Catheterization in Childhood and Adult Congenital Heart Disease
Ada C. Stefanescu Schmidt, MD, MSC
Samuel L. Casella, MD, MPH
Michael J. Landzberg, MD
Diego Porras, MD
Catheterization of children and adults with congenital heart disease brings together the breadth of physiology and disease of multiple interacting and, at times, interconnecting vascular beds, abnormal cardiac chambers and loading conditions, individualized surgical repairs, and both adaptive and maladaptive changes in supporting organ systems. Few aspects of medicine display such dynamic pathology over the entirety of patients’ lifetimes. The congenital heart disease catheterizer must rely on an in-depth knowledge of congenital heart lesions and natural disease course, personalized history, review of and alignment with patient and family goals, detailed review of past surgical and catheterization-based procedures, status of vascular access sites, and familiarity with changing physiology and comorbid medical conditions that have potential to influence procedural and life outcomes.
This chapter, reviewing common cardiac and vascular interventions performed on children and adults with congenital heart disease, is subdivided so as to focus on individualized lesions and to allow the reader greater knowledge and ability to partner in congenital heart disease care. In bulleted fashion, each section reviews indications, technique, outcomes, and risks of particular procedures, together with representative images, illustrative patient case examples and references.
RIGHT VENTRICULAR OUTFLOW TRACT AND PULMONARY VALVE INTERVENTIONS
Hemodynamic Assessment
Pressure gradient across the stenotic valve or conduit is assessed before the procedure with echocardiography (transthoracic echocardiogram [TTE]), with the mean gradient by echo usually being a close correlate of the peak-to-peak (maximum instantaneous) gradient during catheterization.
Severe pulmonic stenosis is classified as a mean gradient >35 mm Hg and peak gradient >64 mm Hg (peak velocity >4 m/s).
Moderate pulmonic stenosis is classified as a peak gradient of 36 to 64 mm Hg (peak velocity 3-4 m/s).
Mild pulmonic stenosis is classified as a peak gradient of <36 (peak velocity <3 m/s).
Indications and Risks of Intervention1,2a,b
Symptoms of heart failure, exercise limitation, and cyanosis from interatrial right-to-left communication, thought to be caused by the moderate or severe pulmonary regurgitation or stenosis.
Asymptomatic severe pulmonic stenosis.
Asymptomatic severe pulmonary regurgitation with progressive dilation of the right ventricle (RV) should prompt further clinical workup to assess symptoms more closely, such as a cardiopulmonary exercise test, and consideration of transcatheter pulmonary valve replacement in selected patients.
Evaluation of supravalvar and branch pulmonary stenosis (PS), as well as pulmonary hypertension, should be performed when considering right ventricular outflow tract (RVOT) or pulmonary valve interventions, as they may be contributing to or be the predominant cause of symptoms.
Balloon Pulmonary Valvuloplasty
Background and Indications1
First described by Kan et al in 1982 in an 8 year old male with valvar PS3
Valvar PS with an echocardiographic maximum instantaneous gradient > 40 mm Hg
Critical PS with cyanosis and/or ductal dependency
Severe PS with RV dysfunction
May be considered as a temporary palliation in high-risk patients with tetralogy of Fallot (TOF) (prematurity or comorbid conditions)
Contraindicated in patients with pulmonary atresia with intact ventricular septum (PA/IVS) and RV-dependent coronary circulation
Risks
Generally considered a safe procedure.
Perforation of the valve annulus or right ventricular outflow tract (RVOT) has been reported and is generally avoided with a balloon diameter to annulus ratio of 1.4:1.
Damage to the tricuspid valve apparatus is avoided with initial passage through the valve with a balloon end-hole catheter.
Procedure4
Routine hemodynamics are obtained with attention to the pulmonary valve gradient after pullback from the main pulmonary artery (MPA).
A right ventricular angiogram is obtained with cranial angulation on the posterior-anterior (PA) camera and straight lateral projection.
The pulmonary valve annulus is measured in systole and an appropriately sized balloon is selected based on this measurement, usually 120% of the annulus diameter.
An exchange wire is placed in a distal PA, and the balloon is advanced across the pulmonary valve.
The balloon is inflated by hand with attention to the level of the waist that is completely resolved at maximal inflation.
The patient is allowed to recover, after which the balloon is reinflated to ensure that there is not a residual waist.
The balloon is deflated and removed from the body, after which a gradient is repeated.
A right ventricular angiogram is performed at the end of the case to rule out subvalvar obstruction or damage to the RVOT or MPA (FIGURES 6.1 and 6.2).
Short- and Long-Term Results
Initial studies showed an average reduction in the transvalvar gradient by 61% or 43 mm Hg immediately following BPV, with 25% of patient having gradients of ≤15 mm Hg and 8% of patients having gradients >30 mm Hg.5
Predictors of unfavorable outcome include more severe initial obstruction and pulmonary valve dysplasia.
Long-term follow-up is limited; however, studies have shown an 84% to 94% and 84% freedom from intervention at 2 and 10 years, respectively.6,7
More recent data have shown a 70% to 80% incidence of pulmonary regurgitation in late follow-up of patients who underwent balloon pulmonary valvuloplasty (BPV).6
 FIGURE 6.1 Antegrade right ventriculogram in the lateral projection shows valvar PS with slightly thickened and doming leaflets. The subvalvar and supravalvar regions are unobstructed. |
 FIGURE 6.2 Lateral projection of a 12 mm × 2 cm Tyshak II balloon (B. Braun Medical Inc., Bethlehem, PA) inflated by hand with a mild residual waist at the level of the valve annulus and maximal balloon diameter of 12 mm (balloon to annulus ration of 1.2:1). |
CASE 1 Representative Cineangiography Loops
A 14-month-old female with valvar PS followed as an outpatient with subsequent increase in the gradient by echocardiography prompting referral for catheterization. A preoperative echocardiogram showed severe valvar PS with a maximum instantaneous gradient of 80 to 90 mm Hg and mean gradient of 45 to 55 mm Hg and a patent foramen ovale (PFO) with bidirectional flow. Initial hemodynamics revealed a normal cardiac index of 4.1 L/min/m2 and systemic RV systolic pressure of 66 mm Hg with a 55 mm Hg peak-to-peak gradient across the pulmonary valve with no gradient from the main pulmonary artery (PA) to the branch pulmonary arteries. A right ventriculogram confirmed the diagnosis of valvar PS with a pulmonary valve annulus measuring 10 mm (FIGURE 6.3; 
Videos 6.1 and 6.2). A 12 mm × 2 cm Tyshak II balloon was subsequently inflated by hand with relief of a discrete waist located at the valve leaflet tips and maximal balloon diameter of 12 mm (balloon to annulus ratio of 1.2:1) (FIGURES 6.4 and 6.5; 
Videos 6.3 and 6.4). Following dilation, the gradient decreased to 15 mm Hg with an RV systolic pressure of 37 mm Hg.
Videos 6.1 and 6.2). A 12 mm × 2 cm Tyshak II balloon was subsequently inflated by hand with relief of a discrete waist located at the valve leaflet tips and maximal balloon diameter of 12 mm (balloon to annulus ratio of 1.2:1) (FIGURES 6.4 and 6.5; Videos 6.3 and 6.4). Following dilation, the gradient decreased to 15 mm Hg with an RV systolic pressure of 37 mm Hg. FIGURE 6.3 A, Frontal and (B) lateral projection of a right ventriculogram in a patient with valvar PS. Straight lateral projection usually clearly delineates the valve annulus as demonstrated in this image. |
 FIGURE 6.4 A-D, A 0.018″ moderately stiff, exchange length guide wire (ThruWay Wire, Boston Scientific, Marlborough, MA) is positioned in the RPA after which a 12 mm × 2 cm Tyshak II (B. Braun Medical Inc., Bethlehem, PA) is positioned across the pulmonary valve and inflated by hand with relief of a discrete waist at the valve leaflet tips and maximal balloon diameter of 12 mm (balloon to annulus ration of 1.2:1). |
 FIGURE 6.5 A-C, Lateral projection of a pulmonary balloon valvuloplasty with relief of a discrete waist at the valve leaflet tips. |
Right Ventricle to Pulmonary Artery Conduit Interventions
Indications and Risks of Intervention
Symptomatic patients with discrete obstructions with >50% stenosis or peak gradient >50 mm Hg or mean gradient >30 mm Hg.
Asymptomatic patients with a bioprosthetic pulmonary valve with peak gradient >50 mm Hg.
Preprocedural imaging can help elucidate the main etiology for conduit or bioprosthetic valve stenosis; focal lesions are more amenable.
Transcatheter Pulmonary Valve Interventions
Indications and Risks of Intervention
The Melody (Medtronic, Minneapolis, MN) and Sapien XT (Edwards Lifesciences, Irvine, CA) are FDA-approved for treatment of stenotic or regurgitant RV to PA conduit or bioprosthetic PVR.
Off-label use of the Melody valve in native RVOT (usually in patients with PS and a smaller native RVOT) has been reported.
Off-label use of the Sapien valves has been reported for treatment of native RVOT that are too large for Melody implantation.
Key Aspects of Intervention
Preprocedural imaging with computed tomography (CT) or magnetic resonance imaging (MRI) is often used to determine RVOT/annular size and candidacy for valve implantation, as well as distance from the valve implantation site to the PA bifurcation, and size of the PAs. 3D rotational angiography can also be performed (FIGURES 6.6 and 6.7;
Video 6.5).
Access is usually obtained from the femoral vein, although subclavian, jugular, or transhepatic access can also be used.
A Swan-Ganz catheter is used to perform hemodynamic assessment and to establish position in the distal PA of a Super Stiff wire.
Angiography is performed in the main PA to assess size of the RVOT landing zone and morphology of the branch PAs.
The size and compliance of the conduit and pulmonary valve annulus are tested by serial inflation of a low-pressure balloon (FIGURE 6.8A and B).
Coronary compression testing is performed by inflating a balloon to target diameter in the RVOT and doing a root aortogram with a pigtail catheter, in both anteroposterior (AP) and lateral projections. Alternatively, selective coronary angiography can be performed during balloon inflation (FIGURE 6.9;
Video 6.6).
Once a decision is made to proceed with valve implantation, prestenting is usually performed with a bare-metal stent. A covered stent can be used if there is evidence of conduit tear during the predilation (FIGURES 6.10 and 6.11;
Videos 6.7 and 6.8).
 FIGURE 6.6 Preprocedural imaging with CT or MRI is often used to determine RVOT/annular size and candidacy for valve implantation, as well as distance from the valve implantation site to the PA bifurcation, and size of the PA. 3D rotational angiography can also be performed. |
 FIGURE 6.7 3D rotation angiography to demonstrate RVOT, pulmonary valve, main PA, and branch PA anatomy. Additional angulated imaging can typically optimize visualization of precise mechanism, anatomy, and measurements associated with obstruction. |
Short- and Long-Term Results
Postprocedural hospitalization length is shorter, but other early clinical outcomes appear similar between TPVR and surgical PVR in a recent single-center propensity-matched comparison.8
The short- and mid-term results from the Melody trials have reported good longevity of the valve, although 25% of patients required reintervention at 4 years in the early Melody experience, in particular in patients who did not have prestenting and developed Melody stent fracture leading to stenosis.9,10
New York Heart Association (NYHA) class improves in most symptomatic patients after TPVR, with improvements lasting up to 6 years in the Melody IDE trial.9
Despite short-term improvement in PR fraction and indexed right ventricular end-diastolic volume (RVEDVi), observational studies suggest progression of PR and increase in ventricular size starting 2 years after intervention in some patients.11,12,13
The reported incidence of Melody valve endocarditis is 3% per year14,15; it appears higher, although is better tracked and reported through prospective registries and clinical trials than
the incidence based on case reports and retrospective studies of surgical PVR. Patient selection, differential ascertainment, as well as biomechanical factors that influence flow dynamics through the valve are being further studied.
 FIGURE 6.8 A and B, Balloon sizing in a patient with a stenotic bioprosthetic valve in an RV-PA conduit. The RV and its outflow are often best visualized from lateral projections, although associations with the branch pulmonary arteries or with surgical attachment from the RV to a conduit can oftentimes be best imaged and assessed with additional angulation. |
 FIGURE 6.9 Compression of the RCA during balloon inflation of in an RV-PA conduit, in a patient with TOF and a single coronary origin. |
Subvalvar and Supravalvar Pulmonary Stenosis
Subvalvar PS is usually due to malposition or hypertrophy of the infundibular muscle. Balloon dilation rarely has a lasting effect and is not recommended.
Supravalvar PS at the site of prior surgical intervention can be treated with balloon dilation. There is often recoil and recurrent stenosis after balloon dilation; longer lasting results can be obtained with stenting in the lesions that are distal enough to the pulmonary valve.
Peripheral Pulmonary Stenosis Interventions
Indications and Risks of Intervention
Consequences of branch PS are not only increased RV afterload but also lack of circulation and growth of affected lung segments, as well as overcirculation to the unaffected pulmonary arteries.
Symptoms related to decreased pulmonary blood flow, abnormal differential perfusion (<35% in 1 lung), and elevated RVSP (between 1/2 and 3/4 of systemic blood pressure).1
There is an increasing experience with PA balloon angioplasty in patients with chronic thromboembolic pulmonary hypertension who are not candidates for surgical embolectomy.16
 FIGURE 6.10 A-C, Deployment of transcatheter valve (Melody) within a prestented conduit. |
 FIGURE 6.11 A-D, Deployment of transcatheter valve (Sapien XT) within a prestented RVOT. |
Key Aspects of Intervention
Venous access and hemodynamics are performed as described above. Access to the right PA may be easier from the left subclavian or internal jugular approach.
Injection in the central PA allows estimation of blood flow to each lung segment, as well as caliber of distal vessels (FIGURE 6.12).
The end-hole catheter used for angiography and measurement of pressure gradient is exchanged over the wire for a balloon catheter. Wire position is maintained in a distal PA.
A high-pressure balloon with diameter not more than that of the adjacent normal vessel is used to dilate the stenotic area.
Cutting balloons may be used for lesions that are difficult to dilate, especially if planning stent implantation (FIGURE 6.13).
 FIGURE 6.12 Angiography in the main PA demonstrating relatively hypoplastic left PA and more focal proximal branch stenosis (full arrow) distal to a previously placed stent and in-stent stenosis within the proximal branch of the right PA. |
 FIGURE 6.13 Balloon angioplasty of stenosis in the distal portion of previously placed right PA stent. Guide wire location is often chosen to optimize stability of balloon dilation catheter, as well as to provide access into a more distal vessel that has sufficient diameter to optimally seat the dilation balloon. |
Short- and Long-Term Results
In older children, who have completed their growth, and in adults, stents are favored, especially in more proximal segments of the PAs (that will demonstrate more recoil after balloon angioplasty).
PA dissection, either due to wire trauma or at the site of balloon angioplasty, hemothorax, and hemoptysis are rare procedural complications. Reperfusion pulmonary edema and lung injury are more common and were reported in 22% of patients in 1 institutional series.17
Stent fracture, PA aneurysm formation, and restenosis have been reported in follow-up,18,19 with restenosis seen in 15% of patients in early series.20 The incidence of unplanned reintervention varies based on the severity of disease and age at intervention, with the majority of children <5 years of age with multiple stenoses requiring percutaneous reintervention.19
INTERVENTIONS FOR PULMONARY VEIN STENOSIS
Hemodynamic Assessment
The degree of obstruction is usually best assessed angiographically, as low gradients can still cause hemodynamic sequelae and clinically important flow disturbances in the low-pressure, parallel constructed, pulmonary venous system.
As isolated pulmonary vein (PV) stenosis will lead to decreased pulmonary arterial flow in only a lung segment and may not affect RV systolic pressures until late in the course of disease, a high degree of suspicion is needed. In children, the most common causes are after surgical manipulation (such as repair of anomalous pulmonary venous return or lung transplantation), idiopathic stenosis (which tends to affect multiple veins and cause more severe pulmonary hypertension), and extrinsic compression, while in adults the most common cause is scarring after a PV isolation/ablation for atrial fibrillation (occurring in 3% of patients, up to 40% in early series21), as well as occasional fibrotic diseases of the mediastinum.
Isolated gradients may occur and can be estimated by measurement of the difference between the pulmonary capillary wedge pressure (PCWP) and systemic ventricular end-diastolic pressure (EDP) (assuming no other obstructions at the level of the atrium or mitral valve). Flow imbalance can be identified by nuclear lung scintigraphy or MRI.
 FIGURE 6.14 Patient with D-looped transposition of the great arteries, pulmonary atresia, atrioventricular canal defect, and total anomalous pulmonary venous return who underwent a bidirectional Glenn shunt and repair of venous return to the left atrium; (A) injection in the right lower segmental PA. B and C, Anteroposterior and lateral views venous return phase showing stenosis of the right lower PV at the site of surgical anastomosis, with prestenotic dilation. |
Indications for Intervention
Angiographic stenosis ≥ 50%
Gradient > 3 to 5 mm Hg
Flow imbalance coupled with otherwise unexplained symptomatology or RV or PA hypertension
Key Aspects of Intervention
Angiographic evaluation of PV stenosis is most easily performed by (1) an injection in a segmental PA through the tip of a Swan-Ganz catheter, with the balloon inflated to prevent mixing, and follow-through to pulmonary venous phase, (2) direct access of the left atrium, and (3) angiography within the affected PV (FIGURE 6.14).
Access into the left atrium is usually obtained by transseptal puncture, via existing atrial septal defect (ASD), or transbaffle puncture. Crossing through a PFO may direct catheters inferiorly and makes manipulation more difficult.
Angioplasty alone has a higher risk of restenosis but is the procedure of choice in infants and children who risk outgrowing their initial stent and if a repeat surgical procedure is considered (FIGURE 6.15A-C).1
Short- and Long-Term Results
Procedural complications, especially in small children, have been reported in up to 25% of patients, with clinically evident systemic embolization in 3% of patients.22
Restenosis is common in children, in particular for congenital PV stenosis,23 with 75% of children needing repeat intervention by 12 months after intervention. Treatment with systemic antineoplastic agents has been described as a way to reduce restenosis.24
Angioplasty in adults with iatrogenic PV stenosis has better long-term results, with restenosis rates <30%, in particular if the final diameter of the stent is ≥10 mm.1,25 Use of coronary drug-eluting stents in adults with iatrogenic PV stenosis has been reported to be associated with a higher restenosis rate than large diameter (≥ 8 mm) peripheral bare-metal stents.26
 FIGURE 6.15 Retrograde venogram into the stenosed right lower PV (A). Access obtained through the inferior vena cava (IVC), right atrium, and large ASD into the left atrium. Serial balloon dilations were performed (B), and postangioplasty venogram showed improvement in the degree of stenosis (C). |
SHUNT CREATION
Balloon Atrial Septostomy
Background and Indications
First performed by Rashkind and Miller on a neonate with dextro transposition of the great arteries in 1966.27
Cyanotic heart disease is the most common indication (ie, transposition of the great arteries) with insufficient mixing of systemic and pulmonary venous blood.1
The septum is deliberately torn, effectively enlarging the interatrial communication, allowing for improved mixing of pulmonary venous and systemic venous blood.
Complicating lesions include a bowing or aneurysmal atrial septum, juxtaposed atrial appendages, and patients with a left subclavian vein to coronary sinus.
Risks
Procedure
Usually performed at bedside unless complicated septal anatomy or associated lesions.
Venous access is usually sufficient and obtained via the umbilical or femoral vein.
Heparinization is obtained at the treating provider’s discretion.
A septostomy balloon is advanced across the PFO or ASD.
The balloon is filled with a predetermined amount of saline.
Echocardiography confirms appropriate position of the balloon in the left atrium, clear of the PVs, left atrial appendage, or mitral valve apparatus.
The balloon is pulled across the atrial septum with a rapid “jerking” motion with the provider’s hand anchored against the table until it crosses the septum to the right atrium after which it is deflated.
Echocardiography assesses the size of the ASD and excludes mitral regurgitation or pericardial effusion.
The patient’s saturations usually increase rapidly.
May repeat several times with incrementally increasing balloon sizes until an effective atrial communication is created.
Hemostasis is obtained and a trial at discontinuing prostaglandin administration may be attempted while the patient is monitored before surgical intervention.4
Short- and Long-Term Results
BAS is usually a successful procedure and results in an abrupt increase in systemic arterial saturation in most patients with reports of absolute increases in the SaO2 of 25% to 30% allowing for stabilization of the patient and discontinuation of prostaglandins in some patients before surgical repair (FIGURES 6.16 and 6.17).27,36,37
 FIGURE 6.16 Subcostal short-axis imaging of the atrial septum shows a PFO bowing into the RA before BAS. |
 FIGURE 6.17 Following BAS there is a large atrial communication with a flail septum primum, which was intentionally torn during the BAS. |
CASE 2 Cineangiography Loops
Newborn, 3.63 kg, full-term female transferred from a referring hospital with postnatally diagnosed D-looped transposition of the great arteries. Intubated in the delivery room and started on PGE with improvement of saturations to the low 80s. On arrival to the CICU an echocardiogram confirmed the diagnosis and identified a small PFO with accelerated left to right flow (FIGURE 6.18; 
Video 6.9). A BAS was subsequently requested owing to concern for LA hypertension and inadequate atrial mixing. A bedside BAS was performed via the umbilical vein with 4 attempts (FIGURES 6.19 and 6.20; 
Videos 6.10 and 6.11). Following the BAS the atrial communication appeared unrestrictive, measuring up to 6 mm (FIGURE 6.21; 
Video 6.12), and saturations rose to 97% to 99% with 30% FiO2. The patient subsequently underwent complete repair with an arterial switch operation, repair of the atrial septum, and patent ductus arteriosus (PDA) ligation 4 days later.
Video 6.9). A BAS was subsequently requested owing to concern for LA hypertension and inadequate atrial mixing. A bedside BAS was performed via the umbilical vein with 4 attempts (FIGURES 6.19 and 6.20; Videos 6.10 and 6.11). Following the BAS the atrial communication appeared unrestrictive, measuring up to 6 mm (FIGURE 6.21; Video 6.12), and saturations rose to 97% to 99% with 30% FiO2. The patient subsequently underwent complete repair with an arterial switch operation, repair of the atrial septum, and patent ductus arteriosus (PDA) ligation 4 days later. FIGURE 6.18 Subcostal long-axis projection of a PFO with accelerated left to right flow in a patient with D-looped transposition of the great arteries. |
 FIGURE 6.19 An atrioseptostomy catheter (B. Braun Medical, Inc., Bethlehem, PA) is advanced over a 0.018″ wire, across the PFO, into the left atrium with position confirmed by echocardiography. |
 FIGURE 6.20 The balloon is inflated with the appropriate amount of contrast (2 cc in this example, diameter 14 mm) during which echocardiography confirms clearance of the mitral valve or PVs. After inflation, the balloon is rapidly pulled across the atrial septum as illustrated in the above image, after which the balloon is deflated in the RA. |
 FIGURE 6.21 Following BAS the ASD is noticeably larger with a visible torn flap of septum primum. |
STENTING OF A DUCTUS ARTERIOSUS
Background
First described by Gibbs et al 1992.38
An effective temporary palliation for some neonates with insufficient pulmonary blood flow with avoidance of the morbidity associated with a surgical palliative shunt.
The need for reintervention due to restenosis, usually secondary to ductal tissue ingrowth, remains high.38,39,40,41,42
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