肺高压与肺动脉高压是两个不同的概念，前者是疾病名称，后者是病理改变，但在文字表述时，经常二者混用。肺高压(pulmonary hypertension, PH)的疾病特征是肺动脉压（pulmonary arterial hypertension ，PAH）升高，即静息时平均肺动脉压≥20mmHg。
Pulmonary hypertension (PH) is a disease characterized by elevated pulmonary artery pressure (mean pulmonary artery pressure ≥20 mmHg at rest).
肺高压，Pulmonary hypertension (PH)，可根据病因分为5种类型。目前认为1型患者有肺动脉高压(pulmonary arterial hypertension, PAH)，而其余4型患者有肺高压。
Pulmonary hypertension (PH) is classified into five groups based upon etiology. Patients in the first group are considered to have pulmonary arterial hypertension (PAH), whereas patients in the remaining four groups are considered to have PH.
●Group 1 – Pulmonary arterial hypertension (PAH)
●Group 2 – PH due to left heart disease
●Group 3 – PH due to chronic lung disease and/or hypoxemia
●Group 4 – PH due to pulmonary artery obstructions
●Group 5 – PH due to unclear multifactorial mechanisms
因此，肺动脉高压（PAH）其实是1型肺高压（PH），即动脉性肺动脉高压（ pulmonary arterial hypertension，Group1），而在统称全部5型时使用肺高压（PH）。
The term PAH is used to describe those included in group 1, while the term PH is used when describing all five groups.
1.PAH的病因
PAH的病因包括：系统性硬化症，先天性心脏病，HIV，门脉性肺动脉高压，血吸虫病，肺静脉闭塞性疾病(pulmonary veno-occlusive disease, PVOD)，新生儿持续性肺高压(persistent pulmonary hypertension of the newborn, PPHN)。
血吸虫病似乎在是PAH的最常见病因，但在世界上无血吸虫病流行地区的登记数据显示，超过半数的PAH病例为特发性PAH(idiopathic pulmonary arterial hypertension, IPAH)，且可有多达10%为遗传性PAH(heritable pulmonary arterial hypertension, HPAH)。
While schistosomiasis appears to be the most common cause of PAH
worldwide, registry data in regions of the world without endemic
schistosomiasis, report that over half of cases of PAH are idiopathic
(IPAH) and up to 10 percent are heritable (HPAH) .
PAH的其他病因包括，系统性硬化症，先天性心脏病（如隔缺损、艾森曼格综合征），HIV，门脉性肺动脉高压，血吸虫病，肺静脉闭塞性疾病(pulmonary veno-occlusive disease, PVOD)，新生儿持续性肺高压(persistent pulmonary hypertension of the newborn, PPHN)。
艾森曼格综合征是分流相关PAH最严重且为终末期的形式。这一群体还包括正好也有心脏缺损或小缺损的PAH患者(其缺损不是PVR升高的原因)，以及缺损关闭后PAH仍持续存在或不断恶化的患者。
Eisenmenger syndrome is the most severe and end-stage form of shunt-related PAH. This group also includes patients that have PAH with coincidental or small defects and those with persistent or worsening PAH despite closure of the defect.
2.PAH的发病人群
与其他类型PH相比，IPAH常累及较年轻成人，而在年龄较大人群中，1型PAH相对不常见。一项病例系列研究中，246例65岁以上的PH成人患者中仅15%为PAH(最常与结缔组织病有关)。人群中，PAH以中年人群发病，女性似乎多见。
Compared to other groups of PH, IPAH affects younger adults. In contrast, in older populations, group 1 PAH is relatively uncommon. In one series, only 15 percent of 246 adults with PH older than 65 years had PAH, most frequently in association with connective tissue disease. PAH is now a disease that affects men and women most commonly presenting in midlife, and women are more likely to be affected.
3.PAH的发病机制
肺动脉高压的形成机制，按照以下公式：
按照平均肺动脉压=(右室心输出量x肺血管阻力) 肺泡阻塞压
显著PH的主要原因几乎都是肺血管阻力（pulmonary vascular resistance，PVR）增加。单纯血流量增加(即，右心室输出量增加)通常不会引起显著PH，因为血流量增加时肺血管床会扩张并利用更多血管。同样，单纯肺静脉压增高（表现为肺泡阻塞压增高，alveolar occlusion pressure）通常也不会引起显著PH。然而，血流量和/或肺静脉压长期增加均可导致PVR增加。
4.PAH的病理改变
PAH是增生性血管病变，特征为血管收缩、细胞增殖、纤维化和微血栓形成。病理学改变在直径小于50μm肺动脉中，血管壁的全部3层(内膜、中膜和外膜)发生增生和肥厚(即，位于小的肺肌性微动脉)。
PAH is a proliferative vasculopathy, characterized by vasoconstriction, cell proliferation, fibrosis, and microthrombosis. Pathologic findings include hyperplasia and hypertrophy of all three layers of the vascular wall (intima, media, adventitia) in pulmonary arteries <50 microns (ie, localizes to the small pulmonary muscular arterioles).
5.PAH的预后
若不治疗，PAH会进展甚至致命。不治疗时，PAH患者的预后较差。REVEAL注册研究的数据显示，确诊后，PAH患者的1年、3年、5年和7年生存率分别为85%、68%、57%和49%。
预后不良相关因素包括，年龄>50岁和男性，重度肺动脉高压Ⅲ级或Ⅳ级等。现认为PAH患者的主要死因是右心衰竭合并心肺衰竭。
5.PAH的患者管理
支持治疗包括疫苗接种，营养支持等。对症治疗，包括氧疗，抗凝，利尿等。医生应告知育龄期女性PAH患者：妊娠可增加肺血管血流动力学恶化的风险、引发急性心血管衰竭和死亡，以及导致胎儿低氧血症。
6.PAH的影像学表现
PAH影像学可见肺动脉的明显扩张（Chest radiograph showing markedly dilated pulmonary arteries），CT肺动脉主干明星增宽，测量肺动脉主干直径≥29mm或/和肺动脉主干/升主动脉直径≥1。
联系客服
