Koç Mevlüt, Bozkurt Abdi, Yildiray-Sahin Durmus, Unal Ilker, Acartürk Esmeray
Department of Cardiology, Adana Numune Education and Research Hospital, Adana, Turkey.
Cardiol J. 2009;16(1):43-9.
It has been demonstrated in numerous studies that N-terminal pro-B-type natriuretic peptide (NT-proBNP) is strongly associated with left ventricular ejection fraction (LVEF), functional capacity (FC), and cardiovascular (CV) mortality in heart failure (HF) patients. The aim of the present study was to determine the predictive cutoff values of NT-proBNP for predicting these parameters.
One hundred HF patients (88 male, 12 female, mean age 53.6 +/- 8.9 years) with left ventricular (LV) systolic dysfunction and impaired exercise capacity were enrolled into the study. Echocardiographic examination was performed. The NT-proBNP concentration was measured after resting for 20 min in the supine position. The modified Bruce protocol was utilized for exercise testing. The patients were followed for between 690 and 840 days (mean 750 +/- 30 days) for the occurrence of CV events.
There was a strong negative correlation between NT-proBNP concentration and LVEF (p < 0.004). It was found that NT-proBNP is a strong predictor of LVEF < 30% (p < 0.001). When 940 pg/mL was accepted as a cutoff value for NT-proBNP for the prediction of an LVEF < 30%, the sensitivity and the specificity were 89.8% and 71.4%, respectively. NT-proBNP and left atrial diastolic dimension were the most significant parameters for predicting FC (p < 0.001, each one). An NT-proBNP cutoff value of 940 pg/mL responded to 78.8% sensitivity and 81% specificity for the prediction of FC < 5 METs. The observed independent predictors for the CV events were NT-proBNP, LV mass index, and resting heart rate (p < 0.001, p = 0.02 and p = 0.006, respectively). Every 1000 pg/mL elevation in NT-proBNP level resulted in a 27% increase in the occurrence of CV events (p < 0.006). Moreover, 940 pg/mL NT-proBNP cutoff value revealed a sensitivity and specificity of 86.7% and 64.7% respectively for the prediction of incident CV events.
Use of NT-proBNP cutoff values is easy and reliable method for the prediction of low FC and decreased LVEF, and may aid identification of patients at the highest risk for future CV events. We suggest to use NT-proBNP cutoff value of 940 pg/mL for predicting these parameters.
众多研究已表明，N末端B型脑钠肽原（NT-proBNP）与心力衰竭（HF）患者的左心室射血分数（LVEF）、功能能力（FC）及心血管（CV）死亡率密切相关。本研究旨在确定NT-proBNP用于预测这些参数的临界值。
纳入100例左心室（LV）收缩功能障碍且运动能力受损的HF患者（88例男性，12例女性，平均年龄53.6±8.9岁）。进行超声心动图检查。患者仰卧位静息20分钟后测量NT-proBNP浓度。采用改良布鲁斯方案进行运动试验。对患者随访690至840天（平均750±30天），观察CV事件的发生情况。
NT-proBNP浓度与LVEF之间存在强负相关（p<0.004）。发现NT-proBNP是LVEF<30%的强预测指标（p<0.001）。当将940 pg/mL作为NT-proBNP预测LVEF<30%的临界值时，敏感性和特异性分别为89.8%和71.4%。NT-proBNP和左心房舒张内径是预测FC的最显著参数（p均<0.001）。NT-proBNP临界值为940 pg/mL时，预测FC<5代谢当量的敏感性和特异性分别为78.8%和81%。观察到的CV事件独立预测因素为NT-proBNP、LV质量指数和静息心率（分别为p<0.001、p=0.02和p=0.006）。NT-proBNP水平每升高1000 pg/mL，CV事件发生率增加27%（p<0.006）。此外，NT-proBNP临界值为940 pg/mL时，预测新发CV事件的敏感性和特异性分别为86.7%和64.7%。
使用NT-proBNP临界值是预测低FC和降低的LVEF的简便可靠方法，可能有助于识别未来CV事件风险最高的患者。我们建议使用940 pg/mL的NT-proBNP临界值来预测这些参数。
