Pediatric Unbalanced Atrioventricular Septal Defects Treatment & Management
- Author: Mark A Law, MD; Chief Editor: Howard S Weber, MD, FSCAI more...
Admit patients for testing and surgical intervention.
Optimize management of congestive heart failure (CHF) before surgical repair and/or palliation. Generally, treat congestive heart failure (CHF) with digoxin, diuretics, and ACE inhibitors as needed before surgical palliation and/or repair.
The most important prerepair medical care involves the decision-making process regarding univentricular versus biventricular repair. A successful biventricular repair requires creation of 2 competent atrioventricular valves (AVVs), and both ventricles must be large enough to carry a full cardiac output. Note the following:
Preoperative left ventricular (LV) volume calculations can greatly underestimate the potential volume of the LV once the right ventricle (RV) is unloaded.
In 1997, Van Son and colleagues predicted postoperative LV volumes based on preoperative echocardiography in patients with RV-dominant unbalanced atrioventricular (AV) septal defects.  They found that a preoperative indexed volume of greater than 15 mL/m 2 was sufficient for a biventricular repair. They also noted that the commonly held notion that the LV should be apex forming is misleading; this is not essential for a successful biventricular repair.
The use of echocardiography to derive an AVV index has been described. The advantage to this approach is that it is less affected by volume load differences than ventricular cavity volumes. They suggest that a left-to-right AVV area ratio of less than 0.67 in the presence of a large ventricular septal defect (VSD) or ductal-dependent circulation precludes biventricular repair. 
Neither of these strategies takes into account potential for growth, particularly in small infants. 
Consult with a pediatric cardiologist and a pediatric cardiothoracic surgeon. Consult with a geneticist, if indicated.
After diagnosis is made, or to ensure an accurate diagnosis, transfer the patient to a tertiary facility where pediatric cardiologists and/or cardiovascular surgeons are available.
Surgical techniques for the treatment of patients with AV septal defects have evolved considerably since Lillehei first reported successful repair of an AVC defect using cross-circulation in 1955. Results have remarkably improved over the past 20 years.
Most patients who are eligible for a biventricular repair undergo repair before age 6 months (as with other patients with balanced AV septal defects). Most institutions are comfortable performing a biventricular repair in symptomatic patients aged 3-4 months or younger and can do so with a mortality rate of less than 3%.
The following 2 surgical approaches are commonly used with excellent results to repair balanced AV septal defects:
The 2-patch technique uses a synthetic (eg, Dacron, Gore-Tex) ventricular patch and a separate pericardial atrial patch.
The 1-patch technique, usually pericardial, covers both the ventricular and atrial components.
In one study that compared the 2-patch technique with a modified 1-patch technique, the outcomes were similar. The modified 1-patch technique was performed with shorter cross-clamp and cardiopulmonary bypass times.
In patients with severe hypoplasia of one ventricle, the single-ventricle pathway offers the best long-term results, although it is palliative at best. Drinkwater and Laks reported on 34 patients with unbalanced AV septal defects who underwent cavopulmonary shunt procedures between 1988 and 1996. Of these patients, 25 (73%) were RV-dominant. The hospital mortality rate was 9% (3 of 34 patients). Of 31 survivors, 3 late deaths occurred (9.6% of patients). Of the 16 patients who underwent completion of the Fontan operation, 1 died in the hospital and 5 late deaths occurred.
In the early postoperative period, nitric oxide may be beneficial for those patients who have elevated pulmonary vascular resistance.
No specific diet is needed.
Maximizing nutrition and caloric intake is important in every child with CHF symptoms and before surgical repair and/or palliation.
Increased caloric density of formula is often required for growth.
Activity restrictions must be determined on a patient-by-patient basis and vary considerably, depending on whether a 1-ventricle or 2-ventricle repair is achieved. In addition, residual defects such as AVV regurgitation or LV outflow tract obstruction may influence exercise performance.
After staged completion, patients who underwent single-ventricle repair may experience as much as 80% of normal exercise tolerance.
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