Department of Cardiovascular Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8603, Japan.
Department of Health Care Administration, Nippon Medical School, Tokyo, Japan.
ESC Heart Fail. 2023 Jun;10(3):1706-1716. doi: 10.1002/ehf2.14327. Epub 2023 Feb 23.
Maintenance of euvolaemia with diuretics is critical in heart failure (HF) patients with chronic kidney disease (CKD); however, it is challenging because no reliable marker of volume status exists. Fractional excretion of urea nitrogen (FEUN) is a useful index of volume status in patients with renal failure. We aimed to examine whether FEUN is a surrogate marker of volume status for risk stratification in HF patients with CKD.
We examined 516 HF patients with CKD (defined as discharge estimated glomerular filtration rate < 60 mL/min/1.73 m ) whose FEUN was measured at discharge (median age, 80 years; 58% male). The patients were divided into four groups according to quartile FEUN value at discharge: low-FEUN, FEUN ≤ 32.1; medium-FEUN, 32.1 < FEUN ≤ 38.0; high-FEUN, 38.0 < FEUN ≤ 43.7; and extremely-high-FEUN, FEUN > 43.7. FEUN was calculated by the following formula: (urinary urea × serum creatinine) × 100/(serum urea × urinary creatinine). During the 3 year follow-up, 131 HF readmissions occurred. Kaplan-Meier analysis showed that the HF readmission rate was significantly lower in the medium-FEUN group than in the other three groups (log-rank test, P = 0.029). Multivariate Cox regression analysis identified the low-FEUN, high-FEUN, and extremely-high-FEUN values as independent factors associated with post-discharge HF readmission. In the analysis of 130 patients who underwent right heart catheterization during hospitalization, a significant correlation between FEUN value and right atrial pressure was observed (R = 0.243, P = 0.005). Multivariate linear regression analysis revealed that FEUN value at discharge decreased in a dose-dependent manner with loop diuretics.
In HF patients with CKD, FEUN is a potential marker of volume status for risk stratification of post-discharge HF readmission. Low FEUN value (FEUN ≤ 32.1) may represent intravascular dehydration, whereas high FEUN value (FEUN > 38.0) may represent residual congestion; both of them were independent risk factors for HF readmission. FEUN may be useful to determine euvolaemia and guide fluid management in HF patients with CKD.
在患有慢性肾脏病（CKD）的心力衰竭（HF）患者中，用利尿剂维持血容量正常至关重要；然而，由于没有可靠的容量状态标志物，这是一项具有挑战性的任务。尿素氮排泄分数（FEUN）是肾功能衰竭患者容量状态的有用指标。我们旨在研究 FEUN 是否可作为 HF 合并 CKD 患者风险分层的替代容量状态标志物。
我们检查了 516 例 CKD 合并 HF 患者（定义为出院时估计肾小球滤过率 < 60 mL/min/1.73 m ），他们在出院时测量了 FEUN（中位年龄 80 岁；58%为男性）。根据出院时 FEUN 值的四分位距将患者分为四组：低 FEUN 组，FEUN ≤ 32.1；中 FEUN 组，32.1 < FEUN ≤ 38.0；高 FEUN 组，38.0 < FEUN ≤ 43.7；极高 FEUN 组，FEUN > 43.7。FEUN 通过以下公式计算：（尿尿素 × 血清肌酐）× 100/（血清尿素 × 尿肌酐）。在 3 年的随访期间，有 131 例 HF 再入院。Kaplan-Meier 分析显示，中 FEUN 组的 HF 再入院率明显低于其他三组（对数秩检验，P = 0.029）。多变量 Cox 回归分析确定低 FEUN、高 FEUN 和极高 FEUN 值是与出院后 HF 再入院相关的独立因素。在对 130 例住院期间接受右心导管检查的患者进行的分析中，观察到 FEUN 值与右心房压之间存在显著相关性（R = 0.243，P = 0.005）。多变量线性回归分析显示，出院时 FEUN 值呈剂量依赖性下降。
在 CKD 合并 HF 患者中，FEUN 是预测出院后 HF 再入院风险的潜在容量状态标志物。低 FEUN 值（FEUN ≤ 32.1）可能代表血管内脱水，而高 FEUN 值（FEUN > 38.0）可能代表残余充血；两者都是 HF 再入院的独立危险因素。FEUN 可能有助于确定 HF 合并 CKD 患者的血容量正常，并指导液体管理。
