The precise relationship between nonbacterial thrombotic endocarditis
(NBTE) and infective endocarditis (IE) remains to be clearly establish
ed, some believing that IE might develop from NBTE once the latter bec
omes secondarily infected during bacteremia. To compare the features o
f the two lesions, 175 cases of NBTE and 145 cases of IE encountered i
n more than 25,000 autopsies performed over a period of 24 years (1970
-1993) were reviewed, and the relevant clinical, pathological, and bac
teriological findings assessed. The results show that IE is a genuine
suppurative infection of cardiac valves ab initio, whereas, in NBTE, i
nflammation is lacking and the lesion is a result of a usually paraneo
plastic disturbance of thrombosis/thrombolysis.