Sarcoidosis is a complex inflammatory disease that causes the harmful accumulation of tiny clumps of cells called granulomas in the body. In most cases, sarcoidosis manifests in the lungs and lymph nodes. However, in approximately 10% of patients, the heart is affected; This condition is known as ‘cardiac sarcoidosis (CS)’. Although relatively rare, CS can cause life-threatening complications, including arrhythmias, heart failure, or sudden cardiac death.
A surprising aspect of CS is that the condition sometimes involves the heart alone, without clinically apparent symptoms in other organs. This is referred to as isolated CS (iCS) in contrast to the multi-organ condition called systemic CS (sCS). According to previous studies, patients diagnosed with ICS have a poorer prognosis than patients with sCS, although the latter condition involves multiple organs rather than just the heart.
This seemingly contradictory finding prompted a research team to investigate the issue in more detail. Researchers led by Daiichi Maeda, assistant professor in the Department of Cardiovascular Biology and Medicine at Juntendo University Graduate School of Medicine in Japan, recently conducted a detailed statistical analysis to explain the above findings. Their research, published European Journal of Heart Failure 12 Octoberm2023, co-authored by Juntendo University’s Yuya Matsu and Tohru Minamino, among others.
The team obtained data for this study from the ‘Management Imaging and Study of Japanese Patients with Cardiac Sarcoidosis (ILLUMINATE-CS)’ cohort, a large multi-centre, retrospective cohort database. They compared prognosis and selected clinical characteristics among a total of 475 patients with ICS or SCS. The primary outcome was a composite end point including all-cause mortality, hospitalization for heart failure, and fatal ventricular arrhythmia events.
Analysis showed that iCS patients were more likely than sCS patients to have a history of atrial fibrillation or heart failure, as well as lower ventricular ejection fraction (LVEF) and thus more impaired heart function. According to Cox proportional hazards analysis using an unadjusted model, patients with ICS were more likely to have a worse prognosis than patients with sCS based on defined primary outcomes. However, this association disappeared when the model was adjusted for other confounding factors.
These findings have important implications, as Dr. Maeda explained: “Our findings suggest that conditions at diagnosis determine prognosis rather than whether a patient has ICS or SCS. Therefore, early detection of ICS is important, although there is little chance of suspecting the disease before symptoms appear.He added that once a patient has decreased LVEF or experienced a cardiac event, the possibility of CS should be investigated so that they can be treated with immunosuppressants. Notably, this study also showed that both iCS and sCS patients responded equally well to steroids. .Treatment
Overall, this work sheds valuable light on some intriguing aspects of CS and highlights the need for further investigation. “We hope that our present study facilitates the development of an early diagnostic tool for CS and that researchers around the world engage in research on CS.Dr. Maeda finished.
We envision a future where all forms of sarcoidosis can be diagnosed and managed in a timely manner.