Horseshoe-shaped guide catheter and procedure for ductus arteriosus angioplasty in newborn and infant patients

Abstract

A horseshoe-shaped guide catheter for stent angioplasty of the ductus arteriosus in newborn and infants with ductal-dependent cardiopathies, characterized by a long, straight, hollow first section merged at the distal end thereof to a second section formed by a curved portion shaped as a circle section with radius (Ra) of 7.5 mm to 9 mm, arc (b) of 180° to 280° and distance (d) between the tip of the second section and the straight part of the first section without deformations of 7 mm and 15 mm. The angioplasty makes it possible to insert one or more stents that keep the ductus open in extrauterine life, improving survival of the newborn and young infants, allowing weight gain and undergo corrective surgery a few months later with safer and with better outcomes.

Claims

1. A method for performing stent angioplasty of the ductus arteriosus by inserting a guide catheter, using a retrograde access through a femoral artery, comprising the steps of: i) inserting the catheter with a guidewire through the femoral artery up to the aorta and until a tip of the catheter has gone beyond the start of the ductus or is close to it on its aortic side; ii) withdrawing the guidewire from inside the catheter so that a distal end section of the catheter acquires its curved form and rests on two points of the aorta, namely, the aortic wall opposite to the junction between the aorta and the ductus arteriosus, and the adjacent wall to the junction; iii) sliding the catheter upwards and causing the catheter to bend even more and firmly rest on the two points of the aorta previously mentioned; iv) sliding the catheter downwards or upwards so that its tip enters the lumen of the ductus arteriosus; v) advancing a floppy guidewire inside the catheter and with aid of blood flow, making the floppy guidewire travel the total length of the ductus and enter the pulmonary artery until firmly attached to a distal pulmonary artery avoiding its release during the next steps of the procedure; vi) using the floppy guidewire, advancing a stent-carrying catheter through the lumen of the guide catheter; vii) expanding the stents from the pulmonary distal end of the ductus to the proximal aortic end of the ductus, until the entire ductus is covered with stents, wherein the guide catheter has a curved section at the distal end of the catheter rest on an external arch of the aortic wall, the tip of the guide catheter slides on an internal arch of the aortic wall until finding the aortic ductal ostium such that the guide catheter accesses the ductus and allows the stent carrying catheter loaded with stents to perform ductal stent angioplasty.

2. The method of claim 1, wherein the guidewire used in step i) has a diameter of 0.89 mm (0.035 inches).

3. The method of claim 1, wherein the floppy guidewire used in steps v) and vi) has a diameter of 0.36 mm (0.014 inches).

4. The method of claim 1, wherein the stents have a diameter in the range of 3 to 4 mm.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1A shows a diagram of a healthy heart where all the heart and vessel structures relevant to the invention's description and use are pointed out.

(2) FIG. 1B shows a diagram of a zoomed in view on the aorta 5 and pulmonary artery 3 which are communicated through the ductus arteriosus 4.

(3) FIG. 2A shows a diagram of a heart with pulmonary atresia and single ventricle 6.

(4) FIG. 2B shows a diagram of a heart with pulmonary atresia and ventricular septal defect 11.

(5) FIG. 2C shows a diagram of a heart with pulmonary atresia and intact ventricular septum 12.

(6) FIG. 3 shows a diagram of different ductal 4 morphologies observed in patients with pulmonary atresia and the acute angle generally formed between the axis of the descending aorta 5b and the axis of the ductal proximal side 4a in newborns with pulmonary atresia. This angle is one of the key features in the geometry of the ductus 4, which hinders accessibility with current proprietary and commercial catheters.

(7) FIG. 4 shows an isometric view of the proposed guide catheter 16 showing the shape of the distal tip 18.

(8) FIG. 5 shows the front and lateral view of the proposed guide catheter 16. A cross-sectional view of the proposed catheter is also provided with detail on inner and outer diameters.

(9) FIG. 6A shows the process of insertion of the catheter inside the ductus arteriosus 4 after reaching the aorta 5. Images A-1, B-1, C-1, and D describe how to handle the catheter 16 if its tip goes beyond the origin of the ductus 4 when entering the aorta 5.

(10) FIG. 6B shows the process of insertion of the catheter inside the ductus arteriosus 4 after reaching the aorta 5. The images A-2, B-2, C-2, and D describe how to handle the catheter 16 if its tip has not yet gone beyond the origin of the ductus 4.

(11) FIG. 7 shows steps E-I, which must be followed once the catheter 16 is inside the ductus 4 to perform the angioplasty procedure.

DETAILED DESCRIPTION OF THE INVENTION

(12) The horseshoe-shaped guide catheter 16 is a long tube with a circular cross-section, comprising mainly of two sections with different geometric preshapes. Both sections are part of the catheter and there is no marked physical division between them. However, both sections are described separately so as to better illustrate the overall shape of the catheter.

(13) The first section of the guide catheter 17 is a long, straight conventional section, long enough to be inserted in the patient and be handled from the insertion point towards the targeted heart point during the procedure. This catheter is intended for pediatric patients; therefore, the total length in the straight section (see “L”, FIG. 5) ranges between 55 and 65 cm, preferably, 55 cm.

(14) Connected to the first section of the guide catheter, there is a second section 18 comprising a curved portion shaped as a circle section. This portion has a radius (see “R a”, FIG. 5) of 7.5-9 mm (preferably, 9 mm) with an arc (see “b”, FIG. 5) of 180-280° (preferably, 270°). The distance between the tip and the straight part of the catheter without deformations (see “d”, FIG. 5) is 7-15 mm (preferably, 7 mm).

(15) The inner diameter or lumen of the catheter (see “e”, FIG. 5) can range between 1.42-1.65 mm (0.056-0.065 inches) so as to enable a stent-carrying catheter 15 to be advanced inside it (and which are able to expand from 3 mm up to 4 mm as final diameter), preferably, 1.5 mm (0.059 inches). Likewise, the outer diameter of the catheter 16 (see “f”, FIG. 5) can range between 4 (1.35 mm) and 5 “French” (F) (1.67 mm), so as to enable the catheter 16 to go through the small vessels of the newborn and reach the ductus 4, without damaging them, preferably 4 F (1.35 mm).

(16) The guide catheter 16 can be made of any shape-memory polymeric material suitable for human use, so as to allow the catheter to return to its original three-dimensional shape once it has been manipulated and deformed after being inserted in the patient. Furthermore, the polymeric material must be rigid enough to allow the interventionalist to handle and guide it through the vessels until it reaches the ductus arteriosus 4 without damaging the arteries, veins or organs.

(17) While the previously described shape is preferred, the sections of the catheter can be modified as long as the shape and general dimensions of the catheter are close to those described herein and meet the aforementioned specifications.

(18) Detailed Description of the Procedure Used with the Proposed Catheter

(19) The ductus arteriosus angioplasty 4 with stents 15, can be performed according to the conventional angiography procedure, combined with some methods and instruments currently used in medical practice for placing this type of devices. The procedure is performed with the patient under general anesthesia and the preferred route of access is retrograde through the femoral artery. However, the procedure can also be performed with an antegrade approach by the femoral vein, accessing the ascending aorta 5a through the interventricular communication 11 or through the single ventricle 6, when present. The complete procedure is described below, as well as the possible variations of the method. 1. First, the horseshoe-shaped guide catheter 16 is inserted with an angiographic guidewire 19, preferably of 0.89 mm (0.035 inches) through the femoral artery or through the femoral vein up to the aorta 5 and until the catheter's tip 16 has gone beyond the origin of the ductus 4 (FIG. 6.A-1) or is lodged in its proximity (FIG. 6.A-2) on its aortic side 4a. 2. Then, the guidewire 19 is withdrawn from inside the catheter 16, in such a way that the distal end section 18 of the horseshoe-shaped catheter acquires its curved shape and rests on two points of the aorta 5, namely, the aortic wall opposite to the junction between the aorta and the ductus arteriosus 4a, and the adjacent wall to the junction 4a (see FIGS. 6.B-1 and 6.B-2). 3. Slide the catheter 16 upwards in such a way that this movement causes it to bend even more and firmly rest on the two points mentioned above. 4. Slide the horseshoe-shaped catheter 16 downwards (see FIG. 6.C-1) or upwards (see FIG. 6.C-2) so that its tip enters the origin of the ductus arteriosus 4a (see FIG. 6.D). 5. Advance a new floppy guidewire 20, preferably of 0.36 mm (0.014 inch) inside the horseshoe-shaped catheter 16 (see FIG. 7.E), and using the blood flow, make the floppy guidewire travel the total length of the ductus and enter the pulmonary artery 3 until it is firmly attached to a distal pulmonary artery 21 (see FIG. 7.F), thus avoiding its release during the next steps of the procedure. 6. Using the new guidewire 20, advance a catheter 22 carrying stents 15 through the horseshoe-shaped catheter 16 with a preferred final diameter of 3-4 mm (see FIG. 7. G). 7. Expand the stents 15 from the pulmonary distal end of the ductus (distal end, 4b) to the end connected to the aorta 5 (proximal end, 4a) (see FIG. 7.H), until the ENTIRE ductus 4 is covered with stents 15 (see FIG. 7. I). The implanted stents 15 should protrude from the ductus at both ends by about 2-3 mm.

(20) It should be stressed that if any area of the ductus 4 is not covered by stents 15, it can become narrow and occlude the ductus 4, thus requiring a new procedure. Likewise, it should be noted that the ductus arteriosus 4 is very sensitive to handling and may be closed. If the procedure fails on the first attempt, there might very well not be a second opportunity to keep it open.

BIBLIOGRAPHY

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