A patient with type ICD36 deficiency whose myocardium accumulated 123I-BMIPP after 4 years

A 73-year-old man with aortic regurgitation was examined by I-123-alpha -methyl-p-iodophenylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) in 1995. Myocardial accumulation was not evident on either the early or the delayed image obtained 15 minutes and 3 hours, respectively, after injecting I-123-BMIPP. Flow cytometric analysis of CD36 expression in monocytes and platelets identified a type I CD36 deficiency. The patient was hospitalized for severe heart failure in 1999. Upon admission, the cardiothoracic ratio on chest Xrays was 73%, and the left ventricular end-diastolic diameter on echocardiograms was enlarged to 77 mm. On the second day, we performed I-123-BMIPP myocardial SPECT. Myocardial accumulation was evident in the delayed, but not in the early image. We repeated I-123-BMIPP myocardial SPECT on the 10th day after admission. Myocardial accumulation was evident on both early and delayed images. Tc-99m-tetrofosmin myocardial SPECT was immediately performed after I-123-BMIPP myocardial SPECT to distinguish myocardial from pooling images in the left ventricle, but, because the images from both 99mTc-tetrofosmin and I-123-BMIPP myocardial SPECT were idential, we considered that the 123I-BMIPP myocardial SPECT images reflected the actual myocardial condition. The CD36 molecule transports long-chain fatty acid (LCFA) on the myocardial membrane, but I-123-BMIPP scintigraphy does not show any myocardial accumulation in patients with type I CD36 deficiency, indicating that myocardial LCFA uptake occurs through CD36 on the human myocardial membrane. Even though our patient had type I CD36 deficiency, BMIPP was uptaken by the myocardium during heart failure, suggesting a variant pathway on the human myocardial membrane for LCFA uptake.