Pediatric Cardiac Critical Care, The Heart Institute for Children, Advocate Hope Children's Hospital, Oak Lawn, IL, USA.
Am Heart J. 2011 Sep;162(3):562-8. doi: 10.1016/j.ahj.2011.06.014. Epub 2011 Aug 11.
Pediatric pulmonary arterial hypertension (PAH), whether idiopathic PAH (iPAH) or PAH associated with congenital heart disease (aPAH), carries high morbidity and mortality. Low pulmonary arterial capacitance (PAC), defined as right ventricular stroke volume/pulmonary artery pulse pressure, is a risk factor for mortality in adults with PAH. However, the relation of PAC to pulmonary vascular resistance (PVR), exercise endurance, and survival is poorly defined in children.
Catheterization and clinical data of children with PAH (mean pulmonary artery pressure >25 mm Hg) were reviewed. Children with pulmonary shunts, stents, collaterals, or pulmonary venous hypertension were excluded. Primary outcomes were 6-minute walk distance and freedom from death/lung transplant.
Forty-seven patients were studied. Nineteen (43%) had iPAH, and 28 (57%) had aPAH (7.1 ± 6.2 vs 8.4 ± 5.5 years, P = .45). Patients with iPAH had higher PVR indexed for body surface area (PVRi), lower indexed PAC (PACi), lower exercise tolerance, and lower freedom from death/lung transplant than patients with aPAH. Both higher PVRi (P < .0001) and lower PACi (P = .02) were associated with shorter 6-minute walk distance. A PACi <0.70 mL/mm Hg per square meter or >1.25 mL/mm Hg per square meter and a PVRi >13 Wood units × m(2) were associated with decreased freedom from death or lung transplant. The relationships between PVRi and PACi and survival were independent of each other and not confounded by etiologic group.
Low PACi and high PVRi are independently associated with low 6-minute walk distance and survival in children with PAH. Therefore, both should be assessed for better prognostication and management in this high-risk population.
小儿肺动脉高压（PAH），不论是特发性 PAH（iPAH）还是与先天性心脏病相关的 PAH（aPAH），都具有较高的发病率和死亡率。右心室每搏量/肺动脉脉搏压降低定义为肺动脉低压储备（PAC），是成人 PAH 患者死亡率的一个危险因素。然而，在儿童中，PAC 与肺血管阻力（PVR）、运动耐力和生存率的关系尚未明确。
回顾了患有 PAH（平均肺动脉压>25mmHg）的患儿的导管插入术和临床数据。排除存在肺分流、支架、侧支循环或肺静脉高压的患儿。主要研究终点为 6 分钟步行距离和免于死亡/肺移植。
共研究了 47 例患儿。19 例（43%）为 iPAH，28 例（57%）为 aPAH（7.1±6.2 岁 vs. 8.4±5.5 岁，P=0.45）。iPAH 患儿的 PVR 指数（PVRi）更高，PAC 指数（PACi）更低，运动耐量更低，免于死亡/肺移植的比例更低。PVRi 更高（P<0.0001）和 PACi 更低（P=0.02）均与 6 分钟步行距离更短相关。PACi<0.70ml/mm Hg·m² 或 >1.25ml/mm Hg·m² 以及 PVRi>13 伍德单位·m² 与死亡或肺移植的风险增加相关。PVRi 和 PACi 与生存率之间的关系相互独立，不受病因分组的影响。
在 PAH 患儿中，低 PACi 和高 PVRi 与 6 分钟步行距离和生存率降低独立相关。因此，在这个高危人群中，应同时评估这两个指标以更好地进行预后和管理。
