In all, 31% had isolated CABG, 30% had isolated valve surgery, 11% had CABG and valve surgery, 6% had thoracic aortic surgery, 2% had left ventricular assist device (LVAD) implantation/heart transplant, and 20% were categorized as other.
Overall, 2.4% of patients in the registry had pneumonia, 1.1% had blood stream infection, 1% had C. difficile colitis, and 0.5% had deep sternal infections.
The overall mean time to infection was 19 days and the median was 14 days. The mean time to infection for pneumonia was 15 days. Overall, more than 40% of infections occurred after the index hospitalization. However, 68% and 66% of pneumonias and blood stream infections, respectively, occurred during hospitalization. The three most common organisms were Pseudomonas aeruginosa (12%), Enterobacter cloacae (8%), and Klebsiella pneumoniae (7%).
Increased risk of pneumonia was associated with surgery time (RR, 1.42), a creatinine level of at least 1.5 mg/dL (RR, 1.94), mild to moderate COPD (RR, 1.78), severe COPD (RR, 4.12), and heart failure (RR, 1.76). The reference category was those without COPD.
In terms of process-of-care factors, only nasal decontamination with mupirocin was associated with reduced risk of pneumonia (RR, 0.77). Nasal decontamination with other agents (RR, 1.44); antibiotics given within 24 hours after surgery (RR, 1.26) and within 48 hours postop (RR, 2.70); ventilator use of 24-48 hours (RR, 2.31) and more than 48 hours (RR, 4.58); nasogastric tube (RR, 2.07); and use of PRBCs (RR, 1.10) were all associated with increased risk of pneumonia.
In terms of mortality, "pneumonia, among all the factors analyzed, had the greatest association with mortality, with an odds ratio greater than seven ... which was far and away greater than anything else that was examined," said Dr. Ailawadi.
Pneumonia was significantly associated with an increased risk of mortality (RR, 7.07), as were heart failure (RR, 1.87), creatinine levels of at least 1.5 mg/dL (RR, 2.97), and surgery duration (1.27). However, black race appeared to be protective, with a significantly decreased risk of pneumonia (RR, 0.43).
Pneumonia significantly increased the length of stay by a median of 13 days (19 days with pneumonia and 6 days without). A number of factors – mild to moderate COPD, severe COPD, heart failure, creatinine levels of at least 1.5 mg/dL, surgery time, age of 65-79 years, age 80 years and older, and black or Hispanic race – were significantly associated with increased risk of longer length of stay. Male sex was significantly associated with decreased length of stay (RR, 0.79).
Both Dr. Horvath and Dr. Ailawadi reported that they have no relevant financial disclosures.