Jason S. Fritz

Baseline and follow-up 6-min walk distance and brain natriuretic peptide predict 2-year mortality in pulmonary arterial hypertension.

BACKGROUND Six-minute walk distance (6MWD) and brain natriuretic peptide (BNP) levels at baseline and after initiation of treatment have been associated with survival in patients with pulmonary arterial hypertension. Our objective was to determine the individual and additive ability of pretreatment and posttreatment 6MWD and BNP to discriminate 2-year survival in patients with pulmonary arterial hypertension. METHODS We included patients enrolled in two randomized clinical trials of ambrisentan who had 2-year follow-up (N 5 370). 6MWD and BNP were assessed before and after 12 weeks of treatment. Receiver operating characteristic curve analyses were performed to identify optimal cutoffs that defi ned subgroups with a high 2-year mortality. Classifi cation and regression tree analysis was used to determine the incremental prognostic value of combined assessments. RESULTS 6MWD at baseline and after 12 weeks of therapy were similarly discriminatory of 2-year survival (c-statistics 5 0.77 [95% CI 0.70-0.84] and 0.82 [95% CI 0.75-0.88], respectively), whereas change in 6MWD from baseline to week 12 was not discriminating. The same observation was true of BNP at baseline and after 12 weeks of therapy (c-statistics 5 0.68 [95% CI 0.60-0.76] and 0.74 [95% CI 0.66-0.82], respectively). After consideration of baseline 6MWD, there was no prognostic information added by the week 12 6MWD or BNP at either time point. CONCLUSIONS 6MWD and BNP values at baseline or week 12 identifi ed a population with an elevated risk of death at 2 years. A repeat assessment of 6MWD or BNP after 12 weeks of ambrisentan therapy did not provide additional prognostic information beyond that obtained from baseline values.

Pulmonary Vascular Complications of Liver Disease

Hepatopulmonary syndrome and portopulmonary hypertension are two pulmonary vascular complications of liver disease. The pathophysiology underlying each disorder is distinct, but patients with either condition may be limited by dyspnea. A careful evaluation of concomitant symptoms, the physical examination, pulmonary function testing and arterial blood gas analysis, and echocardiographic, imaging, and hemodynamic studies is crucial to establishing (and distinguishing) these diagnoses. Our understanding of the pathobiology, natural history, and treatment of these disorders has advanced considerably over the past decade; however, the presence of either still increases the risk of morbidity and mortality in patients with underlying liver disease. There is no effective medical treatment for hepatopulmonary syndrome. Although liver transplantation can resolve hepatopulmonary syndrome, there appears to be worse survival even with transplantation. Liver transplantation poses a very high risk of death in those with significant portopulmonary hypertension, where targeted medical therapies may improve functional status and allow successful transplantation in a small number of select patients.

Higher Estradiol and Lower Dehydroepiandrosterone-Sulfate Levels Are Associated with Pulmonary Arterial Hypertension in Men.

RATIONALE Recent studies have focused on the role of female sex and estradiol (E2) in pulmonary arterial hypertension (PAH), but it is not known whether sex hormones are risk factors for PAH in men. OBJECTIVES We performed a case-control study to determine whether hormone levels (E2, dehydroepiandrosterone-sulfate [DHEA-S], and testosterone) are associated with PAH in men. METHODS Plasma sex hormone levels in men with idiopathic, heritable, or connective tissue disease-associated PAH were compared with those from age- and body mass index-matched men without clinical cardiovascular disease. MEASUREMENTS AND MAIN RESULTS There were 23 cases with PAH (70% had idiopathic PAH, 65% were functional class III/IV) and 67 control subjects. Higher E2 and E2/testosterone levels were associated with the risk of PAH (odds ratio per 1 ln[E2:testosterone], 6.0; 95% confidence interval, 2.2-16.4; P = 0.001), whereas higher levels of DHEA-S were associated with a reduced risk (odds ratio per 1 ln[DHEA-S], 0.1; 95% confidence interval, 0.0-0.3; P = 0.001). E2 and DHEA-S levels were strong predictors of case status (C statistic for both, 0.82) but testosterone was not (C statistic, 0.53). Higher levels of E2 were associated with shorter 6-minute-walk distances (P = 0.03), whereas higher levels of DHEA-S were associated with lower right atrial pressure (P = 0.02) and pulmonary vascular resistance (P = 0.01) in men with PAH. CONCLUSIONS Higher levels of E2 and lower levels of DHEA-S were associated with PAH in men. Sex-based differences in sex hormone processing and signaling may contribute to unique phenotypes in pulmonary vascular disease.

Endothelial Krüppel-Like Factor 4 Modulates Pulmonary Arterial Hypertension

Krüppel-like factor 4 (KLF4) is a transcription factor expressed in the vascular endothelium, where it promotes anti-inflammatory and anticoagulant states, and increases endothelial nitric oxide synthase expression. We examined the role of endothelial KLF4 in pulmonary arterial (PA) hypertension (PAH). Mice with endothelial KLF4 knockdown were exposed to hypoxia for 3 weeks, followed by measurement of right ventricular and PA pressures, pulmonary vascular muscularization, and right ventricular hypertrophy. The effect of KLF4 on target gene expression was assessed in lungs from these mice, verified in vitro by small interfering RNA (siRNA) knockdown of KLF4, and further studied at the promoter level with cotransfection experiments. KLF4 expression was measured in lung tissue from patients with PAH and normal control subjects. We found that, after hypoxia, right ventricular and PA pressures were significantly higher in KLF4 knockdown animals than controls. Knockdown animals also had more severe pulmonary vascular muscularization and right ventricular hypertrophy. KLF4 knockdown resulted in increased pulmonary expression of endothelin-1 and decreased expression of endothelial nitric oxide synthase, endothelin receptor subtype B, and prostacyclin synthase. Concordant findings were observed in vitro, both with siRNA knockdown of KLF4 and promoter activity assays. Finally, KLF4 expression was reduced in lungs from patients with PAH. In conclusion, endothelial KLF4 regulates the transcription of genes involved in key pathways implicated in PAH, and its loss exacerbates pulmonary hypertension in response to chronic hypoxia in mice. These results introduce a novel transcriptional modulator of PAH, with the potential of becoming a new therapeutic target.

Anastrozole in Pulmonary Arterial Hypertension. A Randomized, Double-Blind, Placebo-controlled Trial.

Rationale: The aromatase inhibitor anastrozole blocks the conversion of androgens to estrogen and blunts pulmonary hypertension in animals, but its efficacy in treating patients with pulmonary arterial hypertension (PAH) is unknown. Objectives: We aimed to determine the safety and efficacy of anastrozole in PAH. Methods: We performed a randomized, double‐blind, placebo‐controlled trial of anastrozole in patients with PAH who received background therapy at two centers. Measurements and Main Results: A total of 18 patients with PAH were randomized to anastrozole 1 mg or matching placebo in a 2:1 ratio. The two co‐primary outcomes were percent change from baseline in 17&bgr;‐estradiol levels (E2) and tricuspid annular plane systolic excursion (TAPSE) at 3 months. Anastrozole significantly reduced E2 levels compared with placebo (percent change: −40%; interquartile range [IQR], −61 to −26% vs. −4%; IQR, −14 to +4%; P = 0.003), but there was no difference in TAPSE. Anastrozole significantly increased the 6‐minute‐walk distance (median change = +26 m) compared with placebo (median change = −12 m) (median percent change: anastrozole group, 8%; IQR, 2 to 17% vs. placebo −2%; IQR, −7 to +1%; P = 0.042). Anastrozole had no effect on circulating biomarkers, functional class, or health‐related quality of life. There was no difference in adverse events. Conclusions: Anastrozole significantly reduced E2 levels in patients with PAH but had no effect on TAPSE. Anastrozole was safe, well tolerated, and improved 6‐minute‐walk distance in this small “proof‐of‐principle” study. Larger and longer phase II clinical trials of anastrozole may be warranted in patients with PAH. Clinical trial registered with www.clinicaltrials.gov (NCT 1545336).

Are Hemodynamics Surrogate End Points in Pulmonary Arterial Hypertension

Background— Although frequently assessed in trials and clinical practice, hemodynamic response to therapy has never been validated as a surrogate end point for clinical events in pulmonary arterial hypertension (PAH). Methods and Results— We performed a patient-level pooled analysis of 4 randomized, placebo-controlled trials to determine whether treatment-induced changes in hemodynamic values at 12 weeks accounted for the relationship between treatment assignment and the probability of early clinical events (death, lung transplantation, atrial septostomy, PAH hospitalization, withdrawal for clinical worsening, or escalation in PAH therapy). We included 1119 subjects with PAH. The median (interquartile range) age was 48 years (37–59 years), and 23% were men. A total of 656 patients (59%) received active therapy (101 [15%] iloprost, 118 [18%] sitaxsentan, 204 [31%] sildenafil, and 233 [36%] subcutaneous treprostinil). Active treatment significantly lowered right atrial pressure, mean pulmonary artery pressure, and pulmonary vascular resistance and increased cardiac output and index (P<0.01 for all). Changes in hemodynamic values (except for right atrial pressure and mean pulmonary artery pressure) were significantly associated with the risk of a clinical event (P<0.02 for all). Although active treatment approximately halved the odds of a clinical event compared with placebo (P<0.001), changes in hemodynamics accounted for only 1.2% to 13.9% of the overall treatment effect. Conclusions— Treatment-induced changes in hemodynamics at 12 weeks only partially explain the impact of therapy on the probability of early clinical events in PAH. These findings suggest that resting hemodynamics are not valid surrogate end points for short-term events in PAH clinical trials.

Are Hemodynamics Surrogate Endpoints in Pulmonary Arterial Hypertension

Background— Although frequently assessed in trials and clinical practice, hemodynamic response to therapy has never been validated as a surrogate end point for clinical events in pulmonary arterial hypertension (PAH). Methods and Results— We performed a patient-level pooled analysis of 4 randomized, placebo-controlled trials to determine whether treatment-induced changes in hemodynamic values at 12 weeks accounted for the relationship between treatment assignment and the probability of early clinical events (death, lung transplantation, atrial septostomy, PAH hospitalization, withdrawal for clinical worsening, or escalation in PAH therapy). We included 1119 subjects with PAH. The median (interquartile range) age was 48 years (37–59 years), and 23% were men. A total of 656 patients (59%) received active therapy (101 [15%] iloprost, 118 [18%] sitaxsentan, 204 [31%] sildenafil, and 233 [36%] subcutaneous treprostinil). Active treatment significantly lowered right atrial pressure, mean pulmonary artery pressure, and pulmonary vascular resistance and increased cardiac output and index (P<0.01 for all). Changes in hemodynamic values (except for right atrial pressure and mean pulmonary artery pressure) were significantly associated with the risk of a clinical event (P<0.02 for all). Although active treatment approximately halved the odds of a clinical event compared with placebo (P<0.001), changes in hemodynamics accounted for only 1.2% to 13.9% of the overall treatment effect. Conclusions— Treatment-induced changes in hemodynamics at 12 weeks only partially explain the impact of therapy on the probability of early clinical events in PAH. These findings suggest that resting hemodynamics are not valid surrogate end points for short-term events in PAH clinical trials.

Lower DHEA-S levels predict disease and worse outcomes in post-menopausal women with idiopathic, connective tissue disease- and congenital heart disease-associated pulmonary arterial hypertension

High oestradiol (E2) and low dehydroepiandrosterone-sulfate (DHEA-S) levels are risk factors for pulmonary arterial hypertension (PAH) in men, but whether sex hormones are related to PAH in women is unknown. Post-menopausal women aged ≥55 years with PAH were matched by age and body mass index to women without cardiovascular disease. Plasma sex hormone levels were measured by immunoassay. Lower levels of DHEA-S (p<0.001) and higher levels of E2 (p=0.02) were associated with PAH. In PAH cases (n=112), lower DHEA-S levels were associated with worse haemodynamics (all p<0.01) and more right ventricular dilatation and dysfunction (both p=0.001). Lower DHEA-S levels were associated with shorter 6-min walking distance (6MWD) (p=0.01) and worse functional class (p=0.004). Each Ln(1 µg·dL−1) decrease in DHEA-S was associated with a doubling in the risk of death (hazard ratio 2.0, 95% CI 1.5–2.7; p<0.001). Higher levels of E2 were associated with shorter 6MWD (p=0.03) and worse functional class (p=0.01). High E2 and low DHEA-S levels are associated with the risk and severity of PAH in post-menopausal women. Hormonal modulation should be studied as a treatment strategy in PAH. Lower levels of DHEA-S predict risk of disease, clinical severity and death in post-menopausal women with PAH http://ow.ly/jo6e30jOFni

Slow-paced respiration therapy to treat symptoms in pulmonary arterial hypertension

Objective To determine the feasibility of using slow‐paced respiration therapy to treat symptoms in women with pulmonary arterial hypertension (PAH). Background People with PAH report increased dyspnea, fatigue and sleep disturbance that can impair health‐related quality of life (HRQOL). Methods Ten women with PAH received 8‐weeks of daily, 15 min sessions using slow‐paced respiration therapy via the RESPeRATE™ device. Participants had baseline and follow up assessments including plasma norepinephrine and interleukin‐6 (IL‐6), self‐report questionnaires to measure dyspnea, fatigue, depressive symptoms, sleep and HRQOL along with 7‐day actigraphy and sleep diaries. Results The mean age was 50 years. Adherence to the intervention was 92%. There was decrease in median IL‐6 levels [1.3 ± 0.5 to 1.1 ± 0.4, 95% CI (0.03–0.43)] over the study period. Sleep disturbance decreased, depressive symptoms decreased and HRQOL scores decreased (higher scores indicate worse HRQOL). Conclusions In this pilot study, slow‐paced respiration therapy is feasible in patients with PAH and may improve symptoms and lower IL‐6. HighlightsA pilot study of 10 women there was 100% retention and high adherence to the 8‐week slow‐paced respiration therapy intervention.Slow‐paced respiration therapy was associated with reduced plasma IL‐6 levels and no serious adverse events occurred.Preliminary results suggest decreased wake after sleep onset, increased sleep efficiency and increased total sleep time.Depressive symptoms decreased and HRQOL scores decreased (higher HRQOL scores indicate worse HRQOL.

SAFETY AND TOLERABILITY OF TRANSITION FROM INHALED TREPROSTINIL TO ORAL SELEXIPAG IN PULMONARY ARTERIAL HYPERTENSION: RESULTS FROM THE TRANSIT-1 STUDY

BACKGROUND A long-term trial showed that the oral prostacyclin (PGl2) receptor (IP) agonist, selexipag, delayed disease progression in patients with pulmonary arterial hypertension (PAH). Transition to selexipag in patients treated with more burdensome inhaled therapies that target the prostacyclin pathway may be considered by patients and physicians. The Phase 3b, prospective, open-label TRANSIT-1 (Tolerability and Safety of the Transition From Inhaled Treprostinil to Oral Selexipag in Patients With Pulmonary Arterial Hypertension) study evaluated the safety and tolerability of transition from inhaled treprostinil to oral selexipag. METHODS Patients receiving non-prostanoid oral PAH therapy and inhaled treprostinil at stable doses, in World Health Organization Functional Class II/III, with 6-minute walk distance ≥ 300 meters were enrolled. The 16-week main treatment period included downtitration of inhaled treprostinil over 8 weeks and parallel uptitration of selexipag over 12 weeks. Sustained treatment transition at Week 16 was defined as (1) receiving selexipag at Week 16; (2) no selexipag interruption(s) totaling ≥ 8 days; and (3) no inhaled treprostinil or other prostanoids after Week 8. Clinical parameters and patient-reported treatment satisfaction outcomes were assessed at Week 16. RESULTS All 34 enrolled patients completed the study. At Week 16, 32 patients (94.1%) had stopped inhaled treprostinil and were receiving selexipag. Twenty-eight patients (82.4%) met all criteria for sustained treatment transition. During the study, 3 patients discontinued selexipag due to adverse events. Overall, most adverse events were typical of prostanoid therapies and started during the uptitration phase. In general, patients remained clinically stable throughout treatment and reported improved convenience. CONCLUSIONS Transition to oral selexipag from inhaled treprostinil in PAH patients was successful and well tolerated in most patients, and associated with greater convenience. CLINICAL TRIAL NUMBER NCT02471183.