Background/Purpose: Even though clinically significant heart involvement is rare, cardiovascular complications are leading causes of death in systemic vasculitis (SV). The comprehensive analysis of histopathologic findings is needed to elucidate the driving mechanisms of increased cardiovascular risk in SV. The purpose of this study was to investigate the variation of cardiac pathological findings in autopsy cases of Takayasu arteritis (TAK), polyarteritis nodosa (PAN) and granulomatosis with polyangiitis (GPA).

Methods: Microscopic examinations of the heart were performed in 108 autopsy cases of SV over a period of 15 years, of which 37 were PAN, 60 – TA and 11 – GPA.

Results: The destructive-productive vasculitis affecting myocardial, epicardial medium and small-sized arteries was observed in 81.1% cases of PAN. The most common acute change was panarteritis with intramural, and perivascular lymphocytes, and macrophages infiltrates. The most remarkable lesions in coronary arteries were nodules visible to the naked eye along coronary arteries (30%). In cases of chronic course of PAN, intimal hyperplasia due to proliferation of endothelial cells has been identified. In 5 (16.7%) cases, luminal occlusion due to intimal proliferation, fibrosis and thrombus formation led to the myocardial infarction. The pathological manifestation of cardiac involvement in PAN included the left ventricular hypertrophy due to renovascular arterial hypertension in 26 cases (70.3%). Interstitial myocarditis was observed in 4 cases (10.8%).

The pathological changes in coronary vessels have been found in all cases of GPA. The destructive-productive vasculitis affecting intramyocardial small arteries, arterioles, and capillaries was the most common. The acute stage has been characterized by abnormalities of the vessel wall from mucoid swelling to fibrinoid necrosis. The chronic lesions were characterized by intimal hyperplasia, fibrosis, hyalinosis of the vessels with their luminal narrowing. The most common lesion of myocardial interstitial matrix was extravascular granulomatous inflammation.

Our data show high frequency (76.7%) of pathological changes of coronary arteries in TAK such as intimal hyperplasia, granulomatous arteritis, and coronary atherosclerosis. Intimal hyperplasia consists of areas of musculo-fibrous proliferation or multi-layer scleral hyaline plaques. This pillow-like thickening of the intima around of the coronary orifices leads to their luminal narrowing. The coronary orifices were the site most commonly affected by TAK. Luminal narrowing of coronary arteries with coronary flow reduction led to subsequent fatal myocardial infarction in 15 cases (25%). Coronary atherosclerosis of varying severity was observed in 35 cases (58, 3%). The most common location of atherosclerotic deposits was regions of the pillow-like thickening of the intima around of the coronary orifices.

Conclusion: Our data suggest that cardiac involvement is common in SV with a wide range of acute and chronic changes and can be potentially life-threatening.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/cardiac-involvement-in-systemic-vasculitis-a-retrospective-pathological-study/