Eisenmenger syndrome (ES) is the most severe form of pulmonary arterial hypertension (PAH) associated with congenital heart disease. It is an extremely devastating condition with a serious impact on patients' life. Classical therapy of ES remains directed to avoid complications, such as erythrocytosis, treatment of congestive heart failure, prevention of infection, and secondary haematological abnormalities such as iron deficiency and coagulation disorders. However, the only effective treatment is heart-lung transplantation; still, morbidity and mortality after transplantation remain substantially high. Furthermore, waiting lists for heart-lung transplantation are long. Recent studies examining the use of advanced medical treatment in patients with ES have shown that it may have beneficial effects in patients with ES; however, additional studies need to be done to confirm its efficacy and appropriate clinical use. A 41-year-old female admitted to the Hospital of Lithuanian University of Health Sciences due to progressive dyspnea on minimal effort, heart failure symptoms leading to NYHA functional class III-IV. After clinical and instrumental investigations, ES secondary to unrepaired patent ductus arteriosus with severe PAH was diagnosed. Treatment with sildenafil was initiated together with the standard pharmacological therapy, and the patient was added to the waiting list for the heart and lung transplantation. After 24 months of stable condition, her clinical status deteriorated, and combination therapy (sildenafil and ambrisentan) was initiated. Clinical symptoms and exercise capacity improved, and she has been stable for 4 years thereafter. Our experience of the management of an adult patient with ES showed the benefits of treatment with advanced therapy with pulmonary vasodilators that improved the patient's quality of life and delayed the need for heart and lung transplantation.