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Biomedical subjects

Claudia E Korcarz

Publications and source records attributed to Claudia E Korcarz.

At least 19 recordsLinked to original sources
PubMed2006

Validation of a carotid intima-media thickness border detection program for use in an office setting.

BACKGROUND: A unique semiautomated border detection program (BDP) designed for use on a personal computer was evaluated to determine whether: (1) carotid intima-media thickness (CIMT) measurements were bioequivalent to a reference laboratory; and (2) it would allow a novice (NOV) reader with no medical training to accurately and reproducibly measure CIMT. METHODS: Far-wall CIMT was measured blindly and in duplicate by an experienced and NOV reader using BDP and by a reference laboratory. RESULTS: Mean CIMT using BDP was bioequivalent to the reference laboratory (two 1-sided T-test, P < .05) with small absolute differences (experienced 0.011 +/- 0.004 mm, NOV 0.022 +/- 0.004 mm). Reproducibility was high, with small coefficients of variation when used by either the experienced (3.1%) or NOV (7.8%) reader. CONCLUSION: CIMT measurements using BDP were accurate and reproducible. It was mastered easily by a NOV reader and appeared suitable for use in an office setting.

Adult↗
PubMed2006

Use of carotid intima-media thickness and vascular age to modify cardiovascular risk prediction.

BACKGROUND: This study identified predictors of patients for whom carotid artery intima-media thickness (CIMT) measurement and determination of vascular age could change cardiovascular disease (CVD) risk assessment. METHODS: We studied consecutive patients who were asymptomatic and nondiabetic, referred for ultrasound measurement of CIMT. Individuals with CIMT 75th percentile or greater for age, sex, and race were defined as having advanced subclinical atherosclerosis. CIMT values were converted to vascular age estimates and were used to modify Framingham 10-year CVD risk estimates. RESULTS: Of 506 patients, 261 (51.6%) were not taking lipid-lowering therapy. Advanced subclinical atherosclerosis was present in 77 (30%). There were 62 patients (23.8%) with a change in CVD risk of 5% or more. Predictors of 5% or more change in CVD risk were systolic blood pressure (P < .001), total/high-density lipoprotein cholesterol ratio (P < .001), and male sex (P < .001). Of the 97 patients at moderate or moderately high risk, 56.7% changed risk classification. CONCLUSIONS: Measurement of CIMT and determination of vascular age can identify individuals with advanced subclinical atherosclerosis, resulting in clinically meaningful alterations in CVD risk estimates.

Adult↗
PubMed2006

Use of hand-held ultrasound by a nonsonographer clinician to measure carotid intima-media thickness.

OBJECTIVE: We sought to evaluate the accuracy of carotid intima-media thickness (CIMT) measurements by a nonsonographer clinician using hand-held ultrasound (HHU). BACKGROUND: Use of a HHU for point-of-care CIMT measurement has not been tested previously. METHODS: Participants underwent reference ultrasound and HHU studies. HHU validity was tested by an expert sonographer. Nonsonographer clinician accuracy using the HHU was tested against the expert sonographer. CIMT bioequivalence was tested with .5 pixel limits. RESULTS: The 75 participants were (mean [SD]) 55 [7] years old. CIMT values were bioequivalent (0.714 [0.029] vs 0.685 [0.029] mm, phase I; 0.697 [0.015] vs 0.687 [0.015] mm, phase II; P(two 1-sided t test) < .05). Agreement was 80% for CIMT classifications (intraclass correlation coefficient = 0.451, P < .001) and 90% for plaque presence (intraclass correlation coefficient = 0.797, P < .001). CONCLUSIONS: CIMT measured by HHU was bioequivalent to a reference ultrasound system, when used by an expert sonographer or nonsonographer clinician. Clinical classifications by CIMT quartile and plaque presence were similar. HHU may be suitable for office-based atherosclerosis screening.

Carotid Arteries↗
PubMed2006

Is the ankle-brachial index a useful screening test for subclinical atherosclerosis in asymptomatic, middle-aged adults?

BACKGROUND: Measurement of the ankle-brachial index (ABI) is recommended as a screening test for cardiovascular risk prediction in individuals > or = 50 years old; however, there is little data regarding the utility of the ABI as a screening test in individuals for whom physicians actually order non-invasive testing for cardiovascular risk prediction. METHODS: This study included 493 consecutive asymptomatic patients without known atherosclerotic vascular disease who were referred by their physician for measurement of the ABI and ultrasound measurement of carotid intima-media thickness (CIMT). ABI values were classified as "reduced" (<0.9), "normal" (0.9-1.3), and "increased" (>1.3). RESULTS: The mean age of the patients was 55.3 (standard deviation 7.5) years. Only 1 patient had a reduced ABI (0.2%). ABI values tended to be higher in those with increased CIMT (P=0.051); however, CIMT was not significantly different between those with normal and increased ABI values (P=0.802). There were no significant differences in the prevalence of traditional cardiovascular risk factors or carotid plaque presence among the ABI groups. CONCLUSIONS: Despite recommendations, the ABI is not sensitive as a screening tool for detecting subclinical atherosclerosis in asymptomatic middle-aged individuals.

Ankle↗
PubMed2005

Skin cholesterol content identifies increased carotid intima-media thickness in asymptomatic adults.

BACKGROUND: A noninvasive assay to measure skin Tc recently has become available for use in the outpatient setting as a cardiovascular (CV) risk prediction tool. The purpose of this study was to determine whether skin tissue cholesterol content (skin Tc) levels are associated with increased carotid intima-media thickness (CIMT) after adjusting for known CV risk factors and Framingham CV risk. METHODS: Consecutive patients without known vascular disease who were referred for determination of CIMT underwent B-mode ultrasonography of the carotid arteries and measurement of skin Tc using a noninvasive assay. Use of medications, cardiac risk factors, and Framingham 10-year CV risk were determined prospectively. Multivariable regression was used to determine predictors of increased CIMT. RESULTS: Among 81 subjects, the mean (SD) age was 55.6 (7.7) years and the mean skin Tc was 95.9 (18.3) U. Carotid intima-media thickness was significantly higher among individuals in the highest quartile of skin Tc (0.87 vs 0.76 mm, P = .011). In multivariable analyses, skin Tc was associated with increased CIMT even after adjusting for age, sex, glucose, systolic blood pressure, total/high-density lipoprotein cholesterol ratio, and use of lipid-lowering therapy (odds ratio [OR] per 10-unit increase = 1.590, 95% CI 1.525-1.658, P = .031). Skin Tc also was associated with increased CIMT after adjustment for Framingham risk (OR = 1.341, 95% CI 1.302-1.380, P = .048). CONCLUSIONS: Skin Tc is an easy-to-measure, noninvasive marker that can help identify subclinical atherosclerosis in asymptomatic middle-aged adults, even after controlling for risk factors and CV risk predicted by the Framingham model.

Adult↗
PubMed2005

Ultrasound-detected carotid plaque as a screening tool for advanced subclinical atherosclerosis.

BACKGROUND: There is great need for a simple, noninvasive tool that can be used in an office setting to screen for subclinical atherosclerosis. In patients referred for cardiovascular (CV) risk assessment, we evaluated the ability of ultrasound screening for carotid plaque to identify patients with advanced subclinical atherosclerosis. METHODS: Consecutive asymptomatic patients without vascular disease referred by their physician for measurement of the ankle-brachial pressure index and carotid intima-media thickness (CIMT) were included. Carotid intima-media thickness was measured using the standardized ultrasound protocol from the Atherosclerosis Risk in Communities (ARIC) study. Advanced atherosclerosis was defined as CIMT > or = 75th percentile for age, sex, and race in ARIC. RESULTS: The mean age of the 327 subjects was 55.4 years (SD 7.7 years). The 10-year Framingham CV risk was 5.1% (4.8%). In a multiple logistic regression model that included Framingham CV risk, ankle-brachial pressure index, and use of lipid-lowering medications, plaque presence significantly predicted advanced atherosclerosis (odds ratio 3.08, 95% CI 1.91-4.96, P < .001). In stepwise regression models that included age, body mass index, current tobacco use, family history of premature CV disease, fasting glucose, sex, systolic blood pressure, total/high-density lipoprotein cholesterol ratio, and use of antihypertensive and lipid-lowering medications, plaque presence independently predicted advanced atherosclerosis (P < .001). CONCLUSION: Ultrasound detection of carotid plaque helped identify asymptomatic patients with advanced subclinical atherosclerosis. Screening for carotid plaque is easier than determination of CIMT and may help detect asymptomatic patients at increased CV risk.

Carotid Artery Diseases↗
PubMed2005

The advantages of becoming a clinical site for ultrasound schools.

The field of echocardiography is facing critical staffing shortages. As the field continues to grow and practicing sonographers begin to retire, the need to produce more qualified sonographers is critical. In addition to job openings because of growth, some job openings will arise from the need to replace sonographers who leave the occupation permanently. One way echocardiographers can address this issue is to have their institutions become clinical sites for local accredited ultrasound schools.

Allied Health Personnel↗
PubMed2005

The research grant process: a reference guide for cardiovascular sonographers.

Opportunities for sonographer-initiated research have increased during the past decade. Although research has traditionally been viewed as a nonclinical activity, funding is available for clinical problems. This article aims to increase sonographer awareness of this unique opportunity, encourage the submission of grant proposals, and enhance the understanding of the grant writing process. This review discusses the procedures involved in planning a research project while describing the structure of the research grant proposal including specific aims, background, preliminary studies, methods, potential limitations, significance, budget, and references.

Echocardiography↗
PubMed2005

A semiautomated ultrasound border detection program that facilitates clinical measurement of ultrasound carotid intima-media thickness.

We have developed a novel, semiautomated carotid intima-media thickness (CIMT) border detection program (AUTO) and evaluated its measurement reproducibility and accuracy. Images from 6 carotid segments were acquired in 50 subjects, for a total of 300 segments. Mean and maximum CIMT values were measured blindly at a reference (REF) lab and in duplicate by experienced (EXP) and novice (NOV) readers using manual (MAN) and AUTO methods. Coefficients of variation for AUTO measurements of mean (3.2%) and maximum (4.1%) CIMT were low, and the AUTO method improved the NOV reader's reproducibility. Compared with the REF lab, mean (0.012 +/- 0.006 mm) and maximum (0.144 +/- 0.006 mm) CIMT biases were small and equivalent to those of the REF lab ( P < .001). The AUTO method shortened reading times by 35% to 46% ( P < .001). We conclude that our novel AUTO CIMT measurement program improved reproducibility and was accurate. Compared with MAN tracing, the AUTO method agreed better with the REF lab and decreased reading time.

Adult↗
PubMed2005

The arterial system in pre-eclampsia and chronic hypertension with superimposed pre-eclampsia.

OBJECTIVES: To determine if the normal gestational changes in mechanical properties of the arterial system are altered in pre-eclampsia. DESIGN: Prospective controlled observational study. SETTING: University urban tertiary medical centre. POPULATION: Eleven pre-eclamptics and 10 chronic hypertensives with superimposed pre-eclampsia were compared with 14 normotensive gravidas experiencing preterm labour, all receiving MgSO(4). Two additional control groups were studied as well: (A) nine normal pregnant women receiving neither magnesium nor epidural, for baseline comparisons; and (B) eight normotensive gravidas receiving epidural anaesthesia. METHODS: Two-dimensional targeted M-mode echocardiograms and continuous wave Doppler velocity were used to obtain instantaneous pressure and flow data. Total vascular resistance (TVR) quantified the steady component of systemic arterial load; pulsatile arterial load was characterised by global arterial compliance (AC), aortic input impedance spectrum (Z(1)) and characteristic impedance (Z(0)). MAIN OUTCOME MEASURES: TVR, AC, Z(1), Z(0). RESULTS: Controls, pre-eclamptics and chronic hypertensives with superimposed pre-eclampsia, respectively: TVR index 1328 [299], 1973 [609]*, 2428 [562]*(,#) dyn second cm(-5) m(2); AC area index 1.69 [0.46], 1.19 [0.46]*, 0.93 [0.38]* mL mmHg(-1) m(-2); Z(0) index 253.2 [61.3], 327.0 [135.1], 307.5 [130.9] dyn second cm(-5) m(2); and Z(1) index 184.2 [56.5], 283.6 [81.6]*, 357.1 [119.5]* dyn second cm(-5) m(2) (*P < 0.05 vs control;(#)P < 0.05 vs pre-eclampsia). Normal gravidas (in secondary controls group A) had decreased mean systolic and diastolic blood pressures, and increased AC and cardiac indices, compared with women receiving magnesium tocolysis, verifying the need for these primary controls. No differences were noted between normotensive gravidas receiving epidural anaesthesia (secondary controls group B) and the non-anesthetised controls (group A), eliminating epidural as a confounder. CONCLUSIONS: The normal gestational changes in systemic arterial mechanical properties are significantly altered in pre-eclampsia and these alterations are more marked with superimposed hypertensive disease.

Adult↗
PubMed2004

Effects of pravastatin on lipoproteins and endothelial function in patients receiving human immunodeficiency virus protease inhibitors.

BACKGROUND: Although recommended as initial therapy for patients with dyslipidemia who are taking human immunodeficiency virus protease inhibitors (HIV PIs), the effects of pravastatin on lipoproteins and arterial reactivity have not been elucidated. The purpose of this study was to determine the effects of pravastatin on lipoprotein subfractions and endothelial function in patients with dyslipidemia who are receiving HIV PIs. METHODS: This was a placebo-controlled, double-blind, crossover study comparing pravastatin (40 mg) to placebo in 20 patients who were taking HIV PIs. Lipoprotein subfractions were measured with nuclear magnetic resonance spectroscopic analysis. Flow-mediated vasodilation (FMD) of the brachial artery was evaluated with high-resolution ultrasound scanning. RESULTS: At baseline, subjects had an increased concentration of low-density lipoprotein (LDL) particles (1756 +/- 180 nmol/L), which tended to be small (19.9 +/- 0.2 nm), a low concentration of large high-density lipoproteins (HDL; 0.94 +/- 0.07 mmol/L), and an increased concentration of large very low-density lipoproteins (VLDL; 1.90 +/- 0.58 mmol/L). FMD was impaired (4.5% +/- 1.1%). Compared with placebo, pravastatin resulted in a 20.8% reduction in LDL particles (P =.030), a 26.7% reduction in small LDL (P =.100), and a 44.9% reduction in small VLDL (P =.023). Total and non-HDL cholesterol levels decreased by 18.3% (P <.001) and 21.7% (P <.001), respectively. FMD tended to increase in patients receiving pravastatin (0.7% +/- 0.6%); however, the difference between treatment phases was not statistically significant (P =.080). CONCLUSIONS: This is the first double-blind, placebo-controlled study of the effects of statin therapy on lipids, lipoprotein subfractions, and endothelial function in patients taking HIV PIs. Pravastatin reduced concentrations of atherogenic lipoproteins, particularly those most associated with future coronary events.

Adult↗
PubMed2004

Automated quantitative assessment of wall motion in patients with poor acoustic windows.

BACKGROUND: No technique exists for objective evaluation of left ventricular wall motion in contrast-enhanced images. We tested a new technique for quantification of regional fractional area change using contrast-enhanced power modulation imaging with color kinesis. METHODS: The feasibility of this technique for detecting acute ischemia was first tested in 11 pigs. Next, the accuracy for detecting resting wall-motion abnormalities was determined in 52 patients requiring contrast and compared with conventional interpretation of 2-dimensional images by inexperienced readers. Expert interpretation of 2-dimensional images served as the gold standard. RESULTS: In pigs, coronary occlusion resulted in reversible hypokinesis and reduced regional fractional area change. In patients with poor acoustic windows, this technique's accuracy for quantitative detection of resting wall-motion abnormalities was 86% compared with 81% for conventional interpretation by inexperienced readers (P <.01). CONCLUSIONS: Regional wall motion can be accurately assessed using color-encoded power modulation imaging for patients requiring contrast. This technique may prove a useful diagnostic aid to echocardiographers of varying levels of experience.

Animals↗
PubMed2004

Secondary coronary artery vasospasm promotes cardiomyopathy progression.

Genetic defects in the plasma membrane-associated sarcoglycan complex produce cardiomyopathy characterized by focal degeneration. The infarct-like pattern of cardiac degeneration has led to the hypothesis that coronary artery vasospasm underlies cardiomyopathy in this disorder. We evaluated the coronary vasculature of gamma-sarcoglycan mutant mice and found microvascular filling defects consistent with arterial vasospasm. However, the vascular smooth muscle sarcoglycan complex was intact in the coronary arteries of gamma-sarcoglycan hearts with perturbation of the sarcoglycan complex only within the adjacent myocytes. Thus, in this model, coronary artery vasospasm derives from a vascular smooth muscle-cell extrinsic process. To reduce this secondary vasospasm, we treated gamma-sarcoglycan-deficient mice with the calcium channel antagonist verapamil. Verapamil treatment eliminated evidence of vasospasm and ameliorated histological and functional evidence of cardiomyopathic progression. Echocardiography of verapamil-treated, gamma-sarcoglycan-null mice showed an improvement in left ventricular fractional shortening (44.3 +/- 13.3% treated versus 37.4 +/- 15.3% untreated), maximal velocity at the aortic outflow tract (114.9 +/- 27.9 cm/second versus 92.8 +/- 22.7 cm/second), and cardiac index (1.06 +/- 0.30 ml/minute/g versus 0.67 +/- 0.16 ml/minute/g, P < 0.05). These data indicate that secondary vasospasm contributes to the development of cardiomyopathy and is an important therapeutic target to limit cardiomyopathy progression.

Animals↗
PubMed2003

Use of echocardiography for the phenotypic assessment of genetically altered mice.

Transgenic mice displaying abnormalities in cardiac development and function represent a powerful new tool for understanding molecular mechanisms underlying normal cardiovascular function and the pathophysiological bases of human cardiovascular disease. Complete cardiac evaluation of phenotypic changes in mice requires the ability to noninvasively assess cardiovascular structure and function in a serial manner. However, the small mouse heart beating at rates in excess of 500 beats/min presents unique methodological challenges. Two-dimensional and Doppler echocardiography have been recently used as effective, noninvasive tools for murine imaging, because quality images of cardiac structures and valvular flows can be obtained with newer high-frequency transthoracic transducers. We will discuss the use of echocardiography for the assessment of 1) left ventricular (LV) chamber dimensions and wall thicknesses, 2) LV mass, 3) improved endocardial border delineation using contrast echocardiography, 4) LV contractility using ejection phase indices and load-independent indices, 5) vascular properties, and 6) LV diastolic performance. Evaluation of cardiovascular performance in closed chest mice is feasible in a variety of murine models using Doppler echocardiographic imaging.

Animals↗
PubMed2003

Dynamic three-dimensional color flow Doppler: an improved technique for the assessment of mitral regurgitation.

BACKGROUND: Prior studies have reconstructed mitral regurgitant flow in three dimensions displaying gray scale renditions of the jets, which were difficult to differentiate from surrounding cardiac structures. Recently, a color-coded display of three-dimensional (3D) regurgitant flow has been developed. However, this display was unable to integrate cardiac anatomy, thereby losing spatial information, which made it difficult to determine the jet origin and its spatial trajectory. To overcome this limitation, an improved method of 3D color reconstruction of regurgitant jets obtained from color flow Doppler using a transesophageal approach was developed to allow the combined display of both color flow and gray scale information. OBJECTIVES: To demonstrate the feasibility of 3D reconstruction of regurgitant mitral flow jets using an improved method of color encoding digital data acquired by transesophageal echocardiography (TEE). METHODS: We studied 46 patients undergoing a clinically indicated TEE study. All subjects had mitral regurgitation detected on a previous transthoracic study. Atrial fibrillation or poor image quality were not used as exclusion criteria. The 3D study was performed using a commercial ultrasound imaging system with a TEE probe (Sonos 5500, Agilent Technologies). A rotational mode of acquisition was used to collect two-dimensional (2D) color flow images at 3-degree intervals over 180 degrees. Images were processed off line using the Echo-View Software (TomTec Imaging Systems). Volume-rendered 3D color flow jets were displayed along with gray scale information of the adjacent cardiac structures. RESULTS: Mitral regurgitant flow, displayed in left atrial and two longitudinal orientations, was successfully reconstructed in all patients. The time for acquisition, post-processing, and rendering ranged between 10 and 15 minutes. There were 28 centrally directed jets and 15 eccentric lesions. Eight patients in the study had periprosthetic mitral regurgitant flow. CONCLUSIONS: Three-dimensional imaging of mitral regurgitant jets is feasible in the majority of patients. This improved technique provides additional information to that obtained from the 2D examination. Particularly, in patients with paravalvular leaks 3D color flow Doppler provides information on the origin and the extent of the dehiscence, as well as insight into the jet direction. In addition, in patients with eccentric mitral regurgitation, this new modality overcomes the inherent limitations of 2D echo Doppler by depicting the full extent of the jet trajectory.

Echocardiography, Doppler, Color↗