.01). Furthermore, correlation between H/M by BMIPP scintigraphy and clinical parameters (BMI, systolic blood pressure, FBS, HbAIC, IRI) were found, suggesting that diabetes mellitus patients without over coronary heart disease show abnormal BMIPP imaging when their general glucose utility and ¹²³I-MIBG uptake are severely impaired (progression of insulin resistance and sympathetic nerve involvement). BMIPP scintigraphy may be useful in investigating the pathogenesis and subclinical abnormality of diabetic heart.