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Dive into the research topics where Alan G. Bartel is active.

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Featured researches published by Alan G. Bartel.


The New England Journal of Medicine | 1980

Risk of stroke in asymptomatic persons with cervical arterial bruits: a population study in Evans County, Georgia.

Albert Heyman; William E. Wilkinson; Siegfried Heyden; Michael J. Helms; Alan G. Bartel; Herbert R. Karp; Herman A. Tyroler; Curtis G. Hames

A survey of the rural community in Evans County, Georgia, revealed cervical arterial bruits in 72 (4.4 per cent) of 1620 persons 45 years of age of older without previous stroke, transient ischemic attacks, or overt ischemic heart disease. The prevalence of such asymptomatic bruits increased with age and was greater in women and persons with hypertension. We estimated the risk of stroke associated with cervical bruits during a six-year follow-up period, taking age and blood pressure into account. The presence of asymptomatic bruits was associated with a significantly higher risk of stroke in men but not in women, with odds ratios of 7.5 and 1.6, respectively. Despite the high risk of stroke among men with bruits, the correlation between the location of the bruits and the type of subsequent stroke was poor. Moreover, cervical bruits in men were a risk factor for death from ischemic heart disease. We suggest that asymptomatic cervical bruits are an indication of systemic vascular disease and do not themselves justify invasive diagnostic procedures or surgical correction of underlying extracranial arterial lesions.


Circulation | 1974

Graded Exercise Stress Tests in Angiographically Documented Coronary Artery Disease

Alan G. Bartel; Victor S. Behar; Robert H. Peter; Edward S. Orgain; Yihong Kong

Graded exercise stress tests performed on 650 consecutive patients with proven or suspected coronary disease undergoing evaluation by cardiac catheterization were correlated with clinical, hemodynamic, and angiographic findings. Among 451 patients with significant coronary stenosis, 332 (74%) had interpretable stress tests and 65% of these were positive (sensitivity). The rate of “false positives’ was 8%.The clinical syndrome of typical angina identified significant coronary disease in 89% of the patients, and 58% of that group had a positive exercise test defined by objective electrocardiographic criteria.Patients were not eliminated from this study because of recent digitalis ingestion. Although a higher frequency of uninterpretable exercise tests was found in this group (40%), the test results reflected more severe coronary disease. None of the patients with “false positive’ tests were taking digitalis. It is concluded that recent digitalis ingestion should not be considered a contraindication for exercise stress testing.Among the patients with interpretable exercise tests, the angiographic severity of coronary artery disease correlates strongly with the frequency of positive tests (40%, 66%, and 76%, with 70% or greater occlusion of one, two or three vessels respectively). Left main coronary stenosis of 70% or greater was associated with more severe ST segment changes, inability to achieve target heart rate during stress, and a lower maximum heart rate during exercise. The angiographic occurrence of collateral vessels was related to the extent of coronary disease and was associated with a higher percentage of positive exercise tests; no protective effect of collateral circulation could be demonstrated. Patients with abnormal resting hemodynamics or left ventricular asynergy had no significant difference in the frequency of positive tests after adjustment for the angiographic severity of disease.


American Journal of Cardiology | 1975

Comparison of angiographic and postmortem findings in patients with coronary artery disease

Jared N. Schwartz; Yihong Kong; Donald B. Hackel; Alan G. Bartel

The accuracy of coronary cineangiography in predicting the degree of stenosis in coronary arteries was evaluated by comparing autopsy and premortem cineangiographic findings in 25 patients. Coronary cineangiograms and autopsy specimens were reviewed independently by two cardiologists and two pathologists. Identical diagrams dividing the cononary arteries into 12 segments were used by both groups to record the location and degree of stenosis observed. Cineangiographic findings were in agreement with pathologic findings (less than 25 percent difference in cross-sectional luminal area) in 178 (79 percent) of the 226 segments examined, but overestimated the degree of stenosis in 13 (6 percent) and underestimated it in 34 (15 percent). Thus, cineangiography appears to be a reliable tool in evaluating coronary artery disease. When diagnostic errors are made, they are usually underestimations of the degree of disease; common causes of error are circumferential stenosis, eccentric lesions, obstruction of view by artifical valves and poor opacification due to severe proximal stenosis.


Circulation | 1973

Myocardial Infarction as a Complication of Coronary Bypass Surgery

David L. Brewer; Robert H. Bilbro; Alan G. Bartel

Serial postoperative ECGs were reviewed for all patients undergoing saphenous vein-coronary artery bypass graft (CABG) during 1969-71. Only the development of new pathologic Q waves were accepted as indicative of definite acute myocardial infarction (AMI). ST-T changes regardless of characteristics were not accepted as evidence of AMI. Operative mortality was 11% (27/253) with 59% (10/17) of those autopsied having AMI. Autopsy findings showed no false positives by ECG. Of survivors, 15% (33/220) had AMI. Another 2% (five) developed leftbundle conduction abnormalities and were considered probable for AMI. Among all patients having CABG, 20% (49/243) had AMI by ECG or autopsy.Comparing patients with and without AMI, there was no significant difference in coronary risk factors, hemodynamic data, number of vessels diseased, or site(s) of grafts. There was a significant difference in preoperative functional class for angina in the two groups. Seventy-six percent of those in the MI group had New York Heart Association class IV chest pain, whereas only 52.6% of the group without MI were class IV (P < 0.05). In those with triple grafts (14 patients), five had AMI (36%) compared to 14% (20/143) with one or two grafts (P < 0.02). Of patients with a pump time greater than 120 min, 29% (8/28) had AMI compared to 11% (16/146) with shorter pump times (P < 0.02). A significantly larger number of the MI group developed class IV congestive heart failure postoperatively than the group without MI (13 vs 2%, P < 0.02).Despite the use of stringent criteria, this study shows that AMI complicating CABG is a common event. Those developing AMI at surgery had more severe chest pain preoperatively, had prolonged pump times, and a significantly larger number received triple grafts. Postoperatively, there was a higher incidence of severe congestive heart failure in those having an infarct at surgery.


Circulation | 1974

The Significance of Coronary Calcification Detected by Fluoroscopy A Report of 360 Patients

Alan G. Bartel; James T. T. Chen; Robert H. Peter; Victor S. Behar; Yihong Kong; Richard G. Lester

Cardiac fluoroscopy to detect coronary calcification was performed on 360 patients before undergoing coronary arteriography for proven or suspected coronary artery disease. Among the 154 patients in whom coronary calcification was identified, 97% had significant coronary disease angiographically (≧ 70% stenosis). In this group, the distribution of one, two, and three vessel coronary disease was 9%, 25%, and 66% respectively. The prevalence of coronary calcification increased with age and severity of coronary disease, but no difference in males versus females was demonstrable. The angiographic severity of coronary disease increased with multiple vessel calcification; three vessel disease occurred in 45%, 66%, and 82% of patients with one, two, and three vessel calcification, respectively. Patients with hyperlipidemia or hypertension had no significant difference in the prevalence of coronary calcification. Among the 267 patients with significant coronary lesions, 56% had calcification detected by fluoroscopy.Five of the 93 patients with no significant coronary disease angiographically had coronary calcification fluoroscopically. Four of the five had a prior history of myocardial infarction, and two showed asynergy on left ventriculography.This study demonstrates that cardiac fluoroscopy is a valuable procedure for detecting significant coronary artery disease since this highly specific test is easily performed, inexpensive, noninvasive, and widely applicable for screening large patient populations.


Circulation | 1974

The nature of treatment selection in coronary artery disease. Experience with medical and surgical treatment of a chronic disease.

J. Frederick McNeer; C. Frank Starmer; Alan G. Bartel; Victor S. Behar; Yihong Kong; Robert H. Peter; Robert A. Rosati

This report presents our experience with the medical and surgical management of patients with coronary heart disease and uses this experience to document the role of a computerized medical information system in the long-term management of patients with a chronic disease. Of 781 consecutively evaluated patients, 402 were treated medically and 379 were treated with aortocoronary bypass surgery. At two years post-zero time, more than twice as many surgical survivors were pain free, but the survival was the same in the medical (83%) and surgical (85%) cohorts. The medically and surgically treated patients were compared with respect to 89 baseline characteristics. The cohorts were remarkably similar. Correction for baseline inequalities did not affect the fact that two-year survival was the same in both cohorts. One subgroup was identified in which surgically treated patients had a higher two-year survival. Other subgroups were identified in which therapy did not appear to affect two-year survival.


American Journal of Cardiology | 1974

Ischemic cardiomyopathy: the myopathy of coronary artery disease. Natural history and results of medical versus surgical treatment.

Ronald F. Yatteau; Robert H. Peter; Victor S. Behar; Alan G. Bartel; Robert A. Rosati; Yihong Kong

Abstract Clinical, hemodynamic and angiographic data were analyzed in 66 patients with coronary artery disease and severe generalized left ventricular dysfunction (ischemic cardiomyopathy) in order to determine their prognosis and examine the results of medical and surgical management. Seventy-six percent of patients had angina, 85 percent a history of one or more myocardial infarctions, 73 percent cardiomegaly, 38 percent mitral regurgitation, 98 percent severe stenosis of two or three major coronary arteries, and 100 percent a left ventricular ejection fraction of 25 percent or less. Forty-two patients were managed medically, and 24 surgically with aortocoronary bypass grafts or ventricular plication, or both. The clinical and hemodynamic findings in both groups were nearly identical. In a follow-up period of 12 months, the mortality rate was 31 percent in the medical group and 50 percent in the surgical group, with 83 percent of the surgical deaths occurring within 1 month of operation. There was no significant difference in the functional status of medical and surgical survivors. Regardless of therapy, patients with mitral regurgitation or a left ventricular end-diastolic pressure of 24 mm Hg or greater had a significantly higher mortality rate than patients without these findings. This study indicates that patients with ischemic cardiomyopathy have a poor prognosis, and surgical intervention with current available techniques has a high operative mortality rate without significantly altering the symptoms in the survivors.


Circulation | 1979

The combined effect of smoking and coffee drinking on LDL and HDL cholesterol.

Siegfried Heyden; Gerardo Heiss; Christian Manegold; Herman A. Tyroler; Curtis G. Hames; Alan G. Bartel; Gerald R. Cooper

Conflicting reports on the effect of smoking and coffee drinking on lipoproteins prompted us to study the combined effect of these two associated, widely prevalent habits in 361 persons randomly sampled from the Evans County cohort. Low-density lipoprotein (LDL) cholesterol levels were significantly higher among persons who smoked cigarettes and consumed five or more cups of coffee per day than among nonsmokers who abstained from coffee. Conversely, high-density lipoprotein (HDL) cholesterol was higher in persons who did not smoke or drink coffee than in coffee-consuming smokers. However, this trend was not statistically significant. Triglycerides and very low-density lipoprotein (VLDL) cholesterol were highest among smokers who drank five or more cups of coffee per day, but these differences did not reach statistical significance. Lipoprotein cholesterol levels were adjusted for age, sex and body mass. Smoking and coffee drinking interact in affecting LDL and total cholesterol, but coffee drinking alone did not appear to affect blood lipids.


Circulation | 1973

Exercise Stress Testing in Evaluation of Aortocoronary Bypass Surgery: Report of 123 Patients

Alan G. Bartel; Victor S. Behar; Robert H. Peter; Edward S. Orgain; Yihong Kong

Graded exercise treadmill tests (ET) were performed on 123 patients who had undergone aortocoronary bypass surgery. All had angina preoperatively (preop) and 77% were in Class III or IV for angina. Postoperatively (postop), 68% were free of angina. Eighty-three patients had ST-segment changes of 0.1 mV or greater during stress preop (positive), 38 of which (46%) converted to electrocardiographically negative postop. Among the 30 patients (36%) remaining positive during stress postop, 19 (63%) were angina free despite ST-segment depression during stress. Among the 17 patients with negative ET preop, there were no conversions to positive postop. Twenty-three patients had undetermined ET preop; 13 remained undetermined postop, 4 were positive and 6 were negative. Patients experiencing a perioperative myocardial infarction more frequently had a negative postop ET. Among 27 selected patients undergoing postop angiography, there was good correlation between relief of symptoms and successful myocardial revascularization.This study demonstrates that dramatic improvement in angina after aortocoronary bypass surgery can be objectively substantiated in most patients. Subjective symptoms of angina are frequently absent during myocardial ischemia postop, emphasizing the importance of exercise testing in objective evaluation of surgical results.


Stroke | 1971

Cerebrovascular Disease in the Bi-Racial Population of Evans County, Georgia

Albert Heyman; Herbert R. Karp; Siegfried Heyden; Alan G. Bartel; J. C. Cassel; Herman A. Tyroler; J. Cornoni; Curtis G. Hames; W. Stuart

An epidemiological study was made of cerebrovascular disease in a bi-racial Southern community. The study population comprised about 3,000 men and women aged 15 to 75 years at the time of entry into the study. During the 87-month period between the initial and second examinations, 94 persons developed their first cerebrovascular event. The incidence of stroke among white men (4.77/1,000/year) was almost four times that in white women and more than twice that reported for white men in other sections of the country. The incidence rates of stroke in Negro men and women were equal (5.8/1,000/year). The risk factors predisposing to stroke in white men appeared to be severe hypertension, obesity, high hematocrit levels, and antecedent electrocardiographical abnormalities These factors were not as prominent among the other race-sex groups. The high incidence of cerebrovascular disease found in this semirural population of Georgia supports previous reports of increased mortality rates for stroke in this section of the country and represents a unique situation, the exact cause for which remains to be determined.

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Curtis G. Hames

University of North Carolina at Chapel Hill

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Herman A. Tyroler

University of North Carolina at Chapel Hill

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John C. Cassel

University of North Carolina at Chapel Hill

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Joan C. Cornoni

University of North Carolina at Chapel Hill

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