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Chang A, Wilson SR, Morris S, Wichlan D, LeVarge BL, Little JA. Nocturnal hypoxaemia is common in adults with sickle cell anaemia. Br J Haematol 2024; 204:1495-1499. [PMID: 38311363 DOI: 10.1111/bjh.19305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 02/10/2024]
Abstract
The symptoms and sequelae of sickle cell anaemia (SCA) are caused by the polymerization of deoxygenated sickle haemoglobin, and people with SCA may be uniquely susceptible to adverse outcomes from hypoxia and haemoglobin desaturation. We examined by oximetry adults (aged 18-45 years) with SCA presenting symptoms indicative of polysomnography, at a single institution, irrespective of treatment, for nocturnal hypoxaemia. Clinical labs and blood for in vitro assessments were taken upon enrolment and after 8-12 weeks of oxygen therapy or observation. Of 21 screened participants, nine (43%) had sufficient nocturnal hypoxaemia to warrant oxygen therapy (≥5 min at SpO2 ≤ 88%). Time spent at SpO2 ≤ 88% associated with age (p = 0.0092), annual hospitalizations (p = 0.0018) and anaemia (p = 0.0139), as well as plasma levels of TNFα (p = 0.0019) and IL-4 (p = 0.0147). Longitudinal analysis showed that WBC significantly decreased during the follow-up period in hypoxic individuals but not in non-hypoxic individuals (p = 0.0361 and p = 0.6969 respectively). Plasma levels of CCL2 and IL-1ra tended to increase, while levels of red blood cell reactive oxygen species tended to decrease with oxygen therapy. Overall, nocturnal hypoxaemia was common in this pilot study population and associated with plausible clinical comorbidities; oxygen therapy may decrease inflammation and oxidative damage in hypoxic individuals.
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Affiliation(s)
- Ada Chang
- Department of Medicine, Hematology and Blood Research Center, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Samuel R Wilson
- Department of Medicine, Hematology and Blood Research Center, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Sherri Morris
- Department of Medicine, Hematology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - David Wichlan
- Department of Medicine, Hematology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Barbara L LeVarge
- Department of Medicine, Pulmonary Diseases and Critical Care Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Jane Alison Little
- Department of Medicine, Hematology and Blood Research Center, University of North Carolina, Chapel Hill, North Carolina, USA
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Al-Qadi MO, Holbrook J, Ford HJ, Ceppe A, LeVarge BL. Prognostic Value of Respiratory Variation in Right Atrial Pressure in Patients With Precapillary Pulmonary Hypertension. Chest 2023; 164:481-489. [PMID: 36990147 DOI: 10.1016/j.chest.2023.03.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 02/28/2023] [Accepted: 03/21/2023] [Indexed: 03/30/2023] Open
Abstract
BACKGROUND Precapillary pulmonary hypertension is characterized by elevated mean pulmonary artery pressure from increased pulmonary vascular resistance. Lack of respiratory variation in right atrial pressure can be viewed as a surrogate for severe pulmonary hypertension and inability of the right ventricle to tolerate preload augmentation during inspiration. RESEARCH QUESTION Is the lack of respiratory variation in right atrial pressure predictive of right ventricular dysfunction and worse clinical outcomes in precapillary pulmonary hypertension? STUDY DESIGN AND METHODS We retrospectively reviewed right atrial pressure tracings of patients with precapillary pulmonary hypertension who underwent right heart catheterization. Patients with respiratory variation in right atrial pressure (end expiratory-end inspiratory) ≤ 2 mm Hg were considered to have effectively no meaningful variation in right atrial pressure. RESULTS Lack of respiratory variation in right atrial pressure was associated with lower cardiac index by indirect Fick (2.34 ± 0.09 vs 2.76 ± 0.1 L/min/m2; P = .001), lower pulmonary artery saturation (60% ± 1.02% vs 64% ± 1.15%; P = .007), higher pulmonary vascular resistance (8.9 ± 0.44 vs 6.1 ± 0.49 Wood units, P < .0001), right ventricular dysfunction on echocardiography (87.3% vs 38.8%; P < .0001), higher pro brain natriuretic peptide (2,163 ± 2,997 vs 633 ± 402 ng/mL; P < .0001), and more hospitalizations within 1 year for right ventricular failure (65.4% vs 29.6%; P < .0001). There was also a trend toward higher mortality at 1 year in patients with no respiratory variation in right atrial pressure (25.4% vs 11.1%; P = .06). INTERPRETATION Lack of respiratory variation in right atrial pressure is associated with poor clinical outcomes, adverse hemodynamic parameters, and right ventricular dysfunction in patients with precapillary pulmonary hypertension. Larger studies are needed to further evaluate its utility in prognosis and potential risk stratification in patients with precapillary pulmonary hypertension.
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Affiliation(s)
- Mazen O Al-Qadi
- Division of Pulmonary and Critical Care Medicine and Pulmonary Hypertension Program, University of North Carolina at Chapel Hill, Chapel Hill, NC; Marsico Lung Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC; Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC.
| | - Jason Holbrook
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - H James Ford
- Division of Pulmonary and Critical Care Medicine and Pulmonary Hypertension Program, University of North Carolina at Chapel Hill, Chapel Hill, NC; Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Agathe Ceppe
- Division of Pulmonary and Critical Care Medicine and Pulmonary Hypertension Program, University of North Carolina at Chapel Hill, Chapel Hill, NC; Marsico Lung Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Barbara L LeVarge
- Division of Pulmonary and Critical Care Medicine and Pulmonary Hypertension Program, University of North Carolina at Chapel Hill, Chapel Hill, NC; Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC
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Abstract
Surgical pulmonary embolectomy and pulmonary thromboendarterectomy are well-established treatment strategies for patients with acute and chronic pulmonary embolism, respectively. For both procedures, techniques and outcomes have evolved considerably over the past decades. Patients with massive and submassive acute pulmonary embolism are at risk for rapid decline owing to right ventricular failure and shock. When thrombus is proximal, embolectomy can rapidly restore cardiac function. Chronic thromboembolic pulmonary hypertension is a more complex disease that requires skilled, careful dissection of the arterial wall, including vascular intima. When successful, surgery leads to clinical cure of the associated pulmonary hypertension, with excellent long-term outcomes.
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Affiliation(s)
- Barbara L LeVarge
- Division of Pulmonary Diseases and Critical Care Medicine, Department of Medicine, University of North Carolina, 130 Mason Farm Road CB 7020, Chapel Hill, NC 27599, USA.
| | - Cameron D Wright
- Division of Thoracic Surgery, Department of Surgery, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - Josanna M Rodriguez-Lopez
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
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Abstract
Infection, thrombosis, and catheter dislodgment are well-recognized potential complications of chronic intravenous prostanoid therapy for pulmonary arterial hypertension. As long-term outcomes of pulmonary hypertension patients improve, novel adverse events are likely to arise. We describe the sudden development of unexplained hypotension and lightheadedness in a patient receiving intravenous epoprostenol for several years, ultimately determined to be due to an unusual catheter complication, not previously described in this population.
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Affiliation(s)
- Barbara L. LeVarge
- Pulmonary Diseases and Critical Care Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Anica C. Law
- Pulmonary, Critical Care, and Sleep Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Blanche Murphy
- Central Line Service, Beth Israel Deaconess Medical Center, Boston, MA, USA
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DuBrock HM, Rodriguez-Lopez JM, LeVarge BL, Curry MP, VanderLaan PA, Zsengeller ZK, Pernicone E, Preston IR, Yu PB, Nikolic I, Xu D, Thadhani RI, Channick RN, Ananth Karumanchi S. Macrophage migration inhibitory factor as a novel biomarker of portopulmonary hypertension. Pulm Circ 2017; 6:498-507. [PMID: 28090291 DOI: 10.1086/688489] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Portopulmonary hypertension (POPH) is a poorly understood complication of liver disease associated with significant morbidity and mortality. We sought to identify novel biomarkers of POPH disease presence and severity. We performed a prospective, multicenter, case-control study involving patients with liver disease undergoing right heart catheterization. POPH cases were defined as a mean pulmonary arterial pressure (mPAP) ≥25 mmHg and pulmonary vascular resistance (PVR) >240 dynes˙s˙cm-5. Plasma samples were collected from the systemic and pulmonary circulation, and antibody microarray was used to identify biomarkers. Characterization and validation of a candidate cytokine, macrophage migration inhibitory factor (MIF), was performed using enzyme-linked immunosorbent assay. Continuous variables were compared using a Mann-Whitney U test and correlated with disease severity using Spearman correlation. MIF levels were elevated in both the systemic and pulmonary circulation in patients with POPH compared with controls (median MIF level [interquartile range] in systemic circulation: 46.68 ng/mL [32.31-76.04] vs. 31.19 ng/mL [26.92-42.17], P = 0.009; in pulmonary circulation: 49.59 ng/mL [35.90-108.80] vs. 37.78 [21.78-45.53], P = 0.002). In patients with POPH, MIF levels were positively correlated with PVR (r = 0.58, P = 0.006) and inversely correlated with cardiac output (r = -0.57, P = 0.007). MIF >60 ng/mL or tricuspid regurgitation gradient >50 mmHg had a 92% sensitivity and specificity for the diagnosis of POPH, with a positive predictive value of 86% and a negative predictive value of 96%. MIF is a promising novel biomarker of POPH disease presence and severity in patients with liver disease and portal hypertension.
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Affiliation(s)
- Hilary M DuBrock
- Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | | | | | - Michael P Curry
- Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | | | | | | | | | - Paul B Yu
- Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Ivana Nikolic
- Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Dihua Xu
- Massachusetts General Hospital, Boston, Massachusetts, USA
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Maltz M, LeVarge BL, Graf J. Identification of iron and heme utilization genes in Aeromonas and their role in the colonization of the leech digestive tract. Front Microbiol 2015; 6:763. [PMID: 26284048 PMCID: PMC4516982 DOI: 10.3389/fmicb.2015.00763] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 07/13/2015] [Indexed: 01/02/2023] Open
Abstract
It is known that many pathogens produce high-affinity iron uptake systems like siderophores and/or proteins for utilizing iron bound to heme-containing molecules, which facilitate iron-acquisition inside a host. In mutualistic digestive-tract associations, iron uptake systems have not been as well studied. We investigated the importance of two iron utilization systems within the beneficial digestive-tract association Aeromonas veronii and the medicinal leech, Hirudo verbana. Siderophores were detected in A. veronii using chrome azurol S. Using a mini Tn5, a transposon insertion in viuB generated a mutant unable to utilize iron using siderophores. The A. veronii genome was then searched for genes potentially involved in iron utilization bound to heme-containing molecules. A putative outer membrane heme receptor (hgpB) was identified with a transcriptional activator, termed hgpR, downstream. The hgpB gene was interrupted with an antibiotic resistance cassette in both the parent strain and the viuB mutant, yielding an hgpB mutant and a mutant with both iron uptake systems inactivated. In vitro assays indicated that hgpB is involved in utilizing iron bound to heme and that both iron utilization systems are important for A. veronii to grow in blood. In vivo colonization assays revealed that the ability to acquire iron from heme-containing molecules is critical for A. veronii to colonize the leech gut. Since iron and specifically heme utilization is important in this mutualistic relationship and has a potential role in virulence factor of other organisms, genomes from different Aeromonas strains (both clinical and environmental) were queried with iron utilization genes of A. veronii. This analysis revealed that in contrast to the siderophore utilization genes heme utilization genes are widely distributed among aeromonads. The importance of heme utilization in the colonization of the leech further confirms that symbiotic and pathogenic relationships possess similar mechanisms for interacting with animal hosts.
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Affiliation(s)
- Michele Maltz
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - Barbara L LeVarge
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - Joerg Graf
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
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Abstract
Prostacyclin is an endogenous eicosanoid produced by endothelial cells; through actions on vascular smooth-muscle cells, it promotes vasodilation. Pulmonary arterial hypertension (PAH) is characterized by elevated mean pulmonary artery pressure due to a high pulmonary vascular resistance state. A relative decrease in prostacyclin presence has been associated with PAH; this pathway has thus become a therapeutic target. Epoprostenol, the synthetic equivalent of prostacyclin, was first utilized as short-term or bridging therapy in the 1980s. Further refinement of its long-term use via continuous intravenous infusion followed. A randomized controlled trial by Barst et al in 1996 demonstrated functional, hemodynamic, and mortality benefits of epoprostenol use. This work was a groundbreaking achievement in the management of PAH and initiated a wave of research that markedly altered the dismal prognosis previously associated with PAH. Analogs of prostacyclin, including iloprost and treprostinil, exhibit increased stability and allow for an extended array of parenteral and non-parenteral (inhaled and oral) therapeutic options. This review further examines the pharmacology and clinical use of epoprostenol and its analogs in PAH.
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Affiliation(s)
- Barbara L LeVarge
- Department of Pulmonary and Critical Care Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
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Abstract
Current guidelines recommend measurement of pulmonary artery wedge pressure (PAWP) at end-expiration. However, this recommendation is not universally followed and may not be physiologically appropriate. We investigated the performance of end-expiratory PAWP in the evaluation of precapillary pulmonary hypertension patients. 329 spontaneously breathing patients undergoing right heart catheterisation were retrospectively classified as having a precapillary, post-capillary or mixed phenotype based on standardised clinical criteria. Tracings were reviewed to compare end-expiratory PAWP with PAWP averaged throughout the respiratory cycle; these values were correlated with the clinical classifications. Predictors of large respirophasic variation in PAWP were determined. Elevated end-expiratory PAWP (>15 mmHg) occurred in 29% of subjects with precapillary phenotype. There were no differences in demographics or clinical history between those with elevated and normal end-expiratory PAWP. Those with elevated end-expiratory PAWP had greater right atrial pressure and respirophasic PAWP variation. Among all subjects, the magnitude of respirophasic variation in PAWP was positively correlated with body mass index and respirophasic variation in left ventricular end-diastolic pressure. A significant proportion of precapillary pulmonary hypertension patients have end-expiratory PAWP >15 mmHg. Spontaneous positive end-expiratory intrathoracic pressure may contribute; in those cases, PAWP averaged throughout respiration may be a more accurate measurement.
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Affiliation(s)
- Barbara L LeVarge
- Dept of Pulmonary and Critical Care Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | | | - Richard N Channick
- Dept of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, MA, USA
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Abstract
Treprostinil is a prostacyclin derivative approved for the treatment of pulmonary arterial hypertension by intravenous, subcutaneous and inhalational administration. Unlike its precursor epoprostenol, treprostinil is chemically stable at room temperature and neutral pH, and its plasma half-life is longer. In addition to promoting smooth muscle relaxation in the pulmonary vasculature, treprostinil has suppressive effects on platelet aggregation, smooth muscle proliferation and inflammation. A Phase III study, investigating the addition of inhaled treprostinil to oral bosentan or sildenafil, confirmed significant improvements in exercise capacity and quality of life. This review examines the pharmacodynamics, pharmacokinetics, clinical efficacy and safety of inhaled treprostinil for use in pulmonary arterial hypertension.
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Affiliation(s)
- Barbara L LeVarge
- Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA.
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