Lingering heart inflammation tied to cardiac sarcoidosis relapse risk
Study suggests advanced imaging may identify patients for monitoring
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Heart inflammation that persists after initial treatment may signal disease relapse in people with cardiac sarcoidosis, and advanced imaging could help identify patients who warrant monitoring, a study found.
Most relapses occurred in areas of the heart that had previously been affected, and more than half of patients with imaging-defined disease relapse had no symptoms at the time of disease recurrence.
The findings suggest that “serial FDG-PET [positron emission tomography with 18F-fluorodeoxyglucose] imaging may help characterize disease trajectories and identify patients who may benefit from closer surveillance after treatment response,” the researchers wrote. FDG-PET is an advanced imaging scan that maps the use of a radioactive sugar tracer, 18F-FDG, which is taken up by cells in areas of active inflammation, including the heart muscle in cardiac sarcoidosis.
The study, “Relapse in Cardiac Sarcoidosis: Patterns and Predictors on Serial 18F-FDG PET Imaging,” was published in Journal of Nuclear Cardiology.
Cardiac sarcoidosis is a form of sarcoidosis — a disease marked by the formation of small clumps of inflammatory cells, called granulomas — that affects the heart. Because relapses after an initial response to treatment are common, heart FDG-PET is often used to monitor disease activity and help guide therapeutic decisions. However, imaging features that could help predict which patients are at greater risk of relapses have not been well established.
Data from scans show patterns
A team of researchers retrospectively analyzed data from heart FDG-PET scans of 50 people with cardiac sarcoidosis who were seen at several sites in Canada. Participants’ median age was 54, and 60% were men. The patients were followed for 18.7 months (about 1.5 years).
All underwent three scans: one before starting treatment (baseline), a second after a median of 6.8 months (response scan), and a third at a median of 11.1 months after the response scan (follow-up scan) .
Most patients (86%) received corticosteroids, powerful anti-inflammatory medications associated with serious side effects with long-term use, either alone or with immunosuppressive treatments that can reduce the need for corticosteroids.
At the second PET scan, 40% had a complete response, or no detectable heart FDG uptake, reflecting no inflammation. The remaining 60% showed a partial response, defined as at least a 20% reduction in total heart FDG uptake with residual uptake, meaning they still had signs of active heart inflammation despite treatment.
Forty-six percent experienced an imaging-based relapse, defined as at least a 20% increase in overall heart FDG uptake in the follow-up scan, after initially responding to treatment.
Almost all those who relapsed (91%) showed inflammation in previously affected heart segments. Still, the overall inflammatory burden in relapsed patients was 63.7% lower than at baseline.
More than half of the participants who relapsed (52.2%) had no symptoms when imaging-defined relapse was detected. Other eight participants (34.8%) had new manifestations, including worsening heart failure symptoms, abnormal heart rhythms, or a decline in heart’s pumping function.
Participants with a partial response were more likely to experience a relapse than those with a complete response (63% vs. 20%). Those who relapsed also had a significantly higher inflammatory burden on baseline scans, and were significantly more likely to have sarcoidosis affecting other parts of the body (96% vs. 59%).
Relapsed patients also had a greater number of affected sites outside the heart, both at baseline (2.6 vs. 1.2) and at follow-up (3.1 vs. 0.9). The most frequently involved sites were the lungs, liver, and mediastinum, the area between the lungs.
Treatment information after the second FDG-PET scan was available for 13 patients with relapse and 15 without relapse. All relapsed patients had their immunosuppressive treatment reduced or tapered after the response scan, compared with 80% of those who did not relapse. The remaining patients without relapses either continued stable treatment (13%) or were not receiving immunosuppressive therapy (7%) after the response scan.
Statistical analyses adjusted for potential influencing factors identified persistent heart inflammation after treatment as the only independent predictor of relapses, being associated with a five times higher risk of relapse.
“These findings provide additional insight into imaging-defined disease trajectories in cardiac sarcoidosis and support further investigation into risk-adapted surveillance strategies using serial FDG-PET imaging,” the researchers wrote.
They cautioned, however, that an imaging-defined relapse should not automatically lead to more intensive treatment.
Among the study’s limitations, the researchers noted its retrospective nature, relatively small number of patients, and a lack of standardized treatment and follow-up imaging intervals.
“These findings should be interpreted cautiously and should be considered exploratory and hypothesis generating and would require validation in larger [studies following patients over time] with standardized treatment protocols and clinical outcome ascertainment,” the researchers wrote.
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