Background/Purpose: A series of recent studies indicate that early detection of pulmonary hypertension (PH) improves a survival in patients with systemic sclerosis (SSc). Thus, annual screening based on echocardiography combined with Doppler procedure is recommended in SSc patients. On the other hand, pulmonary function test (PFT) and B-type natriuretic peptide (BNP) are also reported to be useful for identifying patients with PH, but roles of these tests in routine PH screening remain unclear. We evaluated if PFT parameters and BNP, in combination with or without echocardiography, are useful as screening tools for PH in patients with SSc.

Methods: This single-center observational study enrolled 94 consecutive SSc patients who visited our center between January 2008 and June 2012, and underwent PFTs, serum BNP measurement, and echocardiography for PH screening. Our routine screening program consists of two steps: i) selection of patients suspected to have PH based on dyspnea symptoms and echocardiography that assesses morphology and estimated systolic pulmonary arterial pressure (esPAP) calculated from tricuspid regurgitation velocity and presumptive right atrial pressure (5 mmHg), and ii) diagnostic confirmation by right heart catheterization (RHC) in patients with esPAP >50 mmHg, esPAP 37-50 mmHg with echocardiographic variables suggestive of PH, or unexplained dyspnea. Patients with mean pulmonary arterial pressure ≥25 mmHg at rest and pulmonary capillary wedge pressure <15 mmHg were diagnosed as having pre-capillary PH (pre-PH). We also enrolled 14 incident SSc cases with pre-PH. PFT variables recorded were %FVC, %DLCO, %DLCO/VA, and a ratio of %FVC and %DLCO or %DLCO/VA. Receiver-operating characteristic (ROC) curve analysis was performed to obtain area under the curve (AUC) and optimal cut-off values.

Results: Of 94 patients screened, 19 underwent RHC, resulting in diagnosis of pre-PH in 5 patients. Individual screening parameters were compared between 89 patients without pre-PH and 19 with pre-PH consisting of 14 incident and 5 newly identified cases. There were significant differences in %DLCO, %DLCO/VA, %FVC/%DLCO ratio, %FVC/%DLCO/VA ratio, and serum BNP between PH and non-PH groups (P <0.01 for all comparisons). ROC analysis revealed that %FVC/%DLCO was the best PFT parameter that discriminated PH and non-PH cases (AUC 0.76), while BNP and esPAP gave the higher AUC (0.93 and 0.98, respectively). The %FVC/%DLCO ratio provided sensitivity of 79% and specificity of 76% when cut-off was set at 2.45, while BNP gave sensitivity of 84% and specificity of 91% with the cut-off of 86 pg/mL. Diagnostic utility of these two tests was apparently inferior to esPAP, which provided sensitivity of 100% and specificity of 93% with the cut-off of 45 mmHg. When %FVC/%DLCO ratio and BNP were combined with esPAP, the specificity was increased from 93% to 96% without decrease of sensitivity.

Conclusion: Our results clearly indicate PFT or BNP alone was inappropriate for PH screening in SSc. Simultaneous measurement of PFT and BNP with echocardiography slightly improves diagnostic accuracy, indicating limited utility of these tests in current echocardiography-based screening program.

---

« Back to 2012 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/limited-utility-of-pulmonary-function-tests-and-b-type-natriuretic-peptide-as-screening-tools-for-pre-capillary-pulmonary-hypertension-in-patients-with-systemic-sclerosis/