Assessment of pulmonary arterial hypertension in patients with systemic sclerosis: comparison of noninvasive tests with results of right-heart catheterization.

OBJECTIVE: Pulmonary hypertension (PH) is an ominous complication in patients with scleroderma (systemic sclerosis, SSc). We compared noninvasive assessment of PH with pulmonary artery (PA) pressures obtained by right-heart catheterization (RHC).

METHODS: Forty-nine patients with SSc were evaluated for suspected PH based on clinical findings, progressive dyspnea, and pulmonary function tests (PFT). PH was defined as mean PA pressure > or = 25 mm Hg, or > or = 30 mm Hg after exercise, with normal pulmonary capillary wedge pressure (PCW). Doppler echocardiography (echo) and cardiac magnetic resonance imaging (MRI) were performed within 4 hours of RHC, and the predictive accuracy of the tests was compared.

RESULTS: RHC identified 24/49 (49%) patients with PH. The noninvasive cutpoints were: estimated right ventricular systolic pressure > 47 mm Hg by echo; diameter of the main PA > 28 mm by MRI; and the ratio of forced vital capacity to diffusion capacity (%FVC/%DLCO) > 2.0 by PFT. Echo classified 38 subjects correctly (14/24 with and 24/25 without PH; sensitivity 58%, specificity 96%). The area under receiver-operating characteristic curve (AUC) was 0.84 for echo. MRI measurement of PA diameter had a sensitivity of 68% and specificity 71% (AUC 0.78). PFT evaluation had a sensitivity of 71% and specificity of 72% (AUC 0.76).

CONCLUSION: In evaluation of SSc with suspected PH, echo appeared to be the most useful among the noninvasive tests, mainly due to the high specificity, high positive predictive value, and highest AUC. However, due to the low sensitivity of noninvasive testing, RHC should remain the gold standard.