Tetralogy of Fallot. Particularities in evolution according to the degree of severity of pulmonary stenosis

Abstract

Background. Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect, representing about 10% of all congenital heart defects which comprises four structural defects: ventricular septal defect, pulmonary stenosis, overriding aorta, right ventricular hypertrophy. The degree of severity of pulmonary stenosis hugely affects the patient’s presentation, management and evolution. Objective of the study. To analyze the particularities in evolution of TOF according to the degree of severity of pulmonary stenosis and its significance on management and long-term follow ups. Material and methods. Literature reviews on TOF according to mild, moderate and severe degree of pulmonary stenosis were bought into study and its management measures based on clinical data, paraclinical investigations and outcomes were recorded. The evolution, course, and prognosis of the classified groups was determined through analysis. Results. Evaluation of pulmonary stenosis using echocardiography had been done for increased visualization of the pulmonic valve. Most patients with mild pulmonary stenosis are asymptomatic, moderate or severe patients who experience dyspnea on exertion or associated fatigue, depending on the severity of the obstruction. Infants with critical pulmonary stenosis presented with cyanosis after birth. Studies show that patients with mild or moderate stenosis had better outcomes and less mortality than severe stenosis which have poor outcomes and higher mortality. The less severe stenosis is well tolerated than severe stenosis in neonatal ductal dependent stenosis. Conclusion. Catheter-based therapy is corrective for the majority of patients with isolated valvular pulmonary stenosis and surgical therapy in patients with subvalvular and supravalvular obstruction and use of a catheter-based intervention during continued follow-up and surveillance of these patients.