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Biomedical subjects

A C Beall

Publications and source records attributed to A C Beall.

At least 19 recordsLinked to original sources
PubMed1992

Surgical considerations in bypassing coronary arteries with 100% proximal occlusion.

Objective data on the ability of cineangiography to predict the size of reconstituted totally occluded coronary arteries, as well as the clinical outcome of such revascularization, are sparse. Accordingly, we reviewed 200 consecutive cases of coronary revascularization to determine the answers to these questions. Group I patients (n = 57, with 86 totally occluded coronary arteries) had at least one coronary artery with a 100% proximal occlusion that reconstituted distally. Group II patients (n = 143, with 205 subtotally occluded coronary arteries) had 50% to 99% proximal stenosis of at least one coronary artery. Cineangiograms were blindly reviewed to measure the size of the coronary arteries, which were compared with the actual vessel size at operation. In group I, the totally occluded coronary arteries had a cineangiographic size of 1.9 +/- 0.7 mm and an actual size of 1.6 +/- 0.4 mm (p = 0.00004). In group II, the subtotally occluded coronary arteries had a cineangiographic size of 1.8 +/- 0.4 mm compared with an actual size of 1.8 +/- 0.3 mm (p = not significant). The site of bypass grafting was significantly smaller in group I (1.6 +/- 0.4 mm versus 1.8 +/- 0.3 mm; p = 0.00008). The two groups were similar with respect to preoperative and intraoperative parameters. Operative mortalities were similar (group I, 1.8%; group II, 3.5%; p = 0.68). Creatine kinase isoenzyme profiles and electrocardiographic changes were similar, except for a significant late rise of creatine kinase-MB in group I (56.1 +/- 14.7 versus 30.7 +/- 33.7 MIU/mL; p < 0.001). In conclusion, cineangiography significantly overestimates the size of totally occluded coronary arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Usefulness of right ventricular indices in early diagnosis of cardiac tamponade.

Early diagnosis of postoperative cardiac tamponade is impeded by its clinical similarity to left ventricular failure. Moreover, the hemodynamic changes necessary to diagnose cardiac tamponade are detected by conventional monitoring technique only after clinical compromise. Early signs of cardiac tamponade and left ventricular failure were studied with emphasis on right ventricular function in anesthetized dogs. One group (n = 20) had cardiac tamponade produced by incrementally increasing pericardial pressure (2 to 20 mm Hg), and another group (n = 20) had acute left ventricular failure produced by successive ligation of the anterior descending coronary artery at the lower, middle, and upper thirds. Besides standard hemodynamic measurements, right ventricular function was examined with a rapid-response thermodilution catheter. During cardiac tamponade, cardiac output, right ventricular ejection fraction, right ventricular stroke volume, and right ventricular end-diastolic volume were significantly decreased from baseline values after a pericardial pressure of 8 mm Hg or more (p less than 0.05). Right atrial and pulmonary arterial pressures were not significantly elevated until 14 and 20 mm Hg of pericardial pressure, respectively. Although cardiac function in the left ventricular failure group was reduced after each ligation, right ventricular ejection fraction remained unchanged. This study suggests that right ventricular indices may facilitate earlier diagnosis of cardiac tamponade with greater accuracy.

Animals↗
PubMed1991

Benefit from combining blood conservation measures in cardiac operations.

Conventional blood conservation techniques have been insufficient to decrease transfusion needs in increasingly complex cardiac operations. To evaluate combinations of conservation techniques, 300 patients were divided into three equal groups. Group 1 had intraoperative autotransfusion and return of mediastinal drainage for 4 hours postoperatively. Group 2 had these measures plus intraoperative plasmapheresis. These two groups were given a transfusion for a hematocrit of less than 0.21 on cardiopulmonary bypass. Group 3 was treated with the same measures as group 2 but did not receive transfusions while on pump unless the hematocrit decreased to less than 0.15. The percentage of patients in each group given transfusions in the operating room was 34% in group 1, 28% in group 2, and 7% in group 3 (p less than 0.05). The percentage of all patients receiving transfusions during hospitalization was 68% in group 1, 36% in group 2 (p less than 0.05), and 18% in group 3 (p less than 0.05). Average total units transfused were 2.16 +/- 0.25 in group 1, 0.7 +/- 0.15 in group 2 (p less than 0.05), and 0.37 +/- 0.07 in group 3 (p less than 0.05). The perioperative morbidity rates including myocardial infarctions and strokes were similar. There were no deaths in group 3. Combining complementary conservation measures is effective in reducing homologous blood transfusions, and the need for transfusion can be safely reduced by allowing profound hemodilution during bypass.

Aged↗
PubMed1991

Massive hemoptysis due to broncholithiasis.

Massive hemoptysis due to broncholithiasis is rare. Such a case is presented here, and the literature is reviewed. Surgical resection is the preferred definitive therapy, as a lack of bronchial artery collaterals limits the utility of bronchial artery embolization.

Aged↗
PubMed1990

Development of the musculoelastic septation complex in the avian truncus arteriosus.

It is now well established that cells from the cardiac neural crest (CNC) are essential for normal conotruncal septation. The truncal septation complex consists of the aorticopulmonary (AP) septum and the myocardial sheath of the truncus. The principal role of the CNC cells during septation appears to be their differentiation into the elastogenic smooth muscle that forms the AP septum proper. The objective of this study was to integrate serial reconstruction and specific histochemical markers in order to provide a unified analysis of the relationships between the CNC and the other components of the truncal septation complex. The development of the septation complex was compared normal embryos vs. embryos from which the CNC had been surgically ablated. Embryos from each group were harvested after incubation periods of 4-8 days (Hamburger-Hamilton stages 23-34). Histochemical procedures were performed for positive identification of the elastic matrix and smooth muscle alpha-actin; the presence of these proteins was used as the criterion for "septal cells" and to define the boundaries of the septum. The results indicate that the shape, components, boundaries, and degree of organization of the septation complex may be different from previous descriptions. Furthermore, all of the components of the truncal septation complex are dysgenic in the absence of the CNC. Of special significance in the absence of CNC. Of special significance in the absence of CNC are: 1) the failure of the myocardial sheath to retract; 2) the apparently random distribution of surrogate ectomesenchyme; and 3) the impairment of truncal elastogenesis. These results indicate that the cells of neural crest origin interact with the surrounding mesenchyme during septation and that the entire septation complex depends upon the presence of the neural crest cells for normal development.

Actins↗
PubMed1990

Impaired elastic matrix development in the great arteries after ablation of the cardiac neural crest.

The cells that form the aorticopulmonary septum in the avian embryo have been shown to be similar to the cells that form the walls of the great vessels in two ways: both are derived from the cardiac neural crest and both are able to synthesize an elastogenic matrix in the early embryo. Because of these similarities, and because ablation of the cardiac neural crest causes congenital defects of the outflow tract that are related to failure of proper septation, it was hypothesized that such an ablation also would cause the walls of the great vessels to be defective. The purpose of this study was to compare the elastic matrix in the mediae of the great vessels of normal embryos with those from which the cardiac neural crest had been ablated. The results show that the elastic matrix in the great vessels of the experimental embryos was impaired 1) in the rate of downstream propagation of the initiation of elastogenesis among younger embryos, incubation days 4-8 and 2) in the spatial configuration of the elastic matrix among the older embryos, incubation days 16-20. These results may provide a biological explanation for the elastin defect that affects the pulmonary artery of many patients with cyanotic congenital heart defects.

Aldehydes↗
PubMed1990

Smooth muscle cells of neural crest origin form the aorticopulmonary septum in the avian embryo.

Previous studies have shown that the cells of the aorticopulmonary (AP) septum are similar to the smooth muscle cells of the mediae of the great vessels in their common origin from the cardiac neural crest and in their common expression of an elastic extracellular matrix. The purpose of this study was to test the cells of the AP septum for the presence of certain cytoplasmic proteins, especially smooth muscle alpha-actin (SMAA) whose presence is definitive of smooth muscle. A monoclonal antibody against SMAA was applied to normal chicken embryos at 3.5-8 days of incubation and to age-matched embryos from which the cardiac neural crest had been ablated surgically. Antibodies against the intermediate filaments desmin, cytokeratin, and vimentin also were applied. The results showed that the AP septal cells expressed SMAA during the process of septation, days 5-8; but when the cardiac neural crest was ablated and septation was defective, no cells in the conotruncal connective tissue expressed SMAA. None of the intermediate filament proteins were detected in the septum. These results indicate that the AP septal cells are smooth muscle and therefore may be hypothesized to have an active role in septation.

Actins↗
PubMed1989

Five thousand seven hundred sixty cardiovascular injuries in 4459 patients. Epidemiologic evolution 1958 to 1987.

Large epidemiologic analyses of cardiovascular injuries have been limited to studies of military campaigns compiled from many surgeons working in many hospitals with variable protocols. A detailed civilian vascular trauma registry provides a unique opportunity for an epidemiologic evolutionary profile. During the last 30 years in a single civilian trauma center directed by a consistent evaluation and treatment philosophy, 4459 patients were treated for 5760 cardiovascular injuries. Eighty-six per cent of the patients were male, and the average age was 30.0 years. Penetrating trauma was the etiology in more than 90% (GSW,51.5%; SW,31.1%; SGW,6.8%). All other injuries were iatrogenic or secondary to blunt trauma. Truncal injuries (including the neck) accounted for 66% of all injuries treated, while lower extremity injuries (including the groin) accounted for only 19%. Injuries to the abdominal vasculature accounted for 33.7% of the injuries. One thousand fifty-seven patients had 2 or more concurrent vascular injuries, and 32 patients had 4 or more separate vascular injuries. The 27 patients-per-year average of the early 1960s has risen to a current average of 213 patients per year. Economic and population factors influenced wounding agents and injury patterns during the evaluation period. This extensive civilian series presents epidemiologic profiles that are distinctly different from military reports and serves as a guide for current trauma center and health planners.

Adolescent↗
PubMed1988

Use of mechanical devices for distal hemoperfusion during balloon catheter coronary angioplasty.

Previous attempts to protect the dependent myocardium during balloon catheter coronary angioplasty in animals and humans have had generally unsatisfactory results. This paper summarizes the authors' experience in investigating commercially available mechanical pumps for distal coronary hemoperfusion during balloon angioplasty. Both roller and piston pumps can attain adequate distal perfusion without significant side effects in the majority of patients. Our goal was to suppress angina for at least 5 min to prolong balloon inflation in awake patients. Minor T-wave changes without concomitant angina pectoris can be expected when the distal coronary bed is perfused with hypothermic blood. Side branch occlusion by the inflated balloon prevents effective protection of the corresponding part of the dependent myocardium during distal hemoperfusion, which may result in persistent angina and ST-T changes uncorrected by increasing the hemoperfusion rate. Distal coronary diffuse spasm, rare and transient, was the only immediate complication of this procedure. It is suggested that intense local wall stimulation could occur with a higher flow rate (jet effect). Improved balloon catheter pressure/flow characteristics and on-line continuous mechanical pumps should soon make distal coronary hemoperfusion through balloon catheters an accepted clinical technique.

Adult↗
PubMed1988

Determination of brain temperatures for safe circulatory arrest during cardiovascular operation.

Profound hypothermia protects cerebral function during circulatory arrest in the surgical treatment of a variety of cardiac and aortic abnormalities. Despite its importance, techniques to determine the appropriate level of hypothermia vary; studies of temperatures recorded from multiple peripheral body sites show inconsistent findings. The purpose of this study is to establish objective criteria to consistently identify intraoperatively the safe level of hypothermia. Our studies are based on experimental evidence showing a correlation between brain temperature and development of electrocerebral silence (ECS) on the electroencephalogram (EEG), and the recognition that the EEG, as an objective measure of brain function, can easily be recorded intraoperatively. We studied 56 patients who required circulatory arrest during operation for replacement of the ascending aorta or aortic arch (N = 55) or aortic valve replacement (N = 1). Peripheral body temperatures from the nasopharynx, esophagus, and rectum and the EEG were continuously recorded during body cooling. Circulatory arrest time ranged from 14 to 109 minutes. No peripheral body temperature from a single site or from a combination of sites consistently predicted ECS. There was a wide variation in temperature among body sites when ECS occurred: nasopharyngeal, 10.1 degrees to 24.1 degrees C; esophageal, 7.2 degrees to 23.1 degrees C; rectal, 12.8 degrees to 28.6 degrees C. Fifty-one (91%) of the 56 patients survived. Three had neurological deficits, none clearly related to hypothermia. Two patients (3.6%) required reexploration for postoperative bleeding. We conclude that monitoring the EEG to identify ECS is a safe, consistent, and objective method of determining the appropriate level of hypothermia.

Aorta↗
PubMed1988

Delayed diagnosis of injuries to the diaphragm after penetrating wounds.

During a 9-year period, 16 patients with a delay in diagnosis of an injury to the diaphragm after a penetrating wound were treated. The left hemidiaphragm was involved in 15 of 16 patients, and the delay in diagnosis from the time of arrival in the emergency center immediately after injury ranged from 16 hours to 14 years. In the patients in the Acute Group (delay of hours to days), three patients had diaphragmatic defects missed at the time of laparotomy, three patients had chest X-rays not immediately suggestive of diaphragmatic defects, two patients had false-negative lavages, and one patient treated elsewhere did not have a chest X-ray in the emergency room. In the patients in the Chronic Group (hernias presenting months to years after injury), four of seven patients had misreading of a recent chest X-ray or failure to have a chest X-ray performed during numerous return visits to the emergency center. Despite a variety of diagnostic maneuvers, these defects and hernias continue to be diagnosed after a delay. Careful review of early and late followup chest X-rays appears to be the easiest mechanism to avoid significant delays in diagnosis.

Adult↗
PubMed1987

Management of injuries to the suprarenal aorta.

During a 12 year period, 79 patients with a diagnosis of a penetrating wound to the suprarenal aorta were treated. An analysis of the records of these patients has led to the following conclusions: With a midline penetrating wound and presence of a supramesocolic hematoma or hemorrhage, injury to the suprarenal aorta should be suspected. If a midline supramesocolic hematoma is present or if hemorrhage can be controlled by direct pressure, a lateral approach with medial mobilization of the intraabdominal viscera on the left side allows rapid vascular control. Although lateral aortorrhaphy is preferred, patch grafting, and end-to-end anastomosis, or insertion of a prosthetic graft was required in 46 percent of the patients who underwent repair. As in all previous series, the insertion of synthetic patches or prostheses was not complicated by infection. The average survival rate for injuries to the suprarenal aorta in series reported since 1974 is 33 percent. Finally, the continuing problem of irreversible shock suggests the need for rapid transport from the field to the hospital for victims of penetrating wounds to the abdomen.

Aorta, Abdominal↗
PubMed1987

Primary aortoduodenal fistula caused by Salmonella aortitis.

We report the management and follow-up of two cases of primary aortoduodenal fistulas caused by Salmonella aortitis. The origin, presentation, diagnosis, and results of operative therapy for patients with primary aortoduodenal fistulas, especially patients with positive aortic wall cultures, are reviewed. Successful therapeutic principles included early intervention, primary duodenal repair, aneurysm resection, aortic reconstruction with an in situ Dacron graft, and prolonged courses of bactericidal antibiotics.

Adult↗
PubMed1986

Liberal use of emergency center thoracotomy.

Emergency center thoracotomy is a heroic technique of resuscitation and treatment which was revived in the 1960s to improve the survival of patients presenting with cardiac wounds. With excellent survival rates attained in such patients, the technique was extended to victims of trauma with other mechanisms and locations of injury. At present, the technique has a survival rate ranging from 3 to 20 percent; however, most recent series of unselected patients show a survival rate of 8 to 10 percent. In this series, there were no survivors when emergency center thoracotomy was utilized after a period of prehospital cardiopulmonary resuscitation. Patients with isolated stab wounds to the thorax, especially those with cardiac injuries, had the best survival rate of any subgroup in the series. If emergency center thoracotomy was utilized for patients with some vital signs on admission and with neck or truncal gunshot wounds, blunt trauma, or abdominal trauma, the survival rate decreased to 2 to 4 percent; however, the small but constant survival rate in all of these groups justifies its continued use.

Adult↗