Sildenfil prevented death or prolonged the survival time in the ThCD59^RBC mice treated with ILY₁₄₀FI. (A) cGMP levels in the lung of the ThCD59^RBC mice with or without sildenafil pretreatment. *P < .01 vs without sildenafil pretreatment. (B-C) Pretreatment with sildenafil reduced mortality (B) or prolonged survival time (C) in the ThCD59^RBC mice treated with ILY₁₄₀FI. *P < .05 vs ILY (or without sildenafil pretreatment). (D) Representative image shows the dynamic change of RVSP in the sildenafil-pretreated ThCD59^RBC mice given ILY₁₄₀FI. (E) Pretreatment with sildenafil suppressed the RRRVSP in the ThCD59^RBC mice given ILY₁₄₀FI. *P < .05 vs the mice without sildenafil pretreatment. (F) RRRVSP inversely correlated with the time until the death among ThCD59^RBC mice with the different treatments. (G) There were low levels of RRRVSP in the mice that survived with the different treatments.