First in-human modified atrial septostomy combining radiofrequency ablation and balloon dilation

Abstract

Objective: Preclinical research suggests that the combined use of radiofrequency ablation and balloon dilation (CURB) could create stable interatrial communications without device implantation. This study examined the first in-human use of CURB for modified atrial septostomy in patients with severe pulmonary arterial hypertension (PAH).

Methods: Between July 2018 and October 2021, CURB was performed in 19 patients with severe PAH (age: 31.5±9.1 years; mean pulmonary artery pressure: 73 mm Hg (IQR: 66-92); pulmonary vascular resistance: 18.7 Wood units (IQR: 17.8-23.3)). Under guidance of intracardiac echocardiography and three-dimensional location system, (1) fossae ovalis was reconstructed and ablated point-by-point with radiofrequency; (2) then graded balloon dilation was performed after transseptal puncture and the optimal size was determined according to the level of arterial oxygen saturation (SatO2); (3) radiofrequency ablation was repeated around the rims of the created fenestration. The interatrial fenestrations were followed-up serially.

Results: After CURB, the immediate fenestration size was 4.4 mm (IQR: 4.1-5.1) with intracardiac echocardiography, systolic aortic pressure increased by 10.2±6.9 mm Hg, cardiac index increased by 0.7±0.3 L/min/m2 and room-air resting SatO2 decreased by 6.2±1.9% (p<0.001). One patient experienced increased pericardiac effusion postoperatively; the others had no complications. On follow-up (median: 15.5 months), all interatrial communications were patent with stable size (intraclass correlation coefficient=0.96, 95%CI:0.89 to 0.99). The WHO functional class increased by 1 (IQR: 1-2) (p<0.001) with improvement of exercise capacity (+159.5 m, P<0.001).

Conclusion: The interatrial communications created with CURB in patients with severe PAH were stable and the mid-term outcomes were satisfactory.

Trial registration number: NCT03554330.

Keywords: Ablation Techniques; Cardiac Catheterization; Endovascular Procedures; Hypertension, Pulmonary.

Conflict of interest statement

Competing interests: None declared.

© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Figures

Figure 1

Modified atrial septostomy with combined use of radiofrequency ablation and balloon dilation (CURB). Under the guidance of intracardiac echocardiography (left panel) and a three-dimensional location system (right panel), the fossae ovalis was delineated and reconstructed. On the region of the fossae ovalis, radiofrequency catheter ablation (RFA) was conducted point-by-point to reduce the elastic recoil of local tissue and facilitate transseptal puncture and balloon dilation. After transseptal puncture, graded balloon dilation was performed. RFA was repeated around the rims of the created fenestration to cause irreversible damage and prevent spontaneous closure. Finally, the interatrial created fenestration was evaluated with intracardiac echocardiography.

Figure 2

Accurate transseptal puncture assisted with intracardiac echocardiography. The accurate transseptal puncture site and position of the long sheath were confirmed with intracardiac echocardiography (upper left panel) and a three-dimensional location system (upper right panel). The exact location of the interatrial communication (arrow) was demonstrated with transthoracic Doppler echocardiography (lower panels). The fenestration size was 5.1 mm with continuous shunting from right to left (1 year after the procedure).

Figure 3

Aortic pressure before and after combined use of radiofrequency ablation and balloon dilation (CURB). An appropriate interatrial communication was created successfully with CURB, and a right-to-left shunt was detected (left panel, before CURB; right panel, after CURB). The immediate systolic aortic pressure increased from 99 to 106 mm Hg, and there was no significant change in the mean right atrial pressure. Furthermore, the symptoms improved immediately. AO, aorta; RA, right atrium.

Figure 4

Follow-up with transthoracic Doppler echocardiograghy. During follow-up, the interatrial communication (arrows) was patent with a right-to-left shunt. The interatrial fenestration was 4.80 mm at 1 week, 4.86 mm at 3 months, 4.90 mm at 9 months and 4.80 mm at 1.5 years.

Figure 5

Serial follow-up of fenestration size. All interatrial communications were patent and the fenestration size was stable (within 1 week, at 1–3 months, at 3–12 months and at more than 12 months; intraclass correlation coefficient (ICC)=0.96). ICC (two-way mixed with absolute agreement) was used to assess the concordance across the four visits, and the ICCs between the fenestration-size within 1 week and other phases were also calculated.

Figure 6

Follow-up with multi-slice CT. Before combined use of radiofrequency ablation and balloon dilation (CURB) (A), the right atrium and right ventricle were greatly enlarged with a concurrent opposite change in the markedly diminished left atrium and left ventricle. At (B) 3 months after CURB and (C) 1 year after CURB, the sizes of right atrium and right ventricle were alleviated with the increase of the left atrium and left ventricle. The interatrial fenestration (arrows) was patent and approximately oval. It was 10.6 mm × 4.8 mm (D). The reconstructed image is based on the 3month multi-slice CT results and the maximum balloon size was 12 mm in this patient.