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1.
J Neurophysiol ; 121(4): 1368-1380, 2019 04 01.
Article in English | MEDLINE | ID: mdl-30649975

ABSTRACT

Motor responses are fundamentally spatial in their function and neural organization. However, studies of inhibitory motor control, focused on global stopping of all actions, have ignored whether inhibitory control can be exercised selectively for specific actions. We used a new approach to elicit and measure motor inhibition by asking human participants to either look at (select) or avoid looking at (inhibit) a location in space. We found that instructing a location to be avoided resulted in an inhibitory bias specific to that location. When compared with the facilitatory bias observed in the Look task, it differed significantly in both its spatiotemporal dynamics and its modulation of attentional processing. While action selection was evident in oculomotor system and interacted with attentional processing, action inhibition was evident mainly in the oculomotor system. Our findings suggest that action inhibition is implemented by spatially specific mechanisms that are separate from action selection. NEW & NOTEWORTHY We show that cognitive control of saccadic responses evokes separable action selection and inhibition processes. Both action selection and inhibition are represented in the saccadic system, but only action selection interacts with the attentional system.


Subject(s)
Attention , Neural Inhibition , Saccades/physiology , Adult , Choice Behavior , Female , Humans , Male , Psychomotor Performance
2.
Am Heart J ; 174: 68-79, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26995372

ABSTRACT

BACKGROUND: Progression of atherosclerosis is associated with a greater risk for adverse outcomes. Angiotensin II plays a key role in the pathogenesis and progression of atherosclerosis. We aimed to investigate the effects of angiotensin II type-1 receptor blockade with Valsartan on carotid wall atherosclerosis, with the hypothesis that Valsartan will reduce progression of atherosclerosis. METHODS: Subjects (n = 120) with carotid intima-media thickness >0.65 mm by ultrasound were randomized (2:1) in a double-blind manner to receive either Valsartan or placebo for 2 years. Bilateral T2-weighted black-blood carotid magnetic resonance imaging was performed at baseline, 12 and 24 months. Changes in the carotid bulb vessel wall area and wall thickness were primary endpoints. Secondary endpoints included changes in carotid plaque thickness, plasma levels of aminothiols, C-reactive protein, fibrinogen, and endothelium-dependent and -independent vascular function. RESULTS: Over 2 years, the carotid bulb vessel wall area decreased with Valsartan (-6.7, 95% CI [-11.6, -1.9] mm(2)) but not with placebo (3.4, 95% CI [-2.8, 9.6] mm(2)), P = .01 between groups. Similarly, mean wall thickness decreased with Valsartan (-0.18, 95% CI [-0.30, -0.06] mm), but not with placebo (0.08, 95% CI [-0.07, 0.23] mm), P = .009 between groups. Furthermore, plaque thickness decreased with Valsartan (-0.35, 95% CI [-0.63, -0.08] mm) but was unchanged with placebo (+0.28, 95% CI [-0.11, 0.69] mm), P = .01 between groups. These findings were unaffected by statin therapy or changes in blood pressure. Notably, there were significant improvements in the aminothiol cysteineglutathione disulfide, and trends to improvements in fibrinogen levels and endothelium-independent vascular function. CONCLUSIONS: In subjects with carotid wall thickening, angiotensin II type-1 receptor blockade was associated with regression in carotid atherosclerosis. Whether these effects translate into improved outcomes in subjects with subclinical atherosclerosis warrants investigation.


Subject(s)
Atherosclerosis/drug therapy , Carotid Artery Diseases/drug therapy , Valsartan/administration & dosage , Adult , Aged , Aged, 80 and over , Angiotensin II Type 1 Receptor Blockers/administration & dosage , Atherosclerosis/diagnosis , Carotid Artery Diseases/diagnosis , Carotid Intima-Media Thickness , Disease Progression , Dose-Response Relationship, Drug , Double-Blind Method , Female , Follow-Up Studies , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Prospective Studies , Treatment Outcome , Young Adult
3.
J Am Heart Assoc ; 5(1)2016 Jan 25.
Article in English | MEDLINE | ID: mdl-26811165

ABSTRACT

BACKGROUND: We hypothesized that nebivolol, a ß-blocker with nitric oxide-mediated activity, compared with atenolol, a ß-blocker without such activity, would decrease oxidative stress and improve the effects of endothelial dysfunction and wall shear stress (WSS), thereby reducing atherosclerosis progression and vulnerability in patients with nonobstructive coronary artery disease. METHODS AND RESULTS: In this pilot double-blinded randomized controlled trial, 24 patients treated for 1 year with nebivolol 10 mg versus atenolol 100 mg plus standard medical therapy underwent baseline and follow-up coronary angiography with assessments of inflammatory and oxidative stress biomarkers, microvascular function, endothelial function, and virtual histology intravascular ultrasound. WSS was calculated from computational fluid dynamics. Virtual histology intravascular ultrasound segments were assessed for vessel volumetrics and remodeling. There was a trend toward more low-WSS segments in the nebivolol cohort (P=0.06). Low-WSS regions were associated with greater plaque progression (P<0.0001) and constrictive remodeling (P=0.04); conversely, high-WSS segments demonstrated plaque regression and excessive expansive remodeling. Nebivolol patients had decreased lumen and vessel areas along with increased plaque area, resulting in more constrictive remodeling (P=0.002). There were no significant differences in biomarker levels, microvascular function, endothelial function, or number of thin-capped fibroatheromas per vessel. Importantly, after adjusting for ß-blocker, low-WSS segments remained significantly associated with lumen loss and plaque progression. CONCLUSION: Nebivolol, compared with atenolol, was associated with greater plaque progression and constrictive remodeling, likely driven by more low-WSS segments in the nebivolol arm. Both ß-blockers had similar effects on oxidative stress, microvascular function, and endothelial function. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov/. Unique identifier: NCT01230892.


Subject(s)
Adrenergic beta-3 Receptor Agonists/therapeutic use , Adrenergic beta-Antagonists/therapeutic use , Atenolol/therapeutic use , Coronary Artery Disease/drug therapy , Coronary Circulation/drug effects , Coronary Vessels/drug effects , Diagnostic Imaging , Nebivolol/therapeutic use , Plaque, Atherosclerotic , Adult , Biomarkers/blood , Coronary Angiography , Coronary Artery Disease/diagnosis , Coronary Artery Disease/physiopathology , Coronary Vessels/diagnostic imaging , Coronary Vessels/physiopathology , Diagnostic Imaging/methods , Double-Blind Method , Echocardiography, Doppler , Female , Georgia , Hemodynamics , Humans , Male , Middle Aged , Oxidative Stress/drug effects , Pilot Projects , Predictive Value of Tests , Stress, Mechanical , Time Factors , Treatment Outcome , Ultrasonography, Interventional , Vascular Remodeling/drug effects
4.
J Cardiovasc Pharmacol ; 63(4): 369-74, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24336012

ABSTRACT

BACKGROUND: Traditional cardiovascular risk factors lead to endothelial injury and activation of leukocytes and platelets that initiate and propagate atherosclerosis. We proposed that clopidogrel therapy in patients with stable coronary artery disease imparts a pleiotropic effect that extends beyond antiplatelet aggregation to other atheroprotective processes. METHODS: Forty-one subjects were randomized in a double-blind, placebo-controlled, crossover study to receive either clopidogrel 75 mg daily or placebo for 6 weeks and then transitioned immediately to the other treatment for an additional 6 weeks. We assessed (1) endothelial function as flow-mediated dilation of the brachial artery, (2) arterial stiffness and central augmentation index using applanation tonometry, (3) vascular function as fingertip reactive hyperemia index, (4) inflammation by measuring plasma CD40 ligand and serum high-sensitivity c-reactive protein levels, (5) oxidative stress by measuring plasma aminothiols, and (6) circulating progenitor cells, at baseline and at the end of each 6-week treatment period. RESULTS: Clopidogrel therapy resulted in a significant reduction in soluble CD40 ligand (P = 0.03), a prothrombotic and proinflammatory molecule derived mainly from activated platelets. However, clopidogrel therapy had no effect on endothelial function, arterial stiffness, inflammatory and oxidative stress markers, or progenitor cells. CONCLUSIONS: Our findings suggest a solitary antiplatelet effect of clopidogrel therapy in patients with stable coronary artery disease, with no effect on other subclinical markers of cardiovascular disease risk.


Subject(s)
Blood Vessels/drug effects , Coronary Artery Disease/drug therapy , Inflammation/drug therapy , Oxidative Stress/drug effects , Platelet Aggregation Inhibitors/therapeutic use , Stem Cells/drug effects , Ticlopidine/analogs & derivatives , Aged , Biomarkers/analysis , Blood Vessels/physiopathology , Capillaries/drug effects , Clopidogrel , Coronary Artery Disease/metabolism , Coronary Artery Disease/physiopathology , Cross-Over Studies , Double-Blind Method , Elasticity , Endothelium, Vascular/drug effects , Endothelium, Vascular/physiopathology , Female , Humans , Male , Middle Aged , Prospective Studies , Ticlopidine/therapeutic use , Vascular Stiffness/drug effects
5.
J Vis ; 13(6)2013 May 17.
Article in English | MEDLINE | ID: mdl-23685392

ABSTRACT

Visuospatial attention has been shown to have a central role in planning and generation of saccades but what role, if any, it plays in inhibition of saccades remains unclear. In this study, we used an oculomotor delayed match- or nonmatch-to-sample task in which a cued location has to be encoded and memorized for one of two very different goals-to plan a saccade to it or to avoid making a saccade to it. We measured the spatial allocation of attention during the delay and found that while marking a location as a future saccade target resulted in an attentional benefit at that location, marking it as forbidden to saccades led to an attentional cost. Additionally, saccade trajectories were found to deviate away more from the "don't look" location than from a saccade-irrelevant distractor confirming greater inhibition of an actively forbidden location in oculomotor programming. Our finding that attention is suppressed at locations forbidden to saccades confirms and complements the claim of a selective and obligatory coupling between saccades and attention-saccades at the memorized location could neither be planned nor suppressed independent of a corresponding effect on attentional performance.


Subject(s)
Attention/physiology , Saccades/physiology , Adolescent , Adult , Analysis of Variance , Female , Humans , Male , Memory, Short-Term/physiology , Photic Stimulation/methods , Young Adult
6.
J Am Heart Assoc ; 1(4): e002543, 2012 Aug.
Article in English | MEDLINE | ID: mdl-23130168

ABSTRACT

BACKGROUND: Extremes of wall shear stress (WSS) have been associated with plaque progression and transformation, which has raised interest in the clinical assessment of WSS. We hypothesized that calculated coronary WSS is predicted only partially by luminal geometry and that WSS is related to plaque composition. METHODS AND RESULTS: Twenty-seven patients with coronary artery disease underwent virtual histology intravascular ultrasound and Doppler velocity measurement for computational fluid dynamics modeling for WSS calculation in each virtual histology intravascular ultrasound segment (N=3581 segments). We assessed the association of WSS with plaque burden and distribution and with plaque composition. WSS remained relatively constant across the lower 3 quartiles of plaque burden (P=0.08) but increased in the highest quartile of plaque burden (P<0.001). Segments distal to lesions or within bifurcations were more likely to have low WSS (P<0.001). However, the majority of segments distal to lesions (80%) and within bifurcations (89%) did not exhibit low WSS. After adjustment for plaque burden, there was a negative association between WSS and percent necrotic core and calcium. For every 10 dynes/cm(2) increase in WSS, percent necrotic core decreased by 17% (P=0.01), and percent dense calcium decreased by 17% (P<0.001). There was no significant association between WSS and percent of fibrous or fibrofatty plaque components (P=NS). CONCLUSIONS: IN PATIENTS WITH CORONARY ARTERY DISEASE: (1) Luminal geometry predicts calculated WSS only partially, which suggests that detailed computational techniques must be used to calculate WSS. (2) Low WSS is associated with plaque necrotic core and calcium, independent of plaque burden, which suggests a link between WSS and coronary plaque phenotype. (J Am Heart Assoc. 2012;1:e002543 doi: 10.1161/JAHA.112.002543.).

7.
J Invasive Cardiol ; 24(10): 522-9, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23043036

ABSTRACT

BACKGROUND: There is a discrepancy between the marked reduction in adverse events with statins and their modest effect on atheroma regression. We hypothesized that, in a Western population, high-dose atorvastatin will result in alterations in coronary atheroma composition, phenotype, and microvascular function. METHODS: Serial coronary radiofrequency intravascular ultrasound (VH-IVUS), coronary flow reserve (CFR), and hyperemic microvascular resistance (HMR) were performed at baseline and after 6 months of treatment with 80 mg atorvastatin in 20 patients with moderate coronary artery disease (CAD). For each VH-IVUS frame (n = 2249), changes in total plaque atheroma, composition, and phenotype (pathological intimal thickening, fibrotic plaque, fibroatheroma), and serial remodeling were assessed. RESULTS: Total serum cholesterol decreased from 186.0 mg/dL (interquartile range [IQR], 168.0 to 212.5 mg/dL) to 139.0 mg/dL (IQR, 124.3 to 151.3 mg/dL). Percent atheroma volume did not change significantly (-0.5% [IQR, -2.8% to 3.7%]; P=.90) and serial remodeling analysis demonstrated 40% constrictive, 24% incomplete, and 36% expansive patterns. There was a trend toward lower percent fibrous tissue (-3.47 ± 1.78%; P=.07) and percent fibro-fatty tissue (-2.52 ± 1.24%; P=.06) and increase in percent necrotic core (+2.74 ± 1.65%; P=.11) and percent dense calcium (+1.99 ± 0.81; P=.02), which translated into significantly less pathological intimal thickening (4% vs 12%; P<.0001) and more fibroatheromas (67% vs 57%; P<.0001) at follow-up compared to baseline. There were modest non-significant improvements in CFR (+0.26 [IQR, -0.37 to 0.76]; P=.23) and HMR (-0.22 [IQR, -0.56 to 0.28]; P=.12). CONCLUSIONS: In this pilot study of Western patients with moderate CAD, high-dose atorvastatin resulted in alterations in coronary atheroma composition with corresponding changes in plaque phenotype and modest improvement in coronary microvascular function.


Subject(s)
Anticholesteremic Agents/therapeutic use , Coronary Artery Disease/drug therapy , Coronary Vessels/physiopathology , Disease Progression , Heptanoic Acids/therapeutic use , Microvessels/physiopathology , Pyrroles/therapeutic use , Aged , Anticholesteremic Agents/pharmacology , Atorvastatin , Cholesterol/blood , Coronary Artery Disease/diagnostic imaging , Coronary Artery Disease/physiopathology , Coronary Vessels/diagnostic imaging , Coronary Vessels/drug effects , Dose-Response Relationship, Drug , Female , Follow-Up Studies , Heptanoic Acids/pharmacology , Humans , Male , Microvessels/diagnostic imaging , Microvessels/drug effects , Middle Aged , Phenotype , Pilot Projects , Pyrroles/pharmacology , Regional Blood Flow/drug effects , Regional Blood Flow/physiology , Retrospective Studies , Treatment Outcome , Ultrasonography, Interventional , Vascular Resistance/drug effects , Vascular Resistance/physiology
8.
Am Heart J ; 164(4): 547-552.e1, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23067913

ABSTRACT

BACKGROUND: Multiple scoring systems have been devised to quantify angiographic coronary artery disease (CAD) burden, but it is unclear how these scores relate to each other and which scores are most accurate. The aim of this study was to compare coronary angiographic scoring systems (1) with each other and (2) with intravascular ultrasound (IVUS)-derived plaque burden in a population undergoing angiographic evaluation for CAD. METHODS: Coronary angiographic data from 3600 patients were scored using 10 commonly used angiographic scoring systems and interscore correlations were calculated. In a subset of 50 patients, plaque burden and plaque area in the left anterior descending coronary artery were quantified using IVUS and correlated with angiographic scores. RESULTS: All angiographic scores correlated with each other (range for Spearman coefficient [ρ] 0.79-0.98, P < .0001); the 2 most widely used scores, Gensini and CASS-70, had a ρ = 0.90 (P < .0001). All scores correlated significantly with average plaque burden and plaque area by IVUS (range ρ 0.56-0.78, P < .0001 and 0.43-0.62, P < .01, respectively). The CASS-50 score had the strongest correlation (ρ 0.78 and 0.62, P < .0001) and the Duke Jeopardy score the weakest correlation (ρ 0.56 and 0.43, P < .01) with plaque burden and area, respectively. CONCLUSIONS: Angiographic scoring systems are strongly correlated with each other and with atherosclerotic plaque burden. Scoring systems therefore appear to be a valid estimate of CAD plaque burden.


Subject(s)
Coronary Angiography , Coronary Artery Disease/diagnostic imaging , Aged , Atherosclerosis/diagnostic imaging , Coronary Vessels/diagnostic imaging , Female , Humans , Male , Middle Aged , Reproducibility of Results , Ultrasonography
9.
J Biomol Screen ; 17(9): 1163-70, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22885731

ABSTRACT

Vascular injury mobilizes bone marrow-derived proangiogenic cells into the circulation, where these cells can facilitate vascular repair and new vessel formation. We sought to determine the relationship between a new biomarker of circulating bone marrow-derived proangiogenic cell activity, the presence of atherosclerotic cardiovascular disease (CVD) and its risk factors, and clinical outcomes. Circulating proangiogenic cell activity was estimated using a reproducible angiogenic colony-forming unit (CFU-A) assay in 532 clinically stable subjects aged 20 to 90 years and ranging in the CVD risk spectrum from those who are healthy without risk factors to those with active CVD. CFU-A counts increased with the burden of CVD risk factors (p < 0.001). CFU-A counts were higher in subjects with symptomatic CVD than in those without (p < 0.001). During follow-up of 232 subjects with CVD, CFU-A counts were higher in those with death, myocardial infarction, or stroke than in those without (110 [70-173] vs 84 [51-136], p = 0.01). Therefore, we conclude that circulating proangiogenic cell activity, as estimated by CFU-A counts, increases with CVD risk factor burden and in the presence of established CVD. Furthermore, higher circulating proangiogenic cell activity is associated with worse clinical outcome in those with CVD.


Subject(s)
Cardiovascular Diseases/blood , Cardiovascular Diseases/epidemiology , Colony-Forming Units Assay , Hematopoietic Stem Cells/pathology , Adult , Aged , Aged, 80 and over , Atherosclerosis/blood , Atherosclerosis/epidemiology , Atherosclerosis/pathology , Biomarkers/blood , Cardiovascular Diseases/pathology , Female , Humans , Male , Middle Aged , Myocardial Infarction/blood , Myocardial Infarction/epidemiology , Myocardial Infarction/pathology , Myocardial Revascularization , Risk Factors , Severity of Illness Index , Stroke/blood , Stroke/epidemiology , Stroke/pathology
10.
Atherosclerosis ; 223(2): 384-8, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22766333

ABSTRACT

OBJECTIVE: Both coronary microvascular dysfunction and epicardial plaque vulnerability have been associated with adverse cardiovascular outcomes. However, whether microvascular dysfunction is a predictor of plaque vulnerability is not known. We hypothesized that microvascular dysfunction is associated with greater systemic inflammation and is a predictor of virtual histology-intravascular ultrasound (VH-IVUS)-defined coronary thin-cap fibroatheromas. METHODS: Invasive physiologic assessment and VH-IVUS were performed and serum high-sensitivity C-reactive protein (hs-CRP) was measured in 51 patients with non-obstructive CAD [fractional flow reserve (FFR)≥0.75]. Microvascular dysfunction was defined as coronary flow velocity reserve (CFVR)<2.0. Lumen area and plaque burden and composition were assessed in each VH-IVUS frame. Frequency of thin-cap fibroatheroma (TCFA) in each artery was defined as the percentage of VH-IVUS frames with plaque burden≥40% and confluent necrotic core≥10% in contact with lumen for at least 3 consecutive frames. RESULTS: Mean age was 57±12 years and 25% of patients presented with acute coronary syndrome. Despite similar amount of epicardial disease, characterized by lumen area (8.9±3.0 vs. 10.1±3.3mm(2), p=0.3) and FFR (0.90±0.08 vs. 0.92±0.07, p=0.2), patients with microvascular dysfunction had greater hs-CRP (4.2 [2.3, 7.6] vs. 1.0 [0.4, 4.2]ng/ml, p=0.006), greater plaque burden (47±10 vs. 36±13%, p=0.004), and higher frequency of TCFA (17±25 vs. 6±9%, p=0.02). After adjustment for cardiovascular risk factors, hs-CRP, and plaque burden, coronary microvascular dysfunction was an independent predictor of frequency of TCFA (ß=+0.42, p=0.033). CONCLUSION: In patients with non-obstructive CAD, coronary microvascular dysfunction is associated with higher serum hs-CRP and is an independent predictor of more TCFAs, a marker for increased epicardial plaque vulnerability.


Subject(s)
Coronary Artery Disease/pathology , Coronary Circulation , Coronary Vessels/pathology , Microvessels/pathology , Aged , Biomarkers/blood , Blood Flow Velocity , C-Reactive Protein/analysis , Coronary Artery Disease/blood , Coronary Artery Disease/diagnostic imaging , Coronary Artery Disease/physiopathology , Coronary Vessels/diagnostic imaging , Coronary Vessels/physiopathology , Cross-Sectional Studies , Female , Fibrosis , Fractional Flow Reserve, Myocardial , Georgia , Humans , Inflammation Mediators/blood , Male , Microvessels/diagnostic imaging , Microvessels/physiopathology , Middle Aged , Multivariate Analysis , Necrosis , Plaque, Atherosclerotic , Prognosis , Risk Assessment , Risk Factors , Severity of Illness Index , Ultrasonography, Interventional , Up-Regulation
11.
J Biomech Eng ; 134(5): 051001, 2012 May.
Article in English | MEDLINE | ID: mdl-22757489

ABSTRACT

Patient-specific computational fluid dynamics (CFD) is a powerful tool for researching the role of blood flow in disease processes. Modern clinical imaging technology such as MRI and CT can provide high resolution information about vessel geometry, but in many situations, patient-specific inlet velocity information is not available. In these situations, a simplified velocity profile must be selected. We studied how idealized inlet velocity profiles (blunt, parabolic, and Womersley flow) affect patient-specific CFD results when compared to simulations employing a "reference standard" of the patient's own measured velocity profile in the carotid bifurcation. To place the magnitude of these effects in context, we also investigated the effect of geometry and the use of subject-specific flow waveform on the CFD results. We quantified these differences by examining the pointwise percent error of the mean wall shear stress (WSS) and the oscillatory shear index (OSI) and by computing the intra-class correlation coefficient (ICC) between axial profiles of the mean WSS and OSI in the internal carotid artery bulb. The parabolic inlet velocity profile produced the most similar mean WSS and OSI to simulations employing the real patient-specific inlet velocity profile. However, anatomic variation in vessel geometry and the use of a nonpatient-specific flow waveform both affected the WSS and OSI results more than did the choice of inlet velocity profile. Although careful selection of boundary conditions is essential for all CFD analysis, accurate patient-specific geometry reconstruction and measurement of vessel flow rate waveform are more important than the choice of velocity profile. A parabolic velocity profile provided results most similar to the patient-specific velocity profile.


Subject(s)
Carotid Arteries/anatomy & histology , Carotid Arteries/physiology , Computer Simulation , Hemodynamics , Hydrodynamics , Carotid Arteries/diagnostic imaging , Humans , Magnetic Resonance Angiography , Middle Aged , Models, Anatomic , Pulsatile Flow , Radiography , Stress, Mechanical
12.
Circulation ; 124(7): 779-88, 2011 Aug 16.
Article in English | MEDLINE | ID: mdl-21788584

ABSTRACT

BACKGROUND: Experimental studies suggest that low wall shear stress (WSS) promotes plaque development and high WSS is associated with plaque destabilization. We hypothesized that low-WSS segments in patients with coronary artery disease develop plaque progression and high-WSS segments develop necrotic core progression with fibrous tissue regression. METHODS AND RESULTS: Twenty patients with coronary artery disease underwent baseline and 6-month radiofrequency intravascular ultrasound (virtual histology intravascular ultrasound) and computational fluid dynamics modeling for WSS calculation. For each virtual histology intravascular ultrasound segment (n=2249), changes in plaque area, virtual histology intravascular ultrasound-derived plaque composition, and remodeling were compared in low-, intermediate-, and high-WSS categories. Compared with intermediate-WSS segments, low-WSS segments developed progression of plaque area (P=0.027) and necrotic core (P<0.001), whereas high-WSS segments had progression of necrotic core (P<0.001) and dense calcium (P<0.001) and regression of fibrous (P<0.001) and fibrofatty (P<0.001) tissue. Compared with intermediate-WSS segments, low-WSS segments demonstrated greater reduction in vessel (P<0.001) and lumen area (P<0.001), and high-WSS segments demonstrated an increase in vessel (P<0.001) and lumen (P<0.001) area. These changes resulted in a trend toward more constrictive remodeling in low- compared with high-WSS segments (73% versus 30%; P=0.06) and more excessive expansive remodeling in high- compared with low-WSS segments (42% versus 15%; P=0.16). CONCLUSIONS: Compared with intermediate-WSS coronary segments, low-WSS segments develop greater plaque and necrotic core progression and constrictive remodeling, and high-WSS segments develop greater necrotic core and calcium progression, regression of fibrous and fibrofatty tissue, and excessive expansive remodeling, suggestive of transformation to a more vulnerable phenotype. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT00576576.


Subject(s)
Coronary Artery Disease , Coronary Vessels , Plaque, Atherosclerotic , Ultrasonography, Interventional/methods , Aged , Calcinosis/diagnostic imaging , Calcinosis/pathology , Calcinosis/physiopathology , Coronary Artery Disease/diagnostic imaging , Coronary Artery Disease/pathology , Coronary Artery Disease/physiopathology , Coronary Vessels/diagnostic imaging , Coronary Vessels/pathology , Coronary Vessels/physiopathology , Disease Progression , Female , Fibrosis , Humans , Hydrodynamics , Male , Middle Aged , Necrosis , Plaque, Atherosclerotic/diagnostic imaging , Plaque, Atherosclerotic/pathology , Plaque, Atherosclerotic/physiopathology , Prospective Studies , Stress, Mechanical
13.
Atherosclerosis ; 219(1): 266-72, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21703624

ABSTRACT

BACKGROUND: Although oxidative stress is considered a key pathogenic step in mediating vascular dysfunction and atherosclerosis development, their association has not been evaluated in human coronary circulation in vivo. Accordingly, we hypothesized that higher oxidative stress would be associated with abnormal coronary epicardial structure and microvascular function. METHODS: We measured coronary flow velocity reserve (CFVR) and hyperemic microvascular resistance (HMR) as indices of microvascular function, and epicardial plaque volume and necrotic core using intravascular ultrasound (IVUS) in 47 patients undergoing cardiac catheterization. Plasma glutathione, cystine and their ratio served as measures of oxidative stress while high-sensitivity C-reactive protein (hs-CRP) served as a measure of inflammation. RESULTS: Lower glutathione, a measure of increased oxidative stress was associated with impaired microvascular function [CFVR (r=0.39, p=0.01) and HMR (r=-0.43, p=0.004)], greater plaque burden (r=-0.32, p=0.03) and necrotic core (r=-0.39, p=0.008). Similarly, higher cystine/glutathione ratio was associated with impaired microvascular function [CFVR (r=-0.29, p=0.04)] and greater necrotic core (r=0.37, p=0.01). In comparison, higher hs-CRP was associated only with greater necrotic core (r=0.45, p=0.003). After multivariate adjustment for age, gender, hypertension, diabetes, acute coronary syndrome presentation, body mass index, tobacco abuse, statin use and hs-CRP, glutathione remained an independent predictor of CFVR, HMR and necrotic core (p<0.05). CONCLUSIONS: Lower plasma glutathione level a measure of increased oxidative stress, was an independent predictor of impaired coronary microvascular function and plaque necrotic core.


Subject(s)
Coronary Circulation/physiology , Cysteine/blood , Glutathione/blood , Oxidative Stress/physiology , Plaque, Atherosclerotic/pathology , Aged , Blood Flow Velocity , C-Reactive Protein/metabolism , Cardiac Catheterization , Coronary Artery Disease/physiopathology , Coronary Vessels/diagnostic imaging , Coronary Vessels/pathology , Coronary Vessels/physiopathology , Cystine/blood , Female , Humans , Male , Middle Aged , Pericardium/pathology , Plaque, Atherosclerotic/diagnostic imaging , Plaque, Atherosclerotic/physiopathology , Risk Factors , Ultrasonography
14.
J Cardiovasc Med (Hagerstown) ; 12(8): 578-80, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21709577

ABSTRACT

Appropriate diagnosis of patients with chest pain and no significant angiographic coronary artery disease remains challenging. We present the case of a 65-year-old woman with recurrent chest pain that was triggered by exertion as well as emotional stress. She underwent coronary angiography and intravascular ultrasound which demonstrated no atherosclerosis. Coronary flow reserve assessment was also normal suggesting no significant microvascular disease. Intracoronary infusion of acetylcholine, however, resulted in an increase in blood velocity and epicardial vasoconstriction, confirmed by chest pain, electrocardiogram changes and complete closure of a coronary artery by angiography, suggesting the diagnosis of coronary vasospasm or variant angina. This report highlights the importance of considering vasoconstriction when markedly increased blood velocity is observed in response to acetylcholine.


Subject(s)
Chest Pain/etiology , Coronary Vasospasm/diagnosis , Aged , Blood Flow Velocity , Coronary Angiography , Coronary Vasospasm/complications , Coronary Vasospasm/drug therapy , Female , Humans , Nitroglycerin/therapeutic use , Ultrasonography, Interventional , Vasoconstriction , Vasodilator Agents/therapeutic use
15.
Am Heart J ; 161(3): 508-15, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21392605

ABSTRACT

BACKGROUND: Although culprit lesions in ST-segment elevation myocardial infarction (STEMI) cluster in the proximal coronary arteries, their relationship to bifurcations and curvatures, where blood flow is disturbed, is unknown. We hypothesized that (a) culprit lesions localize to disturbed flow distal to bifurcations and curvatures and (b) the distribution of culprit lesions in the left (LCA) and right coronary arteries (RCA) and resulting infarct size are related to the location of bifurcations and curvatures. METHODS: Emory University's contribution to the National Cardiovascular Data Registry was queried for STEMIs. Using quantitative coronary angiography, the distances from the vessel ostium, major bifurcations, and major curvatures to the culprit lesion were measured in 385 patients. RESULTS: Culprit lesions were located within 20 mm of a bifurcation in 79% of patients and closer to the bifurcation in the LCA compared with the RCA (7.4 ± 7.3 vs 17.7 ± 14.8 mm, P < .0001). Of RCA culprit lesions, 45% were located within 20 mm of a major curvature. Compared with those in the RCA, culprit lesions in the LCA were located more proximally (24.4 ± 16.5 vs 44.7 ± 28.8 mm, P = .0003) and were associated with larger myocardial infarctions as assessed by peak creatine kinase-MB (208 ± 222 vs 140 ± 153 ng/dL, P = .001) and troponin I (59 ± 62 vs 40 ± 35 ng/dL, P = .0006) and with higher in-hospital mortality (5.2% vs 1.1%, P = .04). CONCLUSIONS: In patients with STEMI, culprit lesions are frequently located immediately distal to bifurcations and in proximity to major curvatures where disturbed flow is known to occur. This supports the role of wall shear stress in the pathogenesis of STEMI.


Subject(s)
Coronary Vessels/pathology , Myocardial Infarction/diagnostic imaging , Myocardial Infarction/pathology , Plaque, Atherosclerotic/pathology , Acute Coronary Syndrome/pathology , Aged , Coronary Angiography , Female , Humans , Male , Middle Aged , Myocardial Infarction/physiopathology , Plaque, Atherosclerotic/physiopathology , Regional Blood Flow
16.
Expert Rev Cardiovasc Ther ; 8(4): 545-56, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20397828

ABSTRACT

Although traditional cardiovascular risk factors 'prime the soil' for atherogenesis systemically, atherosclerosis primarily occurs in a site-specific manner with a predilection towards the inner wall of curvatures and outer wall of bifurcations with sparing of flow-dividers. Wall shear stress is a frictional force exerted parallel to the vessel wall that leads to alteration of the endothelial phenotype, endothelial cell signaling, gene and protein expression leading to a proinflammatory phenotype, reduced nitric oxide availability and disruption of the extracellular matrix, which in turn leads to plaque development. Clinical and experimental data are emerging that suggest the pathobiology associated with abnormal wall shear stress results in atherosclerotic plaque development and progression.


Subject(s)
Atherosclerosis/etiology , Carotid Arteries/physiopathology , Stress, Mechanical , Animals , Atherosclerosis/physiopathology , Disease Progression , Endothelium, Vascular/physiopathology , Humans , Nitric Oxide/metabolism , Oxidative Stress , Risk Factors , Signal Transduction
19.
Am J Cardiol ; 103(7): 902-6, 2009 Apr 01.
Article in English | MEDLINE | ID: mdl-19327413

ABSTRACT

Low levels of high-density lipoprotein (HDL) cholesterol are a marker of coronary artery disease progression and are associated with cardiovascular events. However, whether low HDL cholesterol is a useful prognostic indicator after percutaneous coronary intervention (PCI) is not known. In a sample of 4,088 patients who underwent PCI we evaluated 1-year mortality and repeat revascularization as a function of baseline HDL levels classified into approximate quartiles of very low (<35 mg/dl), low (35 to 40 mg/dl), medium (41 to 47 mg/dl) and high (48 to 120 mg/dl) HDL cholesterol. Decreasing levels of HDL cholesterol were associated with younger age, male gender, smoking, diabetes mellitus, and a history of bypass surgery (p <0.0001 for all). One-year mortality and coronary revascularization were significantly higher in the very low HDL cholesterol group compared with the other groups (very low HDL cholesterol 6.5% and 25.4%, respectively; low HDL cholesterol 3.1% and 20.8%; medium HDL cholesterol 4.3% and 22.7%; high HDL cholesterol 3.1% and 20.6%, p = 0.0001 and p = 0.007). One-year mortality was significantly higher in men with an HDL cholesterol level <33 mg/dL and in women with an HDL cholesterol level <38 mg/dL. In multivariable analysis, very low HDL was associated with nearly twofold the risk of death after adjusting for other independent predictors of outcome. In conclusion, in patients with coronary artery disease undergoing PCI, a baseline HDL cholesterol level <35 mg/dl is an important prognostic indicator. Baseline HDL cholesterol levels <33 mg/dl for men and <38 mg/dl were associated with higher one-year mortality after PCI.


Subject(s)
Angioplasty, Balloon, Coronary/methods , Cholesterol, HDL/blood , Myocardial Ischemia/mortality , Aged , Biomarkers/blood , Female , Follow-Up Studies , Georgia/epidemiology , Humans , Male , Middle Aged , Myocardial Ischemia/blood , Myocardial Ischemia/therapy , Prognosis , Prospective Studies , Recurrence , Risk Factors , Sex Factors , Survival Rate/trends
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