Transcatheter pulmonary valve replacement | |
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Other names | TPVR, percutaneous pulmonary valve implantation (PPVI) |
Specialty | Interventional cardiology |
Uses | Congenital defects of the right ventricular outflow tract, failing artificial valves |
Complications | Stent fracture, infective endocarditis |
Other options | Open heart surgery |
Outcomes | 92%-98% successful implantation [1] |
Transcatheter pulmonary valve replacement (TPVR), also known as percutaneous pulmonary valve implantation (PPVI), is the replacement of the pulmonary valve via catheterization through a vein. It is a significantly less invasive procedure in comparison to open heart surgery and is commonly used to treat conditions such as pulmonary atresia. [2] [3]
TPVR can be used to repair congenital defects in the pulmonary valve or right ventricular outflow tract dysfunction, such as pulmonary atresia, Tetralogy of Fallot, or persistent truncus arteriosus. [4] TPVR can also be used to replace dysfunctional artificial heart valves. [1]
For those experiencing symptoms, TPVR is indicated when the right ventricular systolic pressure is above 60 mmHg and/or when there is moderate to severe pulmonary regurgitation. [4] For those not experiencing any symptoms, TPVR is indicated if there is severe right ventricular outflow tract narrowing and/or severe pulmonary insufficiency, with decreased exercise capacity, progressive right ventricular dilation, progressive right ventricular dysfunction, progressive tricuspid valve regurgitation, right ventricular systolic pressure above 80 mmHg, or cardiac fibrillation. [4]
For dysfunctional artificial conduits, TPVR immediately resolves pulmonary regurgitation and normalizes the right ventricular outflow tract gradient, and is associated with significant improvements in symptoms and improvements in long-term ventricular function. [1]
Active infection, central vein occlusion, coronary occlusion, and need for other surgeries such as for arrhythmia are contraindications for TPVR. [4] [1]
If coronary compression (which impairs coronary blood flow) is observed with balloon dilation in the right ventricular outflow tract, TPVR is also contraindicated. [4] This test is performed to prevent potentially fatal complications, for which approximately 5% of candidates are at risk. [4]
TPVR is not recommended for tracts that are less than 16 mm [4] or more than 29 mm in diameter. [1]
There is a low incidence of major complications, which is likely due to pre-procedural assessments preventing individuals with unfavourable anatomy from undergoing the procedure. [5]
The most common complication is fracture of the stent frame. [4] This is seen in up to 30% of cases. [4] The majority of stent fractures are diagnosed by routine imaging and are not clinically relevant. [4] Stent fractures leading to obstruction of the right ventricular outflow tract is the most common reason for repeat intervention and can be treated with valve-in-valve procedures (placing a new valve inside the failed valve). [4] More severe fractures may require surgery. [4] Risk factors for stent fractures include younger age, smaller tract diameter, and position of the valve directly below the sternum. [4]
Tears or ruptures of the right ventricular outflow tract may occur during the procedure, especially if the tract is already heavily calcified. [4] This is reported to occur in up to 9% of procedures. [4] Most cases are manageable by using a covered stent and do not lead to severe bleeding. [4]
Infective endocarditis occurs at a rate of about 1%-3%. [1] Most cases do not directly impact the implanted valve, and most cases can be treated with antibiotics. [4] However, infective endocarditis can also cause valve explantation or sepsis, which can lead to death. [4]
Rare complications that may require urgent surgery include valve migration, valve embolization, pulmonary artery occlusion, pulmonary artery rupture, or coronary artery compression impeding blood flow. [4] [5]
Death is rare, and is usually attributable to other comorbidities rather than from the implantation procedure itself. [4]
Several tests are performed before the procedure to assess whether the procedure is suitable for the individual and to record their anatomy in preparation for the procedure. [4] [6] Ventricular function and size are assessed with an echocardiogram. [4] The right ventricle and the anatomy of the outflow tract, including any anatomical variations, are also assessed with cardiac magnetic resonance imaging. [4] [6] The severity of the outflow tract defect or pulmonary regurgitation is assessed with Doppler ultrasonography. [4]
TPVR is a percutaneous procedure, meaning the device is brought into the body through the skin and into a vein. Patients are put under general anesthesia. [4] The heart is typically reached by passing through the femoral vein, jugular vein, or subclavian vein. [4] A balloon dilation test is performed first, to confirm that coronary compression will not occur and the procedure can continue. [4] [6] Stent fractures can be prevented by using pre-stenting, using a bare metal stent before TPVR. [5] After the valve is implanted, balloon dilation is used to create the diameter of the valve. [6] At the end of the procedure, pressure is applied to the area to encourage hemostasis (stop bleeding). [6]
Patients undergoing TPVR are typically ambulatory within 6 hours of finishing the procedure and can be discharged home within 24 hours. [6] As cardiopulmonary bypass is not required, a stay in the intensive care unit and an extended hospital stay are generally not needed. [6]
TPVR was developed as a less invasive alternative to other treatment options requiring open heart surgery, such as patch augmentation, replacing the native valve with an artificial heart valve, or using a valved conduit. [4] These surgeries typically require repeat surgeries to repair issues including pulmonary regurgitation, valve narrowing, kinking of the conduit, or calcification, leading to significant morbidity. [4]
The first TPVR was performed in 2000. [4] [7] This device was further developed into the Melody transcatheter pulmonary valve by Medtronic. [4] [6] The Melody device received approval from Health Canada in 2006 and from the US Food and Drug Administration (FDA) in 2010. [6] A similar device, the Edwards Sapien pulmonic transcatheter heart valve, produced by Edwards Lifesciences, first received FDA approval in 2015. [4] [8]
The comparatively lower risks of TPVR and reduced need for reintervention compared to traditional surgical treatments has led to a paradigm shift favouring earlier treatment for right ventricular outflow tract defects, which were previously postponed due to the risks of traditional surgery. [1] [9]