Catheter-Based Treatment of Congenital Heart Disease in Adults

Advances in surgical and medical care have led to rapid growth in the number and state of adults living with congenital heart disease (see Chapter 82 ). Consequently there has been an increase in the volume and variety of transcatheter interventional procedures applicable to adult congenital heart disease (ACHD) patients. ACHDs span a wide spectrum with heterogeneous anomalies involving all aspects of cardiovascular physiology such that specialized training has become a necessity for anyone caring for such patients. Multiple professional societies including ACC, AHA, and SCAI have published recommendations regarding the delivery of ACHD interventional care. Current consensus explicitly states that interventional procedures should be performed at regional ACHD centers by qualified and experienced ACHD specialists, and in laboratories with appropriate staffing and experience to fulfill this task. ^, In addition, because of the complexity of disorders in these patients, any site undertaking the care of adults with congenital heart disease must have a well-established multidisciplinary team that includes congenital cardiothoracic surgeons, cardiac anesthesiologists, cardiac intensivists, and congenital cardiologists. ^, Pediatric interventional cardiologists are also key persons on the team, and partnerships between adult congenital interventionalists and pediatric interventional cardiologists are mandatory. As the capabilities of the congenital catheterization laboratory continue to evolve, the line between surgical and catheter-based interventions will become more and more blurred. Many interventions already take place in highly specialized hybrid operating suites whereby interventional cardiologists work alongside their cardiothoracic surgery colleagues. This combined model of intervention will continue to be adapted for adult congenital interventions, and it is this ongoing evolution that makes the field so exciting. Furthermore, as interventional approaches change, the indications for intervention become a “moving target.” As a result, national guidelines outdate sooner than later; therefore, interventional cardiologists who treat adults must remain current about the ever-changing medical literature on this topic. In this chapter, we review major areas in which catheter-based interventions have become well established for adults with congenital heart disease. The topic of congenital heart disease in adults is reviewed in Chapter 82 .

Valvular Interventions

The first static pulmonary balloon valvuloplasty was performed in 1982; successful catheter-based interventions have since been performed on all types of cardiac valves. Although valvuloplasty defined the early era of congenital interventional catheterization, valve replacement is defining the current era.

Pulmonary Valvuloplasty

Congenital valvular pulmonary stenosis accounts for 5% to 10% of all congenital heart disease. In most cases, the stenosis is due to fusion of commissures with normal valve leaflets leading to “doming” of the valve leaflets, but rarely due to dysplastic leaflets. Static pulmonary valvuloplasty (aimed at separating the fused leaflets) was first performed in the early 1980s and has replaced surgical valvotomy as the initial intervention in cases of typical isolated valvar pulmonary stenosis. Valvuloplasty for thick and/or dysplastic valves is less successful; moreover, balloon dilation will be unsuccessful in relieving any muscular subvalvar stenosis. Indications for pulmonary valvuloplasty in adults with congenital heart disease have been outlined elsewhere (see Chapter 82 ). Before pulmonary valvuloplasty is performed, a complete right heart catheterization should be performed, followed by right ventricular (RV) angiography to profile the right ventricular outflow tract (RVOT). Angiographic measurements of the pulmonary annulus allows for the selection of the appropriately sized balloon, which is approximately 120% of the measured pulmonary annulus. Successful balloon valvuloplasty can usually be achieved with low pressure inflation of a compliant balloon. In patients with large annulus, double balloons can be used to achieve adequate dilation. After dilation of the pulmonary valve, repeat angiography should be performed to rule out vascular injury. Pulmonary regurgitation is best assessed on post procedure echocardiography.

Outcomes and Complications

Case selection is critical for optimizing outcomes. Patients with typical pulmonary valve stenosis will have relatively thin leaflets with partial fusion and will respond well to balloon valvuloplasty. The most common complication of pulmonary valvuloplasty is pulmonary regurgitation (<10% with 2+ or greater pulmonary regurgitation), which is usually well tolerated. Major adverse events or unplanned surgeries were not reported for patients with typical valvar stenosis in the most recent report from the National Cardiovascular Data Registry (NCDR).

Pulmonary Valve Replacement

Patients presenting for pulmonary valve replacement typically have a history of congenital heart disease and may have undergone multiple cardiac surgeries. The most common initial pathologies present in these patients are tetralogy of Fallot with associated pulmonary atresia, stenosis, or absence of the pulmonary valve, pulmonary valve dysfunction following a Ross procedure and truncus arteriosus. The unifying component of the surgical repair in these patients is the frequent presence of a RV to pulmonary artery conduit, which is a prosthetic or tissue graft that is placed to bypass or reconstruct the RVOT. Over time, these conduits often develop progressive stenosis, regurgitation or a combination of these. Patients can present with symptoms of exercise intolerance, congestive heart failure and dysrhythmias heralding significant RV dysfunction. In an effort to avoid such dysfunction, relief of stenosis and placement of a competent valve are warranted. Determining the optimal timing for pulmonary valve replacement remains an issue; there are currently several indications in symptomatic and asymptomatic patients with pulmonary valve disease (see Chapter 82 ).

Pulmonary Valve Systems

There are currently two available valve systems approved by the Food and Drug Administration (FDA) for transcatheter pulmonary valve replacement (TPVR): Melody Transcatheter Pulmonary Valve (Medtronic, Inc., Minneapolis), and SAPIEN XT Pulmonic Valve (Edwards Lifesciences, Irvine, CA). Each has its own unique strengths and weaknesses.

Melody Valve

In 2000, Bonhoeffer and colleagues published the first successful percutaneous placement of his prototype stent-mounted valve in the pulmonary valve. The rights to Bonhoeffer’s valve design were acquired by Medtronic, Inc. (Minneapolis, MN) to develop the Melody valve ( Fig. 83.1A ). The Melody valve is composed of a valved segment of bovine internal jugular vein that is fixed with glutaraldehyde and then sutured to a platinum-iridium stent frame. A percutaneous introducer, Ensemble Delivery sheath (Medtronic, Inc., Minneapolis, MN) covers the valve and is used to deliver the valve. Once in proper position, the sheath on the Ensemble system is pulled back to expose the valve, and via two sequential balloon dilations, the valve is deployed. RVOT stenting is routinely performed prior to valve deployment to prevent stent fractures of the Melody valve frame. There are currently two sizes of Melody valves available: 20 and 22 mm, with the delivery system available in three sizes: 18, 20, and 22 mm ( Video 83.1 ).

SAPIEN Valve

The Edwards SAPIEN transcatheter heart valve (Irvine, CA) was originally designed for placement in the aortic position, but was found to have high success rates when placed in the pulmonary valve position, with the first successful pulmonary implantation in 2006. ^, This device is composed of bovine pericardium of three equal-sized leaflets that are hand-sewn to a cobalt chromium balloon-expandable stent with a polyethylene terephthalate fabric cuff ( Fig. 83.1B ). Additionally, the S3 has a new outer polyethylene terephthalate skirt which decreases the incidence of paravalvular leak. The Sapien XT and S3 system is crimped onto the Novaflex and Commander delivery system (Edwards Lifesciences, Irvine, CA), respectively ( Fig. 83.1C ). The delivery systems minimize profile by allowing the valve to be crimped onto the shaft of the balloon and then pushed onto the balloon in vivo once advanced through the introducer sheath. The Sapien delivery system does not cover the valve as it is advanced through the right heart. The SAPIEN valve comes in larger diameters of 23, 26, and 29 mm. These larger valve sizes allow for percutaneous intervention in patients with large native RVOTs, transannular patches, and large RV to PA conduits. The Sapien XT valve has received FDA approval for percutaneous placement in pulmonary conduits since 2012. The Sapien S3 valve has completed primary endpoint data collection under the COMPASSION S3 trial (NCT02744677) for placement in stenotic conduits. There is ongoing enrollment for Sapien S3 placement in bioprosthetic valves ( Video 83.2 ).

Outcomes and Complications

The Melody valve received US Food and Drug Administration approval under a Humanitarian Device Exemption (HDE) in 2010 and Pre‐Market Approval in 2015 for the treatment of conduit dysfunction. In 2016, it received approval for valve-in-valve placement to combat bioprosthetic valve dysfunction. Early and intermediate outcome data have demonstrated excellent procedural success and freedom from RVOT reintervention at rates of 98% at 3 years and 91% at 5 years from intervention. SAPIEN valves have had similarly good early outcomes and favorable comparisons with the Melody valve. Valve selection is influenced by patient cohort (conduit versus transannular patch), ease of use of the delivery system (stiffness and lack of flexibility of the delivery system for the Sapien), and operator experience/preference. Important procedural complications include vascular injury, conduit disruption, pulmonary artery perforation, stent or valve embolization, coronary artery compression, ventricular arrhythmias, and tricuspid valve injury. Long-term complications include stent frame fracture (Melody valve), valve dysfunction, and endocarditis.