Predicting Survival in Patients With Pulmonary Arterial Hypertension: The REVEAL Risk Score Calculator 2.0 and Comparison With ESC/ERS-Based Risk Assessment Strategies.

BACKGROUND: Pulmonary arterial hypertension is a progressive, fatal disease. Published treatment guidelines recommend treatment escalation on the basis of regular patient assessment with the goal of achieving or maintaining low-risk status. Various strategies are available to determine risk status. This analysis describes an update of the Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL) risk calculator (REVEAL 2.0) and compares it with recently published European Society of Cardiology/Respiratory Society guideline-derived risk assessment strategies. METHODS: A subpopulation from the US-based registry REVEAL that survived ≥ 1 year postenrollment (baseline for this cohort) was analyzed. For REVEAL 2.0, point values and cutpoints were reassessed, and new variables were evaluated. The Kaplan-Meier method was used to estimate survival at 12 months postbaseline; discrimination was quantified using the c-statistic. Mortality estimates and discrimination were compared between REVEAL 2.0 and Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA) and French Pulmonary Hypertension Registry (FPHR) risk assessment strategies. For this comparison, a three-category REVEAL 2.0 score was computed in which patients were classified as low-, intermediate-, or high-risk. RESULTS: REVEAL 2.0 demonstrated similar discrimination as the original calculator in this subpopulation (c-statistic = 0.76 vs 0.74), provided excellent separation of risk among the risk categories, and predicted clinical worsening as well as mortality in patients who were followed ≥ 1 year. The REVEAL 2.0 three-category score had greater discrimination (c-statistic = 0.73) than COMPERA (c-statistic = 0.62) or FPHR (c-statistic = 0.64). Compared with REVEAL 2.0, COMPERA and FPHR both underestimated and overestimated risk. CONCLUSIONS: REVEAL 2.0 demonstrates greater risk discrimination than the COMPERA and FPHR risk assessment strategies in patients enrolled in REVEAL. After external validation, the REVEAL 2.0 calculator can assist clinicians and patients in making informed treatment decisions on the basis of individual risk profiles. TRIAL REGISTRY: ClinicalTrials.gov; No. NCT00370214; URL: www.clinicaltrials.gov.

Clinical trial design and new therapies for pulmonary arterial hypertension.

Until 20 years ago the treatment of pulmonary arterial hypertension (PAH) was based on case reports and small series, and was largely ineffectual. As a deeper understanding of the pathogenesis and pathophysiology of PAH evolved over the subsequent two decades, coupled with epidemiological studies defining the clinical and demographic characteristics of the condition, a renewed interest in treatment development emerged through collaborations between international experts, industry and regulatory agencies. These efforts led to the performance of robust, high-quality clinical trials of novel therapies that targeted putative pathogenic pathways, leading to the approval of more than 10 novel therapies that have beneficially impacted both the quality and duration of life. However, our understanding of PAH remains incomplete and there is no cure. Accordingly, efforts are now focused on identifying novel pathogenic pathways that may be targeted, and applying more rigorous clinical trial designs to better define the efficacy of these new potential treatments and their role in the management scheme. This article, prepared by a Task Force comprised of expert clinicians, trialists and regulators, summarises the current state of the art, and provides insight into the opportunities and challenges for identifying and assessing the efficacy and safety of new treatments for this challenging condition.

Totally Implantable IV Treprostinil Therapy in Pulmonary Hypertension Assessment of the Implantation Procedure.

BACKGROUND: Prostacyclins improve symptoms and survival in pulmonary arterial hypertension (PAH). In response to risks associated with external delivery systems, an implantable IV infusion system was developed. A multicenter, prospective, single-arm, clinical trial (DelIVery for PAH) was conducted to evaluate this system for treprostinil in PAH. This analysis describes the findings related to the implant procedure. METHODS: Patients (N = 64) with PAH (World Health Organization group 1) receiving stable IV treprostinil were enrolled. Patients were transitioned to a temporary peripheral IV infusion catheter prior to the procedure. System implantation was performed at 10 centers under general anesthesia or deep IV sedation by clinicians from various specialties. Central venous access was via the cephalic, subclavian, jugular, or axillary vein. Using an introducer and fluoroscopic guidance, the distal tip of the infusion catheter was placed at the superior caval-atrial junction. The catheter was tunneled from the venous access site to an abdominal subcutaneous pocket, where the pump was placed. RESULTS: Of the 64 patients enrolled, four exited prior to implantation. All 60 implant procedures were successful. At baseline, all patients were receiving treprostinil via an external pump at a mean dose of 71.4 ± 27.8 ng/kg/min (range: 22-142 ng/kg/min). The implant averaged 102 ± 32 min (range: 47-184 min). Clinically significant implant procedure-related complications included one pneumothorax, two infections, and one episode of atrial fibrillation. There were three postimplantation catheter dislocations in two patients. Common implant-related events that were not complications included implant site pain (83%) and bruising (17%). CONCLUSIONS: The procedure for inserting a fully implantable system for treprostinil was successfully performed, with few complications. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01321073; URL: www.clinicaltrials.gov.

Utility of B-type natriuretic peptides in the assessment of patients with systemic sclerosis-associated pulmonary hypertension in the PHAROS registry.

OBJECTIVES: To assess the utility of B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP) in detecting and monitoring pulmonary hypertension (PH) in systemic sclerosis (SSc). METHODS: PHAROS is a multicenter prospective cohort of SSc patients at high risk for developing pulmonary arterial hypertension (SSc-AR-PAH) or with a definitive diagnosis of SSc-PH. We evaluated 1) the sensitivity and specificity of BNP≥64 and NT-proBNP≥210 pg/mL for the detection of SSc-PAH and/ or SSc-PH in the SSc-AR-PAH population; 2) baseline and longitudinal BNP and NT-proBNP levels as predictors of progression to SSc-PAH and/or SSc-PH; 3) baseline BNP≥180, NT-proBNP≥553 pg/mL, and longitudinal changes in BNP and NT-proBNP as predictors of mortality in SSc-PH diagnosed patients. RESULTS: 172 SSc-PH and 157 SSc-AR- PAH patients had natriuretic peptide levels available. Median BNP and NT-proBNP were significantly higher in the SSc-PH versus SSc-AR-PAH group. The sensitivity and specificity for SSc-PAH detection using baseline BNP≥64 pg/mL was 71% and 59%; and for NT-proBNP≥210 pg/mL, 73% and 78%. NT-proBNP showed stronger correlations with haemodynamic indicators of right ventricular dysfunction than BNP. Baseline creatinine, RVSP > 40 mmHg, and FVC%:DLco% ratio ≥1.8 were associated with progression from SSc-AR-PAH to SSc-PH but no association with individual or combined baseline BNP and NT-proBNP levels was observed. Baseline and follow-up BNP or NT-proBNP levels were not predictive of death, however, a composite BNP/NT-proBNP group predicted mortality (HR 3.81 (2.08-6.99), p<.0001). CONCLUSIONS: NT-proBNP may be more useful than BNP in the detection and monitoring of PAH in SSc patients, but additional studies are necessary.

CT-based pulmonary artery measurements for the assessment of pulmonary hypertension.

RATIONALE AND OBJECTIVES: Pulmonary hypertension (PH) is a complex and fatal disease that is difficult to diagnose noninvasively. This study evaluated previously published computed tomography-based vessel measurement criteria and investigated the predictive power and diagnostic ability of the main pulmonary artery diameter (MPAD) and the ratio of MPAD to aorta diameter (rPA). MATERIALS AND METHODS: The database for this study consisted of 175 PH patients (for whom mean pulmonary artery pressure [mPAP] was known), 16 patients without PH but with known mPAP (non-PH patients), and 114 "normal" patients without known mPAP. The performance of previously published criteria, MPAD > 29 mm and rPA > 1, was determined. The relationship between vessel measurements and mPAP was evaluated through correlation and linear regression analysis. The ability of these measurements to discriminate between patients with and without PH was determined by receiver operating characteristic analysis. RESULTS: For discriminating between PH and "normal" patients, the sensitivity and specificity of the criterion MPAD > 29 mm were 0.89 (0.84-0.93) and 0.83 (0.76-0.90), respectively, and the sensitivity and specificity of the criterion rPA > 1 were 0.89 (0.85-0.94) and 0.82 (0.74-0.89), respectively. At a specificity of 0.95 in the task of separating PH and "normal" patients, the sensitivity of MPAD was 0.81 (0.72-0.90) and the sensitivity of rPA was 0.76 (0.66-0.85), but the specificity for both decreased when non-PH patients were included. For the combined PH and non-PH patient groups, the correlation between the vessel measurements and mPAP was significant but low, and the ability of the vessel measurements to predict mPAP was limited. CONCLUSION: This study found that the sensitivity of previously published vessel criteria for identifying PH patients is high, but the specificity may not be high enough for routine use in a clinical patient population.

Sample size and cost analysis for pulmonary arterial hypertension drug trials using various imaging modalities to assess right ventricular size and function end points.

BACKGROUND: Placebo-controlled trials for pulmonary arterial hypertension are no longer acceptable because new therapies must show clinically significant effects on top of standard treatment. The purpose of this study was to estimate sample sizes and imaging costs for the planning of a hypothetical pulmonary arterial hypertension drug trial using imaging to detect changes in right ventricular size and function in response to combined therapy. METHODS AND RESULTS: Same-day cardiovascular MR (CMR) and 2-dimensional (2D) and 3D transthoracic echocardiography (2DTTE and 3DTTE) were performed in 22 patients with pulmonary arterial hypertension (54±13 years of age) twice, 6 months apart. Short-axis CMR cines and full-volume 3DTTE data sets of the right ventricle were used to measure end-diastolic volume and ejection fraction. Fractional area change was obtained from 2DTTE. Sample size calculations used a 2-sample t test model incorporating differences between baseline and 6-month measurements. Cost estimates were made using the Medicare fee schedule. No significant differences were noted between baseline and follow-up measurements. Large SDs reflected variable progression of disease in individual patients on standard therapy and measurement variability. These sources of variability resulted in intertechnique differences in sample sizes: to detect a change of 5% to 15% in 3DTTE-derived right ventricular ejection fraction and fractional area change or change of 15 to 30 mL in 3DTTE right ventricular end-diastolic volume; sample sizes were 2× to 2.5× those required by CMR. As a result, the total cost of a trial using complete TTE was greater than CMR, which was greater than limited TTE. CONCLUSIONS: Because of lower measurement variability, CMR is more cost saving in pulmonary arterial hypertension drug trials than echocardiography, unless limited TTE is used.

Survival and predictors of mortality in systemic sclerosis-associated pulmonary arterial hypertension: outcomes from the pulmonary hypertension assessment and recognition of outcomes in scleroderma registry.

OBJECTIVE: To assess cumulative survival rates and identify independent predictors of mortality in patients with incident systemic sclerosis (SSc)-associated pulmonary arterial hypertension (PAH) who had undergone routine screening for PAH at SSc centers in the US. METHODS: The Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma registry is a prospective registry of SSc patients at high risk for PAH or with definite pulmonary hypertension diagnosed by right-sided heart catheterization within 6 months of enrollment. Only patients with World Health Organization group I PAH (mean pulmonary artery pressure >25 mm Hg and pulmonary capillary wedge pressure <15 mm Hg without significant interstitial lung disease) were included in these analyses. RESULTS: In total, 131 SSc patients with incident PAH were followed for a mean ± SD of 2.0 ± 1.4 years. The 1-, 2-, and 3-year cumulative survival rates were 93%, 88%, and 75%, respectively. On multivariate analysis, age >60 years (hazard ratio [HR] 3.0, 95% confidence interval [95% CI] 1.1- 8.4), male sex (HR 3.9, 95% CI 1.1-13.9), functional class (FC) IV status (HR 6.5, 95% CI 1.8 -22.8), and diffusing capacity for carbon monoxide (DLCO) <39% predicted (HR 4.2, 95% CI 1.3-13.8) were significant predictors of mortality. CONCLUSION: This is the largest study describing survival in patients with incident SSc-associated PAH followed up at multiple SSc centers in the US who had undergone routine screening for PAH. The survival rates were better than those reported in other recently described SSc-associated PAH cohorts. Severely reduced DLCO and FC IV status at the time of PAH diagnosis portended a poor prognosis in these patients.

Risk assessment in pulmonary hypertension associated with heart failure and preserved ejection fraction.

BACKGROUND: Pulmonary hypertension (PH) is common in patients with left heart failure (HF), especially those with HF and preserved ejection fraction (HFpEF). However, there is limited data on risk stratification in these patients. METHODS: Baseline clinical and hemodynamic variables of 339 patients with World Health Organization (WHO) Group 2 PH, 90% of whom had HFpEF, were studied to derive a multivariate Cox proportional hazards model. A simplified prognostic risk score was created based on the outcome of all-cause mortality. Nine predictors, significant after stepwise multivariable regression (p < 0.05), were used to create the risk score. Components of the risk score were functional class, diastolic blood pressure, pulmonary artery saturation, interstitial lung disease, hypotension on initial presentation, right ventricular hypertrophy, diffusion capacity of the lung for carbon monoxide, and 2 serum creatinine variables (≤ 0.9 mg/dl and ≥ 1.4 mg/dl). RESULTS: Overall 2-year survival was 73.8% ± 2.4% in the derivation cohort, and 87.5% ± 2.3%, 66.4% ± 4.9%, and 24.4% ± 6.7% for risk scores of 0 to 2, 3 to 4, and 5+, respectively (p < 0.0001 for the trend), with a C-index of 0.76 (95% confidence interval [CI], 0.71-0.81). The risk score was validated in 2 independent PH-HFpEF cohorts: 179 patients with a C-index of 0.68 (95% CI, 0.55-0.80) and 117 patients with a C-index of 0.68 (95% CI, 0.53-0.83). For the 3 cohorts combined (N = 635), the overall C-index was 0.72 (95% CI 0.68-0.76). In all 3 cohorts individually and in the 3 cohorts combined, the risk score predicted death (hazard ratio, 1.4-1.6; p < 0.01). CONCLUSIONS: Several clinical factors independently predict death in PH-HFpEF confirmed by validation. A novel risk score composed of these factors can be used to determine prognosis and may be useful in making therapeutic decisions.

Association of serum creatinine with abnormal hemodynamics and mortality in pulmonary arterial hypertension.

BACKGROUND: Renal dysfunction predicts mortality in patients with cardiovascular disease. How renal dysfunction relates to hemodynamics and mortality in pulmonary arterial hypertension (PAH) remains unclear. METHODS AND RESULTS: We performed a cohort study of 500 patients with World Health Organization group I PAH from 1982 to 2006 with data on demographics, comorbidities, medications, functional class, laboratory tests, exercise testing results, and hemodynamics. Serum creatinine (SCr) was determined on entry into the study (initial PAH clinic visit). Vital status was determined from hospital records and the Social Security Death Index. We used a Cox proportional hazards analysis to determine whether SCr was an independent predictor of mortality. Mean age on entry into the study was 48+/-14 years, and 79% of subjects were female. Mean SCr was 1.05+/-0.35 mg/dL. Elevated SCr was associated with higher right atrial pressure and lower cardiac index. During a median follow-up of 3.5 years, 279 deaths (55.8% of the cohort) occurred. Compared with patients with SCr <1.0 mg/dL, those with SCr 1.0 to 1.4 mg/dL and SCr >1.4 mg/dL had an increased hazard ratio of death (unadjusted hazard ratio 1.65, 95% confidence interval 1.26 to 2.17, P<0.0001 for SCr 1.0 to 1.4 mg/dL; unadjusted hazard ratio 2.54, 95% confidence interval 1.73 to 3.71, P<0.0001 for SCr >1.4 mg/dL). On multivariable analysis, we found a significant interaction between SCr and right atrial pressures (interaction P<0.0001); increased SCr best predicted death in patients with right atrial pressure <10 mm Hg. CONCLUSIONS: Renal dysfunction is associated with a worse hemodynamic profile and is an independent predictor of mortality in PAH. Measurement of SCr is practical and offers a simple way to noninvasively predict outcome.

Genomic assessment of a multikinase inhibitor, sorafenib, in a rodent model of pulmonary hypertension.

Pulmonary hypertension (PH) and cancer pathology share growth factor- and MAPK stress-mediated signaling pathways resulting in endothelial and smooth muscle cell dysfunction and angioproliferative vasculopathy. In this study, we assessed sorafenib, an antineoplastic agent and inhibitor of multiple kinases important in angiogenesis [VEGF receptor (VEGFR)-1-3, PDGF receptor (PDGFR)-beta, Raf-1 kinase] as a potential PH therapy. Two PH rat models were used: a conventional hypoxia-induced PH model and an augmented PH model combining dual VEGFR-1 and -2 inhibition (SU-5416, single 20 mg/kg injection) with hypoxia. In addition to normoxia-exposed control animals, four groups were maintained at 10% inspired O(2) fraction for 3.5 wk (hypoxia/vehicle, hypoxia/SU-5416, hypoxia/sorafenib, and hypoxia/SU-5416/sorafenib). Compared with normoxic control animals, rats exposed to hypoxia/SU-5416 developed hemodynamic and histological evidence of severe PH while rats exposed to hypoxia alone displayed only mild elevations in hemodynamic values (pulmonary vascular and right ventricular pressures). Sorafenib treatment (daily gavage, 2.5 mg/kg) prevented hemodynamic changes and demonstrated dramatic attenuation of PH-associated vascular remodeling. Compared with normoxic control rats, expression profiling (Affymetrix platform) of lung RNA obtained from hypoxia [false discovery rate (FDR) 6.5%]- and hypoxia/SU-5416 (FDR 1.6%)-challenged rats yielded 1,019 and 465 differentially regulated genes (fold change >1.4), respectively. A novel molecular signature consisting of 38 differentially expressed genes between hypoxia/SU-5416 and hypoxia/SU-5416/sorafenib (FDR 6.7%) was validated by either real-time RT-PCR or immunoblotting. Finally, immunoblotting studies confirmed the upregulation of the MAPK cascade in both PH models, which was abolished by sorafenib. In summary, sorafenib represents a novel potential treatment for severe PH with the MAPK cascade a potential canonical target.