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Biomedical subjects

E O Ofili

Publications and source records attributed to E O Ofili.

15 recordsLinked to original sources
PubMed1999

Gender differences and practice implications of risk factors for frequent hospitalization for heart failure in an urban center serving predominantly African-American patients.

To identify the clinical correlates of recurrent heart failure hospitalization in a large urban hospital serving predominately African-American patients, and to provide further insight into modifiable risks for heart failure readmissions, a retrospective period prevalence review of the records of all adult patients admitted with a primary diagnosis of heart failure (International Classification of Diseases-9 code 428.0) between January and December 1995 was performed. The main outcome was the number of heart failure hospitalizations over 12 months. Twelve hundred patients were identified. Mean age was 64 +/- 16 years, 94% were black, 57% were women, and 40% were > or = 65 years old. Ninety-eight percent had a history of systemic hypertension and 55% had uncontrolled hypertension. Other comorbidities were left ventricular (LV) hypertrophy (64%), coronary artery disease (52%), and tobacco abuse (28%). Sixty-five percent of patients were on angiotensin-converting enzyme (ACE) inhibitors, 51% on calcium antagonists, and 8% on beta blockers. Most patients had suboptimal dosing of ACE inhibitors and there was inappropriate use of calcium antagonists in 56% of patients with moderate or severe systolic dysfunction. Diabetes mellitus and echocardiographic wall motion abnormality were independently associated with frequent admissions for women but not for men. Medication-related increase in heart failure hospitalization was seen for calcium antagonists in patients with severe LV dysfunction (odds ratio 2.24, 95% confidence intervals 1.0 to 5.03; p <0.03). Uncontrolled hypertension, underdosing of ACE inhibitors, and overuse of calcium antagonists in patients with significant LV dysfunction are potential targets for intervention.

Adult↗
PubMed1998

Effect of treatment of isolated systolic hypertension on left ventricular mass.

CONTEXT: Left ventricular (LV) hypertrophy is a common problem among elderly patients with isolated systolic hypertension (ISH), but the effect of treatment of ISH on LV mass is not known. OBJECTIVE: To assess the ability of antihypertensive drug treatment to reduce LV mass in ISH. DESIGN: Echocardiographic Substudy of the Systolic Hypertension in the Elderly Program (SHEP). PATIENTS: A total of 104 participants at the St Louis SHEP site who had interpretable baseline echocardiograms, 94 of whom had 3-year follow-up echocardiograms. INTERVENTION: The SHEP participants were randomized to placebo or active treatment with chlorthalidone (12.5-25 mg/d), with atenolol (25-50 mg/d) added if necessary to maintain goal blood pressure. MAIN OUTCOME MEASURE: Change in LV mass assessed by echocardiography. RESULTS: Minimum follow-up was 3 years. In the active treatment group, 91% and 80% of subjects were receiving treatment with chlorthalidone alone by the end of years 1 and 3, respectively. The LV mass index was 93 g/m2 in the active treatment group and 100 g/m2 in the placebo group (P<.001). The LV mass index declined by 13% (95% confidence interval, - 3% to - 23%) in the active treatment group compared with a 6% increase (95% confidence interval, - 3% to + 16%) in the placebo group over 3 years (P=.01). CONCLUSION: Treatment of ISH with a diuretic-based regimen reduces LV mass.

Aged↗
PubMed1998

Prognostic significance of late-peaking left ventricular velocity contour in patients with aortic stenosis undergoing valve replacement.

BACKGROUND: The presence of an abnormal late-peaking left ventricular velocity contour, detected by Doppler echocardiography, has been reported in patients with hypertrophic cardiomyopathy, left ventricular hypertrophy, and aortic stenosis. METHODS AND RESULTS: To evaluate the clinical and prognostic significance of this characteristic Doppler finding, we studied a group of patients (n = 57) with isolated AS undergoing aortic valve replacement. Patients were divided into two groups according to the presence (n = 28) or absence (n = 29) of a hypertrophic late-peaking left ventricular velocity pattern. There were no differences between the groups with respect to age, sex, and presence of coronary artery disease. Peak preoperative aortic valve gradients were similar in both groups (70 vs. 67 mm Hg; p = not significant). The postoperative course of patients with abnormal late-peaking ventricular velocity contour was complicated by a higher incidence of arrhythmias (80% vs. 38%; p = 0.0002). Hypotension and the use of inotropic support were significantly more common in the group with abnormal late-peaking ventricular velocity contour (79% vs. 24%; p = 0.0001 and 76% vs. 26%; p = 0.0001, respectively). Hemodynamically, patients with a late-peaking velocity pattern exhibited a higher pulmonary diastolic pressure (16+/-3 vs 12+/-2 mm Hg; p = 0.0003), wedge pressure (12+/-4 vs 10+/-2; p < 0.05), and systemic vascular resistance (2126+/-459 vs 1553+/-199; p = 0.0001) and lower cardiac index (2.4+/-0.3 vs 2.9+/-0.4; p = 0.0001). CONCLUSIONS: An abnormal late-peaking ventricular velocity contour pattern appears to be a high risk marker for postoperative complications in patients undergoing aortic valve replacement. Routine Doppler evaluation in patients undergoing valve replacement for AS may therefore identify these patients.

Adult↗
PubMed1998

Color Doppler imaging of the myocardium: current status and potential clinical applications.

Doppler myocardial imaging (DMI) is a new technique with potential clinical and research applications. It applies traditional pulsed and color Doppler techniques to the analysis of myocardial contractile velocity. A major area of focus is in the quantitation of regional and global myocardial function and evaluation of myocardial perfusion in conjunction with myocardial contrast studies. DMI may also provide a direct, relatively load-independent assessment of diastolic function. Further work is required to identify its role in clinical and research studies.

Coronary Circulation↗
PubMed1997

Pharmacologic stress-induced regional myocardial blood flow heterogeneity and left ventricular wall thickening abnormality: comparison of intravenous adenosine with dipyridamole in a model of critical coronary stenosis.

Variations in reported sensitivity of myocardial perfusion scans or wall motion abnormalities during pharmacologic stress with intravenous adenosine and dipyridamole may be caused by differences in myocardial oxygen demand or myocardial blood flow redistribution induced by each agent. To investigate the physiologic correlates of functional abnormalities during pharmacologic stress testing, regional myocardial blood flow (radiolabeled microsphere technique) and left ventricular segmental wall thickening (quantitative two-dimensional echocardiography) were measured in 9 dogs with an open chest model of critical stenosis of the left circumflex coronary artery. Data were obtained at baseline and peak drug infusion for intravenous adenosine (0.42 mg/kg over a 3-minute period) and for intravenous dipyridamole (0.56 mg/kg over a 4-minute period). Adenosine and dipyridamole induced regional flow abnormality in 7 (77%) of 9 dogs. Myocardial segments with decreased endocardial/epicardial flow ratio were similar for both agents (2.9 +/- 1.8 vs 2.7 +/- 1.3, p = [NS]). Segments with myocardial flow heterogeneity (ratio of endocardial flow to control left anterior descending/left circumflex endocardial flow) were similar for both agents (2.7 +/- 0.9 vs 2.3 +/- 1.0, p = NS). Adenosine-induced wall thickening abnormality (77% vs 55% with dipyridamole) correlated with regional flow abnormality. Significantly lower mean arterial pressure (53 +/- 1.7 mm Hg vs 64 +/- 1.9 mm Hg, p < 0.01) and more prolonged drug effect (18 +/- 6.4 min vs 3 +/- 1.4 min, p < 0.001) were seen for dipyridamole compared with adenosine. Adenosine induces regional flow abnormality similar to dipyridamole but with less hemodynamic perturbation, and adenosine-induced wall thickening abnormality more closely parallels regional flow abnormality.

Adenosine↗
PubMed1995

Differential characterization of blood flow, velocity, and vascular resistance between proximal and distal normal epicardial human coronary arteries: analysis by intracoronary Doppler spectral flow velocity.

To characterize coronary blood flow velocity parameters and to determine the relation among velocity, volumetric flow, and vascular resistance in awake human beings, we performed paired proximal and distal velocity measurements in 28 angiographically normal coronary arteries. Mean velocity, peak velocity, diastolic-to-systolic velocity ratio, and diameter and cross-sectional area of proximal and distal arteries were determined and coronary flow and vascular resistance computed. Mean velocity and coronary vasodilator reserve were similar for all three native arteries and were preserved from proximal to distal segments. Volumetric flow decreased from proximal to distal segments. The demonstrated inverse and curvilinear (polynomial) relation between volumetric flow and vascular resistance agrees with theoretical and animal models of coronary physiologic characteristics and suggests a nadir of coronary vascular resistance below which coronary flow no longer increases.

Adult↗
PubMed1995

Relation between pulmonary venous flow and pulmonary wedge pressure: influence of cardiac output.

Multiple factors affect the systolic and diastolic components of pulmonary venous flow. It has been suggested that left ventricular function might influence the effects of filling pressures on indexes of pulmonary venous flow. The present study was designed to evaluate the effect of the pulmonary wedge pressures, left ventricular function, and cardiac output on the pulmonary vein flow pattern. Forty-five patients undergoing cardiac surgery were included in this study. Pulmonary venous flow and mitral flow variables were obtained by transesophageal echocardiography with hemodynamic variables obtained simultaneously. In the total group, there was no consistent relation between the pulmonary venous flow or the mitral flow parameters and the capillary wedge pressures. When patients were grouped according to normal (> 2.2 L/min/m2) or low (< 2.2 L/min/m2) cardiac index, a significant and positive relation was found between the systolic component of the pulmonary venous flow and the pulmonary wedge pressure in patients with normal cardiac index (r = 0.69; p = 0.003). Conversely, in patients with low cardiac index there was also a significant although negative correlation between the systolic velocity integral and the pulmonary wedge pressure (r = -0.58; p < 0.001). In conclusion, the systolic component of the pulmonary venous flow correlates closely and significantly with the capillary wedge pressures. The direction of this relation depends to a large extent on the total cardiac output and to a lesser extent on the left ventricular systolic function as assessed by the ejection fraction.

Adult↗
PubMed1994

Three-dimensional and four-dimensional echocardiography.

Since its introduction in 1974, 3-D reconstruction of the heart has undergone significant technological refinements in image acquisition, processing and display techniques. Image acquisition for transthoracic 3-D reconstruction utilizes the parasternal or apical windows, or combinations of the two. The parasternal approach allows better endocardial border detection, while the apical approach allows a more complete visualization of the left ventricular apex. Computer algorithms are used to process images with various display techniques incorporated into the algorithm. Transesophageal image acquisition overcomes a significant limitation of the transthoracic approach, which is variable and sometimes poor image quality. Both a multiplane approach and a computerized tomographic approach have been successfully used by several investigators. Potential applications of 3-D echocardiography include reconstruction of the mitral annulus, dynamic cardiac anatomy and function and volume calculations. A major limitation is the need for considerable computer time for image processing and display; furthermore, errors may be introduced by the various smoothing and contouring algorithms. Despite these limitations, 3-D echocardiography has considerable potential for clinical utility, particularly in the areas of reconstructive cardiac surgery and congenital heart disease.

Echocardiography↗
PubMed1993

Usefulness of transesophageal echocardiography in unexplained cerebral ischemia.

Two-hundred seventy consecutive patients with "unexplained cerebral ischemia" were studied with transesophageal echocardiography to determine the value of this test in identifying potential cardiac sources of cerebral embolism. The findings of this group were compared with those of 772 consecutive patients undergoing transesophageal echocardiographic evaluation for indications other than cerebral ischemia. This study also examined this group of patients with unexplained cerebral ischemia to determine differences in relation to underlying cardiac rhythm and patient age. Intracardiac thrombus, atrial septal aneurysm, patent foramen ovale, spontaneous left atrial contrast and protruding debris in the thoracic aorta were found more often in patients with unexplained cerebral ischemia. Wall motion abnormalities of the left ventricle, as well as mild to moderate valvular lesions including mitral valve prolapse, were found to be similar in both groups. Spontaneous left atrial contrast, as well as mild to moderate valvular abnormalities, were found more often in patients with atrial fibrillation (22% of the group with unexplained cerebral ischemia). However, the presence of intracardiac thrombus was no more frequent in patients with atrial fibrillation than in those with normal sinus rhythm. Patients aged > 50 years were found to have atrial fibrillation and larger left atrial size more often than their younger cohorts, as well as a greater incidence of valvular abnormalities and left ventricular wall motion abnormalities. Mitral valve prolapse was seen more frequently in the younger cohort of patients.

Adolescent↗
PubMed1993

Coronary flow velocity dynamics in normal and diseased arteries.

Distal coronary flow velocity measurements were previously limited to open heart or experimental procedures. Unlike previous Doppler catheter techniques, a Doppler angioplasty flow wire permits flow velocity measurements in both the proximal and distal segments of normal and diseased coronary arteries. In order to determine the potential clinical application of the Doppler flow wire, we performed baseline and hyperemia flow velocity measurements in proximal and distal segments of 20 angiographically normal arteries (right coronary = 8; left circumflex = 7; left anterior descending = 5) and 29 significantly stenosed arteries. All 3 normal coronary arteries had a diastolic-predominant pattern in both proximal and distal segments; the right coronary artery showed significantly less diastolic predominance. The coronary vasodilator reserve was similar in all three normal coronary arteries, and in the proximal and distal arterial segments. Abnormal arteries had significantly lower coronary vasodilator reserve (normal vs abnormal, 2.3 +/- 0.8/1.6 +/- 0.7; p < 0.02). Normal arteries had preservation of velocity parameters in the distal segments; abnormal arteries had a significant decrease in distal velocity parameters. The proximal-to-distal velocity ratio was thus significantly higher in abnormal arteries (2.4 +/- 0.7 vs 1.1 +/- 0.2; p < 0.001). The coronary vasodilator reserve in proximal and distal arteries--in addition to the proximal to distal velocity ratio--may provide functional and hemodynamic data complementary to coronary angiography in the assessment of coronary artery stenosis.

Blood Flow Velocity↗
PubMed1993

Quantitating coronary collateral flow velocity in patients during coronary angioplasty using a Doppler guidewire.

Quantitation of coronary collateral flow in patients has been limited to angiographic techniques, which are subject to well-known methodologic limitations. The use of a Doppler-tipped angioplasty guidewire permits measurement of both antegrade and retrograde flow distal to totally or subtotally occluded vessels that may be supplied with acutely recruitable or angiographically mature collateral conduits. Using coronary flow velocity as an indicator of collateral flow, retrograde flow velocity was quantitated in 17 patients. Mean collateral flow velocity was approximately 30% of normal postangioplasty antegrade flow velocity. The phasic pattern of collateral flow was highly variable, but the retrograde diastolic and systolic flow velocity integrals were 20% and 40% (respectively) of post-procedure antegrade flow velocity. Preliminary studies with pharmacologic stimulation of the contralateral supply artery suggests that collateral flow is not increased by intracoronary nitroglycerin (200 micrograms) or adenosine (12 micrograms), but may be markedly augmented during mechanical stimulation of balloon occlusion. These data represent the first in a series of quantitative observations on control of the coronary collateral circulation in humans. Future investigations using the Doppler Flowire (Cardiometrics) will enhance understanding of factors modulating ischemia through collateral supply.

Angioplasty, Balloon, Coronary↗
PubMed1993

Analysis of coronary blood flow velocity dynamics in angiographically normal and stenosed arteries before and after endolumen enlargement by angioplasty.

OBJECTIVES: This study was designed to assess whether the spectral waveform of coronary velocity on Doppler study is characteristically altered in the presence of significant stenosis with normalization of the spectral waveform after relief of endolumen obstruction. BACKGROUND: Although coronary flow reserve determinations have provided physiologic information complementary to the angiographic percent diameter narrowing, flow velocity measurements have been limited to proximal arteries with inconsistent results after angioplasty. A 12-MHz Doppler guide wire permits flow velocity determination in the proximal and distal coronary artery with fast Fourier spectral analysis. METHODS: With the Doppler guide wire, proximal arterial flow velocity and flow reserve measurements in 17 angiographically normal arteries were compared with measurements in 29 significantly stenosed arteries. Proximal and distal flow velocity measurements were also obtained before and after angioplasty of the 29 abnormal arteries. Velocity spectrum was digitized to compute peak diastolic velocity, peak systolic velocity, mean velocity, diastolic/systolic velocity ratio and first third and first half flow fraction. RESULTS: Compared with proximal stenosed arteries, proximal normal arteries had significantly higher peak diastolic velocity (64 +/- 26 cm/s vs. 41 +/- 26 cm/s) and higher coronary vasodilator reserve (2.3 +/- 0.8 vs. 1.6 +/- 0.7). Normal arteries had higher flows in the first third and first half of the coronary cycle (46 +/- 3% vs. 39 +/- 7% and 65 +/- 2% vs. 56 +/- 10%, respectively). Before angioplasty, coronary velocity variables were significantly lower distal than proximal to the stenosis. After angioplasty, there was a greater mean increase in distal velocities (200% vs. 90% for the proximal arteries) that resulted in near equalization of proximal and distal mean velocity and a significant reduction in proximal/distal mean velocity ratio (2.4 +/- 1.7 vs. 1.2 +/- 0.4). CONCLUSIONS: Before angioplasty, abnormal coronary flow velocity dynamics are more marked distal than proximal to the stenosis. Greater increase in coronary flow velocities in the distal circulation after relief of endolumen obstruction results in a significant reduction in the proximal/distal flow velocity ratio. Thus, normalization of Doppler-derived flow velocity variables with marked reduction of the proximal/distal flow velocity ratios parallels angiographic success and may prove useful as an additional end point measurement in interventional cases with questionable angiographic findings.

Angioplasty, Balloon, Coronary↗
PubMed1992

The technique of transesophageal echocardiography. How to procure detailed views of an array of cardiac structures.

Use of transesophageal echocardiography (TEE) is growing in ambulatory, intensive care, and intraoperative settings. Forward flexion or retroflexion of the TEE probe tip at different levels in the esophagus reveals a variety of intracardiac structures; in the basal short-axis view, for example, the aortic valve can be seen, as can the left atrial appendage lateral to the aorta and pulmonary artery. In the four-chamber view, the mitral and tricuspid valves and interatrial septum can be viewed, and the morphology of the mitral valve leaflets and mitral annulus can be assessed. Cross-sectional views of both ventricles can be obtained in the transgastric short-axis view. In addition, the entire thoracic aorta, as well as the proximal ascending and transverse arch, can be visualized with TEE.

Echocardiography, Doppler↗
PubMed1992

Transesophageal echocardiography: expanding indications for ICU use. How TEE can complement--or surpass--transthoracic techniques.

Transesophageal echocardiography (TEE) is a Doppler technique that uses the esophagus as an acoustic window. In critically ill patients (particularly ventilated patients), TEE may be used to assess left ventricular function, valvular disease, endocarditis, and prosthetic valve dysfunction. It is also helpful in elucidating the cause of hypotension after cardiac surgery, and can detect chronic aortic dissection and transection, valve rupture, and myocardial contusion in trauma victims. TEE is superior to transthoracic echocardiography in evaluating a cardiac source of embolism. Contraindications to TEE include esophageal disorders and an uncorrected bleeding diathesis; a large hiatal hernia may cause suboptimal transgastric images.

Critical Care↗