Manifestation and ultrastructural typing of amyloid deposits in the heart

Cardiac immunocyte-derived (AL) amyloidosis: an endomyocardial biopsy study in 11 patients

The objective of this study was to investigate the spectrum of morphologic features in myocardial biopsy specimens from patients with cardiac immunocyte-derived (AL) amyloidosis. Cardiac involvement is the most important predictor of survival in AL amyloidosis. Myocardial biopsy remains the method of choice for diagnosing cardiac amyloidosis when noninvasive studies give equivocal results. Histologic, immunohistochemical, ultrastructural, and morphometric studies were made on myocardial biopsy specimens from 11 patients in whom the diagnosis of AL amyloidosis was based on the demonstration of a monoclonal immunoglobulinopathy and of amyloid deposits in tissues. Histopathologic study showed amyloid in 10 of the 11 biopsies. In one biopsy (Congo red negative), the diagnosis was made by ultrastructural identification of amyloid fibrils. In all patients, the deposits formed perimyocytic layers that measured up to 18 microns in thickness. These layers formed along the basement membranes, which were partially preserved in 5 patients and unrecognizable in 6. Interstitial nodular deposits were also present in 5 patients. Immunohistochemical studies for the characterization of the proteins in the amyloid deposits were diagnostic in 1 patient and confirmatory in 10. Nodular deposits, thick perimyocytic layers of amyloid and small myocyte diameters were associated with shorter survival of the patients. Small-vessel involvement and myofilament loss occurred in all patients. In conclusion, myocardial biopsy serves to (1) establish the diagnosis of cardiac amyloidosis; (2) characterize immunohistochemically the proteins in the amyloid fibrils and (3) assess the degree of myocyte damage and atrophy.

Recognition of congestive heart failure due to senile cardiac amyloidosis

Senile cardiac amyloidosis has been considered an incidental finding at autopsy in the elderly and of little clinical importance. Autopsy studies have shown that a subset of this group have large deposits of amyloid in their ventricles. Many of these patients had congestive heart failure antemortem. Senile cardiac amyloidosis, however, is rarely diagnosed antemortem and is often confused with primary systemic amyloidosis involving the myocardium. Using endomyocardial biopsy with newly developed immunohistochemical techniques, we have been able to recognize senile cardiac amyloidosis premortem. We have found that these patients have a longer survival than patients with primary systemic amyloidosis. In addition, senile cardiac amyloidosis occurs at a younger age than autopsy studies suggest. Recognition is important because these patients should not be given treatment reserved for the therapy of primary cardiac amyloidosis.

Primary cardiovascular amyloidosis with benign monoclonal gammopathy

A 54-year-old woman is reported whose primary amyloidosis was diagnosed at autopsy. Amyloid deposits were found in the myocardium, the striated muscles, the smooth muscle layers of the gut and the wall of the blood vessels. The deposits showed resistance to induced proteolysis. A large number of mature plasma cells was demonstrated in the bone marrow, and immunocytochemical studies revealed a considerable increase in the proportion of plasma cells which were positive for kappa light chains of immunoglobulins, indicating a monoclonal gammopathy. This view was strongly supported by the unexpected finding that amyloid deposits were positive for kappa light chains. The relationship between the kappa positive reaction of amyloid and its resistance to induced proteolysis are discussed.

Amyloid deposits in aortic and mitral valves. A clinicopathological investigation of material from 100 consecutive heart valve operations

The material from 100 consecutive aortic and mitral valve operations has been studied histologically with particular reference to the presence of amyloid deposits. Sixty seven per cent were positive (aortic 88%, mitral 45%). The simultaneous occurrence of calcification of the valves and amyloid degeneration as well as of calcification and hyalinization was significant. Similarly there was significantly more amyloid in the older age groups, as well as a significant correlation between the degree of hyalinization of the valve and amyloid. Thirty-two patients had previously suffered from rheumatic fever. The heart valves of these patients did not differ histologically from the others, whereas significantly more amyloid was observed in the stenotic mitral valves than in the mitral valves which were insufficient.

Senile amyloidosis: principles of localization in a heterogeneous form of amyloidosis

In order to identify amyloid deposits in patients over 60 years of age (so-called senile amyloid), the following five tissues were investigated under the light and electron microscope: 1. pituitary gland, 2. pancreatic islets of Langerhans, 3. heart, 4. aorta, and 5. brain. In all an increasing incidence of amyloid deposits was found with increasing age, and in the brain a significant quantitative increase in amyloid deposits with increasing age was observed. Despite the biochemical heterogeneity of amyloid found in old age, all the deposits seen in tissues examined were morphologically similar. Typical amyloid fibrils were always found (diameter 60-100 A), and these were invariably deposited extracellularly and primarily on basement membranes. The amyloid-binding basement membranes were in most cases those of myocytic, but were also those of endothelial or epithelial cells. The almost invariable involvement of blood vessels, indicates the importance of these structures in the genesis of the various forms of senile amyloid.