Blood protein, imaging tests can predict risk in cardiac sarcoidosis
Risks: High BNP levels, heart inflammation, reduced left ventricle function
Having elevated levels of a protein called BNP is associated with an increased risk of death and serious heart health problems in people with cardiac sarcoidosis, a study has found.
Results also suggest inflammation of the heart muscle (myocardium) or reduced function of the left ventricle (the part of the heart responsible for pumping oxygen-rich blood out through the body) is associated with a poorer prognosis for cardiac sarcoidosis patients. These abnormalities can be measured via imaging tests of the heart.
“We provide a clinically simple and highly useful triad of risk predictors of future events such as (i) serum [blood] levels of baseline BNP, (ii) the degree of [left ventricle] dysfunction, and (iii) the intensity of myocardial inflammation,” researchers wrote.
The study, “Predictors of outcome in a contemporary cardiac sarcoidosis population: Role of brain natriuretic peptide, left ventricular function and myocardial inflammation,” was published in the European Journal of Heart Failure.
Cardiac sarcoidosis is when granulomas affect the heart
Sarcoidosis is an inflammatory disorder characterized by clumps of immune cells called granulomas that can form in various organs. Cardiac sarcoidosis, or CS, is when the heart is affected.
In this study, scientists reviewed data on 319 people with cardiac sarcoidosis who were treated at Royal Brompton Hospital in the U.K. between 2008 and 2018. About two-thirds of the patients were male and the median age was in the mid-50s. Most patients (64.9%) had experienced sarcoidosis affecting other parts of the body before being diagnosed with CS, with a median disease duration of three years.
“To our knowledge, this study represents the largest single centre CS cohort offering real-life experience of the condition and its natural history over a 3-year period,” the researchers wrote, though they noted that since this study included only patients from one center, further work in larger populations will be needed to verify the results.
Over the course of follow-up, 26 of the patients died, and another 54 experienced serious heart-related issues, such as life-threatening heart problems that were managed with acute care or hospitalization for heart failure. The researchers conducted statistical analyses looking for factors detectable at CS diagnosis that were predictive of these outcomes.
Results showed elevated levels of the protein BNP (brain natriuretic peptide) in serum — the non-cell portion of blood — were associated with a more than twofold increased risk of death or other serious heart problems, even after accounting for other factors.
Poor left ventricle function, heart muscle inflammation linked to increased risk
Poor left ventricle function, as measured by magnetic resonance imaging of the heart, also was associated with a relatively small but statistically significant increased risk of these outcomes, as was inflammation of the heart muscle, measured by an imaging technique called FDG-PET (short for 18F-fludeoxyglucose positron emission tomography).
“Although both [left ventricle] systolic dysfunction and myocardial inflammation have previously been identified as independent predictors of outcomes in CS, serum BNP levels emerged as a very potent and novel risk stratification tool that remained robust in subgroup analysis,” the researchers noted.
Subgroup analyses were generally consistent with the overall findings, though the researchers noted that patients who’d previously been diagnosed with non-cardiac forms of sarcoidosis generally had less severe outcomes if they’d been on immune-suppressing meds. This suggests “that immunosuppressive treatment in CS indeed favourably affects the disease’s natural history,” the researchers wrote.