ABSTRACT
OBJECTIVES: Acute cellular rejection (ACR) remains a major complication of heart transplant (HT). The gold standard for its diagnosis is endomyocardial biopsy (EMB), whereas the role of non-invasive biomarkers for detecting ACR is unclear. This study aimed to identify non-invasive biomarkers for the diagnosis of ACR in patients undergoing HT and presenting with normal left ventricular function. METHODS: We evaluated patients who underwent HT at a single center between January 2010 and June 2019. Patients were enrolled after HT, and those with left ventricular (LV) systolic dysfunction before EMB were excluded. We included only the results of the first EMB performed at least 30 days after HT (median, 90 days). Troponin, B-type natriuretic peptide (BNP), and C-reactive protein (CRP) levels were measured and echocardiography was performed up to 7 days before EMB. ACR was defined as International Society for Heart and Lung Transplantation grade 2R or 3R on EMB. We performed logistic regression analysis to identify the non-invasive predictors of ACR (2R or 3R) and evaluated the accuracy of each using area under the receiver operator characteristic curve analysis. RESULTS: We analyzed 72 patients after HT (51.31±13.63 years; 25 [34.7%] women); of them, 9 (12.5%) developed ACR. Based on multivariate logistic regression analysis, we performed forward stepwise selection (entry criteria, p<0.05). The only independent predictors that remained in the model were CRP level and LV mass index. The optimal cut-off point for CRP level was ≥15.9 mg/L (odds ratio [OR], 11.7; p=0.007) and that for LV mass index was ≥111 g/m2 (OR, 13.6; p=0.003). The area under the receiver operating characteristic curve derived from this model was 0.87 (95% confidence interval [CI], 0.75-0.99), with sensitivity of 85.7% (95% CI, 42.1%-99.6%), specificity of 78.4% (95% CI, 64.7%-88.7%), positive predictive value of 35.3% (95% CI, 14.3%-61.7%), and negative predictive value of 97.6% (95% CI, 87.1%-99.9%). CONCLUSIONS: Among patients undergoing HT, CRP level and LV mass were directly associated with ACR, but troponin and BNP levels were not.