The Declining Relevance of Age in the Treatment of Atrial Septal Defects

Atrial septal defects (ASD), which comprise roughly 10% of all congenital cardiac disease, are frequently first encountered in the adult population.¹ Significant shunting results in the insidious development of symptoms, culminating in overt heart failure typically in the third to fifth decade of life.^2–4 Despite this typically late presentation, management of these defects has historically centered on the belief that early surgical repair during the asymptomatic period prevents progression, improving both the quality and quantity of life. Indeed, the age of 25 years was initially seen as a cutoff after which a survival benefit from repair may no longer be apparent.⁵ So what then to do with the majority that present later in life, when anatomy and hemodynamics indicate chronic volume overload and patients are almost uniformly symptomatic? Is repair justified and, if so, up to what age? This precise question, and the resultant controversy between medical, surgical and, more recently, percutaneous treatment modalities, dominated center- stage in the ASD literature for almost 30 years.
The earliest literature on surgical ASD repair was fraught with discrepant results, leading to confusion regarding the proper care of patients over the age of 40.^5–7 While survival benefit remained suspect, significant improvement in symptoms was noted almost uniformly, with improved New York Heart Association (NYHA) functional class and exercise tolerance compared with medical therapy.^7,8 Patients with more advanced age and significant comorbidities also seemed to derive benefit. In particular, 2 case series of patients over the age of 60 undergoing isolated ASD surgical repair showed marked improvements in NYHA functional class, maintained at two years, without operative mortality.^9,10
Despite the apparent symptom benefit of surgical repair, and possible survival benefit, informal age cutoffs remained commonplace due to the higher prevalence of comorbidities with increasing age, fear of increased operative morbidity and mortality at the extremes of age, as well as physician and patient reluctance towards open heart surgery in the elderly.⁹ Indeed, patients with concomitant cardiac disease requiring more complex surgery fared worse, as did those with significant noncardiac comorbidities, lending credence to this practice pattern.^9,10 Minimally-invasive alternatives to open-heart surgery have thrown a welcome wrench into this discussion, allowing us to reevaluate our real-world thresholds for intervening in the older patient.
Although percutaneous closure was first attempted over 30 years ago, it was not until the late 1990s that the procedure was performed with increasing regularity.^11–15 Since then, it has rapidly advanced to the point where endotracheal intubation and transesophageal echocardiography are no longer required, replaced instead by conscious sedation and low-profile intracardiac echocardiography catheters via femoral puncture.¹⁶ As the morbidity, mortality and efficacy continued to improve, increasingly older patients have been safely closed.
In the current issue of the Journal, Elshershari and colleagues describe their experience with percutaneous device closure of isolated secundum ASD in patients over age 60.¹⁷ This is the first series to report on results in the elderly, although the group had previously reported on their experience in patients over 40 years of age.¹⁸ Indications for closure were hemodynamically significant secundum ASD < 40 mm in diameter with adequate anatomy for device placement, along with right ventricular enlargement or clinical symptoms. The mean age was 71 years (range 62–87). Procedural success for the 41 patients was 100%, with 82% instantaneous complete closure by color Doppler and no periprocedural deaths. In 6–24 months of follow up, complete closure increased to 97% in patients who did not require device fenestration. Importantly, and similar to the surgical literature, there were significant improvements in right ventricular enddiastolic dimension and NYHA functional class that were apparent within 24 hours and sustained in follow up.
Taken together, the literature continues to support repair of isolated ASDs in the symptomatic patient at any age, although no randomized, controlled trials comparing medical, surgical or percutaneous therapies have been, or are likely to be, performed. While a survival benefit remains controversial in the elderly, improvements in right ventricular dimension and NYHA functional class appear dramatic and rapid and appear to be maintained at least to 2 years. With its similar efficacy and lower morbidity, including reduced length of stay and the ability to return to normal lifestyle rapidly, percutaneous closure will be the preferred option in newly-diagnosed patients with suitable anatomy regardless of age. One would also expect that elderly patients currently living with significant ASD who have been reluctant to undergo surgery would now proceed to the less invasive option knowing that symptomatic benefit will still be realized.
If we are to recommend closure increasingly in the elderly, we must take special care to distinguish ASD-related symptoms from other diseases that also appear with age, such as coronary or pulmonary disease. Only when symptoms can be reasonably assigned to hemodynamic load from ongoing shunting should percutaneous ASD closure be performed. In addition, as the authors note, older patients must be assessed for occult left ventricular dysfunction, which may become apparent only after closure.
For asymptomatic patients, criteria to undergo repair has been understandably vague, and the current report does not aid us here. Management decisions in the asymptomatic invariably revolve around the pulmonary-to-systemic blood flow ratio, or Qp/Qs, as a measure of likelihood for the development of symptoms. A Qp/Qs ratio of 1.5/1 has historically portended a negative prognosis in the asymptomatic patient, prompting repair.¹⁹ This benefit appears to hold in those over 40 years of age, with improved 10-year survival and functional status compared to medical therapy.⁷ As patients age further, however, the decision becomes more difficult. Indeed, what better assurance of a benign course than having successfully remained asymptomatic for so many years? Nonetheless, it seems that many such patients may in fact be symptomatic when studied objectively. Cardiopulmonary exercise testing may aid in assessment, prompting successful percutaneous closure when abnormal.²⁰ For now, treatment of patients over age 60 who are both subjectively and objectively asymptomatic remains controversial, although many experts extrapolate what little data there are to recommend closure.²¹ At the very least, they should be reevaluated at regular intervals.
In summary, while we have advised for some time now that age is not relevant in the treatment of ASD, the reality is that it remained a major consideration for many elderly patients when surgery was the only option. Percutaneous treatment, with its similar efficacy and markedly reduced morbidity, should now allow almost all patients to safely realize the benefits of ASD closure.