Mathai, Stephen C.

Our study shows an early increase in kynurenine pathway metabolism in at-risk subjects with systemic sclerosis who develop pulmonary arterial hypertension (PAH). We show that kynurenine pathway upregulation precedes clinical diagnosis and that this metabolic shift is associated with increased disease severity and shorter survival times. We also show that gene expression of TDO2, an enzyme that generates kynurenine from tryptophan, rises with PAH development.

AbstractThe prevalence of acute vasodilator response (AVR) to inhaled nitric oxide (iNO) during right heart catheterization (RHC) is 12% in idiopathic pulmonary arterial hypertension (IPAH). AVR, however, is reportedly lower in other disease‐associated pulmonary arterial hypertension (PAH), such as connective tissue disease (CTD). The prevalence of AVR in patients on PAH therapy (prevalent cases) is unknown. We sought to determine AVR prevalence in Group 1 PH in the PVDOMICS cohort of incident and prevalent patients undergoing RHC. AVR was measured in response to 100% O2 and O2 plus iNO, with positivity defined as (1) decrease in mean pulmonary artery pressure (mPAP) by ≥10 mmHg to a value ≤40 mmHg, with no change or an increase in cardiac output (definition 1); or (2) decrease in mPAP by ≥12% and pulmonary vascular resistance by ≥30% (definition 2). AVR rates and cumulative survival were compared between incident and prevalent patients. In 338 mainly prevalent (86%) patients, positive AVR to O2‐only was <2%, and 5.1% to 16.9%, based on definition 1 and 2 criteria, respectively; following O2 + iNO. IPAH AVR prevalence (4.1%–18.7%) was similar to prior reports. AVR positivity was 7.7% to 15.4% in mostly CTD‐PAH prevalent cases, and 2.6% to 11.8% in other PAH groups. Survival was 89% in AVR responders versus 77% in nonresponders from PAH diagnosis, and 91% versus 86% from PVDOMICS enrollment (log‐rank test p = 0.04 and p = 0.05, respectively). In conclusion, AVR in IPAH patients is similar to prior studies. AVR in non‐IPAH patients was higher than previously reported. The relationship between PAH therapy, AVR response, and survival warrants further investigation.

AbstractChronic thromboembolic pulmonary hypertension (CTEPH) is believed to involve both vascular obstruction and vasoconstriction; hence, pulmonary vasodilators such as riociguat may be beneficial. Acute vasoreactivity testing (AVT) is seldom performed routinely in CTEPH patients, so there is limited understanding of the frequency and significance of an acute vasodilator response. Systematic vasodilator testing with oxygen (O2) and oxygen plus inhaled nitric oxide (O2 + iNO) was performed as part of the Pulmonary Vascular Disease Omics (PVDOMICS) NHLBI project, providing an opportunity to examine AVT responses in CTEPH. Patients with CTEPH enrolled in PVDOMICS (n = 49, 40 with prevalent CTEPH [82%]) underwent right heart catheterization including AVT with O2 and O2 + iNO. Hemodynamics were obtained at baseline and with each challenge. Fourteen of 49 patients (29%) had >20% drop in pulmonary vascular resistance (PVR) with O2. With O2 + iNO, 30/49 (61%) had >20% drop in PVR, 20% had >20% drop in mean pulmonary artery pressure (mPAP) and PVR, and 8% had >10 mmHg decline in mPAP to mPAP < 40 with normal cardiac output. Patients on riociguat had less response to O2 + iNO than patients on phosphodiesterase‐5 inhibitors. Our findings shed light on the significant variability in vascular tone that is present in CTEPH, confirming that CTEPH represents a combination of mechanical obstruction and vasoconstriction that appears similar to that observed with Group 1 PAH. Additional study regarding whether results of acute vasodilator testing predict response to therapy and relate to prognosis is warranted.

Abstract Objectives To establish a framework by which experts define disease subsets in systemic sclerosis associated interstitial lung disease (SSc-ILD). Methods A conceptual framework for subclinical, clinical and progressive ILD was provided to 83 experts, asking them to use the framework and classify actual SSc-ILD patients. Each patient profile was designed to be classified by at least four experts in terms of severity and risk of progression at baseline; progression was based on 1-year follow-up data. A consensus was reached if ≥75% of experts agreed. Experts provided information on which items were important in determining classification. Results Forty-four experts (53%) completed the survey. Consensus was achieved on the dimensions of severity (75%, 60 of 80 profiles), risk of progression (71%, 57 of 80 profiles) and progressive ILD (60%, 24 of 40 profiles). For profiles achieving consensus, most were classified as clinical ILD (92%), low risk (54%) and stable (71%). Severity and disease progression overlapped in terms of framework items that were most influential in classifying patients (forced vital capacity, extent of lung involvement on high resolution chest CT [HRCT]); risk of progression was influenced primarily by disease duration. Conclusions Using our proposed conceptual framework, international experts were able to achieve a consensus on classifying SSc-ILD patients along the dimensions of disease severity, risk of progression and progression over time. Experts rely on similar items when classifying disease severity and progression: a combination of spirometry and gas exchange and quantitative HRCT.

Background Current mortality data for pulmonary arterial hypertension (PAH) in the United States are based on registries that enrolled patients prior to 2010. We sought to determine mortality in PAH in the modern era using the PHAR (Pulmonary Hypertension Association Registry). Methods and Results We identified all adult patients with PAH enrolled in the PHAR between September 2015 and September 2020 (N=935). We used Kaplan‐Meier survival analysis and Cox proportional hazards models to assess mortality at 1, 2, and 3 years. Patients were stratified based on disease severity by 3 validated risk scores. In treatment‐naïve patients, we compared survival based on initial treatment strategy. The median age was 56 years (44–68 years), and 76% were women. Of the 935 patients, 483 (52%) were ≤6 months from PAH diagnosis. There were 121 deaths (12.9%) during a median follow‐up time of 489 days (281–812 days). The 1‐, 2‐, and 3‐year mortality was 8% (95% CI, 6%–10%), 16% (95% CI, 13%–19%), and 21% (95% CI, 17%–25%), respectively. When stratified into low‐, intermediate‐, and high‐risk PAH, the mortality at 1, 2, and 3 years was 1%, 4% to 6%, and 7% to 11% for low risk; 7% to 8%, 11% to 16%, and 18% to 20% for intermediate risk; and 12% to 19%, 22% to 38%, and 28% to 55% for high risk, respectively. In treatment‐naïve patients, initial combination therapy was associated with better 1‐year survival (adjusted hazard ratio, 0.43 [95% CI, 0.19–0.95]; P =0.037). Conclusions Mortality in the intermediate‐ and high‐risk patients with PAH remains unacceptably high in the PHAR, suggesting the importance for early diagnosis, aggressive use of available therapies, and the need for better therapeutics.

AbstractDual combination therapy with a phosphodiesterase‐5 inhibitor (PDE5i) and endothelin receptor antagonist is recommended for most patients with intermediate‐risk pulmonary arterial hypertension (PAH). The RESPITE and REPLACE studies suggest that switching from a PDE5i to a soluble guanylate cyclase (sGC) activator may provide clinical improvement in this situation. The optimal approach to escalation or transition of therapy in this or other scenarios is not well defined. We developed an expert consensus statement on the transition to sGC and other treatment escalations and transitions in PAH using a modified Delphi process. The Delphi process used a panel of 20 physicians with expertise in PAH. Panelists answered three questionnaires on the management of treatment escalations and transitions in PAH. The initial questionnaire included open‐ended questions. Later questionnaires consolidated the responses into statements that panelists rated on a Likert scale from −5 (strongly disagree) to +5 (strongly agree) to determine consensus. The Delphi process produced several consensus recommendations. Escalation should be considered for patients who are at high risk or not achieving treatment goals, by adding an agent from a new class, switching from oral to parenteral prostacyclins, or increasing the dose. Switching to a new class or within a class should be considered if tolerability or other considerations unrelated to efficacy are affecting adherence. Switching from a PDE5i to an SGC activator may benefit patients with intermediate risk who are not improving on their present therapy. These consensus‐based recommendations may be helpful to clinicians and beneficial for patients when evidence‐based guidance is unavailable.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare, morbid, potentially curable subtype of pulmonary hypertension that negatively impacts health‐related quality of life (HRQoL). Little is known about differences in HRQoL and hospitalization between CTEPH patients and idiopathic pulmonary arterial hypertension (IPAH) patients. Using multivariable linear regression and mixed effects models, we examined differences in HRQoL assessed by emPHasis‐10 (E10) and SF‐12 between CTEPH and IPAH patients in the Pulmonary Hypertension Association Registry, a prospective multicenter cohort of patients newly evaluated at a Pulmonary Hypertension Care Center. Multivariable negative binomial regression models were used to estimate incidence rate ratios (IRR) for hospitalization amongst the two groups. We included 461 IPAH patients and 169 CTEPH patients. Twenty‐one percent of CTEPH patients underwent pulmonary thromboendarterectomy (PTE) before the end of follow‐up. At baseline, patients with CTEPH had significantly worse HRQoL (higher E10 scores) (ß 2.83, SE 1.11, p = 0.01); however, differences did not persist over time. CTEPH patients had higher rates of hospitalization (excluding the hospitalization for PTE) compared to IPAH patients after adjusting for age, sex, body mass index, WHO functional class and six‐minute walk distance (IRR 1.66, 95%CI 1.04–2.65, p = 0.03). CTEPH patients who underwent PTE had improved HRQoL as compared to those who were medically managed, but patients who underwent PTE were younger, had higher cardiac outputs and greater six‐minute walk distances. In this large, prospective, multicenter cohort, CTEPH patients had significantly worse baseline HRQoL and higher rates of hospitalizations than those with IPAH. CTEPH patients who underwent PTE had significant improvements in HRQoL.

Compared to idiopathic pulmonary arterial hypertension (IPAH), patients with portopulmonary hypertension (POPH) have worse survival. Health disparities may contribute to these differences but have not been studied. We sought to compare socioeconomic factors in patients with POPH and IPAH and to determine whether socioeconomic status and/or POPH diagnosis were associated with treatment and health‐care utilization. We performed a cross‐sectional study of adults enrolled in the Pulmonary Hypertension Association Registry. Patients with IPAH (n = 344) and POPH (n = 57) were compared. Compared with IPAH, patients with POPH were less likely to be college graduates (19.6% vs. 34.9%, p = 0.02) and more likely to be unemployed (54.7% vs. 30.5%, p < 0.001) and have an annual household income below poverty level (45.7% vs. 19.0%, p < 0.001). Patients with POPH had similar functional class, quality of life, 6‐min walk distance, and mean pulmonary arterial pressure with a higher cardiac index. Compared with IPAH, patients with POPH were less likely to receive combination therapy (46.4% vs. 62.2%, p = 0.03) and endothelin receptor antagonists (28.6% vs. 55.1%, p < 0.001) at enrollment with similar treatment at follow‐up. Patients with POPH had more emergency department visits (1.7 ± 2.1 vs. 0.9 ± 1.2, p = 0.009) and hospitalizations in the six months preceding enrollment (1.5 ± 2.1 vs. 0.8 ± 1.1, p = 0.02). Both POPH diagnosis and lower education level were independently associated with a higher number of emergency department visits. Compared to IPAH, patients with POPH have lower socioeconomic status, are less likely to receive initial combination therapy and endothelin receptor antagonists but have similar treatment at follow‐up, and have increased health‐care utilization.