Reappearance of Cardiac Presynaptic Sympathetic Nerve Terminals in the Transplanted Heart: Correlation Between PET Using
11C-Hydroxyephedrine and Invasively Measured Norepinephrine Release
・千葉大学大学院医学研究院循環病態医科学 小高 謙一 他
Previously, sympathetic reinnervation of the transplanted heart has been described using invasive catheterization techniques and noninvasive radionuclide imaging techniques. However, little is known about the agreement between these 2 methods. Thus, correlation between 11C-Hydroxyephedrine (HED) PET and invasively measured norepinephrine (NE) release was investigated in transplant recipients in this study.
Methods: Using PET and the catecholamine analog HED, 17 patients were studied between 2 mo and 13.6 y after transplantation. Based on results in completely denervated hearts, areas with HED retention > 7 %/min were defined as reinnervated. Additionally, transcardiac NE release induced by intravenous tyramine (55μg/kg) was measured by coronary sinus and aortic catheterization with in 1 wk of the PET study. NE levels between coronary sinus and aortic root, ΔNECS-AO, were calculated at baseline and after tyramine administration. Differences of more than 3 SD of baseline (> 163 pg/mL) were interpreted as reinnervation.
Results: HED retention indicated reinnervation in 10 patients. Maximal HED retention ranged from 4.3 %/min to 16.4 %/min. ΔNECS-AO 1 min after tyramine administration ranged between ﾐ10pg/mL and 1157pg/mL, and 8 patients were above the reinnervation threshold. Fisherﾕs exact test demonstrated good agreement between results of PET and ΔNECS-AO measurements (P = 0.002). Maximal HED retention was also significantly correlated with NE release (r = 0.69 ; P = 0.001). Conclusion: Results of invasively measured NE release and noninvasive 11CﾐHED PET are well correlated. This study further supports the usefulness of PET as a noninvasive approach for detection of reappearance of catecholamine uptake sites after heart transplantation.
J Nucl Med 2001 ; 42 :1011-1016
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