Background

The severity of pulmonary hypertension (PH) is monitored by measuring pulmonary vascular resistance, which is a steady-state measurement and ignores the pulsatile load encountered by the right ventricle (RV). Pulmonary vascular impedance (PVZ) can depict both steady-state and pulsatile forces, and thus may better predict clinical outcomes. We sought to calculate PVZ in patients with PH associated with heart failure with preserved ejection fraction who were administered inhaled sodium nitrite to better understand the acute effects on afterload.

Methods and Results

Fourteen patients with PH associated with heart failure with preserved ejection fraction underwent right heart catherization and were administered inhaled sodium nitrite. A Fourier transform was used to calculate PVZ for both before and after nitrite for comparison. Inhaled sodium nitrite decreased characteristic impedance (inversely related to proximal pulmonary artery compliance) and total work performed by the RV. RV efficiency improved, defined by a reduction in the total work divided by cardiac output. There was a mild decrease in pulmonary steady-state resistance after the administration of inhaled sodium nitrite, but this effect was not significant.

Conclusions

PVZ analysis showed administration of inhaled sodium nitrite was associated with an improvement in pulmonary vascular compliance via a decrease in characteristic impedance, more so than pulmonary steady-state resistance. This effect was associated with improved RV efficiency and total work.

中文翻译：

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吸入亚硝酸钠对射血分数保留的心力衰竭相关肺动脉高压患者肺血管阻抗的影响。

背景

通过测量肺血管阻力来监测肺动脉高压 (PH) 的严重程度，这是一种稳态测量，忽略右心室 (RV) 遇到的脉动负荷。肺血管阻抗 (PVZ) 可以描绘稳态和搏动力，因此可以更好地预测临床结果。我们试图计算与射血分数保留的心力衰竭相关的 PH 患者的 PVZ，这些患者吸入亚硝酸钠以更好地了解对后负荷的急性影响。

方法和结果

14 名伴有射血分数保留的心力衰竭的 PH 患者接受了右心导管插入术并吸入亚硝酸钠。傅里叶变换用于计算亚硝酸盐前后的 PVZ 以进行比较。吸入亚硝酸钠会降低特征阻抗（与近端肺动脉顺应性成反比）和 RV 执行的总功。RV 效率提高，定义为总功的减少除以心输出量。吸入亚硝酸钠后肺稳态阻力轻度下降，但这种影响不显着。

结论

PVZ 分析表明，吸入亚硝酸钠与肺血管顺应性的改善相关，通过降低特征阻抗，比肺稳态阻力更重要。这种效果与 RV 效率和总工作量的提高有关。