The Experts below are selected from a list of 2313 Experts worldwide ranked by ideXlab platform
Gary E Mcveigh - One of the best experts on this subject based on the ideXlab platform.
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nitric oxide modulation of ophthalmic artery blood flow velocity Waveform Morphology in healthy volunteers
Clinical Science, 2006Co-Authors: Christopher J Lockhart, Andrew J Gamble, Derrick J Rea, Sinead M Hughes, Canice R Mcgivern, Clive Wolsley, Michael Stevenson, Mark Harbinson, Rick D Plumb, Gary E McveighAbstract:Quantitative analysis of the arterial pressure pulse Waveform recorded by applanation tonometry of the radial artery can track NO (nitric oxide)-mediated modulation of arterial smooth muscle tone. The changes in pressure pulse Waveform Morphology result from pulse wave reflection arising predominantly from smaller arteries and arterioles. Employing Doppler ultrasound to record the spectral flow velocity Waveform in the ophthalmic artery, we studied the effects of NO modulation on Waveforms recorded in the proximity of the terminal ocular microcirculatory bed. In healthy young men (n=10; age 18-26 years), recordings were made at baseline, following 300 mug of sublingual GTN (glyceryl trinitrate) and during the intravenous infusion of 0.25 and 0.5 mg/kg of L-NAME (N(G)-nitro-L-arginine methyl ester). Peaks (P1, P2 and P3) and nodes (N1, N2 and N3) on the arterial flow velocity Waveform were identified during the cardiac cycle and employed to quantify wave shape change in response to the haemodynamic actions of the pharmacological interventions. The administration of GTN resulted in a significant (P<0.05) increase in heart rate without significant alteration in blood pressure. At the doses employed, L-NAME did not significantly alter systemic haemodynamics. With the exception of peak Doppler systolic velocity, all other peaks and nodes decreased significantly in response to GTN (P<0.05 for all points compared with baseline). In response to the administration of L-NAME, all peaks and nodes decreased significantly (P<0.05 for all points compared with baseline). The resistive index, a ratio calculated from the peak and trough flow velocities employed to assess change in flow resistance, increased significantly in response to GTN (0.77 at baseline compared with 0.85; P<0.05). Quantification of changes in the flow velocity spectral Waveform during the cardiac cycle sensitively identified NO modulation of smooth muscle tone prior to alteration in systemic haemodynamics. Focusing on the resistive index, which identifies isolated points on the Waveform describing the excursions of flow, may provide misleading information in relation to the haemodynamic effects of drug interventions.
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nitric oxide modulation of blood vessel tone identified by arterial Waveform analysis
Clinical Science, 2001Co-Authors: Gary E Mcveigh, Patrick Allen, David R Morgan, Colm G Hanratty, B SilkeAbstract:: Traditionally, nitric oxide-mediated alteration in blood vessel tone has been inferred from changes in flow in response to physical and pharmacological interventions using plethysmographic or ultrasonic techniques. We hypothesized that alteration in pulsatile arterial function may represent a more sensitive measure to detect and monitor nitric oxide-mediated modulation of arterial smooth muscle tone. Healthy male volunteers (n = 15) had radial artery pressure pulse Waveforms recorded using a calibrated tonometer device. A computer-based assessment of the diastolic pressure decay was employed to quantify changes in arterial Waveform Morphology in terms of altered pulsatile (arterial compliance) and steady-state (peripheral resistance) haemodynamics. N(G)-nitro-L-arginine methyl ester (L-NAME), a stereospecific inhibitor of nitric oxide synthesis, was infused intravenously in incrementally increasing doses of 0.25, 0.5 and 0.75 mg/kg for 8 min each. Subjects then received either L-arginine or D-arginine (200 mg/kg over 15 min) intravenously in a blinded fashion. On a separate day, subjects had radial artery pressure pulse Waveforms recorded before and after the sublingual administration of glyceryl trinitrate, an exogenous donor of nitric oxide. Cardiac output and heart rate decreased and mean arterial blood pressure increased significantly (P < 0.01 for all) in response to the incremental intravenous infusion of L-NAME. Small artery compliance decreased, whereas systemic vascular resistance increased in response to nitric oxide synthesis inhibition (P < 0.01 for both). The intravenous infusion of L-arginine restored the pulsatile and steady-state haemodynamic parameters to pre-treatment values, whereas D-arginine had no effect. Sublingual glyceryl trinitrate decreased systemic vascular resistance by 11%, whereas large artery- and small artery-compliance increased by 25% and 44% respectively. Pressure pulse contour analysis represents a sensitive and convenient technique capable of tracking changes in the pulsatile function of arteries accompanying nitric oxide-mediated alteration in arterial smooth muscle tone.
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age related abnormalities in arterial compliance identified by pressure pulse contour analysis aging and arterial compliance
Hypertension, 1999Co-Authors: Gary E Mcveigh, Christopher W Bratteli, Dennis J Morgan, C Alinder, Stephen P Glasser, Stanley M Finkelstein, Jay N CohnAbstract:Abstract —The objective of this study was to evaluate age-related changes in pulsatile arterial function. Aging alters arterial pulsatile function and produces consistent changes in the pressure pulse contour. A reduced systemic arterial compliance that can be derived from analysis of the pulse contour is regarded as the best clinical index of impaired pulsatile arterial function and may mark the presence of early vascular damage. We analyzed intra-arterial brachial artery Waveforms in 115 healthy normotensive volunteers (83 men, 32 women) and radial artery Waveforms obtained with the use of a calibrated tonometer device in 212 healthy volunteers (147 women, 65 men). A computer-based assessment of the diastolic pressure decay and a modified Windkessel model of the circulation were used to quantify changes in arterial Waveform Morphology in terms of large artery or capacitive compliance, oscillatory or reflective compliance in the small arteries, inertance, and systemic vascular resistance. Large artery compliance and oscillatory compliance correlated negatively with age for both invasive and noninvasive groups ( r =−0.50 and r =−0.55; r =−0.37 and r =−0.66; P
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age related abnormalities in arterial compliance identified by pressure pulse contour analysis aging and arterial compliance
Hypertension, 1999Co-Authors: Gary E Mcveigh, Christopher W Bratteli, Dennis J Morgan, C Alinder, Stephen P Glasser, Stanley M Finkelstein, Jay N CohnAbstract:The objective of this study was to evaluate age-related changes in pulsatile arterial function. Aging alters arterial pulsatile function and produces consistent changes in the pressure pulse contour. A reduced systemic arterial compliance that can be derived from analysis of the pulse contour is regarded as the best clinical index of impaired pulsatile arterial function and may mark the presence of early vascular damage. We analyzed intra-arterial brachial artery Waveforms in 115 healthy normotensive volunteers (83 men, 32 women) and radial artery Waveforms obtained with the use of a calibrated tonometer device in 212 healthy volunteers (147 women, 65 men). A computer-based assessment of the diastolic pressure decay and a modified Windkessel model of the circulation were used to quantify changes in arterial Waveform Morphology in terms of large artery or capacitive compliance, oscillatory or reflective compliance in the small arteries, inertance, and systemic vascular resistance. Large artery compliance and oscillatory compliance correlated negatively with age for both invasive and noninvasive groups (r=-0.50 and r=-0.55; r=-0.37 and r=-0.66; P<0.001 for all). The slopes of the regression lines for the decline in oscillatory compliance with age were significantly steeper than those recorded for large artery compliance estimates. The change in blood pressure with age independently contributed to the decrease in large artery compliance but not oscillatory compliance in both groups. Consistent age-related changes were found in the pressure pulse contour by analysis of Waveforms obtained invasively or noninvasively from the upper limb. The change in the oscillatory or reflective compliance estimate was independent of blood pressure change and may represent a better marker than large artery or capacitive compliance of the degenerative aging process in altering pulsatile arterial function.
Philip Weinstein - One of the best experts on this subject based on the ideXlab platform.
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changes in transcranial motor evoked potentials during intramedullary spinal cord tumor resection correlate with postoperative motor function
Neurosurgery, 2005Co-Authors: Alfredo Quinoneshinojosa, Russ Lyon, Andrew T Parsa, Gabriel Zada, Kathleen R Lamborn, Michael W Mcdermott, Nalin Gupta, Philip WeinsteinAbstract:OBJECTIVE: Intraoperative monitoring of transcranial motor evoked potentials (TcMEPs) has been investigated recently as a means of preventing motor deficits associated with resection of intramedullary spinal cord tumors (IMSCTs). In this study, we hypothesized that changes in the intraoperative MEPs during tumor resection correlate with postoperative motor function deficits. METHODS: A retrospective record review was conducted for 28 patients who underwent resection of an IMSCT using myogenic or muscle-recorded TcMEPs during a 44-month period. Intraoperative MEP recordings and results from preoperative, immediate postoperative, and subsequent follow-up neurological examinations were analyzed. RESULTS: Of the 28 patients who underwent resection of an IMSCT using TcMEPs, MEP changes occurred in 13 patients (46%). Impaired motor conduction was detected by changes in pattern and duration of the MEP Waveform Morphology (polyphasic to biphasic in 9 patients and polyphasic to biphasic to loss of MEP response in 5 patients, 1 patient demonstrated both changes) and by an increase in voltage threshold (median, 175 V; range, 100-225 V; n = 22 extremities). Alterations in Morphology and reduction in duration of the MEP response persisted despite significant increases in stimulation voltage. In 12 patients, reductions in the complexity and/or loss of the TcMEP Waveform correlated with motor grade loss in the immediate postoperative period (P < 0.0001), at discharge (P < 0.001), and at follow-up (P < 0.001). The decrease in the duration of the response correlated with motor grade loss immediately after surgery (P < 0.001), at discharge (P < 0.0001), and at follow-up (P < 0.005). CONCLUSION: These results support the application of distal muscle-recorded TcMEPs to predict the occurrence and severity of postoperative motor deficits during resection of IMSCTs. Attention to such quantitative intraoperative monitoring data may help to minimize postoperative motor deficits by avoiding or correcting excessive spinal cord manipulation and modifying surgical technique during tumor resection.
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changes in transcranial motor evoked potentials during intramedullary spinal cord tumor resection correlate with postoperative motor function
Neurosurgery, 2005Co-Authors: Alfredo Quinoneshinojosa, Russ Lyon, Andrew T Parsa, Gabriel Zada, Kathleen R Lamborn, Michael W Mcdermott, Nalin Gupta, Philip WeinsteinAbstract:OBJECTIVE: Intraoperative monitoring of transcranial motor evoked potentials (TcMEPs) has been investigated recently as a means of preventing motor deficits associated with resection of intramedullary spinal cord tumors (IMSCTs). In this study, we hypothesized that changes in the intraoperative MEPs during tumor resection correlate with postoperative motor function deficits. METHODS: A retrospective record review was conducted for 28 patients who underwent resection of an IMSCT using myogenic or muscle-recorded TcMEPs during a 44-month period. Intraoperative MEP recordings and results from preoperative, immediate postoperative, and subsequent follow-up neurological examinations were analyzed. RESULTS: Of the 28 patients who underwent resection of an IMSCT using TcMEPs, MEP changes occurred in 13 patients (46%). Impaired motor conduction was detected by changes in pattern and duration of the MEP Waveform Morphology (polyphasic to biphasic in 9 patients and polyphasic to biphasic to loss of MEP response in 5 patients, 1 patient demonstrated both changes) and by an increase in voltage threshold (median, 175 V; range, 100-225 V; n = 22 extremities). Alterations in Morphology and reduction in duration of the MEP response persisted despite significant increases in stimulation voltage. In 12 patients, reductions in the complexity and/or loss of the TcMEP Waveform correlated with motor grade loss in the immediate postoperative period (P < 0.0001), at discharge (P < 0.001), and at follow-up (P < 0.001). The decrease in the duration of the response correlated with motor grade loss immediately after surgery (P < 0.001), at discharge (P < 0.0001), and at follow-up (P < 0.005). CONCLUSION: These results support the application of distal muscle-recorded TcMEPs to predict the occurrence and severity of postoperative motor deficits during resection of IMSCTs. Attention to such quantitative intraoperative monitoring data may help to minimize postoperative motor deficits by avoiding or correcting excessive spinal cord manipulation and modifying surgical technique during tumor resection.
Robert B Hamilton - One of the best experts on this subject based on the ideXlab platform.
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a review of the use of transcranial doppler Waveform Morphology for acute stroke assessment
Journal of Clinical Neuroscience, 2020Co-Authors: Amber Y Dorn, Kian Jalaleddini, Samuel G Thorpe, Nicolas Canac, Robert B HamiltonAbstract:Acute ischemic stroke is a source of long-term disability in the United States, of which a large portion of cases are a result of large vessel occlusion (LVO). LVO strokes have high rates of morbidity and mortality due to difficulty of treatments in achieving recanalization. Recently, however, results of randomized clinical trials have shown that treatment options are expanding in both availability and efficacy. As these methods of intervention become more optimal, so must the preceding methods of assessment. Transcranial Doppler (TCD) ultrasound is a non-invasive method of evaluating cerebral hemodynamics, and has a long history in stroke assessment. Despite the importance of information provided by a TCD exam, its utilization in the acute stroke workflow has remained low because of its dependence on expert analysis. Here, we review the evolution of morphological analysis of TCD Waveforms for the indication, localization, and monitoring of acute LVO.
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toward automated classification of pathological transcranial doppler Waveform Morphology via spectral clustering
PLOS ONE, 2020Co-Authors: Samuel G Thorpe, Kian Jalaleddini, Nicolas Canac, Amber Y Dorn, Corey M Thibeault, Seth J Wilk, Fabien Scalzo, Thomas Devlin, Robert B HamiltonAbstract:Cerebral Blood Flow Velocity Waveforms acquired via Transcranial Doppler (TCD) can provide evidence for cerebrovascular occlusion and stenosis. Thrombolysis in Brain Ischemia (TIBI) flow grades are widely used for this purpose, but require subjective assessment by expert evaluators to be reliable. In this work we seek to determine whether TCD Morphology can be objectively assessed using an unsupervised machine learning approach to Waveform categorization. TCD beat Waveforms were recorded at multiple depths from the Middle Cerebral Arteries of 106 subjects; 33 with Large Vessel Occlusion (LVO). From each Waveform, three morphological features were extracted, quantifying onset of maximal velocity, systolic canopy length, and the number/prominence of peaks/troughs. Spectral clustering identified groups implicit in the resultant three-dimensional feature space, with gap statistic criteria establishing the optimal cluster number. We found that gap statistic disparity was maximized at four clusters, referred to as flow types I, II, III, and IV. Types I and II were primarily composed of control subject Waveforms, whereas types III and IV derived mainly from LVO patients. Cluster morphologies for types I and IV aligned clearly with Normal and Blunted TIBI flows, respectively. Types II and III represented commonly observed flow-types not delineated by TIBI, which nonetheless deviate from normal and blunted flows. We conclude that important morphological variability exists beyond that currently quantified by TIBI in populations experiencing or at-risk for acute ischemic stroke, and posit that the observed flow-types provide the foundation for objective methods of real-time automated flow type classification.
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decision criteria for large vessel occlusion using transcranial doppler Waveform Morphology
Frontiers in Neurology, 2018Co-Authors: Samuel G Thorpe, Nicolas Canac, Corey M Thibeault, Seth J Wilk, Thomas Devlin, Robert B HamiltonAbstract:Background: The current lack of effective tools for prehospital identification of Large Vessel Occlusion (LVO) represents a significant barrier to efficient triage of stroke patients and detriment to treatment efficacy. The validation of objective Transcranial Doppler (TCD) metrics for LVO detection could provide first responders with requisite tools for informing stroke transfer decisions, dramatically improving patient care. Objective: To compare the diagnostic efficacy of two such candidate metrics: Velocity Asymmetry Index (VAI), which quantifies disparity of blood flow velocity across the cerebral hemispheres, and Velocity Curvature Index (VCI), a recently proposed TCD morphological biomarker. Additionally, we investigate a simple decision tree combining both metrics. Methods: We retrospectively compare accuracy/sensitivity/specificity (ACC/SEN/SPE) of each method (relative to standard CT-Angiography) in detecting LVO in a population of 66 subjects presenting with stroke symptoms (33 with CTA-confirmed LVO), enrolled consecutively at Erlanger Southeast Regional Stroke Center in Chattanooga, TN. Results: Individual VCI and VAI metrics demonstrated robust performance, with area under receiver operating characteristic curve (ROC-AUC) of 94% and 88%, respectively. Additionally, leave-one-out cross-validation at optimal identified thresholds resulted in 88% ACC (88% SEN) for VCI, vs. 79% ACC (76% SEN) for VAI. When combined, the resultant decision tree achieved 91% ACC (94% SEN). Discussion: We conclude VCI to be superior to VAI for LVO detection, and provide evidence that simple decision criteria incorporating both metrics may further optimize. Performance: Our results suggest that machine-learning approaches to TCD morphological analysis may soon enable robust prehospital LVO identification. Registration: Was not required for this feasibility study.
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algorithm for reliable detection of beat onsets in cerebral blood flow velocity signals
bioRxiv, 2018Co-Authors: Nicolas Canac, Kian Jalaleddini, Samuel G Thorpe, Corey M Thibeault, Seth J Wilk, Shadnaz Asgari, Mina Ranjbaran, Michael J Obrien, Fabien Scalzo, Robert B HamiltonAbstract:Transcranial Doppler (TCD) ultrasound has been demonstrated to be a valuable tool for assessing cerebral hemodynamics via measurement of cerebral blood flow velocity (CBFV), with a number of established clinical indications. However, CBFV Waveform analysis depends on reliable pulse onset detection, an inherently difficult task for CBFV signals acquired via TCD. We study the application of a new algorithm for CBFV pulse segmentation, which locates pulse onsets in a sequential manner using a moving difference filter and adaptive thresholding. The test data set used in this study consists of 92,012 annotated CBFV pulses, whose quality is representative of real world data. On this test set, the algorithm achieves a true positive rate of 99.998% (2 false negatives), positive predictive value of 99.998% (2 false positives), and mean temporal offset error of 6.10 ± 4.75 ms. We do note that in this context, the way in which true positives, false positives, and false negatives are defined caries some nuance, so care should be taken when drawing comparisons to other algorithms. Additionally, we find that 97.8% and 99.5% of onsets are detected within 10 ms and 30 ms, respectively, of the true onsets. The algorithm9s performance in spite of the large degree of variation in signal quality and Waveform Morphology present in the test data suggests that it may serve as a valuable tool for the accurate and reliable identification of CBFV pulse onsets in neurocritical care settings.
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subpeak regional analysis of intracranial pressure Waveform Morphology based on cerebrospinal fluid hydrodynamics in the cerebral aqueduct and prepontine cistern
International Conference of the IEEE Engineering in Medicine and Biology Society, 2012Co-Authors: Robert B Hamilton, Paul Vespa, Kevin Baldwin, Marvin BergsneiderAbstract:The objective of this study is to investigate the relationship between intracranial pressure (ICP) pulse Waveform Morphology and selected hydrodynamic metrics of cerebrospinal fluid (CSF) movement using a novel method for ICP pulse pressure regional analysis based on the Morphological Clustering and Analysis of Continuous Intracranial Pulse (MOCAIP) algorithm.
Alfredo Quinoneshinojosa - One of the best experts on this subject based on the ideXlab platform.
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changes in transcranial motor evoked potentials during intramedullary spinal cord tumor resection correlate with postoperative motor function
Neurosurgery, 2005Co-Authors: Alfredo Quinoneshinojosa, Russ Lyon, Andrew T Parsa, Gabriel Zada, Kathleen R Lamborn, Michael W Mcdermott, Nalin Gupta, Philip WeinsteinAbstract:OBJECTIVE: Intraoperative monitoring of transcranial motor evoked potentials (TcMEPs) has been investigated recently as a means of preventing motor deficits associated with resection of intramedullary spinal cord tumors (IMSCTs). In this study, we hypothesized that changes in the intraoperative MEPs during tumor resection correlate with postoperative motor function deficits. METHODS: A retrospective record review was conducted for 28 patients who underwent resection of an IMSCT using myogenic or muscle-recorded TcMEPs during a 44-month period. Intraoperative MEP recordings and results from preoperative, immediate postoperative, and subsequent follow-up neurological examinations were analyzed. RESULTS: Of the 28 patients who underwent resection of an IMSCT using TcMEPs, MEP changes occurred in 13 patients (46%). Impaired motor conduction was detected by changes in pattern and duration of the MEP Waveform Morphology (polyphasic to biphasic in 9 patients and polyphasic to biphasic to loss of MEP response in 5 patients, 1 patient demonstrated both changes) and by an increase in voltage threshold (median, 175 V; range, 100-225 V; n = 22 extremities). Alterations in Morphology and reduction in duration of the MEP response persisted despite significant increases in stimulation voltage. In 12 patients, reductions in the complexity and/or loss of the TcMEP Waveform correlated with motor grade loss in the immediate postoperative period (P < 0.0001), at discharge (P < 0.001), and at follow-up (P < 0.001). The decrease in the duration of the response correlated with motor grade loss immediately after surgery (P < 0.001), at discharge (P < 0.0001), and at follow-up (P < 0.005). CONCLUSION: These results support the application of distal muscle-recorded TcMEPs to predict the occurrence and severity of postoperative motor deficits during resection of IMSCTs. Attention to such quantitative intraoperative monitoring data may help to minimize postoperative motor deficits by avoiding or correcting excessive spinal cord manipulation and modifying surgical technique during tumor resection.
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changes in transcranial motor evoked potentials during intramedullary spinal cord tumor resection correlate with postoperative motor function
Neurosurgery, 2005Co-Authors: Alfredo Quinoneshinojosa, Russ Lyon, Andrew T Parsa, Gabriel Zada, Kathleen R Lamborn, Michael W Mcdermott, Nalin Gupta, Philip WeinsteinAbstract:OBJECTIVE: Intraoperative monitoring of transcranial motor evoked potentials (TcMEPs) has been investigated recently as a means of preventing motor deficits associated with resection of intramedullary spinal cord tumors (IMSCTs). In this study, we hypothesized that changes in the intraoperative MEPs during tumor resection correlate with postoperative motor function deficits. METHODS: A retrospective record review was conducted for 28 patients who underwent resection of an IMSCT using myogenic or muscle-recorded TcMEPs during a 44-month period. Intraoperative MEP recordings and results from preoperative, immediate postoperative, and subsequent follow-up neurological examinations were analyzed. RESULTS: Of the 28 patients who underwent resection of an IMSCT using TcMEPs, MEP changes occurred in 13 patients (46%). Impaired motor conduction was detected by changes in pattern and duration of the MEP Waveform Morphology (polyphasic to biphasic in 9 patients and polyphasic to biphasic to loss of MEP response in 5 patients, 1 patient demonstrated both changes) and by an increase in voltage threshold (median, 175 V; range, 100-225 V; n = 22 extremities). Alterations in Morphology and reduction in duration of the MEP response persisted despite significant increases in stimulation voltage. In 12 patients, reductions in the complexity and/or loss of the TcMEP Waveform correlated with motor grade loss in the immediate postoperative period (P < 0.0001), at discharge (P < 0.001), and at follow-up (P < 0.001). The decrease in the duration of the response correlated with motor grade loss immediately after surgery (P < 0.001), at discharge (P < 0.0001), and at follow-up (P < 0.005). CONCLUSION: These results support the application of distal muscle-recorded TcMEPs to predict the occurrence and severity of postoperative motor deficits during resection of IMSCTs. Attention to such quantitative intraoperative monitoring data may help to minimize postoperative motor deficits by avoiding or correcting excessive spinal cord manipulation and modifying surgical technique during tumor resection.
Jay N Cohn - One of the best experts on this subject based on the ideXlab platform.
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age related abnormalities in arterial compliance identified by pressure pulse contour analysis aging and arterial compliance
Hypertension, 1999Co-Authors: Gary E Mcveigh, Christopher W Bratteli, Dennis J Morgan, C Alinder, Stephen P Glasser, Stanley M Finkelstein, Jay N CohnAbstract:Abstract —The objective of this study was to evaluate age-related changes in pulsatile arterial function. Aging alters arterial pulsatile function and produces consistent changes in the pressure pulse contour. A reduced systemic arterial compliance that can be derived from analysis of the pulse contour is regarded as the best clinical index of impaired pulsatile arterial function and may mark the presence of early vascular damage. We analyzed intra-arterial brachial artery Waveforms in 115 healthy normotensive volunteers (83 men, 32 women) and radial artery Waveforms obtained with the use of a calibrated tonometer device in 212 healthy volunteers (147 women, 65 men). A computer-based assessment of the diastolic pressure decay and a modified Windkessel model of the circulation were used to quantify changes in arterial Waveform Morphology in terms of large artery or capacitive compliance, oscillatory or reflective compliance in the small arteries, inertance, and systemic vascular resistance. Large artery compliance and oscillatory compliance correlated negatively with age for both invasive and noninvasive groups ( r =−0.50 and r =−0.55; r =−0.37 and r =−0.66; P
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age related abnormalities in arterial compliance identified by pressure pulse contour analysis aging and arterial compliance
Hypertension, 1999Co-Authors: Gary E Mcveigh, Christopher W Bratteli, Dennis J Morgan, C Alinder, Stephen P Glasser, Stanley M Finkelstein, Jay N CohnAbstract:The objective of this study was to evaluate age-related changes in pulsatile arterial function. Aging alters arterial pulsatile function and produces consistent changes in the pressure pulse contour. A reduced systemic arterial compliance that can be derived from analysis of the pulse contour is regarded as the best clinical index of impaired pulsatile arterial function and may mark the presence of early vascular damage. We analyzed intra-arterial brachial artery Waveforms in 115 healthy normotensive volunteers (83 men, 32 women) and radial artery Waveforms obtained with the use of a calibrated tonometer device in 212 healthy volunteers (147 women, 65 men). A computer-based assessment of the diastolic pressure decay and a modified Windkessel model of the circulation were used to quantify changes in arterial Waveform Morphology in terms of large artery or capacitive compliance, oscillatory or reflective compliance in the small arteries, inertance, and systemic vascular resistance. Large artery compliance and oscillatory compliance correlated negatively with age for both invasive and noninvasive groups (r=-0.50 and r=-0.55; r=-0.37 and r=-0.66; P<0.001 for all). The slopes of the regression lines for the decline in oscillatory compliance with age were significantly steeper than those recorded for large artery compliance estimates. The change in blood pressure with age independently contributed to the decrease in large artery compliance but not oscillatory compliance in both groups. Consistent age-related changes were found in the pressure pulse contour by analysis of Waveforms obtained invasively or noninvasively from the upper limb. The change in the oscillatory or reflective compliance estimate was independent of blood pressure change and may represent a better marker than large artery or capacitive compliance of the degenerative aging process in altering pulsatile arterial function.
