Calcification of the internal elastic lamina of coronary arteries

Abstract

Two well-recognized patterns of calcification occur in large- and medium-sized arteries, intimal calcification associated with atherosclerosis and medial calcification described by Mönckeberg. Calcification limited to the internal elastic lamina is a third pattern of calcification not previously reported in coronary arteries. Here we describe 19 cases of coronary artery internal elastic lamina calcification. We serially sectioned and examined the coronary arteries of 66 patients with advanced AIDS and 27 HIV- controls with other chronic illnesses. We observed calcification of the internal elastic lamina in 10 HIV+ patients and 9 controls. HIV- patients with internal elastic lamina calcification were significantly older than HIV- patients without it (P=0.008) and HIV+ patients with it (P=0.006). Occasionally, calcification encroached on adjacent intimal or medial tissue with mild fibrosis. There was frequent disruption of the internal elastic lamina but no evidence of inflammation. Calcification was the dominant histologic feature in all cases. Von Kossa, Alizarin red, and trichrome/elastic stains confirmed these findings. Patients with internal elastic lamina calcification often had extensive medical histories but did not suffer from chronic renal failure or other conditions known to cause calcium dysregulation. We describe coronary internal elastic lamina calcification in HIV+ patients and older HIV- adults. The clinical significance of this finding is unknown. It could lead to arterial stiffening and increased pulse pressure and could be mistaken for intimal calcification on coronary imaging. Internal elastic lamina calcification may result from premature aging due to HIV disease and chronic illness or from metabolic disorders in HIV+ patients.

Figure 1

A 44-year-old woman with AIDS (Table 1). Example of calcification of the internal elastic lamina in a coronary artery with fibromuscular intimal hyperplasia: (a, b) H&E stain demonstrating linear basophilic staining between intima (I) and media (M) ((a) ×40, (b) ×100); (c, d) trichrome/elastic tissue stain confirming that the linear lesion is at the internal elastic lamina, which shows breaks associated with adjacent medial fibrosis (arrows) ((c) ×40, (d) ×100); (e) von Kossa stain; and (f) Alizarin red stain confirming the presence of calcium ((a, f) ×40).

Figure 2

A 46-year-old man with AIDS (Table 1). Internal elastic lamina calcification in the region of atherosclerotic plaque in coronary artery: (a) H&E stain showing basophilic staining (arrow) between media (M) and intimal atherosclerotic plaque (A); (b) trichrome/elastic tissue stain showing breaks in the region of calcification, and (c) Alizarin red stain confirming the presence of calcium (all ×40).

Figure 3

A 39-year-old man with AIDS (Table 1). (a) H&E stain of coronary artery with no intimal thickening showing diffuse linear basophilic staining of internal elastic lamina; (b) trichrome/elastic tissue stain confirming that staining is of the internal elastic lamina, which is not fragmented, and (c) Alizarin red stain confirming the presence of calcium (all ×100).

Figure 4

A 69-year-old HIV-negative woman (Table 1). (a) H&E stain of coronary artery with fibrous plaque with linear basophilic staining in the region of the internal elastic lamina (×40); (b, c) Alizarin red stain confirming the presence of calcium ((b) ×40, (c) ×200): (d) trichrome/elastic tissue stain showing destruction of the internal elastic lamina with fibrosis (asterisk) of the underlying media in the region of the calcification (×200); and (e) close-up of artery shown in (a) showing ‘beads’ of calcification with prominent, eosinophilic internal elastic lamina, which, unlike the basophilic regions, was negative by calcium stains (H&E, ×400).