Background Cardiac involvement is a manifestation of systemic sclerosis (SSc) that contributes to significant mortality and morbidity. Since many SSc patients with cardiac involvement are asymptomatic and it may progress silently, early diagnosis is still challenging. The perfusion-metabolic mismatch in cardiac scintigraphy indicates functional abnormality due to myocardial injury and has been expected to detect early cardiac involvement in various diseases. However, its clinical utility has been poorly evaluated in patients with SSc.
Objectives To evaluate clinical utility of perfusion and myocardial fatty acid metabolism mismatch in SSc patients without cardiac failure.
Methods All patients who visited St. Marianna University Hospital from 2009 to 2015 and performed cardiac scintigraphy using 99mTl and 123I-BMIPP were retrospectively evaluated. Patients who fulfilled American Collage of Rheumatology classification criteria of SSc and systemic lupus erythematosus (SLE) were selected. We subtracted %uptake of metabolism (123I-BMIPP) from that of perfusion (99mTl) on each 17 myocardial segments standardized by American Heart Association. We compared sum of all the scores and each score in 3 coronary artery regions between patients with SSc and SLE. Furthermore, we evaluated incidence of cardiac death or cardiac failure depending on the scores of each coronary artery regions.
Results Among 177 patients, we analyzed the data in 22 cases with SSc and 23 with SLE. The sum of all mismatch scores was not significantly different between the 2 groups (p=0.37). The mismatch score of left anterior descending coronary artery (LAD) region was significantly higher in SSc than SLE (p=0.05) (Figure 1A). We next divided SSc patients into 2 groups depending on degree of the LAD mismatch score and found the group with low score had higher incidence of cardiac death or cardiac failure (p=0.04) than that with high score (Figure 1B).
Conclusions The low mismatch score in LAD region of cardiac scintigraphy could be associated with cardiac death or cardiac failure in SSc patients. Since myocardial fibrosis might replace viable cardiomyocytes leading to loss of ventricular volume, metabolic defect by scintigraphy might be less detectable.
Disclosure of Interest None declared