Schreiber Benjamin E, Valerio Christopher J, Keir Gregory J, Handler Clive, Wells Athol U, Denton Christopher P, Coghlan John G
Royal Free Hampstead NHS Trust, London, UK.
Arthritis Rheum. 2011 Nov;63(11):3531-9. doi: 10.1002/art.30535.
To construct a readily applicable formula for selecting patients with systemic sclerosis (SSc) for right-sided heart catheterization (RHC) based on the results of their pulmonary function tests (PFTs).
The diagnostic value of PFT variables was quantified in 386 patients with SSc against data obtained from RHC.
We derived the following formula using data from 257 patients: predicted mPAP = 136 - SpO₂ - 0.25 × DLCO % predicted, where mPAP is the mean pulmonary artery pressure, SpO₂ is the oxygen saturation as measured by pulse oximetry, and DLCO is the diffusing capacity for carbon monoxide. We validated the formula in the remaining 129 SSc patients. The area under the curve was 0.75 (95% confidence interval [95% CI] 0.67, 0.84). Using a predicted threshold of 25 mm Hg, the sensitivity was 90.1% (95% CI 82, 96) and the specificity was 29.2% (95% CI 17, 44). When used as a screening procedure in a typical scleroderma patient population, it is projected that those with an mPAP below 25 mm Hg are unlikely to have pulmonary hypertension (PH; prevalence 4.4%), those with a predicted mPAP of 25-35 mm Hg are at average risk of having PH (prevalence of 11.3%), and those with a formula-predicted mPAP above 35 mm Hg are likely to have PH (prevalence of 62.9%), thus justifying RHC. In patients with equivocal findings on echocardiography, a high formula-predicted mPAP is strongly associated with the presence of PH.
We derived and validated an easily applied formula for determining pulmonary function in patients with SSc that identifies subgroups with a low, average, or high prevalence of PH. It provides information that is complementary to echocardiography and that should improve the selection of patients for RHC.
基于肺功能测试（PFT）结果构建一个易于应用的公式，用于选择系统性硬化症（SSc）患者进行右心导管检查（RHC）。
针对386例SSc患者，根据RHC获得的数据对PFT变量的诊断价值进行量化。
我们使用257例患者的数据得出以下公式：预测平均肺动脉压（mPAP）=136 - 血氧饱和度（SpO₂）- 0.25×一氧化碳弥散量（DLCO）占预计值的百分比，其中mPAP是平均肺动脉压，SpO₂是通过脉搏血氧饱和度测定法测得的氧饱和度，DLCO是一氧化碳弥散量。我们在其余129例SSc患者中验证了该公式。曲线下面积为0.75（95%置信区间[95%CI]为0.67，0.84）。使用25mmHg的预测阈值时，敏感性为90.1%（95%CI为82，96），特异性为29.2%（95%CI为17，44）。在典型的硬皮病患者群体中用作筛查程序时，预计mPAP低于25mmHg的患者不太可能患有肺动脉高压（PH；患病率4.4%），预测mPAP为25 - 35mmHg的患者患PH的风险平均（患病率11.3%），公式预测mPAP高于35mmHg的患者可能患有PH（患病率62.9%），因此有理由进行RHC。在超声心动图检查结果不明确的患者中，公式预测的高mPAP与PH的存在密切相关。
我们得出并验证了一个易于应用的公式，用于确定SSc患者的肺功能，该公式可识别出PH患病率低、平均或高的亚组。它提供了与超声心动图互补的信息，应能改善RHC患者的选择。
