Increased levels of NT-proBNP and troponin T 2 years after coronary artery bypass grafting complicated by mediastinitis

Abstract

BackgroundMediastinitis after coronary bypass grafting (CABG) increases the risk of the internal mammary artery (IMA) graft obstruction, and has a detrimental effect on long-term survival. The pathogenesis for this increased mortality is poorly understood. In the present study, we aimed to investigate the relationship between mediastinitis and persistently elevated cardiac-specific biomarkers [troponin T (TnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP)] and C-reactive protein (CRP) at mid-term follow-up following CABG.Material and methodsThe epidemiologic design was of an exposed (mediastinitis, n = 41) vs. randomly selected non-exposed (non-mediastinitis) controls (n = 41) cohort. Serum samples for measurements of NT-proBNP, TnT, and CRP were obtained at a median follow up time of 2.7 (range 0.5–5.2) years after CABG surgery.ResultsNT-proBNP (mean 65.0 pg/ml vs. 34.8 pg/ml, p = 0.007) and TnT levels (mean 14.7 ng/L vs. 11.2 ng/L, p = 0.004) were significantly higher in the mediastinitis group than in the control group. Patients with mediastinitis had also higher body mass index (BMI) and were more likely to have diabetes and previous myocardial infarction. There was no difference in serum CRP level between the groups. After controlling for potential confounders (previous myocardial infarction, age, and BMI), the presence of mediastinitis was associated with higher levels of log NT-proBNP (p = 0.02) and log TnT (p = 0.04).ConclusionMediastinitis increases the concentrations of cardiac-specific biomarkers NT-proBNP and TnT at mid-term follow-up, representing persistent myocardial injury and impaired cardiac function.

Troponin T and N-Terminal Pro-Brain Natriuretic Peptide Are Associated with Long-Term All-Cause Mortality in Patients with Post-Sternotomy Mediastinitis following Coronary Artery Bypass Grafting: A 15-Year Follow-Up Study

“…Adding COPD or hypertension (one at a time) to the multivariate model did not change our conclusions (data not shown). Given the fact that circulating TnT and NT-proBNP are associated with mediastinitis [3], in a different multivariate model, these two biomarkers were replaced by LV ejection fraction and COPD. In this new multivariable-adjusted model, age (HR 1.07; 95% CI 1.03-1.12, p = 0.001), lower eGFR (HR 1.06; 95% CI 1.02-1.10, p = 0.003), and the presence of COPD (borderline association: HR 2.00; 95% CI 0.96-4.17, p = 0.064) but not mediastinitis (HR 1.51; 95% CI 0.78-2.94, p = 0.225) were associated with all-cause mortality, independent of the nonsignificant association with LV ejection fraction and atrial fibrillation (both p > 0.02).…”

“…Overall, data on long-term mortality in patient with mediastinitis following CABG are scarce [1][2][3][4][5][6], and the generalizability of previous studies is limited by small sample size, short follow-up, and selection of study population. The present study provides the longest and most complete follow-up data in 82 patient undergoing CABG, including 41 with post-sternotomy mediastinitis.…”

“…In the present cohort study, 82 patients undergoing CABG surgery, including 41 patients suffering from mediastinitis and 41 patients without mediastinitis were enrolled. Study population, methodology, surgical technique for the CABG operation and the procedure for surgical revision of mediastinitis have been described previously [3]. Blood samples were obtained at routine examination at a median follow-up time of 2.7 years after primary CABG surgery to measure NT-proBNP and TnT.…”

“…Deep sternal wound/mediastinitis is a rare but feared complication in CABG patients and seems to increase the risk of cardiac death [1], and is also associated with the risk of early internal mammary artery (IMA) graft obstruction [2]. Most recently, we demonstrated that mediastinitis was associated with increased concentrations of N-terminal pro-brain natriuretic peptide (NT-proBNP) and troponin T (TnT) at mid-term follow-up, potentially representing persistent low-grade myocardial injury and impaired cardiac function in these patients [3]. However, whether mediastinitis is associated with all-cause mortality, or whether the association is driven by these cardiac-specific biomarkers (NT-proBNP and TnT), is not investigated.…”