Percutaneous Intervention of a Complex Ventricular Septal Defect

Case

A 62-year-old female with a known history of congenital heart disease, including coarctation of aorta post-angioplasty and a ventricular septal defect (VSD), presented to our facility for a second opinion regarding her persistent dyspnea on exertion, exertional angina, and back discomfort with activity. All her symptoms were promptly relieved with rest. Physical examination was unremarkable except for a holosystolic murmur at the left lower sternal border. Transthoracic echocardiogram confirmed a 9 mm membranous VSD (Figure 1) with significant left-to-right shunt through the defect (peak velocity – 4.3 cm/s; peak gradient – 75 mmHg). Right heart catheterization and shunt run revealed mild step-up in the right ventricle, with an oxygen saturation of 79%. Coronary angiography demonstrated non-obstructive coronary artery disease.  Left ventriculography in orthogonal projections confirmed VSD with significant angiographic shunting (Figure 2). In the setting of clinical symptoms, and both echocardiographic and angiographic shunting, the decision was made for percutaneous closure of the VSD.

Under general anesthesia, a Judkins right (JR) 4 catheter was advanced from the right femoral arterial access across the aortic valve into the left ventricular cavity and a Glidewire (Terumo) used to cross the VSD into the right ventricle and beyond into the pulmonary artery after systemic intravenous anticoagulation. A 20-40 mm EN Snare retrieval catheter (Merit Medical Systems) was advanced from the right femoral venous access into the right pulmonary artery to capture the Glidewire (Figure 3) and externalize it to create an arteriovenous loop across the VSD (Figure 4). Transesophageal echocardiography (TEE) confirmed the wire across the defect. An 8 French (Fr) TorqVue delivery sheath (St. Jude Medical) was then advanced from the venous access across the VSD into the aorta. Using TEE imaging, a 10 mm VSD occluder device was advanced, and the left-sided disk deployed and brought back against the left ventricular septum (Figure 5). The sheath was then withdrawn to deploy the right-sided disk and occlude the VSD (Figure 6). TEE demonstrated no impingement of the aortic or tricuspid valves, with no significant regurgitation. Final ventriculogram (Figure 7) and TEE showed minimal residual shunting. Limited echocardiogram the following day showed a well-seated VSD occluder device and minimal residual flow, and the patient was discharged home without complications. Follow-up study at one month was unchanged with significant improvement in symptoms.  

Discussion

VSDs, the most common congenital heart defect at birth, account for only 10 percent of those defects in adults, since many close spontaneously.^1,2  VSDs are of various sizes and locations, may be single or multiple, and in adults, may be complicated by subpulmonary stenosis, pulmonary hypertension, and/or aortic regurgitation, making their clinical presentation, natural history, and treatment quite variable and sometimes challenging.

Although VSDs are associated with other congenital heart defects, including atrial septal defect (35 percent), patent ductus arteriosus (22 percent), right aortic arch (13 percent), and subpulmonic stenosis, and even more complex defects such as transposition of the great arteries and tetralogy of Fallot, the majority of congenital VSDs in adults present as an isolated defect.³ 

The ventricular septum is a nonplanar, three-dimensional partition of the ventricle, composed of five segments: membranous, muscular (also known as trabecular), infundibular, inlet, and atrioventricular segments, therefore being classified into five types based on anatomical location of the defect.  Infundibular VSD (type 1; also referred to as surpacristal, subarterial, subpulmonary, conal, or doubly committed juxta-arterial) results from deficiency in the septum above and anterior to the crista supraventricularis, beneath the aortic and pulmonary valves.  Membranous VSD (type 2; also known as conoventricular), results from deficiency of the membranous septum and is the most common type of VSD. Inlet defects (type 3; also referenced as AV canal), result from deficiency of the inlet septum located beneath both mitral and tricuspid valves. Muscular defects (type 4), which account for 5-20%, are bordered only by muscle within the trabecular septum, away from the cardiac valves. The least common VSD is the atrioventricular VSD or Gerbode defect, caused by deficiency of the membranous septum separating the left ventricle from the right atrium, causing a left ventricular to right atrial shunt. 

VSDs become symptomatic when: the defect constitutes a physiologically significant shunt; the aortic valve prolapses from shunting through perimembranous or outlet defects resulting in aortic regurgitation; the associated valves become a source of infective endocarditis; or the right ventricular outflow tract develops obstruction due to magnitude of left-to-right shunting.

An echocardiographic longitudinal study⁴ demonstrated that the rate of spontaneous closure was highest for small (<3 mm) muscular defects, followed by small perimembranous and moderate (3-6 mm) muscular VSDs; lowest for moderate perimembranous VSDs; and negligible for large (>6 mm) defects of either type. Furthermore, another study of adults with small VSDs⁵ found that almost 20% eventually developed serious complications, including infective endocarditis, progressive aortic insufficiency, and arrhythmias.  

Transcatheter device VSD closure is a treatment option for isolated uncomplicated muscular VSDs and certain membranous VSDs, in patients with suitable anatomy. Appropriate anatomy for transcatheter closure includes a VSD location remote from the tricuspid and aortic valves, with an adequate rim. The most widely used device globally for closure of VSDs is the Amplatzer VSD Occluder (St. Jude Medical), which is a self-expanding, self-centering device made of nitinol wire mesh and two ventricular retention discs. The device size ranges in waist diameter from 4-18 mm and can be delivered via sheaths from 5Fr for the smallest occluder to 9Fr for the largest device. The technical success rate of transcatheter closure of selected muscular and membranous VSDs is high, and the mortality rate is low.⁶ In a large series of 848 patients, the technical success rate of the procedure was 98.1% with an adverse event rate of only 12.1%, of which only 0.9% were categorized as major.⁷ The most common complication following device closure of perimembranous VSD is the development of atrioventricular heart block, ranging from 7-13% with complete heart block in 1-5%.⁷ Device embolization is a rare occurrence reported in up to 2.3%, requiring percutaneous or surgical retrieval. Herein, we present a patient with a symptomatic moderate to large membranous VSD that was successfully managed using percutaneous transcatheter closure. 

The authors can be contacted via Dr. Jon George at: georgej@deborah.org.

This case received a double-blind peer review from members of the Cath Lab Digest Editorial Board.

References

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