Muscular Ventricular Septal Defect Treatment & Management

Small muscular ventricular septal defects (VSDs) have a high spontaneous closure rate (80-90%) within the first 2 years of life and often require no medical or surgical management. Larger defects may not close but may become smaller with time.

Medical therapy may be required with large muscular VSDs due to excessive left-to-right shunting and the development of CHF. Therapy is directed at alleviating the symptoms of pulmonary overcirculation and typically includes increased-calorie feedings, diuretics, and, sometimes, an ACE inhibitor.

Diuretic therapy with furosemide is used to lessen volume overload. Significant potassium wasting may warrant the addition of spironolactone or potassium supplementation.

The use of afterload reduction to improve systemic-pulmonary flow ratios may be beneficial in selected cases. ACE inhibitors also inhibit the tissue-based renin-angiotensin system, preventing deleterious remodeling. Be aware that ACE inhibitors have a potassium-sparing effect. When these are used, spironolactone or supplemental potassium should be avoided or judiciously used.

Surgical indications

Failure of medical management to alleviate symptoms in the first 6 months of life requires intervention. Growth failure despite optimal medical therapy and maximized calorie intake is the most important evidence of failure of medical therapy. Intervention is either by surgery or by cardiac catheterization. Very large left-to-right shunts are usually electively repaired within the first year of life.

Elevated pulmonary arteriolar resistance of more than 12 Wood units that does not decrease with oxygen or selective pulmonary vasodilator therapy may be regarded as inoperable.

Diet

In patients with small muscular VSDs, no special diet is required. For patients with large muscular VSDs and significant CHF, caloric supplementation is often required using fortified formula or breast milk.

Activity

Patients with small muscular VSDs can maintain normal activity. Patients with moderate to large defects with significant symptomatology may self-limit strenuous exercise until the defect is repaired. Patients with repaired VSD and no residual cardiac sequelae can resume regular activity.

Inpatient care

Routine inpatient monitoring of infants and children with a small muscular VSD is not necessary. Hospitalization for severe CHF usually indicates the need for early intervention for VSD closure.

Transfer

Transfer to a tertiary care center may be required for further diagnostic evaluation or surgical intervention in patients with large VSDs or multiple VSDs.

Consultations

Consultations may be indicated with the following specialists:

• Pediatric cardiologist
• Pediatric cardiothoracic surgeon

Surgical repair is the most common intervention currently performed.^[11] New surgical approaches using smaller incisions have proven effective in single ventricular septal defect (VSD) closure.^[12] Surgical repair of an isolated large VSD involves closure of the muscular defect with a Gore-Tex patch.

Surgical intervention in younger infants, especially those younger than 1 month, is associated with an increased risk of mortality (historically as high as 10-20%, although currently much lower). Surgical mortality is now very low (approximately 1%) in patients older than 6 months with isolated large muscular VSDs.

Patients with multiple muscular VSDs may undergo pulmonary artery banding if primary repair is deemed too risky. This palliative procedure limits the degree of left-to-right shunting and allows additional time for these defects to decrease in size or undergo spontaneous closure.

Devices are now available for closure of muscular ventricular septal defects (VSDs).^[13] VSD closure devices typically have 2 opposing discs (one for the right ventricular side and one for the left ventricular side), which are released during catheterization under fluoroscopic and transesophageal echocardiographic guidance to occlude the defect. Data suggest that closure of small muscular VSDs in patients with otherwise normal anatomy offers less short-term morbidity with similar results. However, the long-term morbidity is unknown.^{[14, 15, 16, 17]}

The closure devices can be percutaneously placed in the cardiac catheterization laboratory or in the operating room during a "hybrid procedure."^[18] Hybrid procedures may involve inserting the device through a very small incision in the free wall of the right ventricle.

Ongoing investigational trials are currently being performed to assess indications and outcomes in VSD closure with these devices. Data suggest that the ventricular septal occluder does not cause interventricular conduction disturbances in greater numbers than does surgical repair.

Mild to moderate congestive heart failure (CHF) secondary to left-to-right shunting from a ventricular septal defect (VSD) may be managed in an outpatient setting. For routine muscular VSDs, prophylactic antibiotics for the prevention of bacterial endocarditis are no longer recommended by the American Heart Association, except under special circumstances.^[19] A modest risk of endocarditis is still observed; thus, the importance of vigilant oral hygiene should be reinforced.

Small muscular VSDs have a high incidence of spontaneous closure. Serial follow-up care should be performed until spontaneous closure occurs. Moderate-sized VSDs can also be followed in the outpatient setting while awaiting evidence of reduction in size or spontaneous closure. Patients with a large VSD but without significant CHF can be followed as outpatients, with frequent evaluations.

Serial patient follow-up care is required for assessment of patient growth and ongoing evaluation of the need for elective surgical closure.