Morphology of vascular, renal, and heart lesions in the antiphospholipid syndrome: relationship to pathogenesis.

A growing body of evidence suggests that aPL are not only serological markers of the antiphospholipid syndrome (APS), but may also directly contribute to the development of thrombosis and other manifestations, including the APS vasculopathy. The latter has been documented in leptmeninges, lung, skin, myocardium, peripheral arteries, and kidney. Renal lesions, a common feature of primary antiphospholipid syndrome (PAPS), include occlusion of principal renal arteries or their main branches, TMA, cortical ischemia, and renal vein thrombosis. Within the cardiac manifestations associated with aPL, valvular involvement is the most common. Histologic findings in valve specimens are consistent with a noninflammatory lesion characterized by intravalvular capillary thrombosis, laminar or verrucous superficial thrombosis, vascular proliferation, fibrosis, and calcification. Even though there is general consensus that endothelial damage triggers the chain of events that results in valve thickening, fusion, rigidity, and ultimately functional abnormalities, we believe that more experimental work remains to be done on the initial valve insult in APS.