Focal reduction in left ventricular 123I-metaiodobenzylguanidine uptake and impairment in systolic function in patients with Anderson-Fabry disease

Background. We investigated the relationship between abnormalities of cardiac sympathetic innervation and left ventricular (LV) function in patients with Anderson-Fabry disease (AFD). Methods. Twenty-five AFD patients (45 ± 13 years) were studied by 123I-metaiodobenzylguanidine (MIBG) cardiac imaging and echocardiography. MIBG uptake was assessed using the 17-segment model by a 5-point scale. Total defect score (TDS) was calculated by the summation of the 17 segmental uptake scores. Global and segmental LV longitudinal strain values were obtained by speckle- tracking echocardiography. Results. In AFD patients, a significant correlation between segmental MIBG uptake score and longitudinal strain was found. By ROC analysis, a segmental longitudinal strain >-10.1% predicted a segmental MIBG uptake score ≥1, with 84% specificity and 47% sensitivity. TDS resulted 0 in 11 and ≥1 in 14 AFD patients. LV mass index (59 ± 10 vs. 41 ± 10 g/h2.7), relative wall thickness (0.51 ± 0.08 vs. 0.40 ± 0.06), systolic pulmonary artery pressure (36 ± 6 vs. 27 ± 4 mmHg) and longitudinal strain (-14.3 ± 3.9 vs. -19.4 ± 1.8%, were significantly higher (all P <.01) in patients with TDS ≥1 than in those with TDS = 0. At multivariate linear regression analysis, global longitudinal strain was independently associated with TDS (β = 0.025, 95% confidence interval 0.012-0.038, P = 0.001). Conclusions. Reduced cardiac MIBG uptake reflects the severity of cardiac involvement in AFD patients. LV longitudinal function impairment seems to be an earlier disease feature than regional myocardial denervation.