Mediastinitis Post Cardiac Surgery and the Role of the Internal Mammary Artery: An Updated Risk Factors Analysis

BACKGROUND: Mediastinitis is a serious postoperative complication of cardiac surgery (CS) that plastic surgeons are often consulted to help manage. The purpose of this study was to determine preoperative variables that predict mediastinitis as well as the role of the internal mammary artery (IMA) harvest may have. METHODS: Data on 13 preoperative variables were collected retrospectively on 6722 consecutive patients who underwent CS between September 2000 and September 2009 (Table). 91 (1.35%) patients developed mediastinitis post-operatively. Using a case-control approach we matched 2 controls without mediastinitis to each case in order to examine the role of IMA use and pre-operative risk factors on the development of mediastinitis. Controls were matched for age, gender, operative year, and disease burden. RESULTS: Only morbid obesity, chronic obstructive pulmonary disease (COPD), and diabetes were independent predictors for mediastinitis (Table). The use of IMA was not an independent risk predictor (P= 0.16). Multivariate analysis confirmed morbid obesity and COPD were independent predictors. Days of hospital stay before CS also emerged as a significant predictor. CONCLUSIONS: The harvest of IMA was not a risk predictor for the development of mediastinitis post CS. Apart from traditional risk factors like diabetes, COPD, and morbid obesity, our study discovered that the duration of hospital stay prior to CS is an independent risk factor for the development of mediastinitis. We have revealed another focus for decision makers to implement specific strategies and ascertain risk profiles of patients undergoing CS.