Hemodynamic effect of hydralazine in interstitial lung disease patients with cor pulmonale. Immediate and short-term evaluation at rest and during exercise

Hydralazine was administered short-term to 13 patients who had stable interstitial lung disease (ILD), pulmonary arterial hypertension (PAH); mean pulmonary arterial pressure ([PAP] = 26 ± 9 mm Hg), and cor pulmonale (CP). All patients were studied at rest and during exercise. After intravenous hydralazine at rest, there were statistically significant increases in cardiac index (CI) (p<0.001), arterial oxygen saturation (SaO₂) (p<0.01), and mixed venous saturation (Sv̄O₂) (p<0.01). Pulmonary vascular resistance (Rp) (p<0.005) and systemic resistance (Rs) decreased (p<0.001), and PAP did not change. During exercise, PAP did not change; however, CI (p<0.01), PaO₂ (p<0.001), and Sv̄O₂ (p<0.01) increased further. The increase in Rp was significantly reduced (p<0.01). After continuation of oral hydralazine therapy in 12 patients for 7 days, PAP at rest was not statistically different from control; Rp and Rs remained decreased (p<0.001). The same results were found for CI, PaO₂, Sv̄O₂, and Rs during exercise. Although PAP did not change from control values, the drug significantly reduced the increase in Rp ((p<0.005). Vasodilator therapy with hydralazine could be useful in patients with stable ILD who have inflammation with minimal to moderate fibrosis and PAH and might be used as an adjunct to conventional therapy for ILD and CP.