Diastolic dysfunction in patients with systemic sclerosis detected by gated myocardial perfusion SPECT: An early sign of cardiac involvement

Diagnosis of cardiac involvement is important for the management of patient s with systemic sclerosis (SSc). This study was undertaken to determine the significance of gated myocardial perfusion SPECT in patients with SSc and whether diastolic function measured by gated SPECT is an early sign of card iac complications. Methods: Thirty-four patients with SSc and 16 control pa tients were studied using exercise nongated and resting gated myocardial pe rfusion SPECT. The SSc was classified by the modified Rodnan total skin sco re (TSS) into high-TSS (score greater than or equal to 10; n = 18) and low- TSS (score greater than or equal to 10; n = 16) groups. Gated SPECT was per formed using Tc-99m-methoxyisobutyl-isonitrile with 16 frames per cardiac c ycle and quantitatively analyzed by QGS software and Fourier filtering of t he volume curve. The parameters of ejection fraction (EF), peak filling rat e (PFR), one-third mean filling rate, and time to PFR (TPFR) were calculate d. Results: A slight perfusion abnormality was observed in four and five pa tients in the low-TSS and high-TSS groups, respectively (not statistically significant). A decreased resting EF less than 55% was found in no and two patients in the low-TSS and high-TSS groups, respectively. TPFR was 166 +/- 22, 168 +/- 38, and 216 +/- 82 ms (P = 0.05, high-TSS group versus low-TSS group; P = 0.04, control group versus high-TSS group) and TPFR/R-R interva l was 0.18 +/- 0.02, 0.19 +/- 0.04, and 0.26 +/- 0.09 (P = 0.01, high-TSS g roup versus low-TSS group; P = 0.005, control group versus high-TSS group) for the control, low-TSS, and high-TSS groups, respectively. Conclusion: Di astolic function can be evaluated by gated myocardial perfusion SPECT. Sign ificant diastolic abnormalities were shown even in patients with normal per fusion and systolic function and were related to the severity of SSc.