Anatomical Considerations for the Development of a New Transcatheter Aortopulmonary Shunt Device in Patients with Severe Pulmonary Arterial Hypertension

Abstract

Morbidity from pulmonary arterial hypertension (PAH) ensues when the pulmonary pressure reaches suprasystemic levels. A transcatheter alternative to the Potts shunt would allow decompression of the right heart without the surgical risks. To aid development of a transcatheter aortopulmonary shunt (TAPS) device, we described the anatomic relationship between the left pulmonary artery (LPA) and the descending aorta (dAO) in adults with severe pulmonary hypertension. Adults with severe PAH (peak systolic pulmonary arterial pressure [PASP] ≥80 mmHg) who had computed tomography of the chest were enrolled. Measurements were taken on the axial plane at the level of the pulmonary artery bifurcation. Forty patients (male sex, 9 patients; median age ± standard deviation [SD], 59 AE 15 years; median PASP ± SD, 93 AE 12 mmHg) were identified. The mean distance (±SD) between the LPA and dAO was 2:3 AE 3:1 mm. The mean luminal dAO and LPA diameters (±SD) were 23:4 AE 3:8 mm and 25:5 AE 5:1 mm, respectively. The LPA and dAO approximated in 93% of patients, with 38% having aortic calcification at the contact site. The mean "landing zone" width and height (defining an area with distance <4 mm between the outer borders) of the two arteries were 15:7 AE 3:4 mm and 20:6 AE 4:3 mm, respectively, at a mean distance of 28:0 AE 7:6 mm from the main pulmonary artery bifurcation. This study shows that the landing zone is able to accommodate a TAPS device of up to 15 mm in diameter in the majority of patients with severe PAH.

Vascular anatomy in children with pulmonary hypertension regarding the transcatheter Potts shunt

“…Study on adult patients with severe PAH proposed two types of LPA-DAo arrangement based on the distance and presence of the lung tissue between these vessels 21. Interestingly, in our population, we identified only one patient with a LPA-to-DAo distance exceeding the proposed cut-off value of 4 mm.…”

“…Interestingly, in our population, we identified only one patient with a LPA-to-DAo distance exceeding the proposed cut-off value of 4 mm. Furthermore, we did not encounter any patient with the lung tissue between the LPA and DAo, which was present in 7% of adult population with severe PAH 21. Also, no calcifications of the vessels were found in our paediatric population, compared with 38% of adults who had aortic calcification at the contact site 21.…”

“…Several animal experiments18–20 and first-in-men reports16 17 have demonstrated the feasibility of percutaneous perforation of two adjacent vascular walls and deployment of a stent connecting the vessels. For the planning of the transcatheter Potts shunt creation, the comprehensive characterisation of the vascular anatomy is of paramount importance, and has been recently reported for adults with severe PAH 21. The systematic evaluation of the anatomic aspects of such a procedure in children with idiopathic PAH is presently lacking.…”

Treatment of pulmonary arterial hypertension in children

“…One group of investigators demonstrated the feasibility of a novel, catheter-based technique for creating a connection between the left pulmonary artery and the descending aorta, 124 a manoeuver that is possible in patients with a close anatomical relationship between these two vessels. 125,126 Three of four severely ill patients successfully underwent the intervention; the other patient died during the procedure as a result of uncontrolled haemothorax. 124 One short-term survivor who was critically ill at the time of the procedure later died from comorbidities.…”

Current Concepts in Management of Pulmonary Hypertension: Fighting the Old Demon with Modern Weapons

“…Surgical or interventional placement of a right to left shunt between the left pulmonary artery and the descending aorta (Potts shunt), has been described as a palliative measure in children with pulmonary artery hypertension [40]. Lung or lung-heart transplantation remains the final definitive surgical option [41].…”