A 77-year-old man with pulmonary hypertension secondary to chronic pulmonary artery thrombosis and previous pulmonary tuberculosis had been receiving long-term oxygen therapy for chronic respiratory failure. He presented with worsening right-sided heart failure, marked fluid retention, and renal dysfunction. Despite intensive intravenous furosemide therapy at 500 mg/day, adequate decongestion could not be achieved. His serum creatinine had risen to 3.08 mg/dL, raising concern about further deterioration of renal function with continued escalation of loop diuretics. Echocardiography showed significant inferior vena cava dilatation, consistent with persistent systemic venous congestion.

Given refractory volume overload despite high-dose loop diuretic therapy and concomitant renal dysfunction, an alternative approach to fluid removal was considered. A vasopressin V2-receptor antagonist was initiated at 15 mg once daily alongside intravenous dopamine and continued loop diuretic therapy. Following treatment, urine output increased, and body weight decreased. Serum creatinine subsequently improved to 1.35 mg/dL, while the inferior vena cava diameter decreased from 23 to 17 mm. His pulmonary artery systolic pressure remained elevated at approximately 59 mmHg. He was discharged on oral therapy with a reduced furosemide dose and continued clinical monitoring.