2.2. Transcatheter Procedure

All procedures were performed under local anaesthesia and fluoroscopic guidance. After femoral artery (and vein) access completion (6-French sheath), intravenous heparin (50 IU/kg) and cefazolin were administered. Right and left heart pressures were measured, followed by angiography in lateral and/or right anterior oblique projections. PDA anatomy was classified as type A in 65.6% (21/32), B in 9.4% (3/32), C in 15.6% (5/32), D in two patients, and E in one patient [7]. Pronounced calcifications within PDA were observed in 51.5% patients (17/33) by fluoroscopy. In two patients with decompensated renal failure, preimplantation angiography was abandoned, and the device was selected and deployed on the basis of PDA calcifications and its measurements (Figure 1 and Video 1 in supplementary material). The median narrowest PDA diameter and length were 4.2 mm (1.5–7) and 9 mm (3–24), respectively. Static balloon calibration with an 18 mm Amplatzer sizing balloon (AGA Medical Corp., Plymouth, MN, USA) for better duct visualisation was performed in 7 patients (21.2%) and only during the beginning of our expierience in PDA closure in those patients. Recently, computed tomography has been used for this purpose and performed in 4 patients (12.1%). The median mean pulmonary artery pressure (mPAP) was 30.5 mm Hg (12–55) with a value >25 mm Hg in 66% patients. In one patient with a mPAP of 55 mm Hg (>50% of systemic pressure), the balloon occlusion test was performed before PDA closure, and mPAP decreased to 27 mm Hg. Nitinol wire mesh occluders were applied in all but two patients, and depending on their availability: duct occluder type I in 17 patients (DO I: among them 8 Amplatzer, 5 HeartR, 3 Cardi-O-Fix, and 1 Hyperion), Amplatzer duct occluder type II (ADO II: Figure 2 and Video 2 in supplementary material) in 7 patients, Amplatzer Duct Occluder II Additional Sizes (ADO II AS) in 2 patients, Amplatzer muscular VSD occluder (VSO; Figure 3) in 3 patients, Amplatzer vascular plug type II (AVP II) in 2 patients, Amplatzer septal occluder in 1 patient, as well as StarFlex device in 2 patients. As majority of ducts were type A and >3 mm in wide, DO I was our first choice until introduction of devices with symmetrical retention discs (AVP II, ADO II, and II AS). Moreover, in PDA type B atrial septal occluders and in patients with high mPAP (>50 mm Hg), VSO were generally used. DO I minimally 2 mm greater than the narrowest PDA diameter were chosen. In 24 patients, the anterograde (venous) and in 9 patients, the retrograde (arterial) delivery approach was employed. The latter devices were ADO II (n = 6), ADO II AS (n = 2), VSO (n = 1), and AVP II (n = 1). In 11/24 patients (46%), due to difficulty with anterograde crossing of PDA, the retrograde wire-assisted technique modification was applied. The snare introduced with a left Judkins catheter retrogradely through the PDA was used to catch the tip of a 0.035″ hydrophilic guidewire in the pulmonary artery and to pull it into the descending aorta. Then, the delivery system was introduced over the stiff guidewire from the venous access. Devices were released after confirmation of a stable position by control angiography. In selected patients, the PAP measurement was repeated.

(a) Three-dimensional computed tomography reconstruction of a 5 mm PDA type A with calcifications (arrow). (b) Fluoroscopy in lateral view. 5 × 4 mm Amplatzer duct occluder type II on its delivery cable deployed on the basis of PDA aortic ampulla calcifications (arrow).

Fluoroscopy/aortography in lateral view. (a) Severely calcified 5 mm PDA type A. ^∗Pulmonary end of PDA. (b, c) 6 × 4 mm Amplatzer duct occluder type II implanted from arterial approach, a small (transient) residual shunt in aortography.

Aortography in lateral view. (a) Calcified 4 mm PDA type C in patient with a mean pulmonary artery pressure of 51 mm Hg. (b) 10 mm ventricular septal occluder implanted from arterial approach.

Protrusion was defined as blood flow turbulence either in the descending aorta or in the pulmonary artery with a velocity >2.0 m/s by Doppler echocardiography.