Durst, Louise A.

Background Right ventricular (RV) maladaptation to elevated pulmonary afterload is the primary determinant of outcomes in pulmonary artery (PA) hypertension; however, the pathobiological mechanisms underlying RV decompensation remain poorly understood. Methods We performed global untargeted metabolomics on plasma from 55 patients who underwent gold‐standard RV‐PA coupling measurements using multibeat pressure volume loop assessment in a single‐center cohort and from 1027 patients with coupling surrogate measurements in a larger multicenter cohort, the PVDOMICS (Pulmonary Vascular Disease Phenomics) study. Age and sex‐adjusted linear regression was performed to identify associations between metabolites and coupling metrics. Additionally, we performed a metabolic flux analysis using gene expression data from RV tissue in an independent cohort of 32 patients. Partial least squares–discriminant analysis was used to identify metabolites and reactions characteristic of the decompensated RV. Results RV‐PA coupling was negatively associated with tricarboxylic acid (TCA) cycle intermediate levels. Specifically, plasma α‐ketoglutarate and fumarate were significantly associated with all coupling metrics in both cohorts. Metabolic flux analysis indicated that decompensated RVs exhibited aberrant TCA cycle activity, including reduced acetyl coenzyme A entry and increased lactate elimination, suggesting a shift from the TCA cycle toward glycolysis at the RV tissue level. Conclusions We identify an association between circulating TCA cycle intermediate levels and RV‐PA uncoupling in 2 independent cohorts, and dysregulated TCA cycle metabolism in decompensated PA hypertension RVs, suggesting that aberrant TCA cycle metabolism could represent a hallmark of RV maladaptation in PA hypertension. Further study of this pathway is warranted to develop novel biomarkers of RV function or RV‐targeted therapies.

AbstractChronic lung disease (CLD) is the second leading cause of pulmonary hypertension (PH) and is associated with significant morbidity and mortality. Although PH associated with CLD (PH‐CLD) leads to impaired health‐related quality of life (HRQOL), there are no validated tools to assess HRQOL in PH‐CLD. The Pulmonary Arterial Hypertension–Symptoms and Impact Questionnaire (PAH‐SYMPACT) is an HRQOL instrument aimed at assessing the symptoms and impact of PH on overall function and well‐being. We performed a single‐center prospective cohort study using PAH‐SYMPACT scores to compare symptoms, exercise capacity and HRQOL in patients with PAH and PH‐CLD. One hundred and twenty‐five patients (99 patients with idiopathic/heritable PAH and 26 with PH‐CLD) completed the PAH‐SYMPACT questionnaire which consists of 22 questions that assess HRQOL across four domains: cardiopulmonary (CP) symptoms, cardiovascular (CV) symptoms, physical impact (PI), and cognitive/emotional (CE) impact. Higher scores indicate worse HRQOL. We compared patients with PAH and PH‐CLD using a Wilcoxon rank sum or chi‐squared test as appropriate. Multivariate linear regression analysis was used to assess the relationship between PH classification and SYMPACT scores. Compared to PAH, patients with PH‐CLD were older, more likely to use oxygen and had worse functional class and exercise capacity. While there was no significant difference between the two groups in CP, CV, or CE domain scores, patients with PH‐CLD had significantly worse PI scores by univariate (1.79 vs. 1.13, p < 0.001) and multivariate analysis (1.61 vs. 1.17, p = 0.02) and overall worse SYMPACT scores (1.19 vs. 0.91, p = 0.03). In conclusion, patients with PH‐CLD have worse HRQOL as assessed by the PAH‐SYMPACT questionnaire versus patients with PAH. Although PAH‐SYMPACT has not been validated in PH‐CLD, the results of this study can guide clinicians in understanding the symptoms and impact of PH‐CLD relative to PAH.

AbstractPulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disease that negatively impacts health‐related quality of life (HRQOL). The PAH‐symptoms and impact (PAH‐SYMPACT) questionnaire is a validated disease‐specific patient‐reported outcome (PRO) instrument that assesses a patient's symptoms and the impact of PAH and its treatment on well‐being. We performed a single‐center prospective cohort study of patients with PAH to determine the feasibility of assessing PROs in clinical practice and to determine the association between PAH‐SYMPACT domains and clinical characteristics and outcomes. One hundred and ten patients completed the 1‐day version of the PAH‐SYMPACT questionnaire which consists of 22 Likert‐scale questions that assess HRQOL across four domains: cardiopulmonary (CP) symptoms, cardiovascular (CV) symptoms, physical impact (PI), and cognitive and emotional (CE) impact. Higher scores indicate worse HRQOL. Patients were predominantly female (n = 86, 78%) with a mean age of 57.8 ± 16.2 years. While several patient characteristics were associated with CP and PI domains, few were associated with CV and CE domains. PI and CE impact scores were associated with recent hospitalizations and mortality and CE impact score was independently associated with an increased risk of death after adjustment for disease severity (hazard ratio: 3.29, 95% confidence interval: 1.56–6.91, p = 0.002). In conclusion, the assessment of PROs in clinical practice using the PAH‐SYMPACT questionnaire is both feasible and valuable. PAH‐SYMPACT scores have independent prognostic value and are not adequately reflected by traditional measures of disease severity. These findings underscore the importance of assessing HRQOL in clinical practice.

Abstract Rationale Prostacyclin-associated leg pain is a potentially debilitating adverse effect of prostacyclin therapy for patients with pulmonary arterial hypertension (PAH). However, to our knowledge, this entity has not been systematically studied. Objectives To characterize the clinical features and metabolic risk factors for prostacyclin-associated leg pain. Methods At one academic medical center, we assembled and analyzed a case series of patients with PAH and prostacyclin-associated leg pain. Measurements and Main Results Over a period of 2 years, we identified 11 patients with PAH and prostacyclin-associated leg pain who agreed to participate in this study. Subjects underwent a standardized clinical evaluation, electrodiagnostic assessment, and serologic screen for metabolic causes of peripheral neuropathy. All 11 patients were female; their mean (SD) age was 50 (±9) years; their median (interquartile range) PAH duration was 56 (20–96) months; and their prostacyclin therapy duration was a median (interquartile range) of 20 (14–36) months. All patients reported leg pain beginning soon after prostacyclin initiation and varying with dose. All described a neuropathic pain in a symmetric, distal, stocking distribution. Neurologic examination revealed a sensory, small-fiber, predominantly peripheral neuropathy in seven (78%) patients. Results of autonomic reflex testing and thermoregulatory sweat testing were abnormal in 82% and 90% of patients, respectively, suggesting small-fiber neuropathy. Serologic evaluation identified a new, previously unrecognized contributor to neuropathy in eight (73%) patients, including vitamin B12 deficiency in six (55%), uncompensated hypothyroidism in three (27%), and diabetes mellitus in one (9%). Conclusions Chronic prostacyclin-associated leg pain is associated with a small-fiber neuropathy. Treatable metabolic contributors (vitamin B12 deficiency, thyroid dysfunction, or diabetes) appear to be common possible “second hits” that may be underrecognized. We recommend screening for possible metabolic contributors in patients who have otherwise unexplained leg pain in the setting of PAH and current or anticipated prostacyclin therapy.

Pulmonary arterial hypertension (PAH) is a chronic, symptomatic, life‐threatening illness; however, it is complex, with variable expression regarding impact on quality of life (QOL). This study investigated attitudes and comfort of physicians regarding palliative care (PC) for patients with PAH and explored potential barriers to PC in PAH. An internet‐based, mixed‐methods survey was distributed to Pulmonary Hypertension Clinicians and Researchers, a professional organization within the Pulmonary Hypertension Association. Only responses from physicians involved in clinical care of patients with PAH were analyzed. Of 355 clinicians/researchers, 79 (22%) returned surveys, including 76 (21%) providers involved in clinical care. Responding physicians were mainly pulmonologists (67%), practiced in university/academic medical centers (89%), had been in practice a mean of 12 ± 7 years, cared for a median of 100 PAH patients per year, and reported a high level of confidence in managing PAH (87%), advanced PAH‐specific pharmacologic interventions (95%), and end‐of‐life care (88%). Smaller proportions were comfortable managing pain (62%) and QOL issues (78%). Most physicians (91%) reported utilizing PC consultation at least once in the prior year, primarily in the setting of end‐of‐life/active dying (59%), hospice referral (46%), or symptomatic dyspnea/impaired QOL (40%). The most frequent reasons for not referring patients to PC included nonapproval by the patient/family (51%) and concern that PC is “giving up hope” (43%). PAH may result in symptoms that impair QOL despite optimal PAH therapy; however, PC awareness and utilization for PAH providers is low. Opportunities may exist to integrate PC into care for PAH patients.

Purpose: Among phosphodiesterase type 5 inhibitors, tadalafil offers clinicians a once-daily alternative to 3 times daily sildenafil for the treatment of pulmonary arterial hypertension (PAH). This study assessed the safety and patient satisfaction with conversion from sildenafil to tadalafil. Methods: In this multicenter, prospective, 6-month study, patients with PAH were instructed to take their last dose of sildenafil in the evening and initiate tadalafil 40 mg/d the next morning. Patients completed the Treatment Satisfaction Questionnaire for Medication at baseline and 30, 90, and 180 days after transition to assess PAH symptoms and patient satisfaction. Safety was assessed on the basis of recorded adverse events (AEs). Results: Of the 35 patients who met the study criteria, 56% were receiving ≥2 PAH therapies. At the time of transition, the sildenafil dose ranged from 40 to 300 mg/d, with 20% of the patients on >20 mg of sildenafil 3 times daily. Transition to tadalafil was generally well tolerated, and the incidence of common AEs, except for myalgia, appeared to decrease over time on tadalafil therapy. Five (14%) patients switched back to sildenafil. A greater percentage of patients were satisfied than were dissatisfied after conversion to tadalafil (55% vs 19% at 90 days), while 26% felt about the same degree of satisfaction. Conversion to tadalafil resulted in significant improvement in patient ratings of therapy convenience. Conclusions: Transition of patients from sildenafil to tadalafil was usually well tolerated, with improved convenience and may enhance treatment satisfaction.