P57 IGG4-related disease causing sudden cardiac death
Authors: Haigh Richard , Smyth Lucy , Ludman Andrew 
Published: April 2020

Abstract

Background
IgG4-related disease (IgG4-RD) is a chronic systemic inflammatory disorder presenting with mass lesions in various organs and showing plasma cell infiltration, storiform fibrosis and obliterative phlebitis on histology. IgG4-RD has previously been identified as a rare cause of sudden cardiac death (SCD) in case reports, but in settings where pathology has been unexpectedly found on post-mortem examination. To our knowledge, there are no published case reports of SCD in patients during treatment for IgG4-RD.

Methods
A 43-year old chef with a 15 pack-year smoking history presented with portal vein thrombosis, widespread lymphadenopathy, proptosis and inflammatory lung changes. He was found to have IgG4-RD on submandibular lymph node biopsy with storiform fibrosis and abundance of IgG4-positive plasma cells. Test showed a high IgG and low complement levels and a persistent eosinophilia. He was anticoagulated with warfarin for the HPV thrombosis. Treatment with steroids (initially prednisolone 40mg/day) was initially successful and he continued at work and kept fit in the gym. There was also a good biochemical and radiological response to steroids, with normalisation of eosinophil count, IgG level, complements and CRP along with regression of imaging changes. After a period of 12 months steroid weaning (prednisolone 5mg) and having been well at OPD review, he was unexpectedly found dead at home. Post-mortem examination identified IgG4-RD coronary pan-arteritis as the cause of death. The finding of this unanticipated severe complication raises new questions about surveillance and prevention.

Results
Coronary involvement in IgG4-RD is thought to be rare but may reflect difficulty obtaining coronary artery tissue and clinically silent disease remaining undiagnosed. A systematic review of IgG4-RD outcomes (7 studies comprising 294 patients, follow-up mean of 29 months) identified 26 deaths (8.8%). One was from an aneurysm and four from other cardiovascular disease, while most deaths were from disease progression or cancer. Case reports describe IgG4-RD coronary artery disease pathologies, including inflammatory pseudotumour, periarterial thickening, coronary artery aneurysm and coronary artery stenosis.

Conclusion
This case raises important questions about identifying and monitoring for asymptomatic cardiovascular involvement in IgG4-RD. Steroid treatment may be less effective for coronary involvement, and in theory, could precipitate rupture or dilatation of the arteries. Recent IgG4-RD management guidelines have not addressed surveillance for cardiovascular disease. ECG and echocardiography are reasonable initial surveillance options, but we suggest clinicians have a low threshold for CT coronary angiography and/or cardiac MR. Invasive coronary angiography and CT-PET can then be used to provide additional information if required. We noted a normal CRP despite active coronary inflammation in our patient and therefore look forward to improved biomarkers for disease activity in IgG4-RD.

Disclosures
R. Haigh None. L. Smyth None. A. Ludman None.