AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

INTRODUCTION

Section 2 of 11  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

A ventricular septal defect (VSD) is a congenital abnormal opening in the ventricular septum that allows communication of blood between the left and right ventricles. VSDs are caused by embryologic malformations of the ventricular septum. They can occur as an isolated lesion or in combination with other congenital cardiac anomalies. The defect can range from a lesion that might require surgery to a miniscule hole in the muscular septum. Blood flow across the defect is typically left to right and depends on the size of the defect and the pulmonary vascular resistance (PVR).

History of the Procedure

In 1950, Bailey first attempted pulmonary artery banding for the treatment of VSDs. Three years later, he attempted direct suture of a VSD using hypothermia and vena caval occlusion. In 1956, Kirklin reported the first cases of direct-vision intracardiac repair of VSDs using the mechanical pump oxygenator. In 1957, Lillehei demonstrated the feasibility of the transatrial approach to VSD repair using cardiopulmonary bypass.

Frequency

VSDs rank first in frequency on all lists of cardiac defects. They account for 25-40% of all cardiac malformations at birth. US and international frequencies are identical—approximately 1-2 cases per 1000 live births. Studies have shown that the prevalence of VSDs has increased in the United States during the past 30 years. A twofold increase in the prevalence of VSD was reported by the Centers for Disease Control and Prevention from 1968-1980. The Baltimore-Washington Infant Study (BWIS) reported a twofold increase in the prevalence of VSD from 1981-1989. The BWIS study reported that the increase is primarily attributed to more sensitive detection through echocardiography.

Etiology

VSDs result from a deficiency of growth or a failure of alignment or fusion of component parts of the ventricular septum. Incomplete closure of the interventricular foramen and failure of the membranous part of the interventricular septum to develop result from failure of tissue to grow from the right side of the fused endocardial cushions and to fuse with the aorticopulmonary septum and muscular part of the interventricular septum.

The increase of alcohol and illicit drug use has been identified as possible risk factors for VSD. The National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention produced data that show maternal marijuana use during the preconception period is associated with an increased risk of simple VSD. The study goes on to show an increase in use correlated with an increase in VSD prevalence.

A twofold increase in the risk of VSD associated with maternal cocaine use during pregnancy was found in a study at Boston City Hospital in 1991. The BWIS further reported correlations between membranous isolated VSD and paternal cocaine use. Abnormal blood flow to the heart due to the vasoconstricting effects of cocaine is a postulated reason for these increases.

Finally, alcohol consumption has also been associated with increased VSD. The BWIS found that maternal alcohol consumption was associated with small muscular VSD. No correlation was found with membranous VSDs. A study from Finland further found that alcohol consumption was associated with a 50% increase in VSDs.

Correlations are not detected between the muscular VSDs and maternal use of NSAIDs or acetaminophen. Such correlations were also not detected between maternal fever and VSDs.

Pathophysiology

The VSD permits a left-to-right shunt to occur at the ventricular level. A left-to-right shunt at the ventricular level has 3 adverse hemodynamic consequences: (1) left ventricular (LV) volume overload, (2) increased pulmonary blood flow, and (3) compromise of systemic cardiac output.

The functional disturbance caused by a VSD depends on the magnitude of the shunt, which is a function of the size of the VSD and the status of the pulmonary vascular bed rather than the location of the VSD. A small VSD with high resistance to flow permits only a small left-to-right shunt. A large interventricular communication allows a large left-to-right shunt only if no pulmonic stenosis or high PVR exists because these factors also determine shunt flow. Quantifying the shunt by the ratio of pulmonary-to-systemic circulation (QP/QS) is useful.

The severity of pulmonary vascular disease correlates to the size of the shunt. In time, as PVR increases, irreversible histologic changes may occur within the pulmonary vascular bed. Untreated, a reversal of the flow occurs, leading to a right-to-left shunt with the development of increasing cyanosis (Eisenmenger complex).

The natural history of VSDs encompasses a wide spectrum, ranging from spontaneous closure to congestive cardiac failure and death in early infancy. The spectrum includes possible development of pulmonary vascular obstruction, right ventricular (RV) outflow tract obstruction, aortic regurgitation, and infective endocarditis.

Clinical

The clinical picture and functional impairment of VSDs primarily depend on the size of the defect, the status of the pulmonary vasculature, and the degree of shunting, and less on the location of the VSD. Note the following features:

• A small VSD usually causes no symptoms.
• Respiratory distress and mild tachypnea result from abnormal pulmonary compliance due to mild left-to-right shunting.
• Because of compromised systemic output and vasoconstriction, infants with moderately sized VSDs may be pale and are often diaphoretic.
• Patients with moderately sized VSDs and decreased pulmonary compliance frequently have a history of 1 or more episodes of pneumonia and/or upper respiratory tract infections.
• Infants with a large left-to-right shunt often have congestive heart failure and fail to gain weight.
• Patients with VSDs complicated by pulmonary hypertension and reversed shunts (ie, Eisenmenger complex) may present with exertional dyspnea, chest pain, syncope, hemoptysis, cyanosis, clubbing, and polycythemia.
• Bacterial endocarditis can develop regardless of the size of the VSD and is related to turbulent blood flow through the defect.
• The most common physical finding is a harsh grade IV-VI holosystolic murmur. The murmur is best heard along the left sternal border, is usually louder at the third and fourth intercostal spaces, and is widely transmitted over the precordium. The murmur of VSD does not radiate to the left axilla, as with mitral regurgitation, and does not increase in intensity with inspiration, as with tricuspid regurgitation.
• Generally, the smaller the defect, the more turbulent the blood flow through it and the louder the murmur. A grade V-VI murmur may be associated with a very high-velocity flow through only a small, hemodynamically insignificant VSD.
• A systolic thrill can commonly be palpated in the region of the murmur along the lower left sternal border. A systolic thrill is less common with large VSDs than with moderate or small defects.
• Large defects, with appreciable left-to-right shunts, have wide splitting of the S₂, which varies with respiration, and the pulmonic component is accentuated.
• When the left-to-right shunt is large, a diastolic, low-pitched flow rumble, suggesting increased flow through the mitral valve, is present. This rumble, which is audible at the lower left sternal border, is often associated with LV S₃ gallop.
• If pulmonary hypertension develops, the holosystolic murmur diminishes and the thrill disappears. In these patients, the pulmonic component of S₂ becomes loud, and an RV lift (indicative of RV hypertrophy) may develop. Cyanosis may become evident, and polycythemia follows. A pulmonary ejection sound may also be noted. The murmur of pulmonary insufficiency can develop (ie, Graham Steell murmur).
• Supracristal VSDs in the outlet septum may produce murmurs and thrills more prominent in the first or second left intercostal space with radiation upward.
• Patients with a supracristal VSD may develop a diastolic blowing murmur of aortic regurgitation. The holosystolic murmur followed immediately by a blowing diastolic murmur may simulate a continuous murmur.
• Patients with VSD are especially at risk for endocarditis, pulmonary infection, ventricular arrhythmias, heart failure, and pulmonary hypertension.
• Of patients with congenital VSD, 20% have additional cardiac abnormalities. Most abnormalities were detected at the initial assessment stage; however, aortic prolapse and pulmonary stenosis may also develop subsequently.
• Aortic regurgitation may result from the high velocity flow beneath a poorly supported right aortic cusp.

INDICATIONS

Section 3 of 11  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

The indications for surgical intervention and its timing may be simple or complex. While many investigators have tried to establish an algorithm for management, the decision to intervene is often a combination of the judgment of pediatric cardiologists and surgeons. The approach must carefully consider the patient's age, symptoms, physiology, and anatomy. Many areas are open to interpretation.

• Symptomatic infants with large shunts who cannot be managed medically should undergo closure of the defect.
• Surgical repair in patients younger than 6 months is undertaken for control of intractable congestive heart failure, recurrent lower respiratory tract infections, or failure to thrive despite medical treatment.
• In children younger than 2 years, prompt surgical repair is indicated if pulmonary hypertension begins to develop before an inoperable predominant right-to-left shunt ensues.
• Criteria for surgery in children older than 2 years include presence of symptoms, a QP/QS greater than 2:1, cardiomegaly, or elevated pulmonary artery pressure (PAP).
• In adults, surgery is usually recommended if the QP/QS is more than 1.5:1. Once the PVR exceeds 60-70% of systemic vascular resistance and the left-to-right shunt diminishes, closure of the ventricular septal defect (VSD) may no longer be indicated.
• Surgery is not indicated in asymptomatic patients with normal findings on chest radiographs and ECGs and a QP/QS of less than 1.5:1.
• Patients with subarterial VSD and aortic cusp prolapse, supracristal VSD with aortic regurgitation, or perimembranous VSD with aortic regurgitation are ordinarily referred for surgery to prevent progression of aortic regurgitation.
• Even small VSDs should be closed after a single episode of infective endocarditis if the defect remains open once the infection has been cured.

RELEVANT ANATOMY

Section 4 of 11  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

Ventricular septal defects (VSDs) are classified by the position they occupy in the ventricular septum. The septum is divided into 4 components: the membranous septum, the inlet, the trabecular, and the outlet parts of the muscular septum. (The outlet septum is also called the conal or infundibular septum.) Thus, 4 anatomic types of VSDs exist.

• Type I defects are also known as subarterial, outlet, or conal defects. These defects comprise 5% of all VSDs and are located in the outlet portions of the left and right ventricles. The superior edge of the VSD is the conjoined annulus of the aortic and pulmonary valves. Because the aortic and pulmonary valves are in fibrous continuity, this type of defect may also be referred to as doubly committed subarterial. (They are also called juxta-arterial, supracristal, subpulmonary, infundibular, or conoseptal defects.) This VSD is associated with prolapse of the unsupported aortic valve cusps and progressive aortic regurgitation.
• Type II defects are also called infracristal, subaortic, perimembranous, or paramembranous defects. These defects are the most common type of VSD, comprising 75% of all VSDs. They occur around the membranous septum and the fibrous trigone of the heart and are associated with a muscular defect at a portion of their perimeter. The defect is near the aortic valve, and the annulus of the tricuspid valve contributes to the rim of the defect. Perimembranous defects are divided into 3 major subtypes according to the adjacent portion of the muscular septum: perimembranous inlet, perimembranous trabecular, and perimembranous outlet.
• Type III defects (10% of all VSDs), also called atrioventricular (AV) canal, AV septal, or inlet septal defects, are located in the posterior region of the septum beneath the septal leaflet of the tricuspid valve.
• Type IV defects (10% of all VSDs), also called muscular defects, have entirely muscular rims. They may be single but are commonly multiple. Muscular defects may be divided into several categories: inlet, trabecular, central, apical, marginal, and outlet (infundibular). Most commonly, multiple defects occur in the apical trabecular septum. In its most severe form, multiple defects of the ventricular septum are sometimes descriptively referred to as Swiss cheese septum.

CONTRAINDICATIONS

Section 5 of 11  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

A pulmonary-to-systemic vascular resistance ratio greater than 0.9:1 or pulmonary arteriolar resistance greater than 12 Wood units is regarded as an absolute contraindication to surgery.

• Pulmonary hypertension is not a contraindication to surgery provided the pulmonary-to-systemic vascular resistance is less than 0.75:1. Furthermore, PVR may be described as reactive when it is lowered by higher inspired oxygen content or vasodilators such as nitric oxide. Nonresponders are described as fixed. Patients whose PVR is reactive may benefit more from repair than those whose PVR is fixed.
• A PVR of more than 8 Wood units obtained during cardiac catheterization with pulmonary vasodilatation is a contraindication to surgery.

WORKUP

Section 6 of 11  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

Lab Studies

• No laboratory tests are specific to the workup of ventricular septal defects (VSDs).
• Routine preoperative tests include CBC count, serum electrolyte levels, BUN level, serum creatinine level, and coagulation panel. Patients routinely require type and crossmatch for cardiopulmonary bypass and should have a routine urinalysis.
• Occasionally, preoperative arterial blood gas analysis may be helpful if systemic desaturation is present.

Imaging Studies

• Chest radiography
• • With a small left-to-right shunt, chest radiograph findings are usually normal.
  • In patients with moderately sized defects, the cardiac silhouette is enlarged (cardiomegaly), with a prominent LV contour.
  • In patients with large defects with high flow, chest radiographs show cardiomegaly with a more globular cardiac silhouette because of RV and LV enlargement, as well as left atrial and, occasionally, right atrial enlargement. The main pulmonary artery is prominent, and the pulmonary vascular markings are increased. The lungs are usually hyperexpanded, and interstitial edema is often evident. The aortic arch is small.
  • If pulmonary hypertension is present, the right ventricle may be enlarged as well. The left atrium is usually enlarged. The increased pulmonary blood flow is evidenced by enhancement of the pulmonary vascular markings, both centrally and peripherally.
• Echocardiography
• • A complete segmental 2-dimensional echocardiographic study can provide accurate information about the size, location, and number of septal defects, as well as associated lesions. Studies have shown that real time 3-dimensional echocardiographic imaging of muscular VSD can accurately present the exact shape and structure of the defect. Such information can have significant impact on treatment strategies of individual patients.
  • Perimembranous VSDs are identified by septal dropout in the area adjacent to the septal leaflet of the tricuspid valve and below the right border of the aortic annulus.
  • The subaortic VSD appears just below the posterior semilunar valve cusps, entirely superior to the tricuspid valve.
  • The subpulmonary VSD appears as echo dropout within the outflow septum and extending to the pulmonary annulus.
  • The inlet AV septal-type of VSD extends from the fibrous annulus of the tricuspid valve into the muscular septum and is often entirely beneath the septal tricuspid leaflet.
  • Muscular VSDs are identified by echocardiography by echo-free septal areas located in the inlet, trabecular, or outlet portions.
  • Contrast echocardiography has been used to enhance the sensitivity and amplify the assessment of VSD by both M-mode and 2-dimensional techniques.
  • Doppler echocardiography has provided methods for calculation of QP/QS flow ratios, for estimation of gradients across the VSD, and for prediction of right-sided heart pressures.
  • Combined color flow and pulsed Doppler assessments can provide substantial reliable information about the magnitude of left-to-right VSD flow and RV PAP and resistance, in most cases obviating catheter study.
  • Echocardiography with color flow mapping is a more effective technique for the detection of VSD than cardiac catheterization. Echocardiography has been shown to be more sensitive than cardiac catheterization in the detection of certain other cardiac anomalies as well.
  • Color flow Doppler processing has been the most important advance in the detection of VSD. Flow across the interventricular septum can be detected with greater ease compared with previous methods.
• MRI
• • Gated MRI provides excellent anatomic delineation of VSD as well as other cardiac malformations.
  • Cine-MRI provides functional assessment of wall topology and shunt flow.
• Axial cineangiography
• • The left ventriculogram in the long axial view is the most useful projection for angiographic identification of a perimembranous VSD. The defect appears as a discontinuity of the chamber immediately beneath the anterior contour of the aortic valve.
  • The muscular VSD is observed as a discontinuity in the septal wall away from the semilunar and AV valves, indicating that it is entirely surrounded by septal muscle.

Other Tests

• Electrocardiography
• • ECG findings may suggest the severity of VSD.
  • Findings on ECG tracing may be normal if the VSD is small.
  • In patients with small VSDs, a deeper-than-normal S wave in the right precordial leads or a mildly increased R wave in lead V₅ or V₆ sometimes indicates mild LV hypertrophy associated with volume overload of the left ventricle.
  • With moderately sized defects, ECG usually shows some degree of LV hypertrophy. RV hypertrophy may also be evident, depending on PAP.
  • Large VSDs may manifest LV hypertrophy alone on surface ECG, but evidence of biventricular hypertrophy is nearly always present in the form of large, equiphasic RS complexes in the midprecordial leads (Katz-Wachtel phenomenon).
  • Right-axis deviation of the frontal plane QRS vector often accompanies the biventricular hypertrophy of large VSD. This finding reflects the systemic pressure load of the right ventricle.
  • Perimembranous defects of the inlet septum may be associated with an ECG pattern of left-axis deviation of the frontal plane QRS vector, with Q waves in standard leads I and aVL. This pattern, characteristic of AV canal defects, suggests an abnormal position of the specialized conduction system.
  • With the development of pulmonary hypertension, biventricular hypertrophy is observed, often with the Katz-Wachtel phenomenon.

Diagnostic Procedures

• Cardiac catheterization
• • In patients with left-to-right shunts, oxygen saturation is increased in the right ventricle compared with the right atrium because of shunting of highly oxygenated blood from the left ventricle into the right ventricle.
  • Cardiac catheterization also provides precise information about the magnitude of the left-to-right shunt and estimates PAP and PVR.
  • The most frequent indication for catheter studies is assessment of the response of the pulmonary vascular bed to oxygen or vasodilating agents. This response allows a prediction of surgical outcome because a PVR of more than 8 Wood units with pulmonary vasodilatation indicates inoperability.
• Swan-Ganz catheterization: Swan-Ganz catheters demonstrate an oxygen saturation step-up (>8 mm Hg) from the right atrium to the distal pulmonary artery.

TREATMENT

Section 7 of 11  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

Medical therapy

• The medical treatment of infants with ventricular septal defect (VSD) is directed at the control of congestive heart failure. The goals of therapy are to relieve symptoms, to minimize frequency and severity of respiratory infections, and to facilitate normal growth.
• Restricting the activities of a child with an isolated VSD is rarely necessary.
• Patients with small VSDs do not require treatment because approximately 80% of such lesions heal spontaneously. A VSD that either decreases in size or closes completely during the first year of life presents no problems to the practicing physician.
• Older children with VSDs are seldom symptomatic and require little in the way of medical therapy.
• Medical management includes endocarditis antibiotic prophylaxis for all patients with VSDs.
• Respiratory infections require prompt evaluation and treatment.
• Evaluate children with VSD at least once or twice yearly to detect changes in the clinical picture that suggest the development of pulmonary vascular obliterative changes.
• Patients with VSD and pulmonary vascular obstructive disease who are deemed inoperable because of irreversibly elevated resistance require more intensive support and symptomatic therapy as cyanosis progresses and activity becomes more limited. Improvement in the symptoms associated with the polycythemia of Eisenmenger complex (headache, extreme fatigue, and extreme dyspnea) may be provided by partial exchange transfusion for RBC volume reduction.

Surgical therapy

• Small and moderate VSDs with normal PVR have a natural tendency to become smaller and eventually close. Surgery is not indicated for these defects.
• For symptomatic patients or patients with larger VSDs or elevated PVR, surgical closure is indicated. However, the timing of surgery varies. The ideal time to intervene is when the likelihood of spontaneous VSD closure is lowest and the risk of irreversible pulmonary vascular disease and ventricular dysfunction is minimized.
• In subarterial VSDs, the risk of irreversible aortic valve damage caused by cusp prolapse leads to earlier intervention.
• With perimembranous and muscular defects, surgery may be reasonably delayed up to 1 year or more if the infant is thriving and the PAP is known to be near normal.
• Multiple VSDs present a different problem. If a large shunt is present and persists longer than 6-8 weeks, pulmonary artery banding and removal after age 2 years with an attempt at septation is reasonable. Banding is also reasonable in VSDs complicated by straddling or overriding of the AV valves.
• Another surgical approach is percutaneous transcatheter device occlusion of membranous VSDs. This technique may be associated with further complications, including conduction anomalies and valve dysfunction.
• Procedures have been proposed for patients with double outlet right ventricle (DORV) with subpulmonary ventricular septal defects or Taussig-Bing anomaly. Intraventricular repair with rerouting has fewer complications and conserves the indigenous aortic valve. The disadvantage of this operation is that obstruction results in the aorta or right ventricle. Correction with arterial switch operation and closure of the VSD has emerged as the criterion standard because it is applicable in most patients.
• Treatment of patients with VSD and transposition of great arteries (TGA) is controversial. The Rastelli procedure was once the first choice in many cases. Difficult anatomical morphologies such as restrictive VSD or straddling AV valves may complicate this operation. Left ventricular dysfunction and arrhythmia may also lead to mortality. Nikaidoh described a new surgical approach that consisted of an aortic translocation without coronary transfer with biventricular outflow tract reconstruction. Rather than harvesting the aortic root, together with the coronary arteries, which could lead to coronary ischemia, Nikaidoh proposed a complete transfer of the aortic root. The procedure avoids any postoperative ischemic events.
• Treatment of patients with aortic arch obstruction associated with VSD is also achieved with good results. Aortic arch reconstruction is accomplished by direct anastomosis using continuous absorbable sutures. Mortality and morbidity are primarily related to noncardiac causes rather than to the procedure itself. Residual VSD shunting requiring reoperation is not a major consideration.
• Treatment of patients with VSD and aortic regurgitation is controversial. In patients with a large, hemodynamically significant left-to-right shunt, repair of the VSD is indicated, but aortic regurgitation is repaired only if at least moderate aortic regurgitation exists.
  • If a supracristal VSD without aortic regurgitation is identified at cardiac catheterization in early childhood, a sensible argument for prophylactic closure of the VSD can be put forth to prevent the potential complication of aortic valve incompetence.
  • In the presence of moderate or severe aortic regurgitation, valvuloplasty is preferred to valve replacement.
  • Operation should probably be deferred in asymptomatic patients with a subcristal VSD and an insignificant left-to-right shunt when aortic regurgitation is not severe.

Preoperative details

• Management of patients with VSDs depends upon the size of the VSD, the age and symptoms of the patient, the PVR, and the presence of other associated cardiac defects.
• Small and moderate VSDs with normal PVR have a natural tendency to become smaller and eventually close. Patients with such defects can be observed because surgery is not indicated.
• When clinical findings suggest a moderate shunt but no pulmonary hypertension, elective hemodynamic evaluation should be undertaken before age 3 years. Of prime importance in the hemodynamic evaluation is determination of pressure and blood flow in the pulmonary artery. Surgical treatment is not recommended for children who have normal PAPs with small shunts (pulmonary-systemic flow ratios of <1.5-2:1).
• Identifying patients who may develop irreversible pulmonary vascular obstructive disease (Eisenmenger complex) is crucial. If early primary closure is not recommended, perform recatheterization before age 18 months and make a second determination of PVR in these patients to decide whether surgical intervention is obligatory to prevent development of fixed obliterative changes in the pulmonary vessels.
• For patients who develop Eisenmenger complex, surgical therapy is ineffective and thus not recommended. These patients are managed medically and may be considered for lung or heart-lung transplantation.

Intraoperative details

• Pulmonary artery banding as a palliative procedure is occasionally useful in certain high-risk patients such as those with multiple VSDs, VSDs with coarctation of the aorta, or VSDs with straddling and/or overriding of one AV valve. Banding is also sometimes useful in extremely small patients or those with concomitant lung disease. However, for most patients with simple VSD who require operative intervention, primary intracardiac repair is the procedure of choice.
• Operations for intracardiac repair of VSDs are performed through midline sternotomy incision. The procedure aims to obtain a secure and complete closure of the defect without damaging any important structure, particularly the conduction tissue of the heart, which is responsible for maintaining atrioventricular synchrony.
• Most centers use conventional hypothermic cardiopulmonary bypass with cold cardioplegia for older infants and children. Alternatively, the technique of profound hypothermia and low-flow bypass, or even total circulatory arrest, is used by some centers for VSD repair in infants younger than 1 year.
• Depending on their location in the interventricular septum and the presence or absence of associated cardiac anomalies, VSDs are closed through the right atrium, the right ventricle, the left ventricle, or one of the great arteries.
  • Closure through the right atrium is chosen to close most isolated VSDs of the perimembranous or inlet muscular types.
  • Trabecular muscular defects and infundibular muscular defects are often accessible through the right atrium.
  • Defects of the lower part of the muscular trabecular septum, particularly when multiple, are often best approached through a left ventriculotomy.
  • Closure through the right ventricle can be used for the perimembranous outlet, infundibular defects, and some trabecular defects.
  • Defects of the outlet septum are best approached through the pulmonary artery.
  • Subarterial defects are approached through the pulmonary valve.
• Many small defects associated with low PAP are closed by suture; larger VSDs and VSDs with accompanying pulmonary hypertension are closed using a patch. Patches are made of Dacron velour, Teflon, Gore-Tex, or xenograft pericardium.
• In some centers, the use of intraoperative transesophageal echocardiography has provided accurate assessment of patch integrity and revealed the presence of additional muscular defects after termination of cardiopulmonary bypass.
• Several centers have investigated transcatheter closure of VSD using a clamshell double umbrella device. The device is inserted via a venous catheter through a long sheath; ultimately, the device is placed across the ventricular septum from the RV side. The devices do not appear to be useful for perimembranous defects, which are readily approachable by the surgeon, but they can be successfully used to close defects of the trabecular septum, well distanced from the semilunar and AV valves.
• Tricuspid valve detachment (TVD) may allow for improved visualization of the margins of a VSD, thus diminishing the chances of a residual shunt. The TVD can be performed without additional complications. The procedure does not lead to a longer cross-clamp time. This procedure is not known to cause tricuspid insufficiency or tricuspid stenosis.

Postoperative details

• Postoperatively, monitoring the left atrial and PAP simplifies management in patients with large defects, preexisting heart failure, and known pulmonary hypertension.
• Precautions are taken to limit the responsiveness of the pulmonary vascular bed, and ventilatory management becomes an important tool. Hyperventilation (low carbon dioxide) and hyperoxia (elevated fraction of inspired oxygen) tend to increase pulmonary blood flow and decrease PVR. The opposite is also true. With persistent, severe pulmonary hypertension, nitric oxide is available in many centers.
• Standard bacterial endocarditis prophylaxis is recommended for patients with repaired VSD with residual defect. For operated VSDs without residual defects, prophylactic antibiotics are indicated for only the first 6 postoperative months.
• Complete heart block is the most significant surgically induced conduction system abnormality, occurring immediately after surgery in fewer than 1% of patients. Late-onset complete heart block is occasionally a problem, especially in the 10-25% of patients whose postoperative ECG findings show complete right bundle branch block with left anterior hemiblock.

Follow-up

Medical follow-up care in the older age groups consists of periodic evaluation, encouragement of full activity, and education about the use of antibiotic prophylaxis for bacterial endocarditis. After surgical closure of a VSD, trivial residual shunting is detected with echocardiographic techniques.

In closing a VSD, temporary tricuspid valve detachment may provide a better postoperative visualization of the margins of VSDs. This can diminish the chance of residual shunt creation, creation of a heart block, or a distortion of the tricuspid valve.

COMPLICATIONS

Section 8 of 11  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

Complications of ventricular septal defects (VSDs) include the following:

• Growth failure
• Congestive heart failure (left heart failure)
• Pulmonary vascular disease as a consequence of left-to-right shunting (The ultimate consequence of pulmonary vascular obstructive disease is irreversible muscular hypertrophy and, ultimately, obliteration of the pulmonary vasculature and pulmonary resistance that equals or exceeds systemic resistance. This condition is known as Eisenmenger syndrome or complex.)
• Severe illness with viral or bacterial pneumonia
• Infective endocarditis (occurs at a rate of 2.4 cases per 1000 patients per year)
• Aortic regurgitation (an especially common complication in patients with subarterial VSDs)
• Stenosis in the RV outflow tract
• Discrete fibrous subaortic stenosis
• Acquired LV outflow tract obstruction
• Aneurysm of the ventricular septum
• Paradoxical emboli
• Sudden death
• Heart block secondary to intracardiac repair
• Impaired left ventricular function in some patients
• Increase in weight following VSD closure

OUTCOME AND PROGNOSIS

Section 9 of 11  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

• The course is variable depending on the size of the VSD.
• Of all VSDs noted at age 1 month, 80% close spontaneously. Spontaneous closure of VSDs occurs as a function of native defect size, anatomy, and patient age. The highest closure rates are observed in the first year of life and in patients with small defects.
• Studies on the mortality rate associated with the natural history of VSD indicate that 27% of patients die by age 20 years, 53% by age 40 years, and 69% by age 60 years.
• For uncomplicated VSD repair, the operative mortality rate should approach 0%. The overall risk for VSD repair is less than 5%. Mortality and morbidity rates increase with multiple VSDs, pulmonary hypertension, and complex associated anomalies.
• When surgical repair is performed before age 2 years, the long-term outlook is excellent, and patients ultimately have a normal-sized left ventricle and normal ventricular function. The patient who undergoes VSD closure in childhood is usually asymptomatic and leads a normal life.
• The overall 25-year survival rate for all patients managed with medical or surgical therapy is 87%; mortality rates increase with the severity of the VSD.

FUTURE AND CONTROVERSIES

Section 10 of 11  

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

Little controversy presently exists regarding the management of VSDs. Improvements in optimizing the timing of surgery and in the prevention or reversal of pulmonary vascular changes remain fertile areas of investigation. As in other specialties, the expansion of minimally invasive techniques will likely play a role in the future of this disorder. Catheter-based interventions and robotically assisted operations through small incisions, as yet unproved, are likely to have increasing roles in congenital heart disease.

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Indications
• Relevant Anatomy
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

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Article Last Updated: Feb 20, 2007