Impact of Transcatheter Patent Ductus Arteriosus Closure on Left Atrial and Ventricular Remodeling in Adults and Adolescents.

During the fetal life, small portion of the RV output passes to the lung through the pulmonary artery, while the greater portion is shunted to the descending aorta through the fetal ductus arteriosus (1) which is a connection between the left pulmonary artery and descending thoracic aorta just distal to the left subclavian artery.

With transition from intrauterine to extrauterine life, physiological changes occur resulting in left to right reversal of the shunt through the ductus arteriosus. Increased oxygenation after birth results in calcium and potassium channel activity ending in ductus closure(2).

Patent ductus arteriosus (PDA ) is a congenital heart disease(CHD) represents 6-11% of all CHDs (3) and results from failure of closure of the ductus beyond the third month of age(4).

However, there are a subset of patients who survive to adulthood undiagnosed, and it is present in adulthood with various clinical presentations. The clinical presentation, hemodynamics, and management of PDA presentation in adults depend on various factors, primarily the size of PDA, magnitude of shunting, and status of pulmonary vasculature (5).

According to the diameter, and length of the duct, the systemic and pulmonary vascular resistance, the duct may be hemodynamically insignificant or may result in pulmonary over circulation with subsequent left sided heart volume overload(5).

This volume overload induces left heart remodeling manifested by left atrial and ventricular dilatation and hypertrophy to compensate for the increased wall stress. Some patients can compensate well and remain asymptomatic, while others can't and develop heart failure and LV systolic dysfunction (6).

Traditional two dimensional (2D) and doppler echocardiography is the cornerstone tool for the diagnosis of PDA, evaluation of the magnitude and direction of its shunting, and measuring the pulmonary artery pressure(6). Speckle tracking echocardiography (STE) is a relatively novel application that helps in the assessment of the LV and RV function by tracking the speckles seen on the grey scale images of the traditional echocardiography (7). Recent studies showed good correlation between the global longitudinal strain (GLS) measured by the STE , left and Right ventricular ejection fraction (LVEF , RVEF ) measured by traditional 2D echocardiography (8). In addition, other studies revealed that STE could detect subtle myocardial dysfunction in heart failure patients with preserved LVEF (9).

Since the first surgical PDA closure by Gross and Hubbard in 1939 and the later transcatheter PDA closure by Portsmann et al. in 1967, there have been many significant developments in the devices used to close a PDA(10)(11) . In the past 20 years, transcatheter closure has become the leading approach to closure of most PDAs(12).

Complete closure rates at follow-up generally exceed 90- 95% in most studies. Serious complications of transcatheter closure of the PDA are rare.

In real world, cardiologists intervene adult patients with PDAs and have access to variable PDA closure coils and devices that can be implanted through different techniques and theoretically this should induce reverse LV remodeling with improvement of the Left heart dimensions and function (13). Fewer studies assessed the adults with PDA and their findings were late improvement of the LVEF after PDA closure (15,16,23)