Long-Term Outcome in Probable Versus Absolute Cardiac Sarcoidosis

Suspicion of cardiac sarcoidosis (CS) arises when a patient has clinical cardiac manifestations and findings on cardiac imaging suggestive of inflammatory cardiomyopathy with or without history of extracardiac sarcoidosis. The additional requirement for diagnosis is proof of sarcoidosis histology. Endomyocardial biopsy (EMB) showing granulomatous inflammation in absence of other explanations confirms an absolute diagnosis of CS while similar histology in an extracardiac biopsy gives a probable diagnosis of CS. Our aim was to study the equivalence of probable to absolute CS in terms of patients' characteristics and outcome. We reviewed the available clinical information, diagnostic procedures, details of treatment and event-free survival of 149 consecutive patients (103 women, mean age 50 y) diagnosed with CS at our institution. The diagnosis was absolute in 68 patients and probable in 81 patients. There was no difference in age or sex distribution between the diagnostic subgroups but left ventricular dysfunction on echocardiography (ejection fraction <50%) was more common in absolute CS (60% vs 36%, p = 0.003) as was abnormal myocardial late gadolinium enhancement on magnetic resonance imaging (96% vs 78%, p = 0.006). Over a median of 54 months of follow-up, 19 of 68 patients with absolute CS versus 15 of 81 with probable CS either died, suffered an aborted sudden cardiac death or underwent cardiac transplantation (log rank p = 0.334). In conclusion, in terms of prognosis, clinical diagnosis of CS supported by extracardiac histology is equivalent to diagnosis confirmed by myocardial histology. No distinction should be made between probable and absolute CS as regards treatment and follow-up.