Cardiac sarcoidosis symptoms at diagnosis help predict long-term risk
Study: Tailored management strategies needed for each clinical phenotype
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In people with cardiac sarcoidosis, patterns of signs and symptoms seen when the person is diagnosed can help predict the risk of long-term outcomes, including hospitalization and death, a new study shows.
“The clinical phenotype [profile] of CS is a useful prognostic indicator,” researchers wrote, adding that these findings highlight the importance of active diagnosis of the CS phenotype before clinical events occur.
The study, “Prognostic value of the clinical phenotype in patients with cardiac sarcoidosis: SARCO phenotype,” was published in the Journal of Cardiology.
Patterns of heart abnormalities can vary widely in cardiac sarcoidosis
Sarcoidosis is a chronic disorder characterized by the formation of abnormal clumps of immune cells in tissues throughout the body. When the heart is affected, the condition is known as cardiac sarcoidosis.
Previous research has established that people with cardiac sarcoidosis generally have a worse prognosis than those with other types of sarcoidosis. However, there hasn’t been as much research into the factors that predict long-term outcomes among people with cardiac sarcoidosis.
At the time of diagnosis, some people with cardiac sarcoidosis have overt signs of heart damage, but others don’t, and specific patterns of heart abnormalities can vary widely. In this study, a team of scientists in Japan sought to determine if the pattern of signs and symptoms, or phenotype, at the time of diagnosis was predictive of long-term outcomes.
The team retrospectively analyzed data from 502 patients with cardiac sarcoidosis who participated in a multicenter Japanese cardiac sarcoidosis registry. In the current study, these participants were divided into four groups based on their phenotype at diagnosis.
The largest group, comprising nearly a third of participants (30.9%), had an arrhythmia phenotype, which was marked by substantial abnormalities in heart rhythm, or arrhythmias.
Another 14.9% of patients were classified as the congestive heart failure phenotype, characterized by signs of heart failure, where the heart isn’t adequately pumping blood out to the body. A further 28.7% of participants were categorized as the overlapping phenotype, as they had both arrhythmia and signs of congestive heart failure.
The remaining 25.5% of patients had signs of heart damage detectable on clinical tests, but no overt signs of heart failure or substantial heart rhythm abnormalities. This fourth group was labeled the subclinical phenotype.
Estimated rate of fatal heart rhythm events high in all phenotypes
For each of the four groups, the researchers used statistical models to estimate the number of patients who reached a composite outcome that included death of any cause, hospitalization due to heart failure, and fatal ventricular arrhythmia events (FVA), or fatal events related to arrhythmias in the lower chambers of the heart.
Over a median follow-up period of nearly three years, 145 composite outcomes were observed. These included 96 FVAEs, 56 hospitalizations for heart failure, and 49 deaths.
Results showed that just over one in five (20.8%) people with the subclinical phenotype were estimated to reach the composite outcome over 10 years of follow-up, compared to more than half of those in each of the other three groups.
“The primary event rate was significantly higher in the arrhythmia, congestive [heart failure], and overlapping phenotypes than in the subclinical phenotype,” the researchers wrote.
The estimated rate of all-cause death at five years was significantly higher in people with the congestive heart failure phenotype or the overlapping phenotype than in those with the arrhythmia phenotype.
The primary event rate was significantly higher in the arrhythmia, congestive [heart failure], and overlapping phenotypes than in the subclinical phenotype.
Estimated rates of hospitalization due to heart failure were higher in the heart failure and overlapping groups than in the other two groups.
“Hospitalization for [heart failure] events was rarely observed in the subclinical and arrhythmia phenotypes, but the congestive [heart failure] and overlapping phenotypes were significantly associated with hospitalization for [heart failure] events,” the researchers wrote. “These findings suggest that the congestive [heart failure] and overlapping phenotypes represent more advanced stages of [heart muscle] involvement compared to the subclinical and arrhythmia phenotypes.”
The estimated rate of fatal heart rhythm events was “high in all clinical phenotypes,” including in the subclinical phenotype group (17.9% at 10 years), the researchers wrote. Still, this rate was particularly high among those with the arrhythmia and overlapping phenotypes.
“Although the prognosis of the subclinical phenotype was better than that of the other phenotypes, FVAEs occurred mainly in the long term,” the team wrote. “Therefore, careful monitoring of patients with [cardiac sarcoidosis] is essential, even for those with subclinical phenotypes.”
Overall, these data indicate that the clinical picture of cardiac sarcoidosis at the time of diagnosis can provide useful prognostic information, and that “tailored management strategies should be implemented for each clinical phenotype,” the researchers wrote.
They emphasized, however, that there is a need for additional multicenter studies, following patients over time, to validate and expand upon these findings.
