Approaching atrial septal defects in pulmonary hypertension

Abstract

Atrial septal defects (ASDs) are one of the most frequent congenital cardiac malformations, accounting for about 8–10% of all congenital heart defects. The prevalence of pulmonary arterial hypertension (PAH) in adults with an ASD is 8–10%. Different clinical PAH scenarios can be encountered. At one end of the spectrum are adults with no or only mild pulmonary vascular disease and a large shunt. These are patients who can safely undergo shunt closure. In the elderly, mild residual pulmonary hypertension after shunt closure is the rule. At the other end of the spectrum are adults with severe, irreversible pulmonary vascular disease, shunt reversal and chronic cyanosis, that is, Eisenmenger syndrome. These are patients who need to be managed medically. The challenge is to properly classify ASD patients with PAH falling in between the two ends of the spectrum as the ones with advanced, but reversible pulmonary vascular disease amenable to repair, versus the ones with progressive pulmonary vascular disease not responding to shunt closure. There are concerns that adults with progressive pulmonary vascular disease have worse outcomes after shunt closure than patients not undergoing shunt closure. Due to the correlation of pulmonary vascular changes and pulmonary hemodynamics, cardiac catheterization is used in the decision-making process. It is important to consider the hemodynamic data in the context of the clinical picture, the defect anatomy and further noninvasive tests when evaluating the option of shunt closure in these patients.

Keywords:

• ASD closure
• atrial septal defect
• cardiac catheterization
• Eisenmenger syndrome
• pulmonary hypertension
• selective pulmonary vasodilator therapy

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Only exceptional cases of PAH due to an ASD are encountered in infancy and even less in childhood, whereas 8–10% of adults with an ASD develop PAH.

• Adults with progressive PAH undergoing ASD closure have a worse outcome than adults with an ASD developing an Eisenmenger syndrome. Therefore, adults with an ASD and advanced pulmonary vascular disease should not undergo ASD closure.

• There is a correlation between shunt-induced histological changes in the pulmonary vasculature and pulmonary hemodynamics. Cardiac catheterization can be used to estimate the severity of the pulmonary vascular disease when evaluating the possibility of shunt closure in these patients.

• Hemodynamic findings have to be interpreted in a clinical context, taking into account defect anatomy and the results of other noninvasive exams, as, for example, saturation measurement at rest and during exercise.

• A PVR cutoff that precludes defect closure in the absence of the clinical picture of an Eisenmenger syndrome has not been established. Cutoffs indicating the feasibility of ASD closure in PAH patients vary from institution to institution.

• Adults with PAH and PVR index of <6 WU * m² or a PVR of <3 WU and an Qp:Qs >2 can safely undergo defect closure.

• Adults with a large ASD and a PVR >5 WU, a PVR index >9 WU * m2, a Qp:Qs <1.5 or PVR : systemic vascular resistance >0.5 should not undergo shunt closure. In these patients, medical therapy with selective pulmonary vasodilators is advised, with re-evaluation of the hemodynamics 3 to 6 months after therapy.

• Adults with hemodynamics in between these 2 groups should be discussed on an individual base. Acute vasodilation testing may also be helpful in these situations.

Notes