Invasive resuscitative and supportive therapy subsequent to accidental trauma, assault, or medical mishap may create lesions that forensic pathologists must interpret. Pulmonary valve nonbacterial endocarditis sometimes complicates placement of flow-directed pulmonary artery (Swan-Ganz) catheters. We examined ten cases of endocarditis from patients dying 0-10 days after removal of a Swan-Ganz catheter, and compared the natural evolution of vegetations in critically ill patients with the reported evolution of similar vegetations in experimental animals in the Freedman model. There was wide variation in macroscopic, as well as in the light- and scanning electron-microscopic, appearances in our cases and we could not establish a direct relationship between vegetation structure and time elapsed after removal of the catheter. These findings suggest that parameters related to critical illness and species account for the differences between this disease in human and animal models.