PTGS2 and pulmonary arterial hypertension: Since modulation of the potential signaling molecules, such as cyclooxygenase-2 or Rho kinase, significantly affects vascular remodeling and blood flow in the aortocaval fistula23, the pharmacological effects on pulmonary hemodynamics and lung histomorphometry are not confined to pulmonary circulation, which make the interpretation of drug effect on flow-induced pulmonary hypertension unfeasible.