Elsevier

Mayo Clinic Proceedings

Volume 76, Issue 12, December 2001, Pages 1204-1212
Mayo Clinic Proceedings

Original Article
Surgical Pathology of Nonbacterial Thrombotic Endocarditis in 30 Patients, 1985–2000

https://doi.org/10.4065/76.12.1204Get rights and content

Objective

To describe the causes, complications, and histological appearance of nonbacterial thrombotic endocarditis (NBTE) in a surgical population compared with those in previously reported autopsy series.

Patients and Methods

Cases were identified by reviewing the surgical pathology reports for all cardiac valvular specimens removed at Mayo Clinic, Rochester, Minn, between 1985 and 2000. Archived microscopic slides and medical records were reviewed for each study patient.

Results

The study group consisted of 30 patients (20 female and 10 male), with a mean age of 49 years (range, 15–89 years). Of these 30 patients, 28 had single valve involvement (19 mitral, 8 aortic, and 1 tricuspid), and 2 had involvement of both their mitral and aortic valves. An underlying immune-mediated disorder was identified in 18 patients (60%), including primary antiphospholipid syndrome (in 8), rheumatic heart disease (in 6), systemic lupus erythematosus (in 2), and rheumatoid arthritis (in 2), 15 (83%) of whom were women. Of the remaining 12 patients with no autoimmune disease, only 5 (42%) were women. No patient had metastatic malignant disease or disseminated intravascular coagulopathy. Systemic embolization was documented in 10 patients (33%), 8 of whom had cerebral involvement. Valvular vegetations were visualized by echocardiography before surgery in 8 patients and were suspected but not confirmed preoperatively in 1 patient. All vegetations consisted primarily of platelets and fibrin. The site and appearance of vegetations did not vary with the underlying disease state.

Conclusions

In contrast to previously reported autopsy series, NBTE in a surgical population was more commonly associated with autoimmune disorders than malignancy or disseminated intravascular coagulopathy. Women were affected twice as often as men. Systemic embolization, particularly to the brain, was prominent in both surgical and autopsy series. Vegetations had a similar appearance regardless of the specific underlying disease. An antemortem diagnosis of NBTE in a patient with no known risk factors should prompt a search not only for occult malignancy, as suggested by autopsy studies, but also for autoimmune or rheumatic diseases, particularly the antiphospholipid syndrome.

Section snippets

PATIENTS AND METHODS

Cases were identified by a manual search of all the surgical pathology reports for cardiac valve specimens removed between January 1, 1985, and December 31, 2000, at Mayo Clinic, Rochester, Minn. Patients were included based on a histological diagnosis of NBTE, noninfectious thrombotic endocarditis, Libman-Sacks endocarditis, marantic endocarditis, or verrucous endocarditis or a description in the pathology report of thrombus or sterile vegetation involving 1 or more heart valves. Patients with

Patient Demographics

The study group consisted of 20 female and 10 male patients (32 valves). The age range was 15 to 89 years, with a mean of 49 years. Female patients were younger than male patients (mean, 43 vs 59 years, respectively). The New York Heart Association functional state was class III or higher in 14 (47%) of all patients and in 11 women (55%) and 3 men (30%) (Table 1).

Among the 30 patients, the mitral valve was affected in 21 (70%) and the aortic valve in 10 (33%) (2 patients had both mitral and

Definition of Valvular Vegetations

Valvular vegetations may be infected or noninfected. Traditionally, noninfected vegetations have been categorized as acute rheumatic endocarditis, Libman-Sacks endocarditis, or NBTE.6 Although some investigators have limited NBTE to vegetations that are grossly visible on otherwise normal valves, this approach provides no diagnostic category for bland valvular thrombi that are small or involve diseased valves. Recognizing this issue and the overlap between some cases of Libman-Sacks

CONCLUSIONS

In a surgical population, NBTE is most commonly associated with autoimmune and connective tissue disorders, in contrast to disseminated malignancy reported in autopsy series. Regardless of the underlying etiology, the vegetations have a uniform appearance and seem to be similar with respect to both valve dysfunction and embolization. An ante-mortem diagnosis of NBTE in a patient with no known risk factors should prompt a search not only for occult malignancy, as suggested by autopsy studies,

REFERENCES (12)

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Presented as an abstract at the American Heart Association scientific sessions, Anaheim, Calif, November 12, 2001.

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