PubMed Health⌕ Search

Biomedical subjects

W C Brogan

Publications and source records attributed to W C Brogan.

At least 19 recordsLinked to original sources
PubMed1993

Rotational coronary atherectomy after unsuccessful coronary balloon angioplasty.

The clinical and angiographic outcome of patients undergoing rotational coronary atherectomy after unsuccessful balloon angioplasty was evaluated using quantitative angiographic methods to provide insight into this procedure's mechanism of benefit. During the study period, 41 patients (50 lesions) were referred for rotational atherectomy after standard balloon angioplasty was unsuccessful. After rotational atherectomy, percent diameter stenosis was reduced from 72 +/- 14% to 41 +/- 16% (p < 0.001); adjunct balloon angioplasty was performed in 44 lesions (88%), resulting in a 25 +/- 17% final diameter stenosis (p < 0.001). The acute gain in minimal lumen diameter was 1.20 +/- 0.59 mm. In lesions needing adjunct balloon dilatation, lesion stretch was 73 +/- 27%, and elastic recoil was 22 +/- 18%, with no variation by etiology of the initial balloon failure. Overall angiographic success (< 50% residual diameter stenosis) was obtained in 49 lesions (98%). Procedural success, defined as < 50% residual diameter stenosis and the absence of major in-hospital complications (death, Q-wave myocardial infarction or emergency bypass surgery), was obtained in 37 of 41 procedures (90%); complications developed in 3 patients (7%), including 2 who needed emergency bypass surgery after development of delayed abrupt closure. It is concluded that rotational coronary atherectomy may be used in selected patients when standard balloon angioplasty is unsuccessful. Its mechanism of benefit appears related, at least in part, to changes in plaque compliance resulting from partial atheroma ablation.

Angioplasty, Balloon, Coronary↗
PubMed1993

Prognosis after valve replacement in patients with severe aortic stenosis and a low transvalvular pressure gradient.

OBJECTIVES: This study was conducted to determine the risks and benefits of valve replacement in patients with severe aortic stenosis and a low transvalvular pressure gradient. BACKGROUND: There is uncertainty regarding the appropriate management of adults with severe aortic stenosis and a transvalvular pressure gradient < or = 30 mm Hg. With only six such patients reported, one study suggested that these subjects have a prohibitive operative risk and little symptomatic improvement if they survive surgical treatment, whereas another showed that they can survive an operation and improve symptomatically. METHODS: In an attempt to clarify the risks and benefits of valve replacement in these patients, we reviewed the records of 18 patients (15 men and 3 women, aged 49 to 81 years) with severe aortic stenosis (valve area < or = 0.4 cm2/m2 body surface area), a mean transvalvular pressure gradient < or = 30 mm Hg and limiting symptoms (New York Heart Association functional class III or IV) who underwent valve replacement. RESULTS: Six patients (33%) (95% confidence interval 13% to 59%) died perioperatively, whereas 10 patients (56%) (95% confidence interval 31% to 78%) improved symptomatically to functional class I (n = 8) or II (n = 2) (p = NS in comparison with the 6 who died). No clinical or hemodynamic variable was predictive of survival or improvement in functional class. CONCLUSIONS: Valve replacement in patients with severe aortic stenosis and a transvalvular pressure gradient < or = 30 mm Hg is accompanied by a considerable operative risk. Although there were no significant differences in this small series between the fraction of patients who died and those who exhibited improvement, we still recommend the procedure because many patients survive the operation and most of the survivors show an improved symptomatic status.

Aged↗
PubMed1992

Effect of coronary angioplasty on late potentials one to two weeks after acute myocardial infarction.

In survivors of acute myocardial infarction (AMI), the restoration of anterograde flow in the infarct artery, even if accomplished beyond the time for myocardial salvage, may reduce the frequency of subsequent arrhythmic events and sudden death. Twelve subjects (8 men and 4 women, aged 39 to 69 years) with a first AMI, signal-averaged electrocardiographic late potentials, and an occluded infarct artery were prospectively identified. Seven (group I) had successful coronary angioplasty 6 to 15 days after AMI, and 5 (group II) were managed conservatively. Follow-up signal-averaged electrocardiography was performed 3 to 7 months later. From baseline to follow-up, the 7 group I subjects had a significant change in QRS duration (117 +/- 13 [mean + SD] to 102 +/- 10 ms), root-mean-square voltage (10.4 +/- 4.7 to 31.0 +/- 7.6 microV), and low-amplitude signal duration (47.5 +/- 8.5 to 32.4 +/- 5.2 ms) (p < or = 0.05 for all 3 variables). No group I patient had a late potential at follow-up. In contrast, the 5 group II patients showed no change in QRS duration or low-amplitude signal duration from baseline to follow-up, and all 5 had a late potential at follow-up. At follow-up, the root-mean-square voltage was significantly greater and the low-amplitude signal and QRS durations significantly less in group I than in group II (p < 0.05 for all 3 variables). Thus, in our patients, the mechanical restoration of anterograde perfusion in an occluded infarct artery 1 to 2 weeks after AMI caused the resolution of signal-averaged electrocardiographic late potentials.

Adult↗
PubMed1992

Comparison of single and biplane ventriculography for determination of left ventricular volume and ejection fraction.

This study was done to compare single and biplane left ventriculography in quantitating left ventricular (LV) volumes and ejection fraction. LV volumes and ejection fraction were measured from a 30 degrees right anterior oblique single plane ventriculogram and a 30 degrees right anterior oblique 60 degrees left anterior oblique biplane ventriculogram in 152 men (aged 59 +/- 9 [mean +/- standard deviation] years), of whom 102 had hypokinesia, akinesia, or dyskinesia. There was excellent agreement between the results of single and biplane ventriculography with respect to LV end-diastolic volume (r = 0.96), end-systolic volume (r = 0.98) and ejection fraction (r = 0.97). The end-diastolic and end-systolic volumes measured by biplane ventriculography were consistently slightly larger than those measured by single plane, whereas ejection fractions measured by the 2 techniques were remarkably similar, even for the 46 patients with biplane ejection fractions less than 0.50 and the 102 with hypokinesia, akinesia or dyskinesia. Thus, LV volumes and ejection fractions determined by single plane ventriculography correlate very well with those determined by biplane ventriculography, even in patients with hypokinesia, akinesia, or dyskinesia and depressed LV systolic performance. Biplane ventriculography appears to provide little information that cannot be obtained reliably from single plane.

Adult↗
PubMed1992

Recurrent coronary vasoconstriction caused by intranasal cocaine: possible role for metabolites.

OBJECTIVE: To define the temporal characteristics of cocaine-induced coronary vasoconstriction in humans and to assess the relation between cocaine-induced coronary vasoconstriction and the blood concentration of cocaine and its main metabolites. DESIGN: Randomized, double-blind, controlled clinical trial. SETTING: Cardiac catheterization laboratory of a large teaching hospital. PATIENTS: Eighteen patients (16 men and 2 women, 37 to 65 years of age) having catheterization for evaluation of chest pain. MEASUREMENTS: At catheterization, patients received intranasal saline (8 patients) or cocaine, 2 mg/kg body weight (10 patients). Cineangiographic examination of the left coronary artery and quantitation of the blood concentration of cocaine and its metabolites were done before (baseline) and 30, 60, and 90 minutes after administration of intranasal saline or cocaine. RESULTS: In response to cocaine, proximal coronary arterial diameter decreased from 2.4 +/- 1.6 mm (mean +/- SD) at baseline to 2.0 +/- 1.4 mm at 30 minutes (P less than 0.05). This change corresponded temporally to the peak blood concentration of cocaine. At 60 minutes, the cocaine concentration decreased and coronary artery diameter returned to baseline (2.3 +/- 1.6 mm) (P greater than 0.05 compared with baseline). At 90 minutes, all patients had recurrent vasoconstriction (1.9 +/- 1.4 mm, P less than 0.05) despite a further decrease in the blood cocaine concentration. This vasoconstriction corresponded temporally with an increasing blood concentration of cocaine's main metabolites, benzoylecgonine and ethyl methyl ecgonine. No changes were observed in the control group. CONCLUSION: Intranasal cocaine causes recurrent coronary vasoconstriction, which may be due to its metabolites.

Administration, Intranasal↗
PubMed1992

Accuracy of various methods of measuring the transvalvular pressure gradient in aortic stenosis.

This study was done to assess the accuracy of various techniques of measuring the pressure gradient and valve area in patients with aortic stenosis (AS). In 18 patients with AS, the pressure gradient was quantitated from (1) simultaneous left ventricular and ascending aortic pressures (LV-AO), (2) nonsimultaneous LV-AO pullback, (3) LV and femoral arterial (FA) pressures unadjusted for the time delay of the FA tracing (LV-FA unadjusted), and (4) LV-FA adjusted for time delay. In comparison to simultaneous LV-AO, the pressure gradient was greater with LV-FA unadjusted and less with LV-FA adjusted for time delay (p less than 0.05). In nine patients with a mean gradient less than 35 mm Hg, the difference in valve area between simultaneous LV-AO and pullback averaged 0.17 +/- 0.10 cm2; between LV-AO and LV-FA unadjusted, the difference averaged 0.11 +/- 0.14 cm2; and between LV-AO and LV-FA adjusted, the difference averaged 0.52 +/- 0.36 cm2. These differences in valve area resulted in a discordant classification of the severity of AS in eight of the nine patients. Thus the use of an LV-AO pullback or an LV-FA gradient for assessing the severity of AS may yield inaccurate results, especially in patients with low (less than 35 mm Hg) gradients.

Aged↗
PubMed1992

The natural history of isolated left ventricular diastolic dysfunction.

STUDY OBJECTIVE: To assess the natural history of isolated left ventricular diastolic dysfunction. PATIENTS AND METHODS: Follow-up (average duration, 68 months) was obtained in 51 patients with isolated left ventricular diastolic dysfunction at cardiac catheterization, characterized by (1) an elevated left ventricular end-diastolic pressure; (2) normal left ventricular end-diastolic and end-systolic volumes; (3) normal left ventricular ejection fraction; (4) no coronary artery disease; and (5) no valvular disease. RESULTS: During follow-up, seven patients died, but only one died of cardiac causes. Of the 44 living subjects, 20 (45%) noted new-onset symptoms of congestive heart failure, with 11 (25%) of these requiring hospitalization, and 12 (27%) required hospitalization for recurrent chest pain. CONCLUSIONS: Isolated left ventricular diastolic dysfunction is associated with a low cardiac mortality; at the same time, however, it is associated with substantial morbidity.

Adult↗
PubMed1991

Simplified formula for the calculation of mitral valve area: potential inaccuracies in patients with tachycardia.

A simplified formula (cardiac output/[transvalvular pressure gradient]1/2) has been proposed as an alternative to the Gorlin equation for determining valve area in patients with mitral stenosis. This study was done (a) to assess the relationship between the results of the simplified formula and those of the Gorlin equation in patients with mitral stenosis and (b) to determine the clinical characteristics most likely to be associated with a disparity between the 2 formulae. In 96 patients with mitral stenosis, the disparity between the 2 formulae was greater than 0.2 cm2 in 43 (45%) and greater than or equal to 0.35 cm2 in 21 (22%). The results of the simplified formula were especially likely to be disparate from those of the Gorlin equation in those whose heart rates were greater than 100 beats/minute. Thus, in the patient with mitral stenosis, the simplified formula should be used with caution and cognizance of its potential inaccuracy, particularly if the patient is tachycardic.

Adolescent↗
PubMed1991

Contrast agents for cardiac catheterization: conceptions and misconceptions.

Ionic and nonionic contrast materials are similarly efficacious in providing excellent images with minimal risk to the patient. In comparison with ionic media, the nonionic agents produce minor alterations in intracardiac and peripheral pressures as well as in electrocardiographic intervals and morphology. In addition, nonionic media are less often associated with undesirable symptoms, such as flushing and vomiting. At the same time, ionic and nonionic media are accompanied by a similar incidence of nephrotoxicity, serious arrhythmias, and death. Finally, nonionic contrast material is substantially more expensive than ionic media. In light of this marked difference in cost, one could argue that nonionic media should be reserved for "high-risk" patients, that is, those with a history of a serious adverse reaction to ionic contrast media and those in whom contrast-induced hypotension would be particularly deleterious.

Blood Coagulation↗
PubMed1991

Alleviation of cocaine-induced coronary vasoconstriction by nitroglycerin.

Cocaine induces vasoconstriction of epicardial coronary arteries in patients with and without coronary artery disease, and this vasoconstriction is particularly marked in segments narrowed by atherosclerosis. To assess the effect of nitroglycerin on cocaine-induced coronary vasoconstriction, computer-assisted quantitative analysis was performed on non-diseased and diseased coronary artery segments in 23 patients (18 men, 5 women, aged 43 to 65 years) 1) at baseline, 2) after administration of intranasal saline solution (in 8 patients) or 2 mg/kg of cocaine (in 15 patients), and then 3) after administration of sublingual placebo (in 6 patients) or 0.4 or 0.8 mg of nitroglycerin (in 9 patients) in the 15 patients given cocaine. In response to cocaine administration, coronary artery cross-sectional area decreased 22 +/- 7% (mean +/- SD) in non-diseased segments (p less than 0.05) and 45 +/- 18% in diseased segments (p less than 0.02). The magnitude of vasoconstriction was greater (p = 0.01) in the diseased segments. Sublingual nitroglycerin abolished the vasoconstriction in both non-diseased and diseased segments. Thus, nitroglycerin alleviates cocaine-induced vasoconstriction in patients with coronary artery disease.

Administration, Intranasal↗
PubMed1984

Effects of carbon tetrachloride on adrenocortical structure and function in guinea pigs.

Studies were carried out to evaluate the effects of carbon tetrachloride (CCl4) on adrenocortical structure and function in guinea pigs. Treatment with CCl4 reduced adrenal microsomal cytochrome P-450 concentrations and markedly decreased adrenal benzo(a)pyrene (BP) hydroxylase and benzphetamine (BZ) demethylase activities. Adrenal microsomal 17 alpha- and 21-hydroxylase activities were relatively unaffected by CCl4. Similar changes in adrenal metabolism resulted from incubation of microsomal suspension with CCl4 plus NADPH in vitro. Morphologically, CCl4 treatment resulted in necrotic changes in the inner portions of the adrenal cortex. The zona reticularis and inner fasciculata contained numerous cells with pyknotic nuclei, fragmented nuclei, and vacuolated cytoplasm. Cells in the outer fasciculata and zona glomerulosa of the adrenals appeared normal. In adrenals obtained from normal guinea pigs, xenobiotic metabolism was highly localized to the inner portion of the cortex, the site of CCl4-induced necrosis. The CCl4-induced type I spectral change, a tentative measure of binding to cytochrome(s) P-450, was also greater in microsomes from the inner than from the outer zones. In addition, the initiation of lipid peroxidation by CCl4 plus NADPH, as well as the formation of covalently bound metabolites from 14CCl4, was far greater with inner than outer zone microsomes. The results indicate that the effects of CCl4 on the adrenal cortex are localized to the inner zone which probably represents the site of activation of the toxin. In addition, adrenal xenobiotic-metabolizing monooxygenases seem to be more vulnerable to the toxic effects of CCl4 than the microsomal steroid hydroxylases.

Adrenal Cortex↗
PubMed1983

Effects of lipid peroxidation on adrenal microsomal monooxygenases.

Incubation of guinea pig adrenal microsomes with 10(-6) M ferrous (Fe2+) ion and adrenal cytosol initiated high levels of lipid peroxidation as measured by the production of malonaldehyde. Cytosol or Fe2+ alone had little effect on microsomal malonaldehyde formation. When microsomes were incubated in the presence of Fe2+ and cytosol, malonaldehyde levels continued to increase for at least 60 min. Accompanying the lipid peroxidation was a decline in adrenal microsomal monooxygenase activities. The rates of metabolism of xenobiotics (benzphetamine demethylase, benzo[a]pyrene hydroxylase) as well as steroids (21-hydroxylation) decreased as malonaldehyde levels increased. In addition, cytochrome P-450 levels, NADPH- and NADH-cytochrome c reductase activities, and substrate interactions with cytochrome(s) P-450 decreased as lipid peroxidation progressed. Inhibition of lipid peroxidation by increasing microsomal protein concentrations during the incubation period prevented the changes in microsomal metabolism. Malonaldehyde had no direct effects on adrenal microsomal enzyme activities. The results indicate that lipid peroxidation may have significant effects on adrenocortical function, diminishing the capacity for both xenobiotic and steroid metabolism.

Adrenal Glands↗