Biomedical subjects
Publications and source records attributed to A C Beall.
A 56-year-old man with confirmed sickle-cell trait AS underwent successful triple-vessel myocardial revascularization with internal mammary artery and vein conduits. Variations in routine technique included limitation in hypothermia (32 degrees C), avoidance of intraoperative autologous salvage, hypoxia, severe anemia (< 25% hematocrit), acidosis and postoperative reinfusion of mediastinal drainage.
It has been assumed that patients with neurological residua after a completed stroke are at increased risk of neurological complications associated with cardiac operations requiring cardiopulmonary bypass. To evaluate these assumptions, we reviewed retrospectively 1,163 consecutive patients undergoing cardiac operations with cardiopulmonary bypass. Among these 1,163 patients were 43 patients having a previously completed stroke with neurological residua, but without clinically significant extracranial carotid artery disease. Forty-one underwent coronary artery bypass grafting; of these, 1 required concomitant aortic valve replacement, 1 had mitral valve replacement, and 1 had aortic valve replacement. There was one death in this group of 43 patients, due to massive pulmonary embolism. Only 1 of these 43 patients experienced new neurological symptoms after operation, which would appear to indicate that patients with a previous, completed stroke may not be at increased risk of neurological complications from cardiac operations requiring cardiopulmonary bypass.
Limitations of myocardial cooling using antegrade infusion cardioplegia have led to the routine use of topical myocardial cooling. However, topical myocardial cooling can injure the phrenic nerves, lungs and heart. Red blood cells are also discarded with the irrigation fluid. To evaluate the selective use of topical cooling, data were collected prospectively from 67 consecutive patients undergoing isolated coronary artery bypass operation. All patients received an inductive dose of 1 liter blood cardioplegia solution. Intramyocardial temperatures were determined in the distribution of the three major coronary arteries after the first 500 ml of cardioplegia solution was administered. If the three temperature readings were all < or = 20 degrees C, patients (group 1, n = 31) received no topical myocardial cooling. If any temperature was > 20 degrees C, patients (group 2, n = 36) received topical cooling while the second 500 ml cardioplegia solution was administered. Cardioplegia solution was subsequently administered at approximately 20-min intervals, at which time the patient did or did not receive topical myocardial cooling, depending on the selected group. Although patients in group 2 were older (mean (s.e.m.) age 63.3(1.6) versus 56.8(1.8) years, P < 0.05), the two groups were not significantly different with respect to sex, ejection fraction, risk factors, and class of the New York Heart Association. There were also no significant differences in the mean number of grafts per patient, use of the internal mammary artery, and cross-clamp or pump times. There were no deaths and only one patient (3%) in group 2 developed new Q waves.(ABSTRACT TRUNCATED AT 250 WORDS)
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)
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.
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.
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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.
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.
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.
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.
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After coronary artery bypass, some patients have diaphragmatic elevation, usually on the left side. To test our hypothesis that this phenomenon is due to phrenic nerve injury resulting from either 1) dissection of the proximal portion of the left internal mammary artery or 2) topical cooling of the heart with icy slush, we performed the following 2-part study. First, we reviewed our hospital records of 99 coronary artery bypass patients, 55 of whom had received left internal mammary artery grafts and 44 of whom had undergone saphenous vein grafting; the results showed no significant difference between the rates of left-sided diaphragmatic paralysis in the 2 groups (47% versus 41%, respectively). Next, we performed a prospective, randomized study in 100 consecutive patients, using a cardiac insulation pad to protect the left phrenic nerve in 58 patients and using no protective pad in 42 patients. At the time of hospital discharge, left-sided diaphragmatic elevation was seen in 6 (10.3%) of the 58 patients in whom insulation had been used and in 19 (45.2%) of the 42 patients whose phrenic nerve had been unprotected (p < 0.001). We conclude that cooling of the left phrenic nerve with icy slush in the pericardial cavity causes left-sided diaphragmatic paralysis and that the frequency of this injury can be reduced if a cardiac insulation pad is placed between the nerve and the icy slush.
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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.
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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.
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.