Benefit of ASD Closure in Older Patients
Abstract & Commentary
By Andrew J. Boyle, MBBS, PhD
Source: Khan AA et al. The impact of transcatheter atrial septal defect closure in the older population. A prospective study. J Am Coll Cardiol Intv. 2010;3:276-281.
Atrial septal defects (ASD) are among the most common congenital heart defect found in the adult population. Although they are often diagnosed and treated in childhood or infancy, some patients survive into adulthood with unrepaired ASDs. It is thought that some smaller ASDs only become symptomatic in later life, when rising LV pressures, secondary to diastolic dysfunction, lead to increased left atrial pressure, which in turn augments left-to-right shunting through the defect. Repair of ASD in childhood is known to improve prognosis, but repair in later life has been less well studied.
Khan et al prospectively evaluated adult patients > 40 years of age undergoing percutaneous device closure of ASD at a single center in the United Kingdom over a two-year period. Inclusion criteria were right heart dilatation on echo and a Qp:Qs ratio ≥ 1.5:1. They excluded patients who could not exercise or who did not give informed consent. All patients underwent device closure of their ASD with the Amplatzer Septal Occluder and were followed up at six weeks and one year with echocardiography, six-minute walk test, quality-of-life questionnaire, and NYHA functional class assessment.
Results: Twenty-three patients (13 women) with a median age 68 years (range 50 to 91) underwent device closure of their ASD. Median ASD size was 18 mm (9 to 30 mm), with a Qp:Qs ratio of 2.2 (1.5–3.0) and a median pulmonary artery pressure of 23 mmHg (12–27 mmHg). Five patients were in atrial fibrillation at the time of the procedure. The median device size was 24 mm (16 to 36 mm).
Procedural success was 100%. Minor complications occurred in five patients: four minor groin hematomas and one episode of atrial fibrillation that reverted with flecainide. ASD closure resulted in significant improvement in symptoms and echo parameters of cardiac remodeling. Six-minute walk-test distance improved by 23.5%, from 400 ± 106 m to 493 ± 89 m (p = 0.001), NYHA functional class improved (p < 0.001), and QOL scores also significantly improved. Right ventricular (RV) end-diastolic diameter (EDD) reduced from 36 ± 8 mm to 26.9 ± 4.5 mm (p < 0.001), and right atrial volume decreased from 126 ± 62 mL to 59 ± 19mL (p < 0.001). Furthermore, left ventricular (LV) changes also occurred, with an increase in LVEDD from 41 ± 4 to 51 ± 4 mm (p < 0.001); LV ejection fraction increased from 65% to 82% (p < 0.001). One late sudden death occurred in an 81-year-old man with chronic renal failure six months after ASD closure; it was presumed to be due to acute coronary syndrome. There were no new persistent arrhythmias at one-year follow-up. The authors conclude that ASD closure at advanced age results in favorable cardiac remodeling and improvement of functional class.
This small single-center series confirms the benefit of ASD closure in adults with significant ASD and evidence of right heart volume overload on echo. Not only did the RA and RV reduce in size over time, but there was evidence of LV changes as well, consistent with ventricular interdependence and relief of the "reverse Bernheim effect." The improvement in exercise capacity may be due to left or right heart changes, or the combination of both. Importantly, in this aging population, there was no increase in the incidence of arrhythmia. Although this is a small single-center study, and has no control group, the results are reassuring that we can provide symptomatic improvement for these patients and change the natural history of RV remodeling that occurs with significant left-to-right shunting.