VENTRICULAR SEPTAL DEFECT (VSD)

VENTRICULAR SEPTAL DEFECT (VSD) - Brent Barber, MD; Brad Friedman, MD
BASICS
DESCRIPTION
• Congenital or acquired defect of the interventricular septum that allows communication of blood between the left and right ventricles
• Other than bicuspid aortic valve, this is the most common congenital heart malformation reported in infants and children. It also occurs as a complication of acute myocardial infarctions (MI).
• Blood flow across the defect is typically left to right and depends on the size of the defect and the pulmonary vascular resistance (PVR).
• Prolonged shunting of blood can lead to pulmonary hypertension and eventually reversal of flow across the defect, and to cyanosis (Eisenmenger complex).
• System(s) Affected: Cardiovascular
ALERT
Geriatric Considerations
In this population, almost entirely associated with myocardial infarction
Pediatric Considerations
Congenital
Pregnancy Considerations
• Pregnancy may exacerbate symptoms and signs of a VSD.
• Tolerated during pregnancy if the septal defect is small
GENERAL PREVENTION
For adults, avoid risk factors for MI and obtain evaluation before pregnancy.
EPIDEMIOLOGY
• Predominant age: Infants and children
• Predominant sex: Male = Female (Male > Female if secondary to myocardial infarction)
Prevalence
In the US
• Congenital: 100-500 of 100,000 live births
• Acute myocardial infarctions: Estimated to complicate 1-3%
RISK FACTORS
• Congenital
- 4.2% risk of sibling being affected
- 4.0% of offspring being affected
• Post-acute MI
- 1st MI
- Limited coronary artery disease
- Hypertension
- Most frequent within 1st week after MI
- Occur in 1-2% of MI, most commonly after anterior MI
Genetics
Multifactorial etiology; autosomal dominant and recessive transmission have been reported.
ETIOLOGY
• Congenital
• In adults, secondary to MI
ASSOCIATED CONDITIONS
• Congenital
- Tetralogy of Fallot
- Aortic valvular deformities, especially aortic insufficiency
- Down syndrome (Trisomy 21), endocardial cushion defect
- Transposition of the great arteries
- Coarctation of the aorta
- Tricuspid atresia
- Truncus arteriosus
- Patent ductus arteriosus
- Atrial septal defect
- Pulmonic stenosis
- Subaortic stenosis
• Adult: Coronary artery disease


DIAGNOSIS
SIGNS AND SYMPTOMS
• Depend on the degree of shunting across the defect
• Respiratory distress, tachypnea, tachycardia
• Diaphoresis with feeds, poor weight gain in infants
• Forceful apical impulse
• Thrill along the left lower or midsternal borders
• High-frequency holosystolic murmur
• S3
• Increased intensity of P2
• Elevated jugular venous pressure
• Diastolic rumble due to increased flow across the mitral valve
• If pulmonary hypertension exists: Cyanosis with exertion
• If Eisenmenger complex is present: Cyanosis and clubbing
TESTS
Lab
Special tests
• ECG may suggest severity of VSD. Initially, left ventricular hypertrophy and left atrial enlargement may be evident. With pulmonary hypertension, right ventricular hypertrophy and right atrial enlargement may be seen.
• After surgical repair, right bundle branch block and left anterior hemi-block are common.
Imaging
• Chest x-ray may demonstrate increased pulmonary vascularity and/or cardiomegaly.
• 2-dimensional ECG for visualization and size of defect.
• Color-flow Doppler, for direction and velocity of ventricular septal defect jet. May be used to estimate right ventricular pressure
Diagnostic Procedures/Surgery
• Cardiac catheterization (left and right heart) can establish the diagnosis, and quantitate degree of shunting.
• Demonstration of an oxygen saturation step-up from the right atrium to the distal pulmonary artery
Pathological Findings
• Congenital VSDs (4 major anatomical types)
- Membranous (70%)
- Muscular (20%)
- Atrioventricular canal type (5%)
- Supracristal (5%; higher percentage in Asian populations)
• Post-MI VSDs: Involve predominantly the muscular septum
DIFFERENTIAL DIAGNOSIS
• Any defect with left to right shunt, such as patent ductus arteriosus, atrial septal defect
• Children: Tetralogy of Fallot
• Adults: Mitral regurgitation
TREATMENT
GENERAL MEASURES
Appropriate health care
• Outpatient, until surgical repair is indicated
• Inpatient in setting of acute MI
• Inpatient for treatment of severe congestive heart failure
Diet
Low sodium
Activity
As tolerated
MEDICATION (DRUGS)
First Line
• Endocarditis antibiotic prophylaxis (1)[A]
• Pediatric
- Furosemide 1-2 mg/kg PO/IV once to twice a day (2)[A]
- Digoxin: Infants 2 years old, 10 ug/kg/d PO divided b.i.d.; children 2-10 years old, 5-10 ug/kg/d PO divided b.i.d.; children >10 years old, 2-5 ug/kg/d PO divided b.i.d.
- Spironolactone: 1-2 mg/kg/d divided b.i.d.
- Captopril: 0.1-0.4 mg/kg PO given q6-24h (max 6 mg/kg per 24 hours)
• Adult: Digoxin and diuretics may be beneficial in some circumstances.
• Precautions
- Drugs that increase peripheral vascular resistance may increase left-to-right shunting and cause signs and symptoms of pulmonary overcirculation.
- Hypotension
• Significant possible interactions: Refer to manufacturer's profile for each drug.
SURGERY
• Surgical closure is generally indicated if the pulmonic-to-systemic flow is >1.5:1.
• Congenital VSD surgery is usually performed before the child enters school or earlier, if hemodynamically indicated. (3)[A]
• Percutaneous transcatheter device closure of muscular and perimembranous is an alternative to surgery which has shown promising results. (4)[B]
• In the post-MI setting, afterload reduction, inotropic support, and intra-aortic balloon pump may be used to stabilize the patient prior to surgery.
FOLLOW-UP
PROGNOSIS
• Congenital:
- Course is variable, depending on the size of the VSD.
- Small VSD: 25-45% will close spontaneously by age 3 years. Muscular defects are more likely to close spontaneously.
- Large VSD: CHF, failure to thrive in infancy, necessitating surgical repair
- 4% of patients with VSD develop infective endocarditis by the 3rd or 4th decade of life.
- Progressive pulmonary vascular disease and pulmonary hypertension are the most feared complications of VSD caused by left-to-right shunting, and may eventually lead to reversal of the shunt (Eisenmenger complex). Death usually occurs in the 4th decade of life if untreated.
• Post-MI:
- With medical management alone, 80-90% mortality in the 1st 2 weeks
- Prognosis worse with inferior MI compared to anterior MI
COMPLICATIONS
• CHF
• Infective endocarditis
• Aortic insufficiency
• Sudden death
• Hemoptysis
• Chest pain
• Cerebral abscess
• Paradoxical emboli
• Cardiogenic shock
• Heart block may rarely accompany surgical closure.
• Pulmonary hypertension
PATIENT MONITORING
Close follow-up of a congenital VSD is necessary until primary intracardiac repair is performed, to ensure that significant pulmonary hypertension does not develop.
REFERENCES
1. Glen S, Burns J, Bloomfield P. Prevalence and development of additional cardiac abnormalities in 1448 patients with congenital VSD. Heart. 2004;90(11):1321-1325.
2. Faris R, et al. Diuretics for heart failure. The Cochrane Database of Systemic Reviews: John Wiley and Sons; 2006.
3. Chang RK, Chen A, Klitzner TS. Factors associated with age at operation for children with congenital heart disease. Pediatrics. 2000;(105):1073-1081.
4. Hein R, et al. Atrial and septal defects can safely be closed by percutaneous intervention. J Interventional Cardiol. 2005;(18):515-522.
MISCELLANEOUS
See also: Down Syndrome; Myocardial Infarction; Tetralogy of Fallot