Catheter Management Pulmonary Valvular Disorders

Excerpt

Due to advances in several medical subspecialties such as pediatric cardiology and pediatric cardiac surgery, the prevalence of congenital heart disease has increased to 1 in 150 in adulthood, in which about half have undergone surgery in childhood. A significant proportion of patients will need re-intervention in adulthood. The right ventricular outflow tract (RVOT) is affected in about 20% of newborns with congenital heart disease, including defects such as tetralogy of Fallot (ToF), truncus arteriosus (TA), pulmonary atresia, etc. Palliation of these defects necessitates various reconstruction techniques with bio-prosthetic valves, trans-annular patches, and conduits between right ventricle (RV) and pulmonary artery (PA). These conduits are usually required when there is an associated anomalous left anterior descending artery (LAD) from the right coronary artery (RCA) crossing the RVOT, thereby precluding a transannular patch repair. While these conduits can restore normal pulmonary valve function, there are subsequent morbidities that can develop, such as conduit calcifications, intimal proliferation, and somatic growth, which therefore make the durability of these conduits limited, and ultimately requiring re-intervention.

The etiology of conduit dysfunction over time is multifactorial and can depend on the patient's age, the defect, tissue type, intervention type, and the material employed. Furthermore, homograft valve deterioration can cause significant RVOT dysfunction, pulmonary regurgitation (PR), and pulmonary stenosis (PS), with about half of the patients requiring re-intervention. Additionally, surgical reoperation can have significant morbidity and even mortality due to chest adhesions, cardiac ischemia, heart failure, and multi-organ dysfunction. Earlier surgical interventions for TOF included the transannular patch procedure with consequences such as pulmonary insufficiency, dilation of tricuspid annulus resulting in tricuspid regurgitation (TR), right ventricular dilation, and atrial and ventricular arrhythmias as a potential etiology of sudden cardiac death (SCD). Transcatheter intervention with balloon angioplasty and stent implantation was a remarkable advancement but still resulted in significant pulmonary regurgitation. Transcatheter pulmonary valve implantation (TPVI), which is a common intervention in adult patients with congenital heart disease patients today, has been introduced as a much less invasive approach, allowing earlier restoration of pulmonary valve function before the onset of irreversible remodeling and dysfunction, and potentially fewer lifetime surgical interventions.