Diagnosis of cardiac thrombosis in patients with atrial fibrillation in the absence of macroscopically visible thrombi

Abstract

Cardiac thrombosis due to atrial fibrillation (AF) has been recognized as the most common cause of cerebral embolism. However, sometimes no macroscopic thrombus is found at autopsy in the heart of a victim of this type of cerebral embolism. We investigated morphological changes in the left atrial endocardium of 31 patients (including 21 cases with AF) who had died of cerebral embolism. "Rough endocardium" (RE) seen macroscopically provided evidence for the existence of atrial thrombosis. The RE that appeared in AF cases was due to a granular and wrinkled appearance of the endocardium associated with oedematous and fibrous thickening. Fibrin-thread deposits were also always distinguishable. Mural thrombi and oedema with neutrophil infiltration in the subendocardium could be seen under the microscope. Small areas of endothelial denudation and thrombotic aggregations were commonly observed by scanning electron microscopy (SEM). These SEM lesions were significantly more frequent in cases with AF than in controls (P < 0.001). The diagnostic success rate for atrial thrombosis among cases with AF increased from 33.3% to 81% when thrombi proven by histological investigation of the areas with RE were added. Left atrial RE may be an anatomically relevant finding for the existence of atrial thrombosis with AF, when the thrombosis cannot be detected upon gross observation at autopsy.

Expression of Cell Adhesion Molecules and the Appearance of Adherent Leukocytes on the Left Atrial Endothelium With Atrial Fibrillation

“…It is interesting that Masawa et al reported morphological changes in the left atrial endothelium of AF patients who died from cerebral embolism; they had mural thrombi and edema with neutrophil infiltration in the subendocardium of the left atrial endocardium. 27 These results indicate a possibility that hemodynamic changes with AF were responsible for abnormalities in the functioning of left atrial endothelial cells.…”

Thrombogenesis in Atrial Fibrillation

“…Goldsmith and colleagues [7] have reported more severe endocardial changes in the LAA than in the right-atrial appendages, especially in atrial fibrillation (compared with sinus rhythm) and in mitral stenosis (compared with mitral regurgitation). Similarly, Masawa and co-workers [8] have described a "rough endocardium" with a wrinkled appearance attributable to oedema and fibrinous transformation; small areas of endothelial denudation and thrombotic aggregation have also been noted in patients with atrial fibrillation and cerebral embolism.…”

Pathophysiological Insights into Atrial Fibrillation Following Cardiac Surgery: Implications for Current Pharmaceutical Design

“…Masawa et al [159]. Described areas of endothelial denudation and thrombotic aggregation in the LA on scanning electron microscopy in subjects (n=31) who died from cerebral embolism, and these areas were more frequent when history of AF was documented (p<0.001) [159].…”