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Biomedical subjects

S Michelle Bierig

Publications and source records attributed to S Michelle Bierig.

7 recordsLinked to original sources
PubMed2006

Serial changes in systolic and diastolic echocardiographic indices as predictors of outcome in patients with decreased left ventricular ejection fraction.

BACKGROUND: Echocardiographic estimation of left ventricular ejection fraction aids in predicting adverse outcomes in coronary artery disease. However, in patients with impaired left ventricular function, further risk stratification is difficult. METHODS: A 2 year retrospective review was performed to identify patients with ejection fraction < or=30%. Echocardiographic measures of systolic and diastolic function were independently performed offline. Outcome information, which included MI, stroke, or death, was obtained. The patient cohort identified those with follow-up having 1) a single echocardiogram and a subset 2) with an initial echocardiogram and a second echocardiogram at greater than one year follow-up. RESULTS: This study included 110 patients, ages 20-94. Mean follow-up time was 29+/-9 months. Ejection fraction did not predict cardiovascular events. LV mass predicted of mortality (p=0.03). Diastolic indexes of mitral inflow E wave was a significant predictor of outcome (p=0.05). Impaired diastolic filling grade 2, 3, or 4 showed a 76% event rate. Decreases in ejection fraction at follow-up were seen in those who had an event, with an average decrease in ejection fraction of 17% versus those who lived with no event of 1%. Changes in mitral inflow E wave and changes in E/A ratio were both significant predictors of outcome. CONCLUSIONS: These data indicate that echocardiographic measures of both systolic and diastolic function aid in risk stratifying patients with decreased ejection fraction. The changed detected in serial echocardiographic information may be important in treatment and secondary prevention of future events.

Adult↗
PubMed2006

Efficacy of atropine as a chronotropic agent in heart transplant patients undergoing dobutamine stress echocardiography.

BACKGROUND: After heart transplant (HTX), the heart is completely denervated. While sympathetic reinnervation is likely to occur, there is conflicting evidence regarding parasympathetic reinnervation. Accordingly, it is unclear if atropine is efficacious as a chronotropic agent in HTX patients undergoing dobutamine stress echocardiography (DSE), since cholinergic cardiac stimulation is required for atropine to exert its effect. The purpose of this study was to demonstrate that atropine can sufficiently increase the heart rate (HR) in HTX patients undergoing DSE. METHODS: A retrospective review was performed on 68 HTX patients who underwent DSE as part of their routine annual HTX follow-ups. Dobutamine was administered in the standard fashion of 10, 20, 30, 40, 50 mcg/kg per minute with blood pressure and electrocardiographic monitoring. If target HR was not attained, atropine was administered to aid in achieving 85% of maximum age-predicted HR. RESULTS: Mean patient age was 58 +/- 10 years. Mean period since transplant was 9 +/- 4 years. Forty-seven (69%) patients received dobutamine only, and 21 (31%) required additional atropine to reach target HR. Of the 21 patients who received atropine, 10 (48%) reached target HR. Neither time from transplant, age, gender, resting HR, medications, nor atherosclerotic risk factors predicted responsiveness to atropine. Those responding to dobutamine had a significantly greater resting HR than those receiving additional atropine. CONCLUSIONS: The adjunctive use of atropine in HTX patients during DSE aids in reaching 85% of maximum predicted HR in some patients. Furthermore, resting HR may predict the additional need of atropine during DSE.

Adult↗
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

Improved visualization of aortic intima-media thickening with the use of perflutren lipid microspheres.

BACKGROUND: Transesophageal echocardiography (TEE) has been used to diagnose atherosclerotic disease for patients who present with systemic embolic events. The primary aim of this study was to assess the supplemental value of echocardiographic contrast to standard TEE in identifying the aortic intima-medial thickness. METHODS: An aorta phantom was used to validate the accuracy of border delineation with and without contrast during TEE imaging. In all, 44 patients underwent TEE imaging of the thoracic aorta with a subsequent administration of a 0.3-mL bolus of perflutren lipid microspheres (Definity). Precontrast and postcontrast images were analyzed semiquantitatively for border delineation and quantitatively for intima-medial thickness and cross-sectional area. RESULTS: Wall thickness in the aortic phantom model with contrast was smaller, more accurate, and more reproducible to the true measurement. The clinical studies reflected similar results with average contrast intima-medial thickness measured at 0.15 +/- 0.08 cm and noncontrast at 0.18 +/- 0.08 cm (P < .01). The lateral wall showed the greatest improvement with a score of 1.23 increasing to an average of 1.82 (P < .001) with contrast. The medial, anterior, and posterior walls improved to an average 1.98, 1.39, and 2.0, respectively (P = .01). CONCLUSIONS: Contrast agents provide better aortic intima-media enhancement during TEE.

Aorta, Thoracic↗
PubMed2005

Clinical application of harmonic power Doppler imaging in the assessment of myocardial perfusion by contrast echocardiography.

Myocardial contrast echocardiography has moved from the research laboratory to clinical echocardiography. As with any emerging technology, background information and understanding the process of image acquisition will help to integrate the technology into everyday practice. Harmonic power Doppler imaging (HPDI) is a high-power, triggered imaging modality used to assess myocardial perfusion. Contrast agents used in echocardiography provide microvascular tracers that enable HPDI to accurately visualize myocardial blood flow. This article aims to provide direction in the clinical performance of myocardial contrast echocardiography by providing background in the theory and physics of HPDI and a guide to the technical acquisition of images and recognition of artifacts that arise during HPDI.

Art↗
PubMed2003

Tertiary care improves the chance for vaginal delivery in women with preeclampsia.

OBJECTIVE: The purpose of this study was to determine whether the level of hospital care affects cesarean delivery rates for women with preeclampsia. STUDY DESIGN: We conducted a population-based cohort study using Missouri birth certificate data for 1993 through 1999. Logistic regression was used to analyze data from 13,646 nulliparous women with preeclampsia who were delivered of singleton live births. RESULTS: After adjustment was made for gestational age and birth weight, the data showed that women with preeclampsia at primary and secondary hospitals were more likely to be delivered by cesarean delivery (odds ratio, 1.37; 95% CI, 1.24,1.51; and odds ratio, 1.16; 95% CI, 1.07,1.26, respectively) than at tertiary hospitals. For women who were delivered at >or=37 weeks of gestation, cesarean delivery rates were 38.0%, 33.7%, and 30.0% for primary, secondary, and tertiary hospitals, respectively. Dysfunctional labor, cephalopelvic disproportion, and fetal distress were more commonly noted at primary and secondary hospitals (P<.001). CONCLUSION: Levels of expertise and staffing at tertiary hospitals may allow greater attempts and success with vaginal delivery among women with preeclampsia compared with primary or secondary hospitals.

Adolescent↗