Dataset for: Vascular narrowing in pulmonary arterial hypertension is heterogeneous: rethinking resistance

Background - In idiopathic pulmonary arterial hypertension (PAH), increased pulmonary vascular resistance is associated with structural narrowing of small (resistance) vessels and increased vascular tone. Current information on pulmonary vascular remodeling is mostly limited to averaged increases in wall thickness, but information on number of vessels affected and internal diameter decreases for vessels of different sizes is limited. Background – Our aim was to quantify numbers of affected vessels and their internal diameter decrease for differently sized vessels in PAH in comparison with non-PAH patients. Methods - Internal and external diameters of transversally cut vessels were measured in 5 control subjects and 6 PAH patients. Resistance vessels were classified in Strahler orders, internal diameters 13μm (order 1) to 500μm (order 8). The number fraction, i.e. % affected vessels, and the internal diameter fraction, i.e. % diameter of normal diameter, were calculated. Results - In PAH not all resistance vessels are affected. The number fraction is about 30%, i.e., 70% of vessels have diameters not different from vessels of control subjects. Within each order the decrease in diameter of affected vessels is variable with an averaged diameter fraction of 50-70%. Conclusions - Narrowing of resistance vessels is heterogeneous: not all vessels are narrowed, and the decrease in internal diameters, even within a single order, vary largely. This heterogeneous narrowing alone cannot explain the large resistance increase in PAH. We suggest rarefaction could be an important contributor to the hemodynamic changes.

研究背景 - 特发性肺动脉高压（idiopathic pulmonary arterial hypertension, PAH）中，肺血管阻力升高与小型（阻力性）肺血管的结构性狭窄及血管张力增高相关。目前关于肺血管重构的研究数据大多仅局限于血管壁厚度的平均增厚情况，而针对不同管径肺血管的受累数量及内径减小程度的相关信息仍较为匮乏。
研究背景 - 本研究旨在对比特发性肺动脉高压患者与非PAH患者，量化不同管径受累肺血管的数量及其内径减小程度。
研究方法 - 本研究纳入5名对照受试者与6名PAH患者，测量横断切面肺血管的内径与外径。依据Strahler分级（Strahler orders）系统对阻力性肺血管进行分级，其内径范围为13μm（1级）至500μm（8级）。本研究计算了血管受累数占比（即受累血管所占百分比）以及内径占比（即受累血管内径与正常血管内径的百分比比值）。
研究结果 - PAH患者并非所有阻力性肺血管均受累。血管受累数占比约为30%，即70%的血管内径与对照组受试者的肺血管无显著差异。在每一Strahler分级中，受累血管的内径减小程度存在异质性，平均内径占比为50%~70%。
研究结论 - 阻力性肺血管的狭窄存在异质性：并非所有血管均发生狭窄，且即使在同一Strahler分级中，受累血管的内径减小程度也存在显著差异。仅依靠这种异质性狭窄无法完全解释PAH患者的肺血管阻力大幅升高现象。我们推测，血管稀疏（rarefaction）可能是导致患者血流动力学改变的重要因素。