Riociguat in patients with sickle cell disease and hypertension or proteinuria (STERIO-SCD): a randomised, double-blind, placebo controlled, phase 1-2 trial.

BACKGROUND: Although nitric oxide based therapeutics have been shown in preclinical models to reduce vaso-occlusive events and improve cardiovascular function, a clinical trial of a phosphodiesterase 5 inhibitor increased rates of admission to hospital for pain. We aimed to examine if riociguat, a direct stimulator of the nitric oxide receptor soluble guanylate cyclase, causes similar increases in vaso-occlusive events. METHODS: This was a phase 1-2, randomised, double blind, placebo-controlled trial. Eligible patients were 18 years or older, had confirmed sickle cell disease documented by haemoglobin electrophoresis or HPLC fractionation (haemoglobin SS, SC, Sß-thalassemia, SD, or SO-Arab), and stage 1 hypertension or proteinuria. Participants were randomly assigned 1:1 to receive either riociguat or matching placebo via a web-based system to maintain allocation concealment. Both treatments were administered orally starting at 1·0 mg three times a day up to 2·5 mg three times a day (highest tolerated dose) for 12 weeks. Dose escalation by 0·5 mg was considered every 2 weeks if systolic blood pressure was greater than 95 mm Hg and the participant had no signs of hypotension; otherwise, the last dose was maintained. The primary outcome was the proportion of participants who had at least one adjudicated treatment-emergent serious adverse event. The analysis was performed by the intention-to-treat. This trial is registered with ClinicalTrials.gov (NCT02633397) and was completed. FINDINGS: Between April 11, 2017, and Dec 31, 2021, 165 participants were screened and consented to be enrolled into the study. Of these, 130 participants were randomly assigned to either riociguat (n=66) or placebo (n=64). The proportion of participants with at least one treatment-emergent serious adverse event was 22·7% (n=15) in the riociguat group and 31·3% (n=20) in the placebo group (difference -8·5% [90% CI -21·4 to 4·5]; p=0·19). A similar pattern emerged in other key safety outcomes, sickle cell related vaso-occlusive events (16·7 [n=11] vs 21·9% [n=14]; difference -5·2% [-17·2 to 6·5]; p=0·42), mean pain severity (3·18 vs 3·32; adjusted mean difference -0·14 [-0·70 to 0·42]; p=0·69), and pain interference (3·15 vs 3·12; 0·04 [-0·62 to 0·69]; p=0·93) at 12 weeks were similar between groups. Regarding the key clinical efficacy endpoints, participants taking riociguat had a blood pressure of -8·20 mm Hg (-10·48 to -5·91) compared with -1·24 (-3·58 to 1·10) in those taking placebo (-6·96 mm Hg (90% CI -10·22 to -3·69; p<0·001). INTERPRETATION: Riociguat was safe and had a significant haemodynamic effect on systemic blood pressure. The results of this study provide measures of effect and variability that will inform power calculations for future trials. FUNDING: Bayer Pharmaceuticals.

The Value of Bedside Echocardiogram in the Setting of Acute and Chronic Pulmonary Embolism.

Echocardiography is valuable in the evaluation and risk stratification of patients with acute and chronic pulmonary embolism (PE). Patients with acute PE who have echocardiographic evidence of right ventricular dilatation and/or right ventricular dysfunction have a worse prognosis. A minority of patients with acute PE can develop chronic thromboembolic pulmonary hypertension. Patients with chronic thromboembolic pulmonary hypertension often have echocardiographic evidence of elevated pulmonary arterial pressures, right ventricular hypertrophy, right ventricular dysfunction, and/or left ventricular impaired relaxation.

Effect of 6-min Walk Test on pro-BNP Levels in Patients with Pulmonary Arterial Hypertension.

BACKGROUND: Plasma pro-BNP (brain natriuretic peptide) levels are often elevated in response to right ventricular (RV) volume and pressure overload, parameters potentially affected by exercise. Plasma pro-BNP levels change in association with long-term changes in pulmonary hemodynamics, thereby serving as a potential biomarker in pulmonary arterial hypertension (PAH). The 6-min Walk Test (6MWT) and pro-BNP level are often checked in a single office visit. There is no universal standard for measuring Pro-BNP levels relative to the timing of the 6MWT. Based on the studies in normal subjects indicating that pro-BNP levels changes after exercise, we hypothesized that the pro-BNP might rise after the 6MWT in PAH patients, potentially impacting clinical decisions. METHODS: Patients at our center with WHO Group 1 PAH on active therapy at a stable dose for 30 days or more were enrolled. After resting the patient for 30 min, blood was drawn for baseline pro-BNP and a 6MWT was performed. Pro-BNP levels were drawn immediately after the 6MWT and 1 and 2 h later. Pro-BNP was measured using a commercially available ELISA kit. The levels before exercise and after exercise were compared using student's paired t tests. RESULTS: There were 17 females and 3 male subjects. The mean age was 53 ± 11 years. Seven patients had systemic lupus erythematosus-related PAH, six had idiopathic PAH, three had scleroderma, three had portopulmonary hypertension, and one had HIV-related PAH. The mean PA pressure was 50 ± 15 mmHg with a mean pulmonary vascular resistance of 10 ± 4 Wood units. The majority of the patients were on multimodality PAH therapy, including parenteral prostacyclins. Mean 6MWT distance was 377 ± 140 m. In 14/20 patients, the pro-BNP level increased immediately after the 6MWT; in 12/20 patients, the pro-BNP level was elevated at 1 h post exercise. In the majority of the patients, the pro-BNP fell to baseline 2 h post 6MWT. CONCLUSION: There appears to be a trend of pro-BNP level increasing immediately after exercise and continuing to be elevated at 1 h. Pro-BNP levels then return to baseline at 2 h post 6MWT.

Thermodilution and Fick cardiac outputs differ: impact on pulmonary hypertension evaluation.

BACKGROUND: The relationship between thermodilution and indirect Fick cardiac output determination methods has not been well described. OBJECTIVE: To describe the relationship between these two cardiac output determination methods in patients evaluated for pulmonary hypertension and to highlight potential clinical implications. METHODS: A retrospective review of charts of all adult patients who underwent a right heart catheterization (RHC) between January 1, 2007 and November 10, 2010, and participated in the pulmonary hypertension program of the pulmonary division at an academic institution was conducted. For validation, the charts of all patients who underwent RHC during the same period within the cardiology division were reviewed. RESULTS: A total of 198 patients underwent 213 RHCs, 79 (40%) of whom had pulmonary arterial hypertension, were included. Forty-three per cent of patients had >20% difference between thermodilution and Fick. The average difference (thermodilution - Fick ±SD) was -0.39±2.03 L/min (n=213; P=0.006). There was no significant difference in bias or variability between thermodilution and Fick among patients with tricuspid regurgitant jet velocity (TRJ) of <3 m/s versus those with TRJ >3 m/s (-0.41±2.10 L/min versus -0.36±1.93 L/min, respectively; P=0.87). In a multivariable analysis, the thermodilution-Fick difference increased with age (P=0.001). DISCUSSION: The presence of such discrepancy in 36% of patients evaluated for heart failure and/or heart transplant validated the results. In total, 37% of the 1315 procedures (213 performed by pulmonologists and 1102 performed by cardiologists) had a difference of >20% between thermodilution and Fick. CONCLUSION: Significant discrepancy exists between thermodilution and indirect Fick methods. This discrepancy potentially impacts pulmonary arterial hypertension prognostication and diagnosis, and is independent of TRJ.

Safety and feasibility of obtaining wedged pulmonary artery samples and differential distribution of biomarkers in pulmonary hypertension.

This study aims to evaluate the safety and feasibility of obtaining wedged pulmonary artery (PA) samples and investigate the differential vascular beds' distribution of select inflammatory and cellular adhesion molecules that are implicated in pulmonary arterial hypertension (PAH) pathogenesis. This is a cross-sectional study of adult patients. Serum samples were simultaneously drawn from three different vascular sites during right heart catheterization as part of PAH evaluation: The superior vena cava, distal pulmonary artery prior to wedging, and distal pulmonary artery after (and distal to) wedging. The study group was comprised of patients with either PAH or chronic thromboembolic pulmonary hypertension (i.e., WHO/Dana Point Group 1 or 4). The internal control group included patients whose hemodynamics were not consistent with pulmonary hypertension. The external control group consisted of healthy volunteers who had a peripheral venous sample drawn. The mean age of the 25 study patients was 55 ± 14 years and mean BMI was 31 ± 10, and those of the 25 internal control patients were 49 ± 14 years and 26 ± 5, respectively. There were no complications resulting from obtaining wedged PA samples. Obtaining adequate wedged samples was successful in 80% of patients. More severe pulmonary hypertension was associated with lower success rates. There were no significant differences in the concentrations of the different biomarkers studied amongst the different vascular sites (n = 25 study patients). There was a nonsignificant trend of decreasing biomarkers concentrations from peripheral to wedged to un-wedged PA samples. Compared to the healthy external controls, sVCAM-1 levels were higher in the study group. Obtaining wedged PA blood samples is safe and feasible in adult patients with pulmonary hypertension. There were no differences in the distribution of markers between the vascular beds within patients.