Absolute quantification of myocardial uptake of 99mTc-DPD in patients with cardiac amyloidosis due to transthyretin deposits (ATTR).

PURPOSE: To determine the diagnostic contribution of the absolute quantification of the myocardial deposit of 99mTc-DPD in patients with cardiac amyloidosis due to transthyretin deposits (ATTR). MATERIALS AND METHODS: SPECT/CT was performed in 41 patients with positive scintigraphic results for ATTR cardiac amyloidosis. The patients were divided into two groups (Perugini grades 2 and 3) and the SUVmax at the level of the bone and both ventricles and the percentage of dose calculated in these areas were calculated. The Student's t-test was used to compare results and the area under the curve (AUC) was calculated to assess differential efficacy and establish discriminatory cut-off points between both groups of patients. RESULTS: Statistically significant differences were observed in all the study variables, with the exception of bone SUVmax. The differences with the greatest statistical power were observed in the variables SUVmaxRV and the percentage of dose in both ventricles (p < 0.001). The cut-off point obtained for the variable SUVmaxLV was 8.620 (sensitivity 87.9% and specificity 100%; AUC 0.966), while that of the variable SUVmaxRV was 6.195 (sensitivity 81.8% and specificity 100%; AUC 0.955). CONCLUSIONS: The absolute quantification of myocardial uptake of 99mTc-DPD in the SPECT/CT images of patients with suspected cardiac amyloidosis due to transthyretin deposits represents a new diagnostic tool that allows adequate classification of patients according to the Perugini visual grading scale.

Re-innervation after heart transplantation: a multidisciplinary study.

BACKGROUND: Several authors have demonstrated the existence and implications of re-innervation in the transplanted heart. Our aim was to study this phenomenon using 3 different techniques and to analyze the correlation among them. METHODS: The study population consisted of 55 patients who had undergone heart transplantation 0.5 to 160 months earlier. We used a control group of 10 healthy individuals for comparison. To detect re-innervation, we used 1) planar and single photon emission computed tomography (SPECT) scintigraphic imaging of cardiac sympathetic activity with 123I-metaiodobenzylguanidine (MIBG), 2) analysis of heart-rate variability based on 24-hour Holter recordings; and 3) immunohistochemical study of endomyocardial biopsy specimens with anti-S100 antibody. RESULTS: The SPECT images showed evidence of sympathetic re-innervation in 17 patients (31%), predominantly in the anterior and in the septal regions of the left ventricle. Sympathetic activity increased during the post-transplant time course (r = 0.32; p = 0.017), although it did not reach normal values. We found a correlation between the low-frequency component of heart-rate variability (a marker of sympathetic activity) and the degree of MIBG uptake according to scintigraphy (r = 0.32; p = 0.015). Immunostaining study demonstrated the existence of nerve fibers in 36 patients (65%) who had greater values of heart-rate variability parameters reflecting parasympathetic activity. CONCLUSIONS: The 3 techniques evidenced re-innervation after heart transplantation. A correlation exists between sympathetic activity detected using MIBG scintigraphy and analysis of heart-rate variability. Patients in whom endomyocardial biopsy specimen reveals the presence of nerve fibers show more parasympathetic activity in the heart-rate variability analysis.

Angina de pecho en el paciente con trasplante cardíaco: una evidencia de reinervación / Angina Pectoris in the Heart Transplant Recipient: Evidence of Reinnervation

El trasplante cardíaco conlleva la extirpación del corazón enfermo con su inervación y la implantación de un corazón donante aislado del control del sistema nervioso autónomo del receptor, es decir funcionalmente denervado. La denervación condiciona diversas alteraciones en la fisiología cardíaca, como la incapacidad para experimentar dolor frente a la isquemia miocárdica, por lo que teóricamente estos pacientes no pueden presentar angina de pecho. Sin embargo, diversos estudios han demostrado evidencias de reinervación y se han descrito casos aislados de pacientes trasplantados con angina de pecho. Describimos el caso de un paciente trasplantado que presentaba angina de esfuerzo típica, enfermedad vascular del injerto y datos de reinervación simpática demostrados por gammagrafía cardíaca con metayodo-benzilguanidina-I-123 (AU)