Univ. Paris-Sud, Faculté de Médecine, Inserm U_999, Le Kremlin Bicêtre, France AP-HP, Services des Explorations Fonctionnelles, Hôpital de Bicêtre, Le Kremlin Bicêtre, France
Univ. Paris-Sud, Faculté de Médecine, Inserm U_999, Le Kremlin Bicêtre, France AP-HP, Services des Explorations Fonctionnelles, Hôpital de Bicêtre, Le Kremlin Bicêtre, France Dept of Respiratory Medicine, Royal Prince Alfred Hospital, University of Sydney, Camperdown, Australia.
Eur Respir J. 2015 Oct;46(4):1178-89. doi: 10.1183/13993003.00741-2015. Epub 2015 Sep 4.
Right ventricular adaptation to the increased pulmonary arterial load is a key determinant of outcomes in pulmonary hypertension (PH). Pulmonary vascular resistance (PVR) and total arterial compliance (C) quantify resistive and elastic properties of pulmonary arteries that modulate the steady and pulsatile components of pulmonary arterial load, respectively. PVR is commonly calculated as transpulmonary pressure gradient over pulmonary flow and total arterial compliance as stroke volume over pulmonary arterial pulse pressure (SV/PApp). Assuming that there is an inverse, hyperbolic relationship between PVR and C, recent studies have popularised the concept that their product (RC-time of the pulmonary circulation, in seconds) is "constant" in health and diseases. However, emerging evidence suggests that this concept should be challenged, with shortened RC-times documented in post-capillary PH and normotensive subjects. Furthermore, reported RC-times in the literature have consistently demonstrated significant scatter around the mean. In precapillary PH, the true PVR can be overestimated if one uses the standard PVR equation because the zero-flow pressure may be significantly higher than pulmonary arterial wedge pressure. Furthermore, SV/PApp may also overestimate true C. Further studies are needed to clarify some of the inconsistencies of pulmonary RC-time, as this has major implications for our understanding of the arterial load in diseases of the pulmonary circulation.
右心室对增加的肺动脉负荷的适应性是肺动脉高压 (PH) 结局的关键决定因素。肺血管阻力 (PVR) 和总动脉顺应性 (C) 量化了肺血管的阻力和弹性特性，分别调节肺动脉的稳态和脉动负荷成分。PVR 通常通过肺血流的跨肺压梯度计算，总动脉顺应性通过每搏量除以肺动脉脉搏压 (SV/PApp) 计算。假设 PVR 和 C 之间存在反比例的双曲线关系，最近的研究流行一种概念，即它们的乘积（肺循环的 RC 时间，以秒为单位）在健康和疾病中是“恒定的”。然而，新出现的证据表明，应该挑战这一概念，因为已经记录到毛细血管后 PH 和血压正常的受试者的 RC 时间缩短。此外，文献中报道的 RC 时间一直显示出均值周围的显著离散度。在毛细血管前 PH 中，如果使用标准的 PVR 方程，可能会高估真正的 PVR，因为零流量压力可能明显高于肺动脉楔压。此外，SV/PApp 也可能高估真正的 C。需要进一步研究来澄清一些肺 RC 时间的不一致性，因为这对我们理解肺循环疾病中的动脉负荷有重大影响。
