Lower left ventricular ejection fraction and higher serum angiotensin-converting enzyme activity are associated with histopathological diagnosis by endomyocardial biopsy in patients with cardiac sarcoidosis

Background: The histopathological diagnosis of cardiac sarcoidosis (CS) is challenging because of sampling error in endomyocardial biopsy (EMB) and the determinants of positive EMB are unclear. Reduced left ventricular ejection fraction (LVEF) is a simple parameter of the extent of myocardial damage, and higher serum angiotensin-converting enzyme (ACE) activity would indicate the spread of disease activity in CS patients. Thus, we sought to examine whether these parameters are related to the histopathological diagnosis of CS by EMB. Methods: A total of 94 consecutive clinically diagnosed CS patients between August 1986 and March 2019 who were admitted to two academic hospitals were examined. We determined EMB as positive if non-caseating epithelioid granulomas were confirmed in the myocardial tissue. Patients were divided into two groups according to positive (n = 37) and negative (n = 57) EMB. We assessed the relationship between LVEF, serum ACE activity and positive EMB. Results: Multivariable analysis revealed that both LVEF and serum ACE were independently associated with positive EMB (OR 0.83, 95% CI 0.70–0.99; OR 1.39, 95% CI 1.02–1.90, respectively). Moreover, patients with both lower LVEF (<37%, median) and higher ACE activity (≥13.5 IU/L, median) had the highest frequency of positive EMB (p =.003). The combination of lower LVEF and higher serum ACE showed better specificity (91.2%) and positive predictive value (73.7%) than either LVEF or serum ACE alone for positive EMB. Conclusions: Lower LVEF and higher serum ACE activity were associated with positive EMB, suggesting that these parameters might be useful for predicting positive EMB in CS patients.