Introduction
A 60-year-old male with repaired Tetralogy of Fallot presented with worsening exercise intolerance and palpitations after a lapse in care. His medical history included severe, long-standing pulmonary insufficiency and left pulmonary artery stenosis. He underwent a left-sided Blalock–Taussig shunt at 18 months, complete repair at 6 years, and two right ventricular outflow tract reconstructions with branch pulmonary artery augmentation at ages 10 and 18. He also underwent multiple cardiac catheterizations for left pulmonary artery balloon angioplasty. Comorbidities included stage 3 chronic kidney disease, hyperlipidaemia, and arthritis.
Follow-up echocardiography demonstrated a markedly dilated right ventricle with reduced systolic function and left ventricular dysfunction (ejection fraction 30%). Cardiac MRI revealed severe pulmonary insufficiency (regurgitant fraction 60%), dilated right ventricle with right ventricle end-diastolic volume index (RVEDVi) 174 mL/m2, right ventricle ejection fraction (RVEF) 34%, left ventricle ejection fraction (LVEF) 40%, tricuspid regurgitation (30%), and markedly unbalanced pulmonary blood flow (93% right lung, 7% left). CT for procedural planning demonstrated a large, pyramidal-shaped right ventricular outflow tract not meeting Harmony TPV 25 oversizing criteria and a severely hypoplastic, stenotic left pulmonary artery, raising concern for potential jailing with right ventricular outflow tract implantation (Figure 1). Repeat analysis for the right pulmonary artery implant was performed and proved good candidacy, but continued to show potential concerns for jailing the left pulmonary artery (Figure 2). Right ventricular outflow tract and right pulmonary artery cross-sectional dimensions in both systole and diastole are shown in Figure 3.
( a ) CTA 3D reconstruction showing the severely hypoplastic LPA (black arrow pointing to the origin of LPA). ( b ) and ( c ) perimeter plot and virtual implant in the RVOT demonstrated the poor interference of the inflow part of TPV 25 Harmony valve and high potential risk for jailing LPA (Black arrow).
Figure 1. Long description
The composite image consists of three elements: a 3D reconstruction from a CTA scan, a perimeter plot, and a virtual implant in the RVOT. The 3D reconstruction shows the severely hypoplastic left pulmonary artery (LPA), with a black arrow pointing to its origin. The perimeter plot and virtual implant demonstrate the poor interference of the inflow part of the TPV 25 Harmony valve and highlight the high potential risk for jailing the LPA, indicated by a black arrow. These images together illustrate the anatomical and functional challenges in the cardiac structure and potential risks associated with the valve implant.
Repeat analysis of RPA implant showing good candidacy for TPV 25 Harmony valve with continued concerns for jailing LPA (White arrow).
Figure 2. Long description
The first image on the left is a medical scan highlighting the target outflow landing zone for a heart valve implant. The middle image is a graph titled ‘Harmony TM TPV Fit Analysis’ comparing the fit of a TPV25 valve during diastole and systole, with annotations for the pulmonary artery bifurcation and right ventricle. The right image is a 3D rendering of a heart valve labeled ‘Virtual Valve’ with a percentage overlay, showing the positioning and potential impact of the TPV25 valve. The white arrow indicates concerns about the left pulmonary artery.
Cross-sectional measurements of both RVOT and RPA at different levels as shown by the multiple blue dots. The left panel for RVOT and right panel for the RPA.
Figure 3. Long description
The image displays cross-sectional measurements of the right ventricle outflow tract (RVOT) and right pulmonary artery (RPA) at different levels, indicated by multiple blue dots. The left panel focuses on the RVOT, while the right panel highlights the RPA. Each section shows measurements during diastole and systole, with specific dimensions and perimeters labeled. The measurements include pre-bifurcation, mid pulmonary artery, annular level, and RPA ostia, providing detailed insights into the cardiac structures.
Due to surgical risk and patient preference, transcatheter intervention was pursued. Given these findings, implantation of a Harmony valve in the right pulmonary artery was planned, with protection and subsequent stenting of the left pulmonary artery.
Procedure
8 Fr sheaths were initially placed in both femoral veins. Baseline hemodynamics demonstrated elevated central venous pressure (30 mmHg), pulmonary artery wedge pressure (17 mmHg), mean pulmonary artery pressure (26 mmHg), and right ventricular pressure two-thirds systemic. A Lunderquist wire was advanced into the right lower lobe, and a super-stiff Amplatzer wire was positioned in the left lower lobe to preserve access to the left pulmonary artery.
The venous sheaths were ultimately upsized into 26 Fr DrySeal on the right side for valve placement and 10 Fr sheath on the left side for left pulmonary artery stenting. Angiograms took place through an angiographic catheter through the left femoral vein access. The Harmony TPV 25 valve was advanced into the distal right pulmonary artery, was partially exposed, and gently retracted until it flowered into the right upper branch. After verifying position by angiography, the valve was fully deployed, ensuring it remained distal to the left pulmonary artery origin. Post-deployment angiography confirmed appropriate positioning, and an intracardiac echocardiogram demonstrated a good valve function.
A long sheath was advanced over the left pulmonary artery wire, and a 10 × 27 mm pre-mounted Visi-Pro stent was deployed in the proximal left pulmonary artery. Follow-up angiography showed improved left pulmonary artery size and flow to the left lung (Figure 4). Immediate repeat hemodynamics after the intervention showed a significant drop in central venous pressure to 16 mmHg. Total fluoroscopy time was 42.70 minutes, and total contrast volume was 95 mL. The patient remained hemodynamically stable and was discharged home the following day. Clopidogrel was initiated after the procedure and was continued for 3 months. At the time of discharge, the patient resumed his aspirin, metoprolol, and losartan. After the patient developed some pulmonary venous congestion, he was additionally started on Furosemide and spironolactone and switched from losartan to sacubitril/valsartan. For endocarditis prophylaxis, the patient was recommended to take amoxicillin with dental appointments.
Series of procedural angiograms: ( a ) Baseline RPA anatomy while LPA wire protection. White arrow showing the LPA origin (Projection RAO/cranial). ( b ) Repeat angiogram after fully exposed Harmony valve and before release showing the proximity of inflow portion of the device to the LPA (White arrow). The White start pointing to the most distal portion of the outflow part of the device by the RPA bifurcation (Projection RAO/cranial). ( c ) Post-LPA stenting angiogram confirming positioning and patency of LPA (White arrow). The white stars most distal part of the device by the RPA bifurcation and the other star most proximal part of the inflow part of the device in the RVOT (Projection LAO/cranial).
Figure 4. Long description
The image displays a series of angiograms focusing on the right pulmonary artery (RPA) and left pulmonary artery (LPA) anatomy. In the first angiogram, a wire is seen protecting the LPA, with a white arrow indicating the LPA origin. The second angiogram shows the Harmony valve fully exposed before release, highlighting the proximity of the device»s inflow portion to the LPA with a white arrow and the most distal portion of the outflow part of the device by the RPA bifurcation with a white star. The third angiogram confirms the positioning and patency of the LPA after stenting, with white arrows and stars marking the most distal part of the device by the RPA bifurcation and the most proximal part of the inflow part of the device in the right ventricular outflow tract (RVOT).
Post-procedure CT scan demonstrated a well-seated right pulmonary artery valve with preserved left pulmonary artery patency (Figure 5). At 10-month follow-up, the patient was asymptomatic with improved left ventricular systolic function (ejection fraction 47%) and a well-functioning Harmony valve.
Follow-up CT scan demonstrated a well-positioned Harmony valve (A) and patent and well-positioned LPA stent.
Figure 5. Long description
The CT scan image consists of two panels labeled (a) and (b). Panel (a) presents a transverse cross-sectional view of the chest, highlighting the well-seated right pulmonary artery valve. The valve appears to be correctly positioned within the right pulmonary artery. The left pulmonary artery is also visible and appears patent, indicating that it is open and unobstructed. Panel (b) provides a coronal view of the chest, offering a different perspective of the same structures. The Harmony valve is clearly visible and well-positioned in the right pulmonary artery. The left pulmonary artery (LPA) stent is also evident and appears to be well-positioned and patent. The surrounding lung tissue and other anatomical structures are visible, providing context for the placement of the valve and stent.
Discussion
Pulmonary insufficiency is a common long-term sequela of Tetralogy of Fallot repair. Chronic pulmonary insufficiency leads to right ventricular dilation and dysfunction, tricuspid regurgitation, left ventricular impairment, arrhythmia, and heart failure if untreated. Since the first percutaneous pulmonary valve replacement in 2000, transcatheter pulmonary valve implantation has become a valuable therapeutic option for right ventricular outflow tract dysfunction, with low complication and reintervention rates. Reference Bonhoeffer, Boudjemline and Saliba1–Reference Ferraz Cavalcanti, Sá and Santos3
Screening reports to analyse the CT scan, including the perimeter plot, have been the standard in preparation for transcatheter pulmonic valve using self-expanding platform devices. Since its early use, implanters have expanded their experience and implanted devices even in some non-fit cases. Reference Gillespie, Benson and Bergersen4,Reference McElhinney, Gillespie and Aboulhosn5 This case demonstrates a novel approach using the Harmony valve in a branch pulmonary artery rather than the right ventricular outflow tract in a patient whose anatomy precluded standard valve implantation. The left pulmonary artery was extremely hypoplastic, and it was felt that it would not contribute much to continued right ventricle dilation if positioned proximal to the valve. The pyramidal right ventricular outflow tract shape did not meet the oversizing criteria for stable anchoring. The proximal right ventricular outflow tract was extremely large and would not provide any interference with the inflow part of the device. In addition, a conventional right ventricular outflow tract valve could have obstructed the stenotic left pulmonary artery. Therefore, a transcatheter right pulmonary artery valve implantation was performed, followed by left pulmonary artery stenting, maintaining bilateral perfusion.
Branch pulmonary artery valve implantation using balloon-expanding valves has been reported in similar anatomic situations, yielding improvements in right ventricle volumes and clinical status. Reference Qureshi, Bansal and McElhinney6–Reference Abu-Anza, Nakamura and Aldoss9 More recently, the use of self-expanding valves in branch pulmonary arteries has been described, reinforcing the feasibility of this approach. Reference Mejia, O’Neill, Lozier and Bocks10,Reference Aldoss, Porayette and Nijres11 In this case, maintaining wire access to the left pulmonary artery during right pulmonary artery valve deployment allowed immediate post-valve intervention, preventing occlusion and ensuring better flow to the left pulmonary artery. Although a balloon-expanding platform has been considered in the right pulmonary artery, we favoured a self-expanding platform for stability and to avoid the risk of ascending aorta compression by using a larger valve size, such as a 29 mm Sapien valve. The appropriate length of right pulmonary artery and left pulmonary artery wire protection made this feasible. Branch pulmonary artery stenting post-pulmonic valve placement is frequently encountered. Nonetheless, this case presents a unique scenario where typical right ventricular outflow tract valve placement was avoided due to the risk of valve instability and jailing a hypoplastic left pulmonary artery. Therefore, the valve was placed more distally in the right pulmonary artery while protecting the left pulmonary artery to be stented afterward. This method allowed us to achieve a significant reduction of volume overload by eliminating most of the pulmonary insufficiency and, at the same time, treat left pulmonary artery stenosis and maintain patency.
This case highlights that, for patients with unfavourable right ventricular outflow tract anatomy, transcatheter branch pulmonary artery implantation can offer a safe and effective alternative to surgical or standard transcatheter pulmonary valve implantation approaches. Right pulmonary artery implantation allowed us to protect the left pulmonary artery with a wire during valve placement, something that we would not have been able to achieve in the right ventricular outflow tract classic position.
Conclusion
Branch pulmonary artery implantation of a Harmony valve, accompanied by contralateral left pulmonary artery stenting, can restore hemodynamic competence and improve clinical outcomes in patients with repaired Tetralogy of Fallot and complex right ventricular outflow tract anatomy unsuitable for conventional intervention. This approach may be particularly useful in patients with severely unbalanced pulmonary blood flow and prohibitive right ventricular outflow tract geometry.
