Clinical and prognostic effect of a positive granulocyte scan in infective endocarditis.

Thirty patients with clinical signs of infective endocarditis and pathologic echocardiographic findings indicating vegetations underwent scanning with In-111 or Tc-99m hexamethylpropylene amineoxime (HMPAO) labeled granulocytes. Blood cultures were positive in 60% of the patients. The other cases were negative as a result of antibiotic pretreatment. The results of scintigraphy were correlated with the subsequent clinical course, and in 20 cases with data obtained by histologic examination of the valves. With regard to the degree of the inflammatory process, the nuclear medical procedure provided the following results: true-positive in 6 cases, false-positive in 1 case, true-negative in 19 cases, and false-negative in 3 cases. In this study, positive granulocyte scans correlate with high activity of the inflammatory process and predict a poor prognosis for the patients concerned.