Incidence and factors associated with surgical site infection following coronary artery bypass grafting in Nepal: a prospective single-center study

Abstract

Background: Surgical site infection (SSI) is an important complication following coronary artery bypass grafting (CABG), yet prospective data from low- and middle-income countries, including Nepal, are limited. This study aimed to determine the 30-day incidence of SSI following CABG and explore associated clinical and perioperative factors at a tertiary cardiac center in Nepal. Materials and methods: This prospective single-center cohort study included 89 adults undergoing elective isolated CABG between July 2023 and June 2024. Patients were prospectively followed for 30 days, and SSIs were identified and classified according to Centers for Disease Control and Prevention definitions. Demographic, clinical, intraoperative, and postoperative characteristics were compared between patients with and without SSI. Given the small number of SSI events, conventional multivariable logistic regression was not performed; ridge-penalized logistic regression was used as an exploratory analysis of the direction and relative magnitude of associations. Results: Nine of 89 patients developed SSI, corresponding to a 30-day incidence of 10.1%. Of these, six (66.7%) were superficial, two (22.2%) were deep, and one (11.1%) was an organ/space infection. Among the three culture-positive infections, two were caused by methicillin-resistant Staphylococcus aureus and one by Pseudomonas aerigunosa. Diabetes mellitus (100% vs. 51.2%; P = 0.004) and chronic kidney disease (33.3% vs. 0%; P = 0.001) were more frequent among patients with SSI. Patients with SSI also had longer operative duration ( P = 0.003), a higher number of grafts ( P = 0.006), greater postoperative blood loss ( P = 0.0004), longer ICU stay ( P = 0.028), and longer hospital stay ( P = 0.014). Ridge-penalized regression similarly showed positive associations of graft number, postoperative blood loss, chronic kidney disease, diabetes mellitus, and operative duration with SSI, although these estimates were exploratory. Conclusion: 10.1% developed an SSI within 30 days of elective CABG in this prospective Nepalese cohort. Diabetes mellitus, chronic kidney disease, operative duration, blood loss, and graft number showed associations with SSI, while SSI was accompanied by longer ICU and hospital stays. These findings underscore the need for strengthened SSI surveillance and prevention in CABG patients and warrant confirmation in larger multicenter studies.