Transcatheter Closure of the Atrial Septal Defect in the Elderly

Atrial septal defect (ASD) is the third most common adult congenital heart defect¹ and was described by Leonardo Da Vince in 1513 as “I have found from a, left auricle, to b, right auricle, the perforating channel from a to b.”² The majority of patients who have a hemodynamically significant ASD remain asymptomatic during the first decade of life but, later develop right ventricular failure, pulmonary artery hypertension, atrial dysrhythmias and thromboembolic events.^3,4 A number of studies have shown the effectiveness of ASD closure by the transcatheter technique in children and adults. In this paper the authors describe the closure of the ASD in the elderly (> 60 years) using the Amplatzer septal occluder. Transcatheter closure of the atrial septum requires an understanding of the anatomy of the atrial septum. The atrium starts out as a single atrium and the ostium primum grows downwards and divides the chamber into the right and left atria. Fenestrations develop in the ostium primum creating the ostium secundum. A second septum known as the septum secundum then develops on the right atrial side covering the opening of the ostium primum. If it fails to close the opening, the result is a secundum atrial septal defect. If there is weakness or an overabundance of tissue in the septum primum, then the abnormality is called an atrial septal aneurysm.^5,6 The magnitude and the direction of the flow is dependent on the diastolic filling properties of the right and left ventricles which can be confounded in the presence of pulmonary artery hypertension or left ventricular restrictive physiology. Most patients with an ASD are asymptomatic, and the age at which symptoms appear is variable and not necessarily related to the size of the shunt. Studies⁷ have demonstrated that asymptomatic patients over the age of 40 should have the ASD closed to avoid the increased risk of hemodynamic compromise. Mills and King⁸ recently provided a 27-year follow up of 5 patients who underwent transcatheter closure of their ASD.
This report focuses primarily on the important issues of feasibility and outcome of transcatheter ASD closure using the Amplatzer septal occluder in patients who are over the age of 60 years. Closure of the ASD was performed in 23 patients who were over the age of 60. The nonstretched mean diameter of the defect was 17.8 ± 5 mm, with a balloonstretched diameter of 22.4 ± 6.3 mm. In 8/23 patients with suspected hemodynamic compromise prior to ASD closure, a 15-minute test occlusion of the ASD with a balloon was performed with assessment of pulmonary artery wedge pressures, left ventricular end-diastolic pressures, systemic arterial pressures and cardiac output. In addition, coronary angiography was performed in 19/23 patients, and right coronary artery stenting was performed in 1 patient in addition to ASD occlusion. The authors selected the device based on the stretched diameter of the ASD with a mean diameter of 25 ± 7 mm. The mean follow-up period of these patients was 29 ± 22 months with clinical and echocardiographic evaluation. At follow up, 2/23 patients developed atrial fibrillation on the third and the fifth days. In 1 patient, there was also transient right hemiparesis with a normal computed tomographic scan, and the transesophageal echocardiography showed no evidence of thrombus on the device. There was a subjective improvement in exercise tolerance in 65% of the patients. The authors conclude that in the absence of severe left ventricular dysfunction, transcatheter closure of the ASD is safe and effective.
At our institution, we routinely perform an intracardiac echocardiogram^9,10 to assess the ASD, and a device 1–2 mm larger than the nonstretched diameter of the ASD is selected. Intracardiac echocardiography effectively defines the margin of the defect and allows placement of the device without the use of general anesthesia.
There are not much data available regarding ASD closure in the elderly with left ventricular restriction. The presence of left ventricular restriction may be masked by the presence of left-to-right shunting at the atrial level effectively unloading the left ventricle¹¹ In an adult patient where the left atrial pressure is > 10 mmHg, we routinely balloon occlude the ASD and reassess the left atrial pressures and the cardiac output with simultaneous assessment by echocardiogram of the mitral valve inflow pattern. In patients with a restrictive left ventricular physiology, there will be further elevation in the left atrial pressure and a reversal of the E/A ratio. Closure of the ASD in this subgroup of patients can result in ventricular failure and pulmonary edema with deterioration in the patient’s clinical status.
A second group of patients are those with pulmonary artery hypertension who have a left-to-right shunt and a reactive pulmonary vascular bed. In this subgroup a combination of pulmonary vascular dilatation therapy and “fenestrated” closure of the ASD maybe an option.
In the absence of left ventricular restrictive physiology or pulmonary vascular restrictive disease closure of the ASD is safe and effective, with the large majority of patients experiencing subjective improvement in exercise tolerance.