Division of Pulmonology, Dept of Internal Medicine, Medical University of Graz, Graz, Austria.
Eur Respir J. 2012 Jan;39(1):119-24. doi: 10.1183/09031936.00109710. Epub 2011 Jul 7.
Chronic thromboembolic pulmonary hypertension (CTEPH) represents an important differential diagnosis to idiopathic pulmonary arterial hypertension (IPAH). We hypothesised that the capillary to end-tidal carbon dioxide gradient at rest and during exercise might help differentiate CTEPH from IPAH. Patients who presented with unequivocal IPAH or CTEPH according to ventilation/perfusion scanning, pulmonary angiography, computed tomography and right heart catheterisation were included in this retrospective study and compared with healthy controls. 21 IPAH patients and 16 CTEPH patients fulfilled the inclusion criteria. Haemodynamics and peak oxygen uptake were comparable, but respiratory rates at rest and during exercise were significantly higher in CTEPH than in IPAH. End-tidal carbon dioxide was significantly lower in CTEPH versus IPAH at rest and during exercise, while capillary carbon dioxide values were similar. Correspondingly, capillary to end-tidal carbon dioxide gradients were significantly increased in CTEPH versus IPAH at rest and during exercise (median (range) 8.6 (3.0-13.7) versus 4.4 (0.9-9.0) (p<0.001) and 9.3 (3.3-13.1) versus 4.1 (0.0-8.8) mmHg (p<0.001), respectively). Although these values were closer to normal in IPAH they were still significantly elevated compared with healthy controls (2.3 (-4.8-8.1) and -1.9 (-5.7-6.2) mmHg, respectively). Capillary to end-tidal carbon dioxide gradients may help to distinguish CTEPH from IPAH based on resting and exercise values.
慢性血栓栓塞性肺动脉高压（CTEPH）是特发性肺动脉高压（IPAH）的重要鉴别诊断。我们假设在休息和运动期间，毛细血管至呼气末二氧化碳梯度可能有助于区分 CTEPH 与 IPAH。根据通气/灌注扫描、肺动脉造影、计算机断层扫描和右心导管检查，将出现明确的 IPAH 或 CTEPH 的患者纳入本回顾性研究，并与健康对照组进行比较。21 例 IPAH 患者和 16 例 CTEPH 患者符合纳入标准。血流动力学和峰值摄氧量相当，但 CTEPH 患者在休息和运动时的呼吸频率明显高于 IPAH。在休息和运动时，CTEPH 患者的呼气末二氧化碳明显低于 IPAH，而毛细血管二氧化碳值相似。相应地，在休息和运动时，CTEPH 与 IPAH 的毛细血管至呼气末二氧化碳梯度显著升高（中位数（范围）分别为 8.6（3.0-13.7）比 4.4（0.9-9.0）（p<0.001）和 9.3（3.3-13.1）比 4.1（0.0-8.8）mmHg（p<0.001））。尽管这些值在 IPAH 中更接近正常，但与健康对照组相比仍明显升高（分别为 2.3（-4.8-8.1）和-1.9（-5.7-6.2）mmHg）。毛细血管至呼气末二氧化碳梯度可帮助基于休息和运动值区分 CTEPH 与 IPAH。
