Abstract 1946: Anatomic and Pathologic Findings in Hearts From Fetuses and Infants With Cardiac Manifestations of Neonatal Lupus
Objective: Cardiac manifestations associated with neonatal lupus (cardiac NL) have been classically confined to the atrioventricular (AV) node, ranging from an innocent first degree block to complete heart block with fibrosis of the conductive tissue as the distinctive histological feature. However, clinical and basic science evidence suggests that other structures and pathogenic mechanisms might be involved. In order to get further insight into anti-Ro mediated tissue injury and cardiac NL pathogenesis, this study examined the anatomic pathology findings in the heart of children with cardiac NL.
Methods: Retrospective evaluation of available 19 autopsy and 1 biopsy reports from 20 children with cardiac NL enrolled in the Research Registry for Neonatal Lupus with emphasis on pathologic abnormalities in the affected hearts.
Results: Aberration of the AV node was found only in 37% (7/19) of the autopsies and this consisted of fibrosis and calcification of the conduction tissue. Remarkably, in two cases 3rd degree block was detected during pregnancy and the AV node was found to be normal with alterations of the surrounding tissue. The sinoatrial node (SA) was affected in 11% (2/19) of the autopsies. Tricuspid lesions consistent with inflammation were seen in 21% (4/19) of the studies and mitral valve lesions in 11% (2/19). Signs indicative of cardiomyopathy comprising endocardial fibroelastosis (EFE), mononuclear inflammatory infiltrates and pancarditis were found in 65% (13/20) of the reports, including the endocardial biopsy.
Conclusions: Fibrosis of the AV node and subsequent advanced block seem to be only the “tip of iceberg” of cardiac-NL. Pancarditis, EFE, SA node fibrosis and valve disease should be also considered part of the spectrum of anti-Ro tissue injury. Autopsies have been underestimated as helpful sources to gain further insight in cardiac NL pathogenesis. Accordingly, in order to accurately trace information to better study the disease, we suggest an autopsy protocol to be followed when a fetus/infant with cardiac-NL is examined.