Three Linked Vasculopathic Processes Characterize Kawasaki Disease: A Light and Transmission Electron Microscopic Study

Kawasaki disease is recognized as the most common cause of acquired heart disease in children in the developed world. Clinical, epidemiologic, and pathologic evidence supports an infectious agent, likely entering through the lung. Pathologic studies proposing an acute coronary arteritis followed by healing fail to account for the complex vasculopathy and clinical course.Specimens from 32 autopsies, 8 cardiac transplants, and an excised coronary aneurysm were studied by light (n=41) and transmission electron microscopy (n=7). Three characteristic vasculopathic processes were identified in coronary (CA) and non-coronary arteries: acute self-limited necrotizing arteritis (NA), subacute/chronic (SA/C) vasculitis, and luminal myofibroblastic proliferation (LMP). NA is a synchronous neutrophilic process of the endothelium, beginning and ending within the first two weeks of fever onset, and progressively destroying the wall into the adventitia causing saccular aneurysms, which can thrombose or rupture. SA/C vasculitis is an asynchronous process that can commence within the first two weeks onward, starting in the adventitia/perivascular tissue and variably inflaming/damaging the wall during progression to the lumen. Besides fusiform and saccular aneurysms that can thrombose, SA/C vasculitis likely causes the transition of medial and adventitial smooth muscle cells (SMC) into classic myofibroblasts, which combined with their matrix products and inflammation create progressive stenosing luminal lesions (SA/C-LMP). Remote LMP apparently results from circulating factors. Veins, pulmonary arteries, and aorta can develop subclinical SA/C vasculitis and SA/C-LMP, but not NA. The earliest death (day 10) had both CA SA/C vasculitis and SA/C-LMP, and an "eosinophilic-type" myocarditis.NA is the only self-limiting process of the three, is responsible for the earliest morbidity/mortality, and is consistent with acute viral infection. SA/C vasculitis can begin as early as NA, but can occur/persist for months to years; LMP causes progressive arterial stenosis and thrombosis and is composed of unique SMC-derived pathologic myofibroblasts

Coronary artery calcium screening: current status and recommendations from the European Society of Cardiac Radiology and North American Society for Cardiovascular Imaging

Current guidelines and literature on screening for coronary artery calcium for cardiac risk assessment are reviewed for both general and special populations. It is shown that for both general and special populations a zero score excludes most clinically relevant coronary artery disease. The importance of standardization of coronary artery calcium measurements by multi-detector CT is discussed

Myocarditis.

<p>A. Low magnification H&E of a poorly-preserved hourglass-shaped epicardial CA showing varying degrees of SA/C peri-arteritis, transmural SA/C, and minimal preserved media. H&E, case 1, original magnification 10×. B. Perivascular and transmural SA/C inflamed adventitia and heavily damaged media with some discernible SMC and IEL, and SA/C-LMP with scattered pleomorphic myofibroblasts. There are some eosinophils intermixed with the small lymphocytes. H&E, case 1, original magnification 16×. C. A higher magnification of a typical area of SA/C-LMP with prominent amphophilic myofibroblasts in a background of mostly small lymphocytes, scattered eosinophils, and likely macrophages in a fibrillar ECM that shows some artifactual spaces. H&E, case 1, original magnification 25×. D. A typical area of the highly edematous interstitial myocarditis especially rich in eosinophils, with scattered lymphocytes, macrophages, and plasma cells. Note the longitudinally-sectioned caterpillar-shaped and cross-sectioned, owl eye-shaped (unidentified) Anitschkow chromatin pattern in a myocyte and two unidentified cell nuclei, respectively. H&E, case 1, original magnification 40×. L=lumen, NV=nerve, IEL=internal elastic lamina, Eo=eosinophil, AM=Anitschkow myocyte, MF=myofibroblast, V=vein, ADV=adventitia, M=media.</p