BACKGROUND: Post-sternotomy mediastinitis is a feared complication for patients undergoing cardiac surgery with an associated morbidity and mortality up to 25%. Approximately 15% of patients will ultimately be readmitted for a recurrent sternal wound infection. The objective of this study is to review a large single surgeon experience with sternal wound patients managed with a variety of soft tissue flaps to assess mitigating factors, involved organisms, and treatment protocols as related to specific cardiac populations.
METHODS: This retrospective study reviews adult cardiac surgery patients treated for post-sternotomy sternal wound infection from January, 2000 to July, 2007. Demographic and medical data related to the cardiac surgery, post-surgical course, infection history, organisms, and treatment protocols were reviewed.
RESULTS: 146 patients were evaluated and treated for sternal wound infections during the study period. Complete records were available for 135 patients averaging 61.1 years of age at presentation. The majority of patients underwent CABG (n=33, 24.4%), CABG+Valve (n=31, 23%), or heart transplant procedures (n=27, 20%). An additional 26 patients had some form of aortic replacement as part of their surgery. 39.2% of patients developed a sternal wound during the same admission as their cardiac surgery, at an average of 16.1 days. This rate was only 6% for CABG-only patients and rose to nearly 50% in heart transplant and CABG+Valve patients. 12 patients (8.9%) had 1 or more recurrent infections requiring surgery; 50% occurring in transplant patients, most of whom had diabetes and/or renal insufficiency. 78% of heart transplant patients with a sternal wound had a history of ventricular assist device and almost one third of all patients had at least 1 previous sternotomy. The most common presenting symptom was drainage (n=75, 55.6%) or wound dehiscence (n=22, 16.3%). 19 different organisms were identified; 25 patients (18.5%) had multiple organisms. Staphylococcus species were most common: Coagulase-Negative Staphylococcus, (n=29, 21.5%), MSSA (n=20, 14.8%), and MRSA (n=17, 12.6%). Plastic surgery intervention occurred on average 109.24 days after cardiac surgery (range 0-1751 days). CABG and CABG+Valve patients most frequently received right pectoralis muscle turnover flaps (n=26, 40.6%) or left pectoralis muscle advancement flaps (n=17, 26.6%). 10 heart transplant patients (37.0%) underwent omental flaps. 16 patients (11.9%) died subsequent to their sternal wound procedure an average of 39.6 days post surgery.
CONCLUSIONS: Post-sternotomy wound infections are a serious complication of cardiac surgery that frequently calls upon the expertise of plastic surgeons for definitive management. Our review demonstrates a wide variety of cardiac procedures resulting in infections, most commonly from staphylococcal organisms. Transplant recipients, diabetics, ventricular assist devices, and prolonged open sternotomies appear to be contributing factors. Time to development of sternal infections is highly variable, averaging well beyond the typically described 30 day complication window. Our sternal wound reconstructive algorithm based on surgical history, wound depth, and severity of infection has been successful with a low rate of recurrent infection and mortality.