Infectious endocarditis and sudden unexpected death: incidence and morphology of lesions in intravenous addicts and non-drug abusers.

BACKGROUND: Intravenous drug (IVD) use is a wellknown risk factor for infectious endocarditis (IE), but there are few morphologic and epidemiologic data comparing IVD-related and non-IVD-related IE in cases of sudden death. MATERIAL AND
RESULTS: Between 1992 and 1994, acute IE was diagnosed in 13 IVD users at the Office of the Chief Medical Examiner in Maryland, indicating a yearly incidence of IE-related sudden unexpected deaths of 12 per 100,000. Eleven (85%) cases of acute IE occurred on apparently previously normal valves, and there was one unicuspid valve and one infected porcine prosthesis. There were three right-sided (tricuspid) lesions (23%), nine left-sided lesions (69%), and one multivalvular lesion (8%). During the same period, there were five cases of healed IE in IVD abusers, three of which involved the tricuspid valve. The prevalence of incidental healed lesions in autopsies of IVD users was 0.2%. The healed tricuspid lesions consisted of smooth-edged defects in the valve leaflet without perforations characteristic of mitral or aortic IE. The mean age of the deceased with healed lesions was 45 +/- 6 years versus 34 +/- 10 years for those with acute endocarditis (p = 0.03). During the same time period, there were six cases of acute IE among non-drug users, indicating a yearly incidence of sudden unexpected death of 0.04 per 100,000. Acute IE occurred on congenitally malformed (n = 5) or prosthetic (n = 1) valves. There were two cases of incidental healed IE (mitral and aortic valves), indicating a prevalence of 0.02%.
CONCLUSION: IVD users are 300 times more likely to die suddenly with IE than non-IVD users, and healed lesions are 25 times more common. Healed IE of the tricuspid valve is associated with IVD abuse, and has a characteristic gross appearance that differs from healed left-sided IE.