Atrial septal defect indications for surgical repair in adults


 * Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [mailto:psingh@perfuse.org]; Assistant Editor(s)-In-Chief: Kristin Feeney, B.S. [mailto:kfeeney@perfuse.org]

Overview
The decision to surgically close an atrial septal defect depends upon many contributing factors including the type of defect, the size of defect, the amount of left-to-right shunting, the development or worsening of symptoms, the presence of pulmonary hypertension and the presence of any associated anomalies.

Amount of shunt
1) Size and amount of left-to-right shunting across the defect serve as a good indicator of the progression and worsening of the disease.

2) The pulmonary-to-systemic flow ratio Qp/Qs gives a good idea of the shunting.

3) Cardiac catheterization gives most accurate diagnosis of Qp/Qs

4) Echocardiography and doppler ultrasound are more commonly used as they are convenient, non-invasive and cheap.

5) Qp/Qs is calculated as Qp/Qs = [PA diameter(2) x VTI-PA] ÷ [LVOT diameter(2) x VTI-LVOT] where


 * PA = pulmonary artery,
 * VTI-PA = velocity time of the Doppler flow signal
 * LVOT = left ventricular outflow tract
 * VIT-LVOT = maximum Doppler flow velocity apical to the aortic valve

6) In case the pulmonary arterial pressure is more than 2/3rd of the systemic systolic pressure, it could cause a net left-to-right shunt of at least 1.5:1 or evidence of reversibility of the shunt when given pulmonary artery vasodilators prior to surgery.

7) If Eisenmenger's syndrome has developed, it must be demonstrated that the right-to-left shunt is reversible with pulmonary artery vasodilators prior to surgery.

8) The American Heart Association has recommended a threshold Qp/Qs ≥1.5:1 for patients 21 years of age or older.

9) The Canadian Cardiac Society recommended a threshold Qp/Qs >2:1, or >1.5:1 in the presence of reversible pulmonary hypertension.

10) The Qp/Qs ratio can change as the disease progresses. Due to this it has been recommended to have a echocardiography every 2-3 years in asymptomatic patients.

Symptoms
1) Development and worsening of symptoms such as shortness of breath, exercise intolerance, fatigue, swelling of feet and ankle or abdomen (suggesting right sided heart failure), recurrent respiratory infections along with echocardiographic abnormalities are an indication for repair.

2) Arrhythmias as an isolated symptom can occur in 1 out of 5 adults patients with atrial septal defects. The surgical closure for patients presenting only with arrhythmia is controversial as not much benefit could be derived even after surgery.

Size of defect
1) Secundum ASDs <6 mm diameter in infants may close spontaneously by the end of two years of life. Thus, in asymptomatic patients with small defects early closure is not indicated.

2) Defects of moderate size (6 to 8 mm) are less likely to close spontaneously. Despite this surgical closure of these defects are not indicated before two years of age, in case these are asymptomatic

Age
1) Closure of an ASD in individuals under age 25 has been shown to have a low risk of complications, and individuals have a normal lifespan (comparable to a healthy age-matched population).

2) Closure of an ASD in individuals between the ages of 25 and 40 who are asymptomatic but have a clinically significant shunt is controversial. Those that perform the procedure believe that they are preventing long-term deterioration in cardiac function and preventing progression of pulmonary hypertension.

Trial supportive data
In a study done by Konstantinides et al. it was found that the surgical repair of an atrial septal defect in patients over 40 years of age, decreases all causes mortality, increases long-term survival and decreases complications like heart failure when compared with medical therapy. However, surgically treated patients may have an increased risk of arrhythmias and thromboembolic episodes and should be closely observed for these complications.

Special conditions
 Pulmonary hypertension

 Eisenmenger's syndrome

Pregnancy
 * ACC/AHA guidelines for reproduction

Migraine