Depto de Fisiopatología, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay.
Int J Cardiol. 2013 Apr 5;164(2):227-31. doi: 10.1016/j.ijcard.2011.07.020. Epub 2011 Jul 23.
Acute vasoreactivity testing (VT) is considered mandatory in the diagnostic work-up of patients with pulmonary arterial hypertension (PAH). We studied the relation between the acute absolute arterial vasodilatation and the severity of vascular remodeling estimated by intravascular ultrasound (IVUS) in patients with idiopathic PAH.
Simultaneous right heart catheterization and IVUS of the pulmonary artery (PA) were performed both in basal conditions and during short-term intravenous epoprostenol infusion in nineteen idiopathic PAH patients. Pulmonary vascular resistance (PVRi) and capacitance indexes (stroke volume/pulse pressure, Cp), were calculated. Local pulsatility was estimated by IVUS (IVUSp) (systolic-diastolic lumen area/diastolic lumen area×100; sA-dA/dA) and PA stiffness was assessed by the elastic modulus (E: pulse pressure/IVUSp).
Epoprostenol infusion (11±2ng/kg/min) determined a real vasodilatation (increment of dA>10%) in six patients. This vasodilation group presented on average significantly higher cardiac index, stroke volume index and Cp, and lower PVRi and IVUSp (P<0.05), with a lower E (P=0.08). Three patients were responders according to the actual criteria, but only one showed a real vasodilator response. Baseline E below the median value (≤190mm Hg) was able to differentiate patients with an acute vasodilator response (sensibility 83%, specificity 73%, area under ROC 0.81; P<0.05). Neither E nor vasodilator response is correlated with delta mean PA pressure and PVRi.
Patients with higher IVUSp and lesser E displayed an absolute PA vasodilation during VT with epoprostenol. The patients with a positive VT according to actual criteria do not necessarily have a real vasodilatation on intravascular ultrasound.
急性血管反应性测试（VT）被认为是肺动脉高压（PAH）患者诊断的必要手段。我们研究了特发性 PAH 患者的急性绝对动脉血管扩张与血管内超声（IVUS）估计的血管重构严重程度之间的关系。
19 例特发性 PAH 患者在基础状态下和短期静脉内依前列醇输注期间同时进行右心导管检查和肺动脉（PA）IVUS。计算肺血管阻力（PVRi）和容量指数（每搏量/脉搏压，Cp）。通过 IVUS（IVUSp）（收缩期-舒张期管腔面积/舒张期管腔面积×100；sA-dA/dA）估计局部搏动性，通过弹性模量（E：脉搏压/IVUSp）评估 PA 僵硬度。
依前列醇输注（11±2ng/kg/min）在 6 例患者中引起了真正的血管扩张（dA 增加>10%）。该血管扩张组的平均心指数、每搏量指数和 Cp 显著更高，PVRi 和 IVUSp 更低（P<0.05），E 更低（P=0.08）。根据实际标准，有 3 例患者为应答者，但只有 1 例显示出真正的血管扩张反应。基线 E 值低于中位数（≤190mmHg）能够区分具有急性血管扩张反应的患者（敏感性 83%，特异性 73%，ROC 曲线下面积 0.81；P<0.05）。E 或血管扩张反应均与 delta 平均 PA 压和 PVRi 不相关。
在依前列醇的 VT 期间，IVUSp 较高且 E 较小的患者出现绝对 PA 血管扩张。根据实际标准 VT 阳性的患者不一定在血管内超声上有真正的血管扩张。
