Risk factors and outcomes for nosocomial infection after prosthetic vascular grafts.

OBJECTIVE: The objective of this study was to determine risk factors for nosocomial infections (NIs) and predictors of mortality in patients with prosthetic vascular grafts (PVGs). METHODS: This was a prospective cohort study of all consecutive patients who underwent PVG of the abdominal aorta with or without iliac-femoral involvement and peripheral PVG from April 2008 to August 2009 at a university hospital. Patients younger than 15 years and those with severe immunodeficiency were excluded. The follow-up period was until 3 years after surgery or until death. RESULTS: There were 261 patients included; 230 (88.12%) were male, and the mean age was 67.57 (standard deviation, 10.82) years. The reason for operation was aortic aneurysm in 49 (18.77%) patients or lower limb arteriopathy in 212 (81.23%) patients. NIs occurred in 71 (27.20%) patients. Of these, 42 were surgical site infections (SSIs), of which 61.9% occurred in the lower extremities (14 superficial, 10 deep, and 2 PVG infections) and 38.1% in the abdomen (7 superficial, 7 deep, and 2 PVG infections); 15 were respiratory tract infections; and 15 were urinary tract infections. Active lower extremity skin and soft tissue infection (SSTI) at the time of surgery was a significant predictor of NI for both types of PVG (abdominal aortic PVG: adjusted odds ratio [OR], 12.6; 95% confidence interval [CI], 1.15-138.19; peripheral PVG: adjusted OR, 2.43; 95% CI, 1.08-5.47). Other independent predictors of NI were mechanical ventilation (adjusted OR, 55.96; 95% CI, 3.9-802.39) for abdominal aortic PVG and low hemoglobin levels on admission (adjusted OR, 0.84; 95% CI, 0.71-0.99) and emergent surgery (adjusted OR, 4.39; 95% CI, 1.51-12.74) for peripheral PVG. The in-hospital mortality rate was 1.92%. The probability of surviving the first month was 0.96, and significant predictors of mortality were active lower extremity SSTI (adjusted risk ratio [RR], 12.07; 95% CI, 1.04-154.75), high postsurgical glucose levels (adjusted RR, 1.02; 95% CI, 1.00-1.04), and noninfectious surgical complications (adjusted RR, 19.38; 95% CI, 2.25-167.29). The long-term mortality rate was 11.88%. The probability of surviving at 12, 24, and 36 months was 0.94, 0.92, and 0.87, respectively. Variables significantly associated with long-term death were older age (adjusted RR, 1.08; 95% CI, 1.01-1.15), high values of creatinine on discharge (adjusted RR, 1.91; 95% CI, 1.08-3.38), and an SSI with the highest adjusted RR (6.35; 95% CI, 1.87-21.53). CONCLUSIONS: SSI was the primary NI. The risk of NI depended primarily on the presence of a lower extremity SSTI at the time of surgery, whereas mortality was determined by age, surgical complications during the operation, and SSI. These findings suggest that in those cases in which surgery is reasonably delayed, surgery should be deferred until the lower extremity SSTIs are resolved.

Clinical course and predictors of death in prosthetic valve endocarditis over a 20-year period.

OBJECTIVE: To compare early and late outcome of patients with prosthetic valve endocarditis treated medically versus surgically and to determine predictors of in-hospital death. We retrospectively reviewed patient's clinical records, including laboratory findings, surgery, and pathologic files, in an acute-care, 1200-bed teaching hospital. METHODS: One hundred thirty-three episodes of definite prosthetic valve endocarditis as defined by the Duke University diagnostic criteria occurred in 122 patients from January 1986 to December 2005. Logistic regression model was used to identify prognostic factors of in-hospital mortality. Long-term follow-up was made to assess late prognosis. RESULTS: Bioprostheses were involved in 52% of cases and mechanical valves in 48%. The aortic valve was affected in 45% of patients. Staphylococcus epidermidis was isolated in 23% of cases, Streptococcus spp in 21%, S aureus in 13%, and Enterococcus in 8%. Cultures were negative in 18% of cases. Twenty-six patients were treated medically and 107 with combined antibiotics and valve replacement. The operative mortality was 6.5% and the in-hospital mortality, 29%. Presence of an abscess at echocardiography, urgent surgical treatment, heart failure, thrombocytopenia, and renal failure were significant predictors of in-hospital death. Kaplan-Meier survival at 12 months was 42% in patients treated medically and 71% in those treated surgically (P = .0007). Freedom from endocarditis was 91% at the end of follow-up. CONCLUSIONS: Prosthetic valve endocarditis is a serious condition with high mortality. Patients with perivalvular abscess had a worse prognosis, and combined surgical and medical treatment could be the preferred approach to improve outcome.