Abstract
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Objectives: An index for detecting early stages of cardiac complication is important for evaluating systemic sclerosis (SSc), because frequent discrepancies between clinical manifestations and real cardiac involvement are observed. Possibility for detecting the early myocardial damage was investigated by perfusion and sympathetic imaging.
Methods: Twenty-three patients with SSc and 14 control subjects were studied. The severity of SSc was defined by disease type (limited and diffuse types), and the severity of scleroderma was quantified by the modified Rodnan's skin thickness score. Myocardial perfusion study was performed by Tc-99m MIBI exercise-rest SPECT, and resting study was performed with 16-frame gated SPECT. Based on quantitative parameters from QGS software, diastolic parameters were calculated from the Fourier-fitted volume curve and differentiation curve. The diastolic parameters were evaluated by peak filling rate (PFR) in the early filling phase, time to early peak filling (TPF) and TPF/RR interval. I-123 MIBG study was evaluated by segmental defects with SPECT, a heart to mediastinum ratio in the early and delayed phase (eH/M, dH/M) and washout rate (WR).
Results: No significant exercise-induced ischemia was observed with the Tc-99m MIBI study and left ventricular ejection fraction was within normal range in patients with SSc. In MIBG study, slight degree of hypoactivity or heterogeneity was observed in 15 of 23 patients with SSc. However, diastolic function calculated by TPFR and TPF/RR were significantly prolonged in SSc compared with the control group. The lower MIBG dH/M and more rapid MIBG WR from the myocardium was observed in SSc. Compared with the control group, the severe group, defined as either diffuse type or skin thickness score >= 10, showed more prolonged TPF/RR than the less severe group. Both diastolic and sympathetic abnormalities were observed in 7 (30%) patients, either of them in 17 (74%) patients, only diastolic dysfunction in 4 (18%) patients and only sympathetic dysfunction in 6 (26%) patients (p=0.0210 vs control group). [table]
Conclusions: In patients with SSc, either diastolic dysfunction or sympathetic derangement or both were observed even without induced ischemia and normal ventricular contractility. These findings might reflect independent pathophysiologic process in the early stages of cardiac complication in SSc.
- Society of Nuclear Medicine, Inc.