1
|
Su J, Simonsen U, Mellemkjaer S, Howard LS, Manisty C, Hughes AD. Limited value of pulse wave analysis in assessing arterial wave reflection and stiffness in the pulmonary artery. Physiol Rep 2021; 9:e15024. [PMID: 34558215 PMCID: PMC8461033 DOI: 10.14814/phy2.15024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 08/11/2021] [Indexed: 01/09/2023] Open
Abstract
We explored the use of the augmentation index (AI) based on pulse wave analysis (PWA) in the pulmonary circulation as a measure of wave reflection and arterial stiffness in individuals with and without pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). Right heart catheterization was performed using a pressure and Doppler flow sensor-tipped catheter to obtain simultaneous pressure and flow velocity measurements in the pulmonary artery in 10 controls, 11 PAH patients, and 11 CTEPH patients. PWA was applied to the measured pressure, while wave intensity analysis (WIA) and wave separation analysis (WSA) were performed using both the pressure and velocity to determine the magnitudes and timings of reflected waves. Type C (AI < 0) pressure waveform dominated in controls and type A (AI > 12%) waveform dominated in PAH patients, while there was a mixture of types A, B, and C among CTEPH patients. AI was greater and the inflection time shorter in CTEPH compared to PAH patients. There was a poor correlation between AI and arterial wave speed as well as measures of wave reflection derived from WIA and WSA. The infection point did not match the timing of the backward compression wave in ~50% of the cases. In patients with type C waveforms, the inflection time correlated well to the timing of the late systolic forward decompression wave caused by ventricular relaxation. In conclusion quantifying pulmonary arterial wave reflection and stiffness using AI based on PWA may be inaccurate and should therefore be discouraged.
Collapse
Affiliation(s)
- Junjing Su
- Department of BiomedicineAarhus UniversityAarhusDenmark
- National Heart and Lung InstituteImperial College LondonLondonUK
| | - Ulf Simonsen
- Department of BiomedicineAarhus UniversityAarhusDenmark
| | | | - Luke S. Howard
- National Heart and Lung InstituteImperial College LondonLondonUK
| | - Charlotte Manisty
- MRC Unit for Lifelong Health and AgingInstitute of Cardiovascular ScienceUniversity College LondonLondonUK
| | - Alun D. Hughes
- MRC Unit for Lifelong Health and AgingInstitute of Cardiovascular ScienceUniversity College LondonLondonUK
| |
Collapse
|
2
|
Revie JA, Stevenson DJ, Chase JG, Hann CE, Lambermont BC, Ghuysen A, Kolh P, Shaw GM, Heldmann S, Desaive T. Validation of subject-specific cardiovascular system models from porcine measurements. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2013; 109:197-210. [PMID: 22126892 DOI: 10.1016/j.cmpb.2011.10.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 09/26/2011] [Accepted: 10/25/2011] [Indexed: 05/31/2023]
Abstract
A previously validated mathematical model of the cardiovascular system (CVS) is made subject-specific using an iterative, proportional gain-based identification method. Prior works utilised a complete set of experimentally measured data that is not clinically typical or applicable. In this paper, parameters are identified using proportional gain-based control and a minimal, clinically available set of measurements. The new method makes use of several intermediary steps through identification of smaller compartmental models of CVS to reduce the number of parameters identified simultaneously and increase the convergence stability of the method. This new, clinically relevant, minimal measurement approach is validated using a porcine model of acute pulmonary embolism (APE). Trials were performed on five pigs, each inserted with three autologous blood clots of decreasing size over a period of four to five hours. All experiments were reviewed and approved by the Ethics Committee of the Medical Faculty at the University of Liege, Belgium. Continuous aortic and pulmonary artery pressures (P(ao), P(pa)) were measured along with left and right ventricle pressure and volume waveforms. Subject-specific CVS models were identified from global end diastolic volume (GEDV), stroke volume (SV), P(ao), and P(pa) measurements, with the mean volumes and maximum pressures of the left and right ventricles used to verify the accuracy of the fitted models. The inputs (GEDV, SV, P(ao), P(pa)) used in the identification process were matched by the CVS model to errors <0.5%. Prediction of the mean ventricular volumes and maximum ventricular pressures not used to fit the model compared experimental measurements to median absolute errors of 4.3% and 4.4%, which are equivalent to the measurement errors of currently used monitoring devices in the ICU (∼5-10%). These results validate the potential for implementing this approach in the intensive care unit.
Collapse
Affiliation(s)
- James A Revie
- Department of Mechanical Engineering, Centre of Bioengineering, University of Canterbury, Christchurch, New Zealand.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
3
|
Abstract
Mortality remains very high among septic patients despite the advanced treatments rendered in intensive care units. The development of septic shock is multifactorial. Tissue damage and organ dysfunction may be caused not only by the microorganisms but also by the inflammatory mediators released in response to the infection. Cytokines (tumor necrosis factor, interleukin-1, interleukin-6, interleukin-8, high-mobility group box-1 protein, macrophage migratory inhibitory factor) and noncytokines (nitric oxide, platelet-activating factor, complements, and eicosonoids) may inflict tissue injury and contribute to multiple organ dysfunction and cell death (or apoptosis). Gram-negative bacteria are the most common organisms identified in septic patients. The pathological effects of gram-negative bacteria are conveyed through lipopolysaccharide derived from the bacterial cell membrane. Lipopolysaccharide activates the nuclear factor kappa B, which triggers the release of inflammatory mediators. Protein components from gram-positive bacteria, fungi, or viruses may evoke the activation of nuclear factor kappa B in a similar fashion as lipopolysaccharide. Endogenous anti-inflammatory mediators are released in response to the infection and act to control the overwhelming systemic inflammatory response. The fragile balance between negative and positive feedback on the inflammatory mediators is the key factor that modulates the cellular damage and influences the clinical outcome.
Collapse
Affiliation(s)
- Eddy Jean-Baptiste
- Columbia University and Nassau University Medical Center, East Meadow, New York, USA
| |
Collapse
|
4
|
Abstract
BACKGROUND Over the past 30 years, efforts have been made to identify therapeutic targets in the host response to infection. METHODS A review of the randomized controlled clinical sepsis trials and meta-analyses of glucocorticoids, mediator-specific anti-inflammatory agents, and anticoagulant agents was performed. RESULTS The effects of glucocorticoids in sepsis appear to be dose-dependent, with high doses decreasing survival and low doses improving survival. As a class, the mediator-specific anti-inflammatory agents have a small beneficial effect on survival; however, no single agent has demonstrated significant benefit. The treatment effects of these agents appear to be related to the patient's risk of death. As a class, the anticoagulant agents do not improve survival; however, the efficacy of these agents may have been confounded by concurrent heparin therapy. Activated protein C demonstrated a beneficial effect on survival that was dependent on severity of illness. CONCLUSION Trials of agents directed at altering the host's response during sepsis have had variable results, and it appears that several different factors may alter the efficacy of these agents.
Collapse
Affiliation(s)
- Katherine J Deans
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | | | | | | | | |
Collapse
|
5
|
Van de Wouwer M, Collen D, Conway EM. Thrombomodulin-protein C-EPCR system: integrated to regulate coagulation and inflammation. Arterioscler Thromb Vasc Biol 2004; 24:1374-83. [PMID: 15178554 DOI: 10.1161/01.atv.0000134298.25489.92] [Citation(s) in RCA: 260] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Late in the 18th century, William Hewson recognized that the formation of a clot is characteristic of many febrile, inflammatory diseases (Owen C. A History of Blood Coagulation. Rochester, Minnesota: Mayo Foundation; 2001). Since that time, there has been steady progress in our understanding of coagulation and inflammation, but it is only in the past few decades that the molecular mechanisms linking these 2 biologic systems have started to be delineated. Most of these can be traced to the vasculature, where the systems most intimately interact. Thrombomodulin (TM), a cell surface-expressed glycoprotein, predominantly synthesized by vascular endothelial cells, is a critical cofactor for thrombin-mediated activation of protein C (PC), an event further amplified by the endothelial cell protein C receptor (EPCR). Activated PC (APC), in turn, is best known for its natural anticoagulant properties. Recent evidence has revealed that TM, APC, and EPCR have activities that impact not only on coagulation but also on inflammation, fibrinolysis, and cell proliferation. This review highlights recent insights into the diverse functions of this complex multimolecular system and how its components are integrated to maintain homeostasis under hypercoagulable and/or proinflammatory stress conditions. Overall, the described advances underscore the usefulness of elucidating the relevant molecular pathways that link both systems for the development of novel therapeutic and diagnostic targets for a wide range of inflammatory diseases.
Collapse
Affiliation(s)
- Marlies Van de Wouwer
- The Center for Transgene Technology and Gene Therapy, University of Leuven and the Flanders Interuniversity Institute for Biotechnology (VIB), Belgium
| | | | | |
Collapse
|
6
|
Affiliation(s)
- F B Taylor
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | | |
Collapse
|
7
|
|
8
|
Abstract
Severe sepsis is common, frequently fatal, and expensive. Many factors related to the pathogenesis of severe sepsis have made it difficult to effectively design clinical trials for the management of this disease. Hence, multiple trials of compounds for the treatment of severe sepsis have yielded largely negative results, except in small subsets of patients. This review provides a synopsis of the complex nature of sepsis and the problems associated with sepsis trials. Emphasis is placed on the difficulties in evaluating investigational agents in patients with severe sepsis because of the heterogeneity of the disorder, lack of correlation between animal and human models, the complexity of the insult and the host reaction, and the interaction between inflammation and coagulation in severe sepsis. Additionally, positive results from trials of steroids, intensive insulin therapy, and activated protein C (drotrecogin alfa [activated]) will be discussed. Because drotrecogin alfa (activated) is the only Food and Drug Administration-approved therapy for severe sepsis, the Phase 3 Protein C Worldwide Evaluation in Severe Sepsis (PROWESS) trial results will be discussed in detail to help define a model for further clinical trials on severe sepsis.
Collapse
Affiliation(s)
- Steven M Opal
- Medicine Infectious Disease Division, Brown University School of Medicine, Pawtucket, Rhode Island 02860, USA.
| |
Collapse
|
9
|
Abstract
In 1914, Schottmueller wrote "Septicemia is a state of microbial invasion from a portal of entry into the blood stream which causes signs of illness." In the last few decades, the evidence that sepsis results from an exaggerated systemic inflammatory host response induced by infecting organisms is compelling; inflammatory mediators are the key players in the pathogenesis of septic shock and multiorgan failure. Sepsis and its sequelae represent a continuum of clinical syndrome encompassing systemic inflammation, coagulopathy, and hemodynamic abnormalities. Severe sepsis and septic shock continue to be the major causes of morbidity and mortality in the United States; sepsis deaths currently match mortality from myocardial infarction. Despite significant advances in our understanding of the pathophysiology and technological innovations in the supportive management, mortality from septic shock remains excessive. After many disappointments with strategies to manipulate the inflammatory response, modulation of coagulation cascade to decrease sepsis mortality has become a clinical reality. This review will highlight and discuss recent advances in the pathophysiology and management of sepsis.
Collapse
Affiliation(s)
- Sat Sharma
- Section of Pulmonary Care Medicine, Department of Internal Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
| | | |
Collapse
|
10
|
Kanji S, Devlin JW, Piekos KA, Racine E. Recombinant human activated protein C, drotrecogin alfa (activated): a novel therapy for severe sepsis. Pharmacotherapy 2001; 21:1389-402. [PMID: 11714212 DOI: 10.1592/phco.21.17.1389.34417] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Sepsis remains a major cause of death in hospitalized patients. Despite a massive research effort over the past 2 decades to identify innovative therapies for sepsis, current treatment strategies consist primarily of antiinfective agents and a variety of supportive measures. Activated protein C, an endogenous protein that inhibits thrombosis and inflammation while promoting fibrinolysis, plays an important role in the pathogenesis of sepsis. Recombinant human activated protein C, drotrecogin alfa (activated), when compared with placebo in a randomized, double-blind study of 1690 patients with severe sepsis (Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis [PROWESS] trial), decreased the relative risk of death at 28 days by 19.4% (95% confidence interval 6.6-30.5%, p=0.005), although there was a trend for more serious bleeding (3.5% vs 2.0%, p=0.06) with its use. Drotrecogin alfa is the first antisepsis drug found to have a mortality benefit. It should be administered only to patients with severe sepsis who meet the PROWESS study inclusion criteria and should be avoided when risk factors for bleeding are present. Ongoing research will help determine the cost-effectiveness of drotrecogin alfa, as well as its role in critically ill populations not studied in the PROWESS trial.
Collapse
Affiliation(s)
- S Kanji
- Department of Pharmacy Services, Detroit Receiving Hospital and University Health Center, USA
| | | | | | | |
Collapse
|
11
|
Isermann B, Hendrickson SB, Zogg M, Wing M, Cummiskey M, Kisanuki YY, Yanagisawa M, Weiler H. Endothelium-specific loss of murine thrombomodulin disrupts the protein C anticoagulant pathway and causes juvenile-onset thrombosis. J Clin Invest 2001. [DOI: 10.1172/jci200113077] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
12
|
Grinnell BW, Joyce D. Recombinant human activated protein C: a system modulator of vascular function for treatment of severe sepsis. Crit Care Med 2001; 29:S53-60; discussion S60-1. [PMID: 11445735 DOI: 10.1097/00003246-200107001-00020] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To review the mechanisms of action and rationale for the use of recombinant human activated protein C in the treatment of severe sepsis. Specifically, we focus on the mechanisms of action in the protein C pathway that converge to modulate the pathophysiology of severe inflammatory disease and sepsis. This analysis includes a discussion of the role of activated protein C in directly modulating cell system biology, independent of antithrombotic activity. DATA SOURCES/STUDY SELECTION Published research and review articles relating to the protein C pathway, recombinant human protein C, and the role of protein C in sepsis. Data were also derived from broad gene profiling in model systems of endothelial dysfunction. DATA EXTRACTION AND SYNTHESIS Relevant studies were included to support discussion of the unique mechanistic aspect of protein C and its role in the pathogenesis of severe sepsis. We discuss the potential of activated protein C as a unique system modulator for the treatment of severe sepsis and other systemic inflammatory responses that result in microvascular coagulopathy, endothelial dysfunction, and vascular bed failure. CONCLUSIONS The protein C pathway plays a unique role in modulating vascular function. As an antithrombotic/profibrinolytic agent, it plays a clear role in maintaining vascular patency. Moreover, it has anti-inflammatory properties and appears to play a unique role as an antiapoptotic and endothelial cell survival factor. In states of systemic inflammatory activation, loss of protein C due to consumptive processes results in a compromised ability to modulate coagulation as well as inflammatory and cell survival functions. This compromise leads to vascular dysfunction, end-organ failure, and death. Replacement with recombinant human activated protein C offers a system-modulating approach to improved outcome.
Collapse
Affiliation(s)
- B W Grinnell
- Division of Research Technology, Lilly Corporate Center, Indianapolis, IN 46285, USA.
| | | |
Collapse
|
13
|
Bernard GR, Vincent JL, Laterre PF, LaRosa SP, Dhainaut JF, Lopez-Rodriguez A, Steingrub JS, Garber GE, Helterbrand JD, Ely EW, Fisher CJ. Efficacy and safety of recombinant human activated protein C for severe sepsis. N Engl J Med 2001; 344:699-709. [PMID: 11236773 DOI: 10.1056/nejm200103083441001] [Citation(s) in RCA: 3790] [Impact Index Per Article: 164.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Drotrecogin alfa (activated), or recombinant human activated protein C, has antithrombotic, antiinflammatory, and profibrinolytic properties. In a previous study, drotrecogin alfa activated produced dose-dependent reductions in the levels of markers of coagulation and inflammation in patients with severe sepsis. In this phase 3 trial, we assessed whether treatment with drotrecogin alfa activated reduced the rate of death from any cause among patients with severe sepsis. METHODS We conducted a randomized, double-blind, placebo-controlled, multicenter trial. Patients with systemic inflammation and organ failure due to acute infection were enrolled and assigned to receive an intravenous infusion of either placebo or drotrecogin alfa activated (24 microg per kilogram of body weight per hour) for a total duration of 96 hours. The prospectively defined primary end point was death from any cause and was assessed 28 days after the start of the infusion. Patients were monitored for adverse events; changes in vital signs, laboratory variables, and the results of microbiologic cultures; and the development of neutralizing antibodies against activated protein C. RESULTS A total of 1690 randomized patients were treated (840 in the placebo group and 850 in the drotrecogin alfa activated group). The mortality rate was 30.8 percent in the placebo group and 24.7 percent in the drotrecogin alfa activated group. On the basis of the prospectively defined primary analysis, treatment with drotrecogin alfa activated was associated with a reduction in the relative risk of death of 19.4 percent (95 percent confidence interval, 6.6 to 30.5) and an absolute reduction in the risk of death of 6.1 percent (P=0.005). The incidence of serious bleeding was higher in the drotrecogin alfa activated group than in the placebo group (3.5 percent vs. 2.0 percent, P=0.06). CONCLUSIONS Treatment with drotrecogin alfa activated significantly reduces mortality in patients with severe sepsis and may be associated with an increased risk of bleeding.
Collapse
Affiliation(s)
- G R Bernard
- Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Abstract
OBJECTIVE To consider the appropriateness of protein C levels as a prognostic indicator for sepsis and related diseases. DATA SOURCES/STUDY SELECTION Published research and review articles related to protein C deficiency in patients with sepsis and related diseases. DATA EXTRACTION AND SYNTHESIS All applicable data were extracted, and relevant literature was cited to support factual statements in the text. The protein C pathway represents one of the major regulatory systems of hemostasis, exhibiting antithrombotic, profibrinolytic, and anti-inflammatory properties. Numerous studies have shown that acquired protein C deficiency is prevalent in the majority of septic patients (>85%) and is associated with increased morbidity and mortality in patients with severe sepsis and septic shock. This deficiency in protein C is not simply a transient marker for sepsis, but parallels the progress of the disease. In addition, protein C deficiency occurs in the presence of a wide range of pathogens and develops early in the disease process. CONCLUSIONS A review of the relevant literature suggests that protein C levels may serve as a useful prognostic indicator of outcome in sepsis and related diseases.
Collapse
Affiliation(s)
- C J Fisher
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN 46285, USA.
| | | |
Collapse
|
15
|
Abstract
In sepsis, levels of the endogenous coagulation inhibitors antithrombin III and protein C are lowered as a result of complex formation with multiple activated clotting factors. In addition, their activity can further be curtailed by proteolytic inactivation. Loss of antithrombin III and protein C activity blocks the endogenous control mechanism for thrombin generation resulting in a state of systemic activation of coagulation and inflammatory processes. Levels of tissue factor pathway inhibitor, a third endogenous coagulation inhibitor, are increased in sepsis rather than decreased, probably reflecting a depletion of the endothelial cell bound tissue factor pathway inhibitor pool with loss of its endothelial protective function. Administration of any of these three inhibitors in various animal species and sepsis models reduces morbidity and mortality. In addition to their anticoagulant effects, these inhibitors also have various anti-inflammatory activities that may contribute to their protective effects. Phase II studies in patients with severe sepsis using coagulation inhibitors have indicated that this therapeutic approach may be useful. Large-scale phase III trials will ultimately decide whether adjunctive coagulation inhibitor replacement will have a place in the treatment of patients with severe sepsis.
Collapse
Affiliation(s)
- L G Thijs
- Medical Intensive Care Unit, Free University Hospital, Amsterdam, The Netherlands
| |
Collapse
|
16
|
Gu JM, Fukudome K, Esmon CT. Characterization and regulation of the 5'-flanking region of the murine endothelial protein C receptor gene. J Biol Chem 2000; 275:12481-8. [PMID: 10777534 DOI: 10.1074/jbc.275.17.12481] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The protein C pathway plays a critical role in the negative regulation of blood coagulation. The nucleotide sequence of the murine endothelial protein C receptor (mEPCR) gene was determined for 8.8 kilobase pairs of the genomic structure and 3.4 kilobase pairs of the 5'-flanking region. RNase protection assay revealed six major transcription start sites clustered at -100 to -109 upstream of the translation initiation site. A series of 5'-promoter deletion fragments were fused to a luciferase reporter gene and transiently transfected into bovine aortic endothelium. Deletion of the sequence from -220 to -180 dramatically reduced luciferase expression in bovine aortic endothelial cells. This region of the murine endothelial protein C receptor gene contains one AP4 site and one SP1 site. Mutations in the core sequence of the AP4 and SP1 sites impaired both nuclear protein binding and luciferase expression. These results suggest important roles for AP4 and SP1 in the constitutive expression of mEPCR. A thrombin response element (CCCACCCC) was found to mediate the induction of mEPCR by thrombin in cell culture. Transgenic mice were developed expressing green fluorescent protein driven by the -350 to -1 or -1080 to -1 promoter. Thrombin up-regulated mEPCR and the transgene in vivo.
Collapse
Affiliation(s)
- J M Gu
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | | | | |
Collapse
|