Kohei Masaki

We aimed to evaluate the role of medical therapy before and after balloon pulmonary angioplasty (BPA) for non‐operable chronic thromboembolic pulmonary hypertension (CTEPH) in the modern management era. This Japanese nationwide, multicenter, prospective observational registry, including 37 centers, analyzed data newly registered from August 2018–December 2023. Pretreatment before BPA was analyzed in patients who were treatment naïve or received medical therapy only at registration ( n = 557). De‐escalation or escalation of medical therapy after BPA was analyzed in patients who underwent BPA ( n = 966). The BPA pretreatment analysis in 557 patients showed that approximately 70% of the patients received medical therapy, of which 18% received combination therapy. Patients who received monotherapy or combination therapy had more severe baseline hemodynamics than those who did not. The 3‐year survival did not significantly differ between the no, mono, and combination pretreatment groups (94%, 98%, and 97%, respectively; p = 0.852). The BPA post‐treatment analysis in 966 patients showed that 20% of patients underwent de‐escalation of medical therapy. Patients with de‐escalation of medical therapy had lower mean pulmonary artery pressure (PAP) (20.9 ± 5.8 vs. 24.1 ± 7.3 mmHg, p < 0.01); however, they had a lower cardiac index at last follow‐up compared to patients without de‐escalation (2.66 ± 0.61 vs. 2.84 ± 0.70 L/min/m ² , p = 0.01). Patients with severe disease tended to undergo pre‐treatment before BPA; however, patient survival did not differ across pretreatment types. De‐escalation of medical therapy after BPA can affect cardiac index. Therefore, de‐escalation or continuation of medical therapy should be carefully considered even after mean PAP normalizes after BPA.

This study demonstrated that chronic treatment with activated factor X (FXa) inhibitor ameliorated NF-κB-IL-6-mediated perivascular inflammation in a rat model with pulmonary arterial hypertension, which is associated with elevated FXa activity. FXa may act on pulmonary arterial smooth muscle cells, inducing cell proliferation and inflammatory response via upregulated PAR₁, thereby contributing to pulmonary vascular remodeling. Understanding the patient-specific pathophysiology is a prerequisite for applying FXa-targeted therapy to the treatment of pulmonary arterial hypertension.

Background: In patients with chronic kidney disease (CKD) on hemodialysis, comorbid pulmonary hypertension (PH) aggravates exercise tolerance and eventually worsens the prognosis. The treatment strategy for pre-capillary PH, including combined pre- and post-capillary PH (Cpc-PH), has not been established. Objectives: This study aimed to evaluate the impact of pulmonary vasodilators on exercise tolerance and pulmonary hemodynamics in patients with CKD on hemodialysis. Methods and Results: The medical records of 393 patients with suspected PH who underwent right heart catheterization were reviewed. Of these, seven patients had isolated pre-capillary PH and end-stage CKD on hemodialysis. Pulmonary vasodilators decreased pulmonary vascular resistance from 5.9 Wood units (interquartile range (IQR), 5.5–7.6) at baseline to 3.1 Wood units (IQR, 2.6–3.3) post-treatment (p = 0.02) as well as increased pulmonary capillary wedge pressure from 10 mmHg (IQR, 7–11) to 11 mmHg (IQR, 8–16) (p = 0.04). Pulmonary vasodilators increased the World Health Organization functional class I or II from 0% to 100% (p = 0.0002) and the 6 min walk distance from 273 m (IQR, 185–365) to 490 m (IQR, 470–550) (p = 0.03). Conclusions: Pulmonary vasodilators for PH in patients with CKD on hemodialysis decrease pulmonary vascular resistance and eventually improve exercise tolerance. Pulmonary vasodilators may help hemodialysis patients with pre-capillary PH, although careful management considering the risk of pulmonary edema is required.

Background: Recent studies have demonstrated that uric acid (UA) enhances arginase activity, resulting in decreased NO in endothelial cells. However, the role of lung UA in pulmonary arterial hypertension (PAH) remains uncertain. We hypothesized that increased lung UA level contributes to the progression of PAH. Methods and Results: In cultured human pulmonary arterial endothelial cells, voltage‐driven urate transporter 1 (URATv1) gene expression was detected, and treatment with UA increased arginase activity. In perfused lung preparations of VEGF receptor blocker (SU5416)/hypoxia/normoxia‐induced PAH model rats, addition of UA induced a greater pressure response than that seen in the control and decreased lung cGMP level. UA‐induced pressor responses were abolished by benzbromarone, a UA transporter inhibitor, or L‐norvaline, an arginase inhibitor. In PAH model rats, induction of hyperuricemia by administering 2% oxonic acid significantly increased lung UA level and induced greater elevation of right ventricular systolic pressure with exacerbation of occlusive neointimal lesions in small pulmonary arteries, compared with nonhyperuricemic PAH rats. Administration of benzbromarone to hyperuricemic PAH rats significantly reduced lung UA levels without changing XOR (xanthine oxidoreductase) activity, and attenuated right ventricular systolic pressure increase and occlusive lesion development. Topiroxostat, a XOR inhibitor, significantly reduced lung XOR activity in PAH rats, with no effects on increase in right ventricular systolic pressure, arterial elastance, and occlusive lesions. XOR‐knockout had no effects on right ventricular systolic pressure increase and arteriolar muscularization in hypoxia‐exposed mice. Conclusions: Increased lung UA per se deteriorated PAH, whereas XOR had little impact. The mechanism of increased lung UA may be a novel therapeutic target for PAH complicated with hyperuricemia.