| 김균희, 최원석, 박선희, 배명환, 이장훈, 양동헌, 박헌식, 조용근, 채성철, 전재은 |
Background: Renal dysfunction has been shown to affect N-terminal pro–brain natriuretic peptide (NT-proBNP) levels and the prognostic value of NT-proBNP levels in patients with chronic kidney disease has been questioned. The purpose of this study was to evaluate prognostic value of NT-proBNP in patients with acute myocardial infarction (AMI) and chronic kidney disease (CKD). Methods: Between November 2005 and January 2008, 834 post-MI patients (560 males; mean age = 64.7 ± 11.7 year-old) followed up more than six-month were included. Glomerular filtration rate was estimated (eGFR) using the abbreviated Modification of Diet in Renal Disease Study equation. Patients were categorized into two groups according to the level of eGFR at baseline; Group 1 (eGFR <60 ml/min/1.73 m2) and Group 2 (eGFR ≥60 ml/min/1.73 m2). The 6-month major adverse cardiac events (MACEs) were defined as a composite of death, non-fatal MI, and revascularizations. Results: During the follow-up, 57 (11.4%) MACEs occurred. Log-transformed NT-proBNP levels increased significantly with increasing eGFR grades and inversely correlated with eGFR in patients with (r = - 0.544, p<0.001) or without CKD (r = - 0.158, p<0.001). In multivariate Cox regression analysis, log-transformed NT-proBNP (hazard ratio [HR] 1.342, 95% confidence interval [CI] 1.013–1.778; p=0.040) in addition to systolic blood pressure (HR 0.988, 95%CI 0.979–0.997; p=0.010), eGFR <60 ml/min/1.73m2 (HR 2.776, 95%CI 1.238–6.244; p=0.013), percutaneous coronary intervention (HR 0.349, 95%CI 0.155–0.786; p=0.011), and multi-vessel disease (HR 2.431, 95%CI 1.188–4.973; p=0.015) were independent predictors for 6-month MACEs after adjustment for clinical characteristics, angiographic findings, and procedural data. In receiver-operator characteristic curve, the area under curve (AUC) of the NT-proBNP for predicting 6-month MACEs was 0.681 ± 0.040 (sensitivity 58.7%, specificity 72.3%; p<0.001), and optimum cut-off value was 10,816 pg/mL in Group 1, whereas the AUC of NT-proBNP was 0.732 ± 0.036 (sensitivity 72.9%, specificity 68.5%; p<0.001), and optimum cut-off value was 691 pg/mL in Group 2. Kaplan-Meier survival curve showed patients with NT-proBNP ≥10,816 pg/mL in Group 1 (52.9% versus 23.2%; log-rank test p < 0.001) and patients with NT-proBNP ≥691 pg/mL in Group 2 (15.6% versus 3.0%; log-rank test p < 0.001) had significantly higher 6-month MACEs. Conclusions: Although renal function is a significant confounder of NT-proBNP level, elevated NT-proBNP levels have clinical significance even in post-MI patients with CKD.
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