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Transcatheter intervention for right ventricular outflow tract obstruction with balloon angioplasty and stent implantation was a remarkable advancement but still resulted in significant pulmonary regurgitation. Transcatheter pulmonary valve implantation, which is a common intervention in adult patients with congenital heart disease today, provides a much less invasive approach, thus allowing earlier restoration of pulmonary valve function before the onset of irreversible remodeling and dysfunction and potentially fewer lifetime surgical interventions. This activity reviews the evaluation and treatment of pulmonary regurgitation and highlights the role of the interprofessional team in evaluating and treating this condition. Objectives: Identify the indications for percutaneous transcatheter pulmonary valve replacement. Describe the technique of transcatheter pulmonary valve replacement. Outline appropriate evaluation of the potential complications of transcatheter pulmonary valve replacement. Summarize interprofessional team strategies for improving care coordination and communication to advance and improve outcomes of transcatheter pulmonary valve replacement. Access free multiple choice questions on this topic.

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.[1][2] 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).[3] 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.[4]

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.[1][2] 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).[3] 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.[4] 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.[5][6] Additionally, surgical reoperation can have significant morbidity and even mortality due to chest adhesions, cardiac ischemia, heart failure, and multi-organ dysfunction.[7][8][9][10][11][12] 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.[13][14] 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.[15][16]

Although uncommon, it is important to be aware of several potential procedural complications in patients with severe RV dysfunction, the combination of pulmonary regurgitation and a stiff wire traversing the tricuspid valve potentially causing tricuspid regurgitation, hypotension, and hemodynamic instability may occur. More significantly, severe hemodynamic compromise may result from valve dislodgment into the PA, causing obstruction of the pulmonary blood flow, coronary compression causing coronary ischemia, and conduit rupture causing major hemorrhage. However, these are fortunately rare. Heavy calcification and the presence of homograft conduits have been identified as risk factors for rupture.[45] In homografts and conduits, pre and post-deployment dilations of the balloon have the potential to cause rupture or a tear. Most cases can be managed successfully with a covered stent, but surgical conduit replacement may be required following rupture.[17][46] Valve migration/embolization remains a potential serious procedural complication, which may require surgical explanation. Fortunately, with adequate conduit assessment and RVOT preparation, this remains rare. Nonetheless, should this occur, valve deployment into a branch pulmonary artery has been proposed as a potential remedy should the valve embolize distally. Furthermore, retrieval with the deployment of the embolized valve into the inferior vena cava (IVC) with subsequent stenting to open the valve leaflets has been also proposed as a potential solution, but this carries a significant risk of injury to TV, RV, and IVC.

Although uncommon, it is important to be aware of several potential procedural complications in patients with severe RV dysfunction, the combination of pulmonary regurgitation and a stiff wire traversing the tricuspid valve potentially causing tricuspid regurgitation, hypotension, and hemodynamic instability may occur. More significantly, severe hemodynamic compromise may result from valve dislodgment into the PA, causing obstruction of the pulmonary blood flow, coronary compression causing coronary ischemia, and conduit rupture causing major hemorrhage. However, these are fortunately rare. Heavy calcification and the presence of homograft conduits have been identified as risk factors for rupture.[45] In homografts and conduits, pre and post-deployment dilations of the balloon have the potential to cause rupture or a tear. Most cases can be managed successfully with a covered stent, but surgical conduit replacement may be required following rupture.[17][46] Valve migration/embolization remains a potential serious procedural complication, which may require surgical explanation. Fortunately, with adequate conduit assessment and RVOT preparation, this remains rare. Nonetheless, should this occur, valve deployment into a branch pulmonary artery has been proposed as a potential remedy should the valve embolize distally. Furthermore, retrieval with the deployment of the embolized valve into the inferior vena cava (IVC) with subsequent stenting to open the valve leaflets has been also proposed as a potential solution, but this carries a significant risk of injury to TV, RV, and IVC. Longer-term complications include the risk of stent fracture, which remains the most common reason for re-intervention with the first-generation valve, even despite pre-stenting (5% to 16%). Younger age, higher pre-and procedural RVOT gradient, smaller angiographic conduit diameter, valve position directly under the sternum, stent recoil, or compression after deployment is the risk factors.[46][47] Type I fracture constitutes of one strut disruption without loss of stent integrity. Type II includes stent integrity loss, and type III includes fractures with fragment separation. Type I can be seen in up to 40% of patients; however, it is not usually associated with any adverse effects. Type II and III stent fractures are associated with early conduit restenosis and valve failure and may require surgical replacement or repeat TPVI. Clinically significant stent fracture with the second-generation valve in the pulmonary position has not yet been reported.

Longer-term complications include the risk of stent fracture, which remains the most common reason for re-intervention with the first-generation valve, even despite pre-stenting (5% to 16%). Younger age, higher pre-and procedural RVOT gradient, smaller angiographic conduit diameter, valve position directly under the sternum, stent recoil, or compression after deployment is the risk factors.[46][47] Type I fracture constitutes of one strut disruption without loss of stent integrity. Type II includes stent integrity loss, and type III includes fractures with fragment separation. Type I can be seen in up to 40% of patients; however, it is not usually associated with any adverse effects. Type II and III stent fractures are associated with early conduit restenosis and valve failure and may require surgical replacement or repeat TPVI. Clinically significant stent fracture with the second-generation valve in the pulmonary position has not yet been reported. More recently, the development of infective endocarditis has emerged as a significant risk, with an incidence of approximately 2.4% per patient-year. Male gender, multiple stents, unprotected dental treatment, previous history of endocarditis, and non-compliance of aspirin constitute the risk factors.[48][49][50][51] Percutaneous pulmonary valve (PPV) endocarditis is characterized by vegetation visualized on the implant or as the new evidence of PPV dysfunction associated with bloodstream infection.[52] A wide spectrum of organisms ranging from coagulase-negative staphylococcus to HACEK organisms can cause TPVI-related endocarditis. Streptococcus viridans and Staphylococcus aureus are the most common causes. Occasionally this can be treated and cleared medically. However, due to the significant dysfunction of the valve post-infection, many patients require surgical replacement of the valve even if the bloodstream is able to be cleared of infection.

Transcatheter pulmonary valve replacement is a safe and effective alternative to surgical valve replacement in patients with native RVOT/surgical RVOT conduit dysfunction with excellent procedural success and low incidence of post-procedural pulmonary valvular regurgitation. Fracture of stent frame is the most common etiology for valve degeneration requiring re-intervention. Current recommendations from professional societies recommend TPVI in symptomatic patients with severe PR/PS (Class 1, CEBM level of evidence 3) and asymptomatic patients with severe PS/PR and evidence of RV dysfunction/RV dilation/recurrent arrhythmias (Class 2a, CEBM level of evidence 3). Future development of valve systems improving valve durability, lowering catheter/valve profile, reducing thrombogenicity, and inflammatory response to valves may further improve outcomes, reduce complications, and expand the patients eligible for TPVI. The interprofessional team approach in the management of patients with RVOT dysfunction plays a critical role in ensuring optimal outcomes for patients. The interprofessional team should include interventional cardiologists, cardiothoracic surgeons, cardiac imaging experts, cardiac anesthesiologists, nurses, and catheterization laboratory technologists who work together to provide an integrated & holistic approach to pre-procedural planning, intra-procedural support, and post-procedural care to ensure optimal outcomes for patients. Communication shared decision making, and collaboration between health care providers is key for excellent outcomes. Interprofessional care also helps identify early and late complications of TPVI, therefore improve the prognosis of the patients. Advancements in imaging techniques and protocols will provide further insight into the pathophysiology of the RVOT dysfunction to help identify appropriate timing for TPVI for the best clinical outcome and long term prognosis.