A 30-year-old man with a history of balloon valvuloplasty for severe congenital pulmonic stenosis at age 5 presents with progressive exertional dyspnea and bilateral lower extremity edema over the past 6 months. On examination, he has elevated jugular venous pressure, a palpable right ventricular heave, a grade II/VI systolic ejection murmur at the left upper sternal border, and a high-pitched decrescendo diastolic murmur in the same area. Transthoracic echocardiography demonstrates severe pulmonic regurgitation with right ventricular end-diastolic volume index of 160 mL/m² and reduced right ventricular ejection fraction. Which of the following is the most appropriate next step in management?