Prognostic Value of NT-proBNP versus Killip Classification in Patients with Acute Coronary Syndromes

Abstract Background: Plasma levels of brain natriuretic peptides have better diagnostic accuracy compared to clinical-radiologic judgment for acute heart failure. In acute coronary syndromes (ACS), the prognostic value of acute heart failure is incorporated into predictive models through Killip classification. It is not established whether NT-proBNP could increment prognostic prediction. Objective: To evaluate whether NT-proBNP, as a measure of left ventricular dysfunction, improves the in-hospital prognostic value of the GRACE score in ACS. Methods: Patients admitted due to acute chest pain, with electrocardiogram and/or troponin criteria for ACS were included in the study. The plasma level of NT-proBNP was measured at hospital admission and the primary endpoint was defined as cardiovascular death during hospitalization. P-value < 0.05 was considered as significant. Results: Among 352 patients studied, cardiovascular mortality was 4.8%. The predictive value of NT-proBNP for cardiovascular death was shown by a C-statistic of 0.78 (95% CI = 0.65-0.90). After adjustment for the GRACE model subtracted by Killip variable, NT-proBNP remained independently associated with cardiovascular death (p = 0.015). However, discrimination by the GRACE-BNP logistic model (C-statistics = 0.83; 95%CI = 0.69-0.97) was not superior to the traditional GRACE Score with Killip (C-statistic = 0.82; 95%CI = 0.68-0.97). The GRACE-BNP model did not provide improvement in the classification of patients to high risk by the GRACE Score (net reclassification index = - 0.15; p = 0.14). Conclusion: Despite the statistical association with cardiovascular death, there was no evidence that NT-proBNP increments the prognostic value of GRACE score in ACS.

研究背景：相较于临床-放射学判断，脑钠肽（brain natriuretic peptides）的血浆水平对急性心力衰竭的诊断准确度更优。在急性冠脉综合征（ACS）中，急性心力衰竭的预后价值通过Killip分级被纳入预测模型。目前尚不明确N末端B型脑钠肽原（NT-proBNP）是否能提升预后预测效能。研究目的：评估作为左心室功能不全标志物的N末端B型脑钠肽原（NT-proBNP），是否可提升急性冠脉综合征（ACS）患者中GRACE评分的院内预后价值。研究方法：本研究纳入因急性胸痛入院，且符合急性冠脉综合征（ACS）心电图或肌钙蛋白检测标准的患者。于患者入院时检测其血浆N末端B型脑钠肽原（NT-proBNP）水平，主要研究终点为住院期间发生的心血管死亡事件。以P值<0.05作为具有统计学显著性的判定标准。研究结果：本研究共纳入352例患者，其心血管死亡率为4.8%。N末端B型脑钠肽原（NT-proBNP）对心血管死亡的预测价值经C统计量（C-statistic）验证为0.78（95%置信区间[CI]：0.65~0.90）。在对剔除Killip分级变量的GRACE模型进行校正后，N末端B型脑钠肽原（NT-proBNP）仍与心血管死亡存在独立相关性（P=0.015）。然而，GRACE-BNP logistic回归模型的区分度（C统计量=0.83；95%置信区间[CI]：0.69~0.97）并未优于传统结合Killip分级的GRACE评分模型（C统计量=0.82；95%置信区间[CI]：0.68~0.97）。GRACE-BNP模型并未使基于GRACE评分划分的高危患者分类得到改善（净重新分类指数[net reclassification index]=-0.15；P=0.14）。研究结论：尽管N末端B型脑钠肽原（NT-proBNP）与心血管死亡存在统计学相关性，但尚无证据表明其可提升急性冠脉综合征（ACS）患者中GRACE评分的预后价值。