Surgical outcomes of infective endocarditis among intravenous drug users

Background: With increasing prevalence of injected drug use in the United States, a growing number of intravenous drug users (IVDUs) are at risk for infective endocarditis (IE) that may require surgical intervention; however, few data exist about clinical outcomes of these individuals. Methods: We evaluated consecutive adult patients undergoing surgery for active IE between 2002 and 2014 pooled from 2 prospective institutional databases. Death and valve-related events, including reinfection or heart valve reoperation, thromboembolism, and anticoagulation-related hemorrhage were evaluated. Results: Of the 436 patients identified, 78 (17.9%) were current IVDUs. The proportion of IVDUs increased from 14.8% in 2002 to 2004 to 26.1% in 2012 to 2014. IVDUs were younger (aged 35.9 +/- 9.9 years vs 59.3 +/- 14.1 years) and had fewer cardiovascular risk factors than non-IVDUs. During follow-up (median, 29.4 months; quartile 1-3, 4.7-72.6 months), adverse events among all patients included death in 92, reinfection in 42, valve-reoperation in 35, thromboembolism in 17, and hemorrhage in 16. Operative mortality was lower among IVDUs (odds ratio, 0.25; 95% confidence interval [CI], 0.06-0.71), but overall mortality was not significantly different (hazard ratio [HR], 0.78; 95% CI, 0.44-1.37). When baseline profiles were adjusted by propensity score, IVDUs had higher risk of valve-related complications (HR, 3.82; 95% CI, 1.95-7.49; P < .001) principally attributable to higher rates of reinfection (HR, 6.20; 95% CI, 2.56-15.00; P < .001). Conclusions: The proportion of IVDUs among surgically treated IE patients is increasing. Although IVDUs have lower operative risk, long-term outcomes are compromised by reinfection.