Improvised bespoke technique for atrial septostomy in the shortage of atrioseptostomy balloon catheters

Abstract

Atrioseptostomy balloon catheter is an essential item to have on our shelves. However, the recall and shortage in production of the commonly used balloon atrioseptostomy catheters posed an imminent threat to our patients. Herein, we present the case of a newborn with a post-natal diagnosis of simple transposition of great arteries and restrictive atrial communication where repeated static balloon atrial septostomy using a 9 mm x 20 mm Sterling balloon failed to improve his status. We had to improvise per-operatively a new bespoke technique to perform a vital pull-through balloon atrial septostomy. The distal third of a 10 mm x 20 mm semi-compliant Cristal balloon was exteriorised out the tip of a 6-Fr 55 cm Cook Flexor sheath in the left atrium, and both were simultaneously pulled back to the right atrium to create an 8 mm septal defect. The procedure was successful without any complications. The baby was weaned off prostaglandin on day 3 and surgically repaired on day 5 with excellent results.

Since it was first reported more than 55 years ago, balloon atrial septostomy remains an essential catheterisation procedure for congenital heart lesions.^1,2 It was such a well-established intervention that new dedicated devices were rarely developed, and the most recent Z-5 septostomy catheter has been on the market for more than 25 years.³ However, the recall of Miller and Fogarty balloon atrioseptostomy catheters (Edwards Lifesciences, USA) in 2019, followed by Rashkind catheters (Medtronic, USA) in 2020, and recently the Z-5 septostomy catheters has dramatically changed the situation.⁴ The Z-6™ atrioseptostomy catheter (NuMED, USA) is the only available alternative worldwide, and the demand on stock supply increased dramatically. Consequently, many centres fell into a critical shortage of standard balloon atrial septostomy catheters. Recently, we found ourselves in an unusual critical situation where the last available atrioseptostomy catheter was utilised and the new supply has not yet arrived. Herein, we report an improvised bespoke technique for atrial septostomy to save the life of a newborn with a post-natal diagnosis of simple transposition of great arteries and restrictive atrial communication.

Case presentation

A term baby (3.5 Kg/50 cm) was born in a peripheral hospital with severe refractory cyanosis. A quick work-up in the neonatal ICU revealed a post-natal diagnosis of simple transposition of great arteries and restrictive atrial communication. The baby was intubated, ventilated, and transferred to our institution as a time-critical emergency. On arrival, her oxygen saturation was 61% on 100% of fraction of inspired oxygen. Blood gas showed a pH of 7.10, serum lactates of 7.2 mmol/L, and base excess of -11 mmol. Ultrasound assessment showed a 2 mm foramen ovale generating a mean gradient of 9 mmHg.

We had an unusual situation in our department because we did not have an atrioseptostomy balloon catheter available in our armamentarium. The last available septostomy catheter was used the week before, and the manufacturer was contacted directly for urgent supply. Tremendous efforts were made to ship three items from the USA, but the baby was born before restocking. We decided to first attempt a static balloon enlargement of the atrial communication. A 6-Fr right femoral vein was obtained under ultrasound guidance. Intravenous heparin (100 UI/kg) was given, and activated clotting time was monitored. Under biplane fluoroscopic fluoroscopy and transthoracic ultrasound guidance, we manage to cross the foramen ovale with a 4-Fr Judkins right coronary catheter (Cordis Corp., USA) and a 0.014-inch Balance Middleweight coronary wire (Abbott, USA). The wire was parked in the left lower pulmonary vein, and a 9 mm x 20 mm Sterling balloon (Boston Scientific, USA) was inflated to the nominal pressure with a clear waist resolution. The manoeuvre was repeated twice. However, there was no change in the size of the atrial communication after balloon deflation.

On the bench-side, we improvised a bespoke pull-through balloon atrial septostomy using a 6-Fr/55 cm Flexor sheath (Cook Medical, USA) and a 10 x 20 mm Cristal semi-compliant balloon (Boston Scientific, USA). The distal third of the balloon was exteriorised out of the long sheath, and the balloon was inflated to nominal pressure (Fig. 1). Meanwhile, we applied some pulling to the proximal shaft of the balloon while fixing the delivery sheath simultaneously, to prevent the balloon milking. This technique gave us an onion-shape shorter balloon inflated up to a 10 mm width and supported with a long sheath. We then mimicked a sudden pullback, deflated the balloon, and tried to pull it back inside the sheath. The non-uniform inflation of the balloon left a ragged waist that prevented the pullback of the balloon. We pushed the balloon completely out of the sheath, inflated it, and deflated it again. This manoeuvre unified the shape of the balloon, and it was easy to pull it back inside the sheath.

Figure 1. Bench-side preparation and testing of the improvised bespoke balloon atrial septostomy using a 10 mm x 20 mm Cristal balloon (white pointed arrow) and a 6-Fr 55 cm Cook Flexor sheath (black pointed arrow).

After trying this technique on the bench, we placed two 0.014-inch Balance Middleweight wires in the lower left and upper right pulmonary veins (Fig. 2). We exchanged the short introducer with the Flexor sheath and used the wires to drive the tip of the long sheath into the left atrium. We advanced the 10 mm x 20 mm Cristal balloon over the two wires and exposed its distal third out of the long sheath (Fig. 2). Under biplane fluoroscopy and ultrasound guidance, we inflated the balloon to nominal pressure with 20% contrast-80% saline fluid and locked the 3-way Stopcock to the balloon lumen. One operator held both wires in place. The other operator used his left hand to hold the long sheath and his right hand to hold the balloon catheter with slight backward traction. He then pulled the balloon catheter and the long sheath together simultaneously as one unit to mimic the sudden and short move we do routinely in the atrial balloon septostomy manoeuvre (Vid. 1). We had a similar feeling of rupturing the atrial septum. This manoeuvre was done twice to ensure the creation of adequate atrial septal defect (Vid. 2). As planned, the system was retrieved towards the inferior caval vein, and the balloon was completely exteriorised, inflated, and then deflated to be easily recaptured inside the sheath and both withdrawn out of the patient (Vid. 3). We paid extra attention to the pulmonary veins, mitral valve, roof of the left atrium, and pericardial effusion. The procedure was successful without any complications. The oxygen saturation improved to 90%. The pH normalised within 10 hours. The post-operative ultrasound showed normal pulmonary veins flow, no mitral regurgitation, no pericardial effusion, and an 8 mm septal defect with a 1 mmHg gradient. The baby was weaned off prostaglandin on day 3 and surgically repaired on day 5 with excellent results.

Figure 2. Anteroposterior (A) and lateral (B) fluoroscopic views of improvised bespoke balloon atrial septostomy positioned into the left atrium. Note the two 0.014-inch Balance Middleweight wires in the lower left and upper right pulmonary veins (white stars) over which the distal third of a 10 mm x 20 mm semi-compliant Cristal balloon (white pointed arrow) is exteriorised out the tip of a 6-Fr 55 cm Cook Flexor sheath (black pointed arrow).

Discussion

Since Rashkind and Miller described the balloon atrial septostomy, other techniques were subsequently developed.^1,2 All reported methods have advantages and disadvantages, but some of them are more frequently associated with complications and are practically limited to certain categories of patients.² For all cases, balloon septostomy should be initially discussed. If difficulties are to be encountered or the child is older than 6-8 weeks and has thickened septum, static balloon atrial dilation and cutting balloon or blade septostomy should be considered.^2,5,6

Here, we report and describe an improvised technique for rescue atrioseptostomy, in unusual circumstances, where the FDA-approved atrioseptostomy balloon catheters were not available in our institution due to international shortage. It can be debated that static atrial septostomy using a 9 mm balloon for a 3.5 kg term baby is too small. According to a recent nationwide survey by K. Baba, et al. on static atrial septostomy in Japan, the most frequently used balloon diameter in newborns is 10 mm followed by 12 mm.⁴ Yet, the most frequently used balloon in this survey was the TMP-Ped valvuloplasty balloon catheter. In our case, we used a Sterling balloon which is a much stiffer angioplasty balloon and we managed to fully dilate the atrial communication with a clear resolution of the balloon waist. However, the atrial septum was elastic and the recoil was important after balloon deflation. Therefore, we thought that upsizing to a larger balloon would have not made any difference in our patient.^5,6 Atrial ballooning cannot create a communication larger than the fossa ovalis because it only pushes away the septum primum membrane.⁷ He needed a Rashkind atrioseptostomy to dislocate the membrane and achieve the intended outcomes. The applied bespoke technique is not a replacement for the standard low-profile atrioseptostomy balloons. In fact, we acknowledge the importance of having those items in every catheterisation laboratory but also understand the pressure on the industry to provide this specific device. Nowadays, Z-6™ atrioseptostomy catheter (NuMED, USA) is the only available worldwide alternative with two 9.5 mm (1cc) and 13.5 mm (2cc) balloon sizes. It leverages the same proven materials used in the production of the Z-5™ but has been enhanced based on input from interventional paediatric cardiologists. Improvements include a short distal tip for improved balloon rewrapping, and the catheter body is radiopaque to facilitate reliable positioning of the catheter. Besides, it also appears that Edwards Lifesciences has started again the production of their Fogarty balloon catheters.

The creation or dilatation of an atrial communication is a risky procedure and therefore should be performed only by highly trained congenital cardiologists with expertise in interventional therapy.⁸ We performed the procedure in a well-prepared biplane catheterisation laboratory, with the possibility of surgical or circulatory backup. We tested our bespoke device on the bench to get familiar with the technique before going in vivo. We used a semi-compliant balloon to reduce the risk of balloon rupture, but we are aware that this is a risk, especially in cases where the atrial septum is rather thick than membranous. We also understand the posing risks on the left atrial roof, pulmonary veins, and mitral valve providing the longer distal tip between the end of the balloon catheter shaft and balloon shoulder. This may be a real challenge in small left atriums.

Conclusion

We report an improvised bespoke life-saving technique for atrial septostomy in the absence of atrioseptostomy balloon catheters. Despite technical difficulties and procedural risks, this technique was performed safely with excellent post-operative outcomes.