From the Guidelines
Patients with an Atrial Septal Defect (ASD) typically experience hemodynamic effects characterized by left-to-right shunting, leading to right heart enlargement and potential pulmonary hypertension, as noted in the 2019 AHA/ACC guideline for the management of adults with congenital heart disease 1. The hemodynamic effects of ASD can be assessed through cardiac catheterization, which measures oxygen saturation, pressures, and calculates the pulmonary-to-systemic flow ratio (Qp:Qs) 1. Key points to consider in the hemodynamic assessment of ASD include:
- The Qp:Qs ratio, with a ratio greater than 1.5:1 typically indicating the need for closure 1
- Right and left heart catheterization to measure pressures in all chambers and great vessels
- Oxygen samples to calculate shunt magnitude
- Assessment of kidney function before the use of contrast agents The goal of this assessment is to determine the significance of the shunt and whether the patient would benefit from transcatheter or surgical closure versus medical management, ultimately improving functional status and long-term outcomes 1. In making decisions about ASD closure, it is essential to consider the potential risks and benefits, including the risk of pulmonary hypertension, arrhythmias, and other complications, as well as the potential for improved functional capacity and reduced morbidity and mortality 1. The most recent and highest quality evidence supports the use of cardiac catheterization to assess the hemodynamic effects of ASD and guide decision-making about closure, with the goal of improving patient outcomes and quality of life 1.
From the Research
Hemodynamic Effects of Atrial Septal Defect (ASD)
The hemodynamic effects of ASD can be characterized by the direction and degree of shunting across the communication, mainly determined by the difference in compliance between the right and left ventricle 2.
- In children, hemodynamics are characterized by left-to-right shunting, dilated right heart structures, and normal pulmonary artery pressures (PAP) 2.
- In adults, long-standing volume overload can lead to complications such as pulmonary artery hypertension and right and left ventricular dysfunction 2.
- The degree and direction of shunting can also depend on underlying conditions, such as other congenital malformations 2.
Effects of Transcatheter Closure of ASD
Transcatheter closure of ASD can lead to significant hemodynamic changes, including:
- Normalization of chamber dimensions 3
- Improvement in abnormal movement of the interventricular septum 3
- Decrease in elevated pulmonary artery pressure values 3
- Improvement in stroke volume and right bundle branch block pattern 3
- Increase in left ventricular end diastolic pressure (LVEDP) 4
- Improvement in right ventricular (RV) and left ventricular (LV) function, as well as reduction in left atrial (LA) volume 5
Considerations for Transcatheter Closure of ASD in Adults
In adults, transcatheter closure of ASD can be a valuable treatment option, but requires careful consideration of:
- Technical difficulties due to morphological features of the defect, such as large size or wide rim deficiency 6
- Hemodynamic features, such as severe pulmonary hypertension, ventricular dysfunction, or restrictive left ventricular compliance 6
- Optimal management of comorbidities, including cardiac function, atrial arrhythmias, respiratory function, and renal function 6
- Establishment of a surgical back-up system and a team approach including pediatric and adult cardiologists, cardiac surgeons, and anesthesiologists 6