Introduction
Transcatheter closure of ventricular septal defects (VSDs) is a less invasive treatment option for patients with suitable anatomy for device closure and those who are considered to be high-risk candidates for surgical therapy. , This chapter provides an overview, procedural techniques, and outcomes of transcatheter VSD closure.
AHA guidelines
Additional indications
Four types of VSD may be amenable to transcatheter closure. This first category includes patients with post–myocardial infarction VSD (PMI-VSD). Medical and surgical therapy is associated with very high mortality in the acute phase of PMI-VSD, and as a result, transcatheter therapy is often used as a temporizing bridge to clinically stabilize patients. The second category includes patients with iatrogenic or postoperative residual VSD. Iatrogenic VSD can occur after procedures such as septal myectomy, and postoperative residual VSD can be due to patch dehiscence, suture disruption, or incomplete closure of the defect. , Transcatheter closure of residual postoperative and iatrogenic VSD is increasingly being used in this population because of the high morbidity and mortality associated with reoperation. ,
Other VSD types that may be amenable to transcatheter closure are congenital muscular VSDs (mVSD) and certain perimembranous VSDs (pmVSD). Surgery remains the standard of care for the treatment of congenital VSD, but transcatheter therapy may be considered in patients with mVSDs that are not easily accessible for surgical closure, especially in the setting of refractory heart failure despite optimal medical therapy. In addition, some patients with pmVSD who have developed a deep aneurysm of the membranous septum but who have a persistent significant shunt may be candidates for device closure.
General technique and approach
Transcatheter VSD closure is generally performed under fluoroscopic and echocardiographic guidance (either intracardiac or transesophageal). All patients should receive peri-interventional antibiotic prophylaxis with a single dose of cefazolin or other antibiotic with similar coverage and unfractionated heparin to maintain activated clotting time (ACT) >250 seconds.
The standard technique for transcatheter closure of mVSD has been described, although there are many potential modifications of the technique. , After vascular access and hemodynamic catheterization, a high-quality left ventriculogram should define the location of the defect. Positioning a camera at 60 degrees left anterior oblique (LAO) with cranial angulation should provide a suitable view of the membranous and upper-to-mid muscular ventricular septum ( Fig. 20.1 ).
In most cases, many of the difficulties associated with catheter and wire exchange, as well as device positioning and deployment, can be avoided by first establishing an arterial-venous (A-V) “rail” from the femoral artery to internal jugular vein ( Fig. 20.2 ) or femoral vein ( Fig. 20.3 ).
A balloon wedge catheter should be used to cross the tricuspid valve to minimize the risk of the A-V rail becoming entangled in the valve chordae. Once the catheter is in a branch pulmonary artery (PA), it can be exchanged over a wire for a snare catheter. We typically use a gooseneck snare. The VSD is then crossed from the left ventricle (LV) to the right using a soft hydrophilic wire through a sharp-angled directional catheter, such as a Judkins right coronary catheter. The wire is directed anteriorly through the right ventricular outflow tract to the pulmonary artery and snared. The wire course across the VSD and out to the PA should be smooth, free of any loops or unusual turns. An unusual or difficult wire course suggests that tricuspid valve chord may be entangled, in which case the wire should be retracted into the LV and the VSD should be recrossed. Real-time echocardiography can be helpful, too, in identifying new or increased tricuspid regurgitation, another indicator of chord disruption.
With the wire snared, the directional catheter can be advanced into the pulmonary artery, where the wire can then be exchanged for a long interventional wire. We typically use a 0.035″ Amplatzer Extra-Stiff wire. The interventional wire is then snared and exteriorized through the right internal jugular vein or, less commonly, the femoral vein, by gently pulling the snared end of the wire retrograde across the pulmonary and tricuspid valves. Any resistance should be investigated to ensure that there is no damage to valve function. Once the tip of the wire is externalized from the venous sheath, it is secured with a small surgical clamp. Enough wire length should be exposed from the venous sheath to accommodate the delivery system of the closure device.
With the rail now in place, device delivery is straightforward. A delivery sheath of appropriate caliber for the selected closure device and the sheath dilator are advanced from the venous access point over the wire rail. When the dilator is well into the LV or across the aortic valve, the dilator is withdrawn and the sheath advanced. When the tip of the delivery sheath is positioned well into the LV, the support wire can be removed through the arterial sheath.
If there is difficulty advancing the sheath over the wire, this is likely due to impingement of the wire/catheter within the tricuspid subvalvular apparatus. This problem can be addressed by removing all catheter and wire systems and beginning the process over again—recrossing the VSD and reestablishing the A-V rail until smooth advancement of the delivery system is achieved.
If there is concern about losing position of the device or delivery system and having to recross the defect, a “buddy wire” parallel to the closure device and delivery cable can be kept in place during device deployment ( Fig. 20.4 ). Should that approach be taken, the delivery sheath will need to be sized appropriately to accommodate both the device and the buddy wire, typically 3 French sizes larger for a 0.035″ wire.
