Pulmonary artery radiofrequency ablation in an acute porcine model of pulmonary arterial hypertension

Abstract Introduction Pulmonary hemodynamics improvement after pulmonary artery denervation (PADN) was demonstrated in PAH. Questions arise regarding PADN perioperative effectiveness and the accuracy of the target nerves damage. The aim of the study was to evaluate whether PADN decreases pulmonary artery pressure (PAP) in acute thromboxane A2 (U46619)–induced PAH, and damages PA perivascular nerve fibers. Materials and methods 10 male Landrace swine (34.7±5.1 kg). In 6 swine acute reversible target mean PAP of 40 mm Hg was induced with synthetic thromboxane A2 infusion (U46619). Control group: 4 swine with PADN. Hemodynamics was assessed throughout the study, PAH modeling was done before and 20 min after PADN (radiofrequency energy, 40 Watts), followed by pathology and immunohistochemical studies. Results The mean number of RF applications was 17.5±3.6. Pulmonary embolism (PE) was observed after PADN in 3 swine with U46619 infusion, which were excluded. There was no differences in mPAP, PVR and U46619 dosage after PADN in PAH model (12.3±3.5 vs 12.1±1 mm Hg, p=0.2; 150.4±48.7 vs 129.2±64.1 dynes s cm–5; p=0.2; 24.9±3.3 vs 22.4±4.1 mcg; p=0.18; respectively). Similar hemodynamic results were observed in the control group after PADN (mPAP; p=0.3; PVR; p=0.58). S100 expression was evident in the majority of RFA PA species and in some species loss in tyrosine hydroxylase and M1 acetylcholine receptors expression was detected with no hemodynamic correlation. Conclusions PADN using an electrophysiological catheter with unipolar energy does not lead to an acute PA perivascular nerve fibers destruction and detectable mPAP changes in U46619-induced PAH. Delayed nerve damage might be attributable to PADN effects observed in previous studies. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Grant from the Ministry of Science and Higher Education of the Russian Federation (agreement #075-15-2020-800).