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Biomedical subjects

E K Shirey

Publications and source records attributed to E K Shirey.

At least 19 recordsLinked to original sources
PubMed1985

Comparison of stress digital ventriculography, stress thallium scintigraphy, and digital fluoroscopy in the diagnosis of coronary artery disease in subjects without prior myocardial infarction.

Exercise thallium scintigraphy is often used for the diagnosis of coronary artery disease (CAD). Exercise digital subtraction ventriculography and digital subtraction fluoroscopy are new diagnostic procedures with roles that have not been determined. To compare the relative accuracies of the digital techniques with thallium scintigraphy, 97 consecutive patients without myocardial infarction underwent all 3 tests on the day before their scheduled coronary angiograms. Forty-two patients had CAD (more than 50% diameter narrowing of 1 major artery). A fixed or reversible perfusion defect defined an abnormal thallium test response and a segmental wall motion abnormality at rest or with exercise defined an abnormal digital ventriculographic response. Any visualized coronary calcific deposit defined an abnormal digital fluorographic response. The sensitivities of digital fluoroscopy (86%) and digital ventriculography (79%) were significantly higher than the sensitivity of thallium (62%) (p less than 0.05). The specificity of thallium (82%) was not significantly higher than that of either digital ventriculography (72%) or fluoroscopy (67%). The diagnostic accuracies of digital fluoroscopy, digital ventriculography, and thallium were 75%, 75% and 73%, respectively. A logistic regression model showed that thallium and digital fluoroscopy were more accurate in younger patients, whereas digital ventriculography was more sensitive in hypertensive persons and in those not taking beta-blocking drugs. The choice of test depends on disease prevalence, clinical variables (such as age and hypertension) and the importance of functional information obtained from stress testing.

Age Factors↗
PubMed1984

Captopril in congestive heart failure resistant to other vasodilators.

In an attempt to study the possible mechanism(s) by which captopril controls resistant heart failure, sequential haemodynamic studies (radioisotope technique) and humoral measurements (plasma renin activity, plasma aldosterone and plasma catecholamines) were obtained in 11 such patients. The studies were made at the time patients became unresponsive to other vasodilators (hydralazine or prazosin); the vasodilator drug was then discontinued and five days later, the 'no-vasodilator' studies were obtained. Captopril therapy was then started. Optimum daily maintenance dose of captopril varied from 75 to 200 mg in different patients. Studies were again repeated after a period of time equal to the duration of the previous vasodilator therapy. Digitalis and diuretic doses were kept constant throughout. Captopril improved effort tolerance in ten patients. Haemodynamically, mean blood pressure and peripheral resistance were lower than during vasodilator therapy (85 +/- 3.1 v. 92 +/- 3.3 mmHg and 47 +/- 4.4 v. 59 +/- 4.4 U.M2, respectively; p less than 0.05 for both). Cardiac index was higher during captopril treatment (1.95 +/- 0.15 v. 1.63 +/- 0.10 l/m2, p less than 0.01) and pulmonary mean transit was normalized by captopril (14.6 +/- 1.7 v. 18.4 +/- 1.3 s, p less than 0.05). Humoral indices revealed a significant (p less than 0.05) reduction in plasma aldosterone during captopril therapy (25.9 +/- 5.6 ng/dl during captopril, v. 62 +/- 22 ng/dl with no vasodilators and 50.9 +/- 6.1 ng/dl with other vasodilators). Moreover, there was a decrease in circulating plasma catecholamines during captopril treatment, but differences between the three treatment periods were not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1983

Selective coronary arteriography: a clinical comparison of two contrast agents.

The radiopacity and complications of meglumine iothalamate 52% and sodium iothalamate 26% (Vascoray) were compared with those of meglumine diatrizoate 66% and sodium diatrizoate 10% (Renografin -76) in 2258 patients with and without cardiac disease. There was no difference in radiopacity and the type and incidence of adverse reactions were similar, but the frequency was significantly higher (p less than 0.05) with Vascoray in patients with constrictive pericarditis, dissecting aortic aneurysm, and primary pulmonary hypertension. The difference in the frequency of hypotension, sinus bradycardia, and transient asystole in the Renografin -76 and Vascoray groups was statistically significant. Ventricular arrhythmias occurred in 6% of the patients with primary myocardial disease compared to an average of 0.7% in those without this cardiac abnormality (p less than 0.01), but there was no significant difference in the frequency in the two contrast agent groups. All reactions were treated and the studies were performed without mortality. Results of this study show that iothalamate formulation with sodium to meglumine ratio of 1:2 containing 410 mEq/L of sodium (Vascoray) is suitable and safe for clinical use for roentgenographic studies of the heart, and coronary artery circulation.

Adult↗
PubMed1982

Thromboxane biosynthesis in platelets of diabetic and coronary artery diseased patients.

We have shown that platelets of diabetic patients (D) with coronary artery disease (CAD) produce more thromboxane A2 (TXA2) compared to normal subjects (N), when induced to aggregate with arachidonic acid. The purpose of this investigation was to determine: 1) whether TXA2 biosynthesis in platelets of D without exogenous substrate is increased, 2) whether platelets of D without CAD produce more TXA2 than N and 3) to compare platelet TXA2 biosynthesis in D with those angiographically diagnosed as having CAD but without D. TXB2 (stable metabolite of TXA2) was measured by RIA in platelets of 100 volunteer subjects: 24 D without other clinical complications, 10 D with retinopathy or nephropathy, 7 D with CAD, 30 CAD without D and 11 had D and hypertension. Eighteen subjects had no D, CAD or hypertension. TXA2 synthesis in platelets, stimulated to aggregate with both endogenous and exogenous substrate was higher in all patient classes studied as compared to normal subjects. Plasma triglyceride concentration was higher in diabetics as compared to controls while total cholesterol as well as platelet phospholipid fatty acid distributions were similar in all groups of subjects indicating a similar substrate concentration for TXA2 biosynthesis. It is concluded that platelets of D and CAD with or without D have greater sensitivity to aggregation which might be due to the increased thromboxane synthetase system at one or more sites.

Blood Platelets↗
PubMed1980

Primary myocardial disease. Correlation with clinical findings, angiographic and biopsy diagnosis. Follow-up of 139 patients.

The purpose of this study was determination of the prognostic value of clinical and tissue (biopsy) findings of 139 patients with cardiomyopathy. The types of cardiomyopathy were congestive (113 patients) and hypertrophic or constrictive (26 patients). The mean follow-up period of all patients was 4.3 years. Follow-up of the survivors was between 13 months and 11.9 years, mean 5.4 years. Of the 47 cardiac deaths (33.8%), the minimum and maximum follow-up was two weeks and 7.5 years, respectively (mean 2.1 years). Patients with congestive heart failure had the highest five year cardiac mortality rate (51.8%). Coexisting cardiac arrhythmia had no influence on prognosis and an arrhythmia only was benign in most patients. Myocardial hypertrophy or fibrosis or both and myocardium with no pathologic diagnosis had prognostic value. Small-vessel disease was infrequent and not associated with specific clinical manifestations.

Alcohol Drinking↗
PubMed1980

HDL-cholesterol concentration and severity of coronary atherosclerosis determined by cine-angiography.

We studied 226 adult male subjects (mean=52yr) who underwent coronary arteriography. Their serum lipid and lipoprotein levels [total cholesterol (TC), triglycerides (TG), HDL-cholesterol (HDL-C), LDL-C, HDL-phospholipid (HDL-P), HDL-TG, HDL-C/TC, HDL-P/TC, LDL-C/TC, LDL-C/HDL-C and LDL-C/HDL-P] were correlated with the severity of coronary artery disease (CAD). Studies showed a slight but statistically significant correlation (linear regression) between CAD and HDL-P/TC (r=-0.24, P < 0.001), HDL-C/TC (r=-0.20, P < 0.002), followed by LDL-C/HDL-P (r=0.19, P < 0.004) and HDL-P (r=-0.18, P < 0.008). HDL-C, LDL-C and TC were significant at the P < 0.05 level; P value of TG was non-significant. Subjects were conveniently grouped based on degree of coronary artery narrowing: normal, mild (1-50%); moderate-severe (51-99%) and very severe (100% occlusion). Of the 11 lipid variables, the best predictor of the stage of the CAD was HDL-P/TC as measured by one-way analysis of variance. This trend was unaltered even after adjustment for covariates. HDL-P, LDL-C/HDL-P and HDL-C/TC were also significant, but the other lipid parameters were not. The study indicates that HDL-C, by itself, is not as effective a predictor of CAD as HDL-P/TC. Also, the small but statistically significant inverse relationship between HDL-P/TC and CAD suggests that a low HDL-P/TC ratio can be considered a risk factor for CAD but not as a dependable clinical diagnostic aid for predicting the severity of CAD on an individual basis.

Adult↗
PubMed1979

Fibrinolysis in familial pulmonary hypertension.

Although an autosomal dominant mode of inheritance has been documented for many cases of primary pulmonary hypertension, the pathogenesis of the disease remains unclear. A report of abnormal fibrinolysis in familial pulmonary hypertension has raised the possibility that the pathogenesis may be related to an impaired ability to lyse recurrent pulmonary microemboli. Primary pulmonary hypertension was diagnosed in three of ten members of a kindred. The pattern of inheritance was compatible with an autosomal dominant gene. Eight members of the kindred were available for study, one of whom has primary pulmonary hypertension. The results of coagulation studies, caseinolytic determinations of plasminogen and antiplasmin, and fibrinolytic titers of antiurokinase did not differ significantly from those of the control group. These findings suggest that a deficient fibrinolytic system is not the cause of primary pulmonary hypertension, although differences in methodology may explain our inability to demonstrate abnormal circulating fibrinolysis in this kindred.

Blood Coagulation↗
PubMed1975

Bridge saphenous vein graft.

Single aorta-coronary artery vein grafts (bridge grafts) were constructed to two coronary branches with a side-to-side anastomosis in 250 patients. Most of these grafts were constructed between circumflex branches (96 grafts), circumflex and diagnol branches (47 grafts), and anterior descending and diagonol branches (79 grafts). The aim of the bridge graft is to decrease the number of anastomoses, decrease the operative time, and improve graft patency. The hospital mortality rate in this group of patients was 1.2 per cent, and the incidence of postoperative myocardial infarction was 3.6 per cent. One hundred ten patients were restudied after surgery; the average time of restudy was 1 year. Ninety-two grafts of 83.6 per cent had two anastomosis patent; 6 grafts (5.4 per cent) had one anastomosis patent; and in 12 grafts (10.9 per cent), both anastomoses were occluded. One hundred twenty-six associated grafts were studied all the same time; the patency rate was 84.1 per cent. From this experience, we believe the bridge graft is a useful procedure for bypassing the small coronary artery branches.

Adult↗
PubMed1975

Vesicular myocardial change: an ultrastructural study of double membrane-bound vesicles in the human heart.

Vesicular myocardial change is a specific and common finding in the diseased hearts of humans and experimental animals. The small to large vesicles are generally bound by a double membrane. They are formed within myocardial cells and then possibly extruded into the extracellular space where they disintegrate or are phagocytosed by mononuclear cells. On the basis of our studies, most vesicles appear to be of mitochonrial origin. In humans, vesicular myocardial change appears to be most extreme in primary cardiomyopathy. It may also be present, but in lesser degree, in the apparently normal hearts of human adults. Vesicular myocardial change probably represents a specific mechanism by which myocardial cells eliminate damage mitochondria or other undesirable elements that build within them as a result of disease, aging, and perhaps normal physiological activity.

Adolescent↗
PubMed1975

The role of myocardial biopsy in cardiac diagnosis.

With the advent of cardiac catheterization, cardioangiography, and selective coronary arteriography, specific types of cardiac disease can be recognized and clearly defined. This is appropriate because myocardial biopsy alone rarely plays a major role in cardiac diagnosis. Excluding Aschoff's nodules in patients with rheumatic valve disease, the light microscopic findings in patients with rheumatic heart disease, congenital heart disease, pericardial disease, hypertensive and arteriosclerotic heart disease are similar and nonspecific. In these, interstitial fibrosis and/or myocardial hypertrophy is the dominant tissue diagnosis. Occasionally a pericardial and myocardial specimen is helpful to distinguish constrictive pericarditis and restrictive cardiomyopathy. Myocardial biopsy has provided the only method for diagnosis in a small number of patients with normal hemodynamics, normal coronary arteriograms and normal ventriculograms. The patients were studied because of chest pain and/or cardiac arrhythmias. Supraventricular and/or ventricular arrhythmias were encountered. In these patients the tissue diagnosis was interstital fibrosis and/or myocardial hypertrophy. These findings are consistent with primary myocardial disease which was not recognized clinically or by angiographic studies. The procedure seems to play a major role in the diagnosis of specific types of primary myocardial disease. It is valuable in the recognition of glycogen storage disease, amyloidosis, hemochromatosis, and myocarditis. On the basis of current experience, the indications for myocardial biopsies depend on the need for a tissue diagnosis in determining the management of the patient and the availability of adequately trained personnel to perform the procedure and manage the complications.

Angiocardiography↗
PubMed1975

Manual coronary endarterectomy. Clinical experience in 315 patients.

From July, 1970, to December, 1973, manual endarterectomies were performed on 330 coronary arteries in 315 patients. The procedures were performed on either an elective or nonelective basis. The over-all hospital mortality rate was 1.27 per cent. Postoperative myocardial infarction occurred in 4.8 per cent of these patients. Postoperative catheterization was performed on 186 endarterectomized arteries; the average time of postoperative catheterization was 13.1 months after surgery. The over-all patency rate was 76.3 per cent. This experience suggests that endarterectomy is a safe and useful adjunct to saphenous vein bypass grafting procedures when used in a restricted fashion as detailed in this presentation.

Adult↗