Outcome of mean pulmonary arterial pressure-based intensive treatment for patients with pulmonary arterial hypertension

Comprehensive Risk Assessment in Patients With Pulmonary Arterial Hypertension Referred for Lung Transplantation

BACKGROUND

Whether comprehensive risk assessment predicts post-referral outcome in patients with pulmonary arterial hypertension (PAH) referred for lung transplantation (LT) in Japan is unknown.Methods and Results: We retrospectively analyzed 52 PAH patients referred for LT. Risk status at referral was assessed using 3- and 4-strata models from the 2022 European Society of Cardiology and European Respiratory Society guidelines. The 3-strata model intermediate-risk group was further divided into 2 groups based on the median proportion of low-risk variables (modified risk assessment [MRA]). The primary outcome was post-referral mortality. During follow-up, 9 patients died and 13 patients underwent LT. There was no survival difference among 3-strata model groups. The 4-strata model classified 33, 16, and 3 patients as low intermediate, high intermediate, and high risk, respectively. The 4-strata model identified high-risk patients with a 1-year survival rate of 33%, but did not discriminate survival between the intermediate-risk groups. The MRA classified 15, 28, 8, and 1 patients as low, low intermediate, high intermediate, and high risk, respectively. High intermediate- or high-risk patients had worse survival (P<0.001), with 1- and 3-year survival rates of 64% and 34%, respectively. MRA high intermediate- or high-risk classification was associated with mortality (hazard ratio 12.780; 95% confidence interval 2.583-63.221; P=0.002).

CONCLUSIONS

Patients classified as high intermediate or high risk by the MRA after treatment should be referred for LT.

Should We Change the Target of Therapy in Pulmonary Hypertension?

Despite the evolution of drug therapy in pulmonary arterial hypertension and the more aggressive treatment approach according to the guidelines, patients continue to have unacceptable mortality rates. Furthermore, specific drug therapy alone in chronic thromboembolic pulmonary hypertension also does not seem to have any beneficial impact on survival. As the function of the right ventricle (RV) determines the prognosis of patients with pulmonary hypertension, the treatment strategy should focus on modifying factors involved in RV dysfunction. Although some previous reports demonstrated that the survival of patients with pulmonary hypertension was associated with mPAP, nevertheless, mPAP is still not considered as a target of therapy. There are many examples of effective mPAP lowering with early and aggressive drug therapy in pulmonary arterial hypertension, or with interventions in chronic thromboembolic pulmonary hypertension. This effective mPAP reduction can lead to reverse RV remodeling, and thus, improvement in survival. In this article, the importance of mPAP lowering is stated, as well as why the change of our current strategy and considering mPAP reduction as the target of therapy could make pulmonary hypertension a chronic but not fatal disease.

Efficacy, safety, and pharmacokinetics of inhaled treprostinil in Japanese patients with pulmonary arterial hypertension

Treprostinil is a chemically stable analog of prostacyclin, and inhaled treprostinil was developed to deliver the effects directly to the pulmonary vasculature while minimizing systemic side effects. The objective of the study was to evaluate the efficacy on hemodynamics and exercise capacity, safety, and pharmacokinetics (PK) of inhaled treprostinil in Japanese patients with pulmonary arterial hypertension (PAH). Inhaled treprostinil was administered at three breaths (18 μg)/session four times daily, and the dose was gradually increased to a maximum of nine breaths (54 μg)/session. Endpoints included change in pulmonary vascular resistance index (PVRI) as primary, other efficacy parameters, safety, and PK. Seventeen PAH patients, the majority of whom (76.5%) had been receiving both an endothelin receptor antagonist (ERA) and a phosphodiesterase type-5 (PDE5) inhibitor/soluble guanylate cyclase (sGC) stimulator, received inhaled treprostinil. At Week 12, PVRI statistically decreased by -39.4 ± 25.5% (95% confidence interval: -52.6 to -26.3). The most frequently reported adverse events related to treprostinil were headache, cough, throat irritation, and hot flush. Regarding PK, there were no notable differences in the geometric mean C _max and AUC_last between Japanese and non-Japanese patients. Treatment with inhaled treprostinil using the dosing regimen approved in the United States resulted in significant improvement in hemodynamics, exercise capacity, and symptoms with a favorable tolerability and safety profile in Japanese patients. Inhaled treprostinil could be a valuable therapeutic option for Japanese patients with PAH, including those receiving a combination therapy with an ERA and a PDE5 inhibitor/sGC stimulator. Trial registration: JAPIC Clinical Trials Information [JapicCTI-194651].

Initial Triple Combination Therapy Including Intravenous Prostaglandin I2 for the Treatment of Patients with Severe Pulmonary Arterial Hypertension

Upfront combination therapy including intravenous prostaglandin I₂ (PGI₂-IV) is recognized as the most appropriate treatment for patients with severe pulmonary arterial hypertension (PAH). This retrospective study aimed to determine reasons why this therapy is not used for some patients with severe PAH and describe the hemodynamic and clinical prognoses of patients receiving initial combination treatment with (PGI₂-IV+) or without (PGI₂-IV-) PGI₂-IV.Data for patients with severe PAH (World Health Organization Functional Class III/IV and mean pulmonary arterial pressure [mPAP] ≥ 40 mmHg) were extracted from the Japan Pulmonary Hypertension Registry. Overall, 73 patients were included (PGI₂-IV + n = 17; PGI₂-IV- n = 56). The PGI₂-IV+ cohort was younger than the PGI₂-IV- cohort (33.8 ± 10.6 versus 52.6 ± 18.2 years) and had higher mPAP (58.1 ± 12.9 versus 51.8 ± 9.0 mmHg), greater prevalence of idiopathic PAH (88% versus 32%), and less prevalence of connective tissue disease-associated PAH (0% versus 29%). Hemodynamic measures, including mPAP, showed improvement in both cohorts (post-treatment median [interquartile range] 38.5 [17.0-40.0] for the PGI₂-IV + cohort and 33.0 [25.0-43.0] mmHg for the PGI₂-IV - cohort). Deaths (8/56) and lung transplantation (1/56) occurred only in the PGI₂-IV - cohort.These Japanese registry data indicate that older age, lower mPAP, and non-idiopathic PAH may influence clinicians against using upfront combination therapy including PGI₂-IV for patients with severe PAH. Early combination therapy including PGI₂-IV was associated with improved hemodynamics from baseline, but interpretation is limited by the small sample size.

Functional capacity testing in patients with pulmonary hypertension (PH) using the one-minute sit-to-stand test (1-min STST)

BACKGROUND

The one-minute sit-to-stand-test (1-min STST) is a quick, space saving test to evaluate functional capacity. Exercise testing plays an important role in the long-term follow-up of pulmonary hypertension (PH) patients and is currently evaluated using the six-minute-walk-test (6MWT). The aim of the study was to assess the convergent validity of the 1-min STST in patients with PH and its association with markers of PH severity.

METHODS

We evaluated 106 PH patients with the 1-min-STST and 6MWT and measured cardiorespiratory parameters (heart rate, blood pressure, oxygen saturation) before and after test conduction. N-terminal pro brain-type natriuretic peptide (NT-proBNP), WHO functional class (WHO-FC) and mean pulmonary artery pressure (mPAP) were defined as markers of PH severity.

RESULTS

Strong correlation was found between performances of 1-min STST and 6MWT (r = .711, p < .001), indicating convergent validity. Both tests were inversely associated with NT-proBNP (STST: r = -.405, p < .001; 6MWT: r = -.358, p < .001), WHO-FC (STST: r = -.591, p < .001; 6MWT: r = -.643, p < .001) and mPAP (STST: r = -.280, p < .001; 6MWT: r = -.250, p < .001). Significant changes in cardiorespiratory parameters were observed in both tests (all p < 0.001). Further the post-exercise cardiorespiratory parameters correlated strongly between the 1-min STST and 6MWT (all r ≥ .651, all p < .001).

CONCLUSION

The 1-min STST demonstrated good convergent validity with the 6MWT and was associated with markers of PH severity. Furthermore, both exercise tests caused similar cardiorespiratory responses.

The Paradox of Pulmonary Vascular Resistance: Restoration of Pulmonary Capillary Recruitment as a Sine Qua Non for True Therapeutic Success in Pulmonary Arterial Hypertension

Exercise-induced increases in pulmonary blood flow normally increase pulmonary arterial pressure only minimally, largely due to a reserve of pulmonary capillaries that are available for recruitment to carry the flow. In pulmonary arterial hypertension, due to precapillary arteriolar obstruction, such recruitment is greatly reduced. In exercising pulmonary arterial hypertension patients, pulmonary arterial pressure remains high and may even increase further. Current pulmonary arterial hypertension therapies, acting principally as vasodilators, decrease calculated pulmonary vascular resistance by increasing pulmonary blood flow but have a minimal effect in lowering pulmonary arterial pressure and do not restore significant capillary recruitment. Novel pulmonary arterial hypertension therapies that have mainly antiproliferative properties are being developed to try and diminish proliferative cellular obstruction in precapillary arterioles. If effective, those agents should restore capillary recruitment and, during exercise testing, pulmonary arterial pressure should remain low despite increasing pulmonary blood flow. The effectiveness of every novel therapy for pulmonary arterial hypertension should be evaluated not only at rest, but with measurement of exercise pulmonary hemodynamics during clinical trials.