Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 38
Filter
1.
Rev Sci Instrum ; 91(2): 023510, 2020 Feb 01.
Article in English | MEDLINE | ID: mdl-32113382

ABSTRACT

The requirements of ITER neutral beam injectors (1 MeV, 40 A negative deuterium ion current for 1 h) have never been simultaneously attained; therefore, a dedicated Neutral Beam Test Facility (NBTF) was set up at Consorzio RFX (Padova, Italy). The NBTF includes two experiments: SPIDER (Source for the Production of Ions of Deuterium Extracted from Rf plasma), the full-scale prototype of the source of ITER injectors, with a 100 keV accelerator, to investigate and optimize the properties of the ion source; and MITICA, the full-scale prototype of the entire injector, devoted to the issues related to the accelerator, including voltage holding at low gas pressure. The present paper gives an account of the status of the procurements, of the timeline, and of the voltage holding tests and experiments for MITICA. As for SPIDER, the first year of operation is described, regarding the solution of some issues connected with the radiofrequency power, the source operation, and the characterization of the first negative ion beam.

2.
Sci Rep ; 9(1): 18732, 2019 12 10.
Article in English | MEDLINE | ID: mdl-31822796

ABSTRACT

The complex inhomogeneous architecture of the human meniscal tissue at the micro and nano scale in the absence of artefacts introduced by sample treatments has not yet been fully revealed. The knowledge of the internal structure organization is essential to understand the mechanical functionality of the meniscus and its relationship with the tissue's complex structure. In this work, we investigated human meniscal tissue structure using up-to-date non-invasive imaging techniques, based on multiphoton fluorescence and quantitative second harmonic generation microscopy complemented with Environmental Scanning Electron Microscopy measurements. Observations on 50 meniscal samples extracted from 6 human menisci (3 lateral and 3 medial) revealed fundamental features of structural morphology and allowed us to quantitatively describe the 3D organisation of elastin and collagen fibres bundles. 3D regular waves of collagen bundles are arranged in "honeycomb-like" cells that are comprised of pores surrounded by the collagen and elastin network at the micro-scale. This type of arrangement propagates from macro to the nanoscale.


Subject(s)
Menisci, Tibial/anatomy & histology , Menisci, Tibial/pathology , Microscopy/methods , Biophysical Phenomena/physiology , Collagen/chemistry , Elastin , Humans , Imaging, Three-Dimensional/methods , Menisci, Tibial/diagnostic imaging , Meniscus/diagnostic imaging , Meniscus/pathology , Microscopy, Electron, Scanning/methods
3.
J. nurs. health ; 8(3): e188306, nov. 2018.
Article in Portuguese | BDENF - Nursing | ID: biblio-1029200

ABSTRACT

Objetivo: analisar a valoração axiológica da mulher-nutriz quanto ao apoio no processo de lactação.Método: estudo de cunho social, exploratório, descritivo, qualitativo, realizado em maio e junho de2014 no alojamento conjunto de um hospital universitário localizado em um município do Rio deJaneiro. Foram entrevistadas quinze mulheres-nutrizes internadas. Os dados coletados foramsubmetidos à análise de conteúdo na modalidade temática e à Teoria dos Valores, de Max Scheler.Resultados: o valor identificado foi o valor útil do apoio ao aleitamento materno e do seu manejocomo processo para o enfrentamento das dificuldades vivenciadas pelas nutrizes no início daamamentação. Conclusão: a valoração da amamentação é importante estratégia para a atuaçãoprofissional, permitindo intervir direta e eficazmente junto às nutrizes com ações para assegurar osucesso da promoção e do apoio ao aleitamento materno.


Objective: to analyze the axiological value of nurturing woman regarding the Objective: to analyzethe axiological value of female nurturers regarding the support in the breastfeeding process.Methods: this is a Social, exploratory, descriptive, qualitative study, conducted between May andJune 2014 in the joint accommodation of a university hospital in Rio de Janeiro. At the time, fifteenhospitalized nursing mothers were interviewed. The data were subjected to content analysis inthematic modality and Max Scheler's Theory of Values. Results: the useful value of breastfeedingsupport was identified and its management as a process for the confrontation with the difficultiesexperienced by nursing mothers at the early stages of breastfeeding were identified. Conclusion:the valuation of breastfeeding is an important strategy for health professional performance, allowing direct and effective interventional on the mothers with actions to ensure the success of promotion and support to breastfeeding.


Subject(s)
Humans , Breast Feeding , Nursing , Obstetric Nursing , Social Values
4.
J Biol Regul Homeost Agents ; 32(6 Suppl. 1): 35-40, 2018.
Article in English | MEDLINE | ID: mdl-30644279

ABSTRACT

The knee is the largest and most complex joint in the human body. Traumatic events, such as anterior cruciate ligament (ACL) tear, can lead to an alteration of joint tissues homeostasis. Literature reports an evident correlation between abnormal joint biomechanics and the status of articular tissues. These alterations, due to a sub-optimal ACL reconstruction, may result in an increasing risk of developing degenerative pathologies, such as osteoarthritis. Thus, the identification of the optimal surgical technique is a highly demanding issue in ACL reconstruction. The aim of this study was to analyze the correlation between joint cartilage conditions and knee biomechanics in ACL reconstructions, by integrating MRI T2 mapping investigations, radiostereophotogrammetry-based gait analysis and subject-specific musculoskeletal modelling.


Subject(s)
Anterior Cruciate Ligament Injuries/diagnostic imaging , Anterior Cruciate Ligament Reconstruction , Cartilage, Articular/diagnostic imaging , Biomechanical Phenomena , Humans , Knee Joint/diagnostic imaging , Magnetic Resonance Imaging
5.
J Mech Behav Biomed Mater ; 72: 200-208, 2017 08.
Article in English | MEDLINE | ID: mdl-28500999

ABSTRACT

In joint arthroplasty one of the main issues related to the failure of prosthetic implants is due to the wear of the ultra-high molecular weight polyethylene (UHMWPE) component. Surface treatments and coatings have been recognized as enhancing methods, able to improve the tribological properties of the implants. Therefore, the main objective of this work was to investigate the possibility to fabricate yttria-stabilized zirconia (YSZ) coatings on a metal (AISI 316-L) substrate by means of Pulsed Electron Deposition, in order to improve the tribological behavior of the polymer-metal coupling, by reducing the initial wear of the UHMWPE component. In order to optimize the coating characteristics, the effects of working gas pressure on both its morphological and tribological properties were analyzed. Morphological characterization of the films was evaluated by Atomic Force Microscopy (AFM). Coating wettability was also estimated by contact angle (CA) measurement. Tribological performance (coupling friction and wear of UHMWPE) was evaluated by using a ball-on-disc tribometer during highly-stressing tests in dry and lubricated (i.e. NaCl and serum) conditions; friction and wear were specifically evaluated at the initial sliding distances - to highlight the main effect of coating morphology - and after 100m - where the influence of the intrinsic materials properties prevails. AFM analysis highlighted that the working pressure heavily affected the morphological characteristics of the realized films. The wettability of the coating at the highest and lowest deposition pressures (CA ~ 60°, closed to substrate value) decreased for intermediate pressures, reaching a maximum CA of ~ 90°. Regarding tribological tests, a strong correlation was found in the initial steps between friction coefficient and wettability, which decreased as the distance increased. Concerning UHMWPE wear associated to coated counterpart, at 100m a reduction rate of about 7% in dry, 12% in NaCl and 5% in presence of serum was obtained compared to the uncoated counterpart. Differently from what highlighted for friction, no correlation was found between wear rate and morphological parameters. These findings, in agreement with literature, underlined the effect of the deposition pressure on the morphological properties, but suggested that physical characteristics are influenced too. Further research on the deposition process will be required in order to improve the tribological performance of the coating at long distances, addressing - above all - orthopedic applications.


Subject(s)
Materials Testing , Prostheses and Implants , Zirconium/analysis , Friction , Humans , Plasma Gases , Polyethylenes , Pressure , Surface Properties , Wettability
6.
Mater Sci Eng C Mater Biol Appl ; 62: 643-55, 2016 May.
Article in English | MEDLINE | ID: mdl-26952468

ABSTRACT

One of the most important issues leading to the failure of total joint arthroplasty is related to the wear of the plastic components, which are generally made of ultra high molecular weight polyethylene (UHMWPE). Therefore, the reduction of joint wear represents one of the main challenges the research in orthopedics is called to address nowadays. Surface treatments and coatings have been recognized as innovative methods to improve tribological properties, also in the orthopedic field. This work investigated the possibility to realize hard ceramic coatings on the metal component of a prosthesis, by means of Pulsed Plasma Deposition, in order to reduce friction and wear in the standard coupling against UHMWPE. Ti6Al4V substrates were coated with a 2 µm thick yttria-stabilized zirconia (YSZ) layer. The mechanical properties of the YSZ coatings were assessed by nanoindentation tests performed on flat Ti6Al4V substrates. Tribological performance was evaluated using a ball-on-disk tribometer in dry and lubricated (i.e. with fetal bovine serum) highly-stressing conditions, up to an overall distance of 10 km. Tribology was characterized in terms of coefficient of friction (CoF) and wear rate of the UHMWPE disk. After testing, specimens were analyzed through optical microscopy and SEM images, in order to check the wear degradation mechanisms. Progressive loading scratch tests were also performed in dry and wet conditions to determine the effects of the environment on the adhesion of the coating. Our results supported the beneficial effect of YSZ coating on metal components. In particular, the proposed solution significantly reduced UHMWPE wear rate and friction. At 10 km of sliding distance, a wear rate reduction of about 18% in dry configuration and of 4% in presence of serum, was obtained by the coated group compared to the uncoated group. As far as friction in dry condition is concerned, the coating allowed to maintain low CoF values until the end of the tests, with an overall difference of about 40% compared to the uncoated balls. In wet conditions, the friction values were found to be comparable between coated and uncoated materials, mainly due to a premature delamination of the coating. Scratch tests in wet showed in fact a reduction of the critical load required to a complete delamination due to a formation of blister, although no change or damage occurred at the coating during the soaking period. Although conditions of high values of contact pressure were considered, further analyses are however required to fully understand the behavior of YSZ coatings in wet environment and additional research on the deposition process will be mandatory in order to improve the coating tribological performance at long distances addressing orthopedic applications.


Subject(s)
Coated Materials, Biocompatible/chemistry , Titanium/chemistry , Zirconium/chemistry , Alloys , Animals , Elastic Modulus , Friction , Hardness , Humans , Materials Testing , Microscopy, Electron, Scanning , Orthopedics , Polyethylenes/chemistry
7.
Mater Sci Eng C Mater Biol Appl ; 58: 381-8, 2016 Jan 01.
Article in English | MEDLINE | ID: mdl-26478324

ABSTRACT

Realizing hard ceramic coatings on the plastic component of a joint prosthesis can be strategic for the mechanical preservation of the whole implant and to extend its lifetime. Recently, thanks to the Plasma Pulsed Deposition (PPD) method, zirconia coatings on ultra-high molecular weight polyethylene (UHMWPE) substrates resulted in a feasible outcome. Focusing on both the highly specific requirements defined by the biomedical application and the effective possibilities given by the deposition method in the perspectives of technological transfer, it is mandatory to optimize the coating in terms of load bearing capacity. The main goal of this study was to identify through Finite Element Analysis (FEA) the optimal coating thickness that would be able to minimize UHMWPE strain, possible insurgence of cracks within the coating and stresses at coating-substrate interface. Simulations of nanoindentation and microindentation tests were specifically carried out. FEA findings demonstrated that, in general, thickening the zirconia coating strongly reduced the strains in the UHMWPE substrate, although the 1 µm thickness value was identified as critical for the presence of high stresses within the coating and at the interface with the substrate. Therefore, the optimal thickness resulted to be highly dependent on the specific loading condition and final applications.


Subject(s)
Ceramics/chemistry , Coated Materials, Biocompatible/chemistry , Finite Element Analysis , Orthopedics/methods , Plastics/chemistry , Materials Testing , Polyethylenes , Stress, Mechanical , Zirconium/chemistry
8.
Environ Sci Pollut Res Int ; 22(24): 19786-92, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26282437

ABSTRACT

In this study, monthly variations in biomass of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) were analysed over a 1-year period by fluorescence in situ hybridization (FISH) at the full-scale Fusina WWTP. The nitrification capacity of the plant was also monitored using periodic respirometric batch tests and by an automated on-line titrimetric instrument (TITrimetric Automated ANalyser). The percentage of nitrifying bacteria in the plant was the highest in summer and was in the range of 10-15 % of the active biomass. The maximum nitrosation rate varied in the range 2.0-4.0 mg NH4 g(-1) VSS h(-1) (0.048-0.096 kg TKN kg(-1) VSS day(-1)): values obtained by laboratory measurements and the on-line instrument were similar and significantly correlated. The activity measurements provided a valuable tool for estimating the maximum total Kjeldahl nitrogen (TKN) loading possible at the plant and provided an early warning of whether the TKN was approaching its limiting value. The FISH analysis permitted determination of the nitrifying biomass present. The main operational parameter affecting both the population dynamics and the maximum nitrosation activity was mixed liquor volatile suspended solids (MLVSS) concentration and was negatively correlated with ammonia-oxidizing bacteria (AOB) (p = 0.029) and (NOB) (p = 0.01) abundances and positively correlated with maximum nitrosation rates (p = 0.035). Increases in concentrations led to decreases in nitrifying bacteria abundance, but their nitrosation activity was higher. These results demonstrate the importance of MLVSS concentration as key factor in the development and activity of nitrifying communities in wastewater treatment plants (WWTPs). Operational data on VSS and sludge volume index (SVI) values are also presented on 11-year basis observations.


Subject(s)
Betaproteobacteria/growth & development , Nitrites/analysis , Nitrobacter/growth & development , Sewage/microbiology , Wastewater/microbiology , Water Purification/methods , Betaproteobacteria/genetics , Biomass , In Situ Hybridization, Fluorescence , Italy , Nitrification , Nitrites/metabolism , Nitrobacter/genetics , Planctomycetales/genetics , Planctomycetales/growth & development , Seasons , Verrucomicrobia/genetics , Verrucomicrobia/growth & development
9.
Euro Surveill ; 17(36): 20260, 2012 Sep 06.
Article in English | MEDLINE | ID: mdl-22971328

ABSTRACT

In July-September 2012, one month earlier than in previous years, 13 confirmed human cases of West Nile virus infection were diagnosed in northern Italy, including five with neuroinvasive disease, three with West Nile fever, and five West Nile virus (WNV)-positive blood donors. In nine cases, the presence of the WNV lineage 1a Livenza strain, characterised in 2011, was ascertained. Symptomatic patients had prolonged viruria with high viral load.


Subject(s)
Disease Outbreaks , RNA, Viral/genetics , West Nile Fever/virology , West Nile virus/genetics , Blood Donors , Follow-Up Studies , Humans , Italy/epidemiology , Population Surveillance/methods , Real-Time Polymerase Chain Reaction , Sequence Analysis , Viral Load , West Nile Fever/epidemiology , West Nile Fever/genetics , West Nile virus/isolation & purification
10.
Euro Surveill ; 17(31)2012 Aug 02.
Article in English | MEDLINE | ID: mdl-22874456

ABSTRACT

We report here the first blood donation positive for West Nile virus (WNV) by nucleic acid amplification testing collected in north-eastern Italy in July 2012.Partial sequencing of the WNV RNA demonstrated identity with a WNV lineage 1a genome identified in the same area in 2011 and divergence from the strain responsible for the outbreak in northern Italy in 2008­09. These data indicate that WNV activity in northern Italy is occurring earlier than expected and that different WNV strains are circulating.


Subject(s)
Blood Donors , RNA, Viral/genetics , West Nile Fever/virology , West Nile virus/genetics , Endemic Diseases , Humans , Italy/epidemiology , Nucleic Acid Amplification Techniques , Phylogeny , Population Surveillance , Sequence Analysis , West Nile Fever/epidemiology , West Nile Fever/genetics
12.
Phys Rev Lett ; 97(7): 075001, 2006 Aug 18.
Article in English | MEDLINE | ID: mdl-17026237

ABSTRACT

Stable operation with control on magnetohydrodynamic modes has been obtained in the modified reversed field experiment employing a set of 192 feedback controlled saddle coils. Improvements of plasma temperature, confinement (twofold), and pulse length (threefold) and, as a consequence of the magnetic fluctuation reduction, strong mitigation of plasma-wall interaction and mode locking are reported.

14.
Phys Rev Lett ; 93(22): 225001, 2004 Nov 26.
Article in English | MEDLINE | ID: mdl-15601096

ABSTRACT

Active feedback stabilization of multiple independent resistive wall modes is experimentally demonstrated in a reversed-field pinch plasma. A reproducible simultaneous suppression of several nonresonant resistive wall modes is achieved. Coupling of different modes due to the limited number of the feedback coils is observed in agreement with theory. The feedback stabilization of nonresonant RWMs also has an effect on tearing modes that are resonant in the central plasma, leading to a significant prolongation of the discharge pulse.

16.
Transfus Apher Sci ; 30(3): 197-203, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15172624

ABSTRACT

BACKGROUND: In transfusional setting introduction of nucleic amplification technique (NAT) for HBV-DNA, HCV-RNA and HIV-RNA in biological qualification of blood units suggest some problems. At first the opportunity to operate on mini-pool, at second the need to store the samples at +4 degrees C. The authors therefore have tried to estimate the impact of these conditions on the operativity of NAT testing in the transfusional setting. METHODS: The following parameters has been estimated: distribution of viral-load in untreated subjects, stability of nucleic acids during storage at +4 degrees C, stability of nucleic acids after repeated cycles of freezing and defrosting, robustness of the test to the cross-contamination, definition of the detection-limit (95%). Quantitative tests has been performed by using the following kits: Cobas Amplicor HBV Monitor, Cobas Amplicor HCV Monitor, Cobas Amplicor HIV Monitor; the qualitative tests has been performed by using the following kits: Ampliscreen HBV, Ampliscreen HCV 2,0, Ampliscreen HIV 1,5 all supplied by Roche Molecular System (Brancburg, NJ). RESULTS: Viral load in untreated subjects showed wide variation for HBV, HCV and HIV. HBV has been demonstrated much stable to the conservation +4 degrees C also until 168 h while for HCV and HIV a greater decrease of the viral-load was observed. For all and three virus the conservation to +4 degrees C until 72 h does not seem to involve meaningful fall in the viral-load. A remarkable reduction of the viral-load has been observed after five cycles of freezing and defrosting. All the tests showed a good robustness to cross-contamination. The detection-limit (95%) was 8 U/ml for HBV, 21 U/ml for HCV and 27 copy/ml for HIV. CONCLUSIONS: Samples for NAT testing, can be stored until 72 h to +4 degrees C without appreciable lowering of the viral-load. Repeated cycles of changes of state should be avoided. The tests showed a good robustness to cross-contamination. NAT tests for biological qualification of blood units had a minimal sensibility around 50 (copy/unit/ml). In our experience the detection-limit (95%) was 21 U/ml for HCV, 27 copies/ml for HIV, 8 U/ml for HBV. The availability of NAT test for HBV-DNA, HCV-RNA e HIV-RNA, sensitive and reliable, together with epidemiological data, suggest the opportunity to place side by side, in the biological qualification of the blood units, to add the tests for HBV-DNA and HIV-RNA to the test for HCV-RNA mandatory by low, in Italy in the biological qualification of blood units.


Subject(s)
Blood Preservation/methods , DNA, Viral/isolation & purification , Nucleic Acids/blood , RNA Stability , RNA, Viral/isolation & purification , Refrigeration/statistics & numerical data , HIV Infections/blood , HIV Infections/prevention & control , HIV-1/genetics , HIV-1/isolation & purification , Hepacivirus/genetics , Hepacivirus/isolation & purification , Hepatitis B/blood , Hepatitis B/prevention & control , Hepatitis B virus/genetics , Hepatitis B virus/isolation & purification , Hepatitis C/blood , Hepatitis C/prevention & control , Humans , Refrigeration/standards , Sensitivity and Specificity , Temperature , Time Factors , Viral Load/statistics & numerical data
17.
Can J Cardiol ; 20(4): 411-6, 2004 Mar 15.
Article in English | MEDLINE | ID: mdl-15057317

ABSTRACT

BACKGROUND: Left ventricular function is the most important determinant of prognosis following myocardial infarction. METHODS: A prospective analytical cohort study of 33 cardiac care unit survivors of acute myocardial infarction was performed to assess the accuracy, reproducibility and observer variation of the bedside Valsalva response in predicting an ejection fraction (EF) less than 40%. RESULTS: Agreement between physicians for the clinical Valsalva response was excellent (kappa coefficient 0.75), as was the comparison between physicians' clinical response to the Finapres (Ohmeda, USA) hemodynamic response (weighted kappa=0.85). The EF was significantly higher among patients with a normal Valsalva response (56.9%) than in patients with either an absent overshoot (48.4%) or a square wave (28.3%) response (P<0.001). Physicians were very accurate at estimating whether the EF was greater or less than 40%. In 40 of 66 situations, the clinicians were confident, based on the clinical examination and the Valsalva response, that the EF was either greater or less than 40%. In these situations, agreement (95.0%) and kappa (0.89) were both excellent. When all patients were considered, the degree of agreement (90.8%) and kappa (0.80) diminished slightly. A square wave response had poor sensitivity (37.5%) but excellent specificity (92.7%), whereas any abnormal response had excellent sensitivity (91.7%) but poor specificity (54.8%). CONCLUSION: Compared with many other aspects of the clinical examination, the bedside Valsalva manoeuvre has acceptable degrees of interobserver variability. A normal response tends to rule in an EF of greater than 40%, whereas a square wave response rules out an EF of greater than 40%. This simple bedside manoeuvre may be useful in predicting low EF following acute myocardial infarction.


Subject(s)
Myocardial Infarction/diagnosis , Myocardial Infarction/physiopathology , Point-of-Care Systems , Stroke Volume/physiology , Adult , Aged , Female , Humans , Male , Middle Aged , Myocardial Infarction/epidemiology , Observer Variation , Ontario/epidemiology , Prospective Studies , Reproducibility of Results , Sensitivity and Specificity , Severity of Illness Index , Statistics as Topic , Valsalva Maneuver/physiology , Ventricular Dysfunction, Left/diagnosis , Ventricular Dysfunction, Left/epidemiology , Ventricular Dysfunction, Left/physiopathology
18.
Minerva Ginecol ; 54(4): 333-8, 2002 Aug.
Article in Italian | MEDLINE | ID: mdl-12114866

ABSTRACT

BACKGROUND: This study report the results obtained in a retrospective analysis of the foetal-maternal alloimmunizations observed from 1993 to 1999 in the South-East area of the Venice province. METHODS: The data concerning 17,000 pregnancy observed in this area from 1993-1999 have been collected. For each pregnancy data concerning maternal ABO, Rh, Kk and IAT as well as foetal ABO, Rh, Kk and DAT were available. Further data (mainly antibodies concentration and specificity) were available if a foetal-maternal alloimmunization was detected and if transfusional support was given after the birth. RESULTS: The authors observed 465 alloimmunizations (prevalence 2.7%): 381 (82%) of these were due to an ABO foetal-maternal incompatibility, 23 due to D incompatibility and the other 61 due to other blood groups antigens. Only 6 cases needed transfusional support: 5 exchange transfusion (a patient needed 2 exchanges) and a delayed transfusion. CONCLUSIONS: Foetal-maternal alloimmunizations are today a rare but not exceptional event (about 3% of pregnancy), the great majority of these alloimmunizations are due to an ABO incompatibility. Despite the prevention of alloimmunization in D negative women by using Rh immune globulin, anti-D alloimmunization is still observed. A great number of other blood groups antigens are involved in foetal-maternal alloimmunization mainly within the Rh system (CcEe, etc.). In the authors' experience the great majority of foetal-maternal alloimmunizations were clinically silent, only 6 cases (1.3% of patients with a positive DAT) needed transfusional therapy.


Subject(s)
Erythroblastosis, Fetal/epidemiology , Pregnancy Complications, Hematologic/epidemiology , Rh Isoimmunization/epidemiology , ABO Blood-Group System/blood , Blood Group Incompatibility/immunology , Coombs Test , Erythroblastosis, Fetal/blood , Female , Fetal Blood/immunology , Fetomaternal Transfusion/immunology , Humans , Infant, Newborn , Maternal-Fetal Exchange , Pregnancy , Pregnancy Complications, Hematologic/blood , Retrospective Studies , Rh Isoimmunization/blood , Rho(D) Immune Globulin/therapeutic use
19.
Hypertension ; 38(6): 1433-9, 2001 Dec 01.
Article in English | MEDLINE | ID: mdl-11751731

ABSTRACT

Pulse pressure, an indirect measure of vascular stiffness and pulsatile load, predicts clinical events in congestive heart failure (CHF), suggesting that abnormal pulsatile load may contribute to CHF. This study was designed to assess more direct measures of central pulsatile load in CHF. Noninvasive hemodynamic evaluations were performed in 28 subjects with CHF and 40 controls using calibrated tonometry of the brachial, radial, femoral, and carotid arteries along with echocardiographic assessment of left ventricular outflow tract (LVOT) diameter and Doppler flow. Characteristic impedance (Z(c)) was calculated as the ratio of DeltaP (carotid) and DeltaQ (LVOT flow) in early systole. Carotid-radial (CR-PWV) and carotid-femoral (CF-PWV) pulse wave velocities were calculated from tonometry. Augmentation index was assessed from the carotid waveform. Total arterial compliance (TAC) was calculated using the area method. Brachial pulse pressure was elevated (62+/-16 versus 53+/-15 mm Hg, P=0.015) in CHF because of lower diastolic pressure (66+/-10 versus 73+/-9 mm Hg, P=0.003). CHF had higher Z(c) (225+/-76 versus 184+/-66 dyne. sec. cm(-5), P=0.020). CF-PWV did not differ (9.7+/-2.7 versus 9.2+/-2.0, P=0.337), whereas CR-PWV was lower in CHF (8.6+/-1.4 versus 9.4+/-1.5, P=0.038). There was no difference in TAC (1.4+/-0.5 versus 1.4+/-0.6 mL/mmHg, P=0.685), and augmentation index was lower in CHF (8+/-17 versus 21+/-13%, P=0.001). CHF subjects have elevated central pulsatile load (Z(c)), which is not apparent in global measures such as augmentation index or TAC, possibly because of contrasting changes in central and peripheral conduit vessels. This increased pulsatile load represents an important therapeutic target in CHF.


Subject(s)
Arteries/physiopathology , Extracellular Matrix Proteins , Heart Failure/physiopathology , Pulsatile Flow , Blood Flow Velocity , Carotid Arteries/diagnostic imaging , Contractile Proteins , Double-Blind Method , Elasticity , Electrocardiography , Female , Heart Failure/complications , Hemodynamics , Humans , Male , Middle Aged , RNA Splicing Factors , Ultrasonography , Ventricular Dysfunction, Left/complications , Ventricular Dysfunction, Left/physiopathology
SELECTION OF CITATIONS
SEARCH DETAIL
...