observations in these 4 patients and review of published reports of infection involving 43 other patients with porcine valve heterografts indicates that infection in these valves : ( 1 ) develops in the fibrin layer that covers the cusps , ( 2 ) can involve the collagen in the leaflets , and ( 3 ) is uncommonly ( three patients ) associated with valve ring abscesses .
C0009450
infection
C0000833
abscesses