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Biomedical subjects

W E Walker

Publications and source records attributed to W E Walker.

At least 19 recordsLinked to original sources

Hypertension control and access to medical care in the inner city.

OBJECTIVES: This study assessed hypertension control among high-risk African Americans. METHODS: We interviewed 583 African Americans aged 18 years and older residing in 438 randomly selected inner-city households. RESULTS: Forty-two percent of the respondents were hypertensive. Blood pressure was uncontrolled in 74% of hypertensive persons, although 64% of hypertensive persons reported having seen a physician within the previous 3 months. Hypertension control was associated with female gender and higher socioeconomic strata but not with public versus private sources of medical care. CONCLUSIONS: Hypertension control is inadequate in this population, although health care services are used frequently. Hypertension control efforts should focus on the effectiveness of health care delivery.

Adult↗

Incorporating socio-economic and risk factor diversity into the development of an African-American community blood pressure control program.

OBJECTIVE: To develop culturally competent community based blood pressure control programs for inner-city African Americans. DESIGN: Cross sectional study of randomly selected households from three experimental and three control communities. SETTING: Very low, moderately low and moderate socio-economic status (SES) inner-city communities in Chicago, Illinois. PARTICIPANTS: 957 African Americans adults, aged 18 and over from target communities. MAIN OUTCOME MEASURE: Household health assessments included employment, education and other demographic information, history of hypertension, disease prevalence, health behaviors, risk factor prevalence, stress, coping/John Henryism, social support, health care utilization and standardized assessments of blood pressure, height, and weight. RESULTS: There were no significant gender differences in blood pressure levels. Men had more hypertension than women, and women in the very low SES community had significantly more hypertension than women in the moderately low SES community. There was significantly more hypertension overall in the moderately low SES community. Age, education and BMI were the only factors significantly associated with systolic and diastolic blood pressure in all three communities. The very low SES community had significantly more obesity and more uninsured persons than the other communities. CONCLUSIONS: Intraracial diversity is an important factor to be considered in the development of community blood pressure control programs for African Americans. Age, gender, educational background and SES play a major role in influencing health behaviors and access to health care.

Adolescent↗

A review of sternal wound complications in a military hospital.

A retrospective review of sternal wound complications was conducted during a recent 13-month period at the Naval Hospital, San Diego. These complications developed in 5 (3.0%) of 168 patients after they underwent coronary artery bypass with saphenous vein grafts. Three or more of these patients were male, obese, and hypertensive, with a significant smoking history. All these factors have been previously reported to be associated with an increase in the incidence of sternal wound complications. All patients had prolonged postoperative intensive care treatment, and ultimately all patients recovered and were discharged from the hospital. Interestingly, as opposed to other reviews, we were unable to show an association of sternal wound complications with the use of internal mammary artery harvesting.

Aged↗

Surgical treatment of cardiac tumors: a 25-year experience.

From 1964 to 1989, we performed operations on 133 patients with cardiac tumors. There were 58 male and 75 female patients ranging in age from three days to 81 years; 101 were adults, and 32 were children (less than 12 years of age). Primary tumors (102 benign and 12 malignant) were found in 114 patients and metastatic tumors in 19. Symptoms included congestive heart failure, arrhythmias, emboli, and chest pain. Diagnosis was accomplished through angiography, echocardiography, computed tomography, and magnetic resonance imaging. Operative treatment encompassed techniques ranging from biopsy to complete excision (including hypothermic circulatory arrest and cardiac autotransplantation) depending on the site of disease and the extent of involvement. Overall operative survival was 91%. Twelve patients died early (within 30 days of operation), and follow-up was obtained for 110 (90.9%) of the remaining 121 survivors (total patient-years of follow-up, 572.8; mean follow-up, 5.2 years). Of the 20 patients who died late, 15 had malignant disease. Operative survival for patients with primary cardiac malignancies and for those with metastatic disease was 83% and 68.4%, respectively, with 3 and 5 patients, respectively, still living. We advocate an aggressive surgical approach, especially in patients with benign tumors, who can expect an excellent outcome. For patients with malignant or metastatic disease, palliation and cure are also possible if aggressive surgical actions are taken.

Adenocarcinoma↗

Cardiovascular surgery in patients with congenital plasma coagulopathies.

From 1978 to 1986, fifteen cardiovascular operations were performed on 13 patients with known congenital bleeding disorders. The patients (10 men and 3 women) had a mean age of 51.1 +/- 3.4 years. Four were seen with cardiovascular lesions and documented hemophilia A (Factor VIII deficiency); 3 had hemophilia B (Factor IX deficiency); 3 had Factor XI deficiency; 2 had von Willebrand's disease, and 1 had dysfibrinogenemia. All patients had a history of major hemorrhage after dental extractions or general surgical procedures, and had clearly documented coagulation disorders on hematological evaluation. Elective cardiovascular procedures performed in these patients included aortocoronary bypass grafting (eight), cardiac valve replacement or repair (five), aortic graft placement (one), and carotid endarterectomy (one). The mainstay of perioperative management included appropriate replacement therapy with blood components. Coagulation factor levels were measured routinely to guide therapy. There were no deaths. Two hemorrhagic complications necessitated reexploration. We conclude that in patients known to have congenital coagulation disorders, cardiovascular operations using systemic heparinization can be performed with minimal morbidity and mortality when carried out with preoperative and perioperative support from the hematology service, adequate replacement therapy using blood components, and careful monitoring of the coagulation status.

Afibrinogenemia↗

Urgent thoracotomy for pulmonary or tracheobronchial injury.

Three hundred eighty-eight of 7,283 (5.3%) admitted trauma patients underwent urgent thoracotomy. In 61 patients (15.7%), pulmonary or tracheobronchial injury prompted thoracotomy (11, blunt; 50, penetrating). Pulmonary hemorrhage necessitated thoracotomy in 54 patients (88.5%); tracheobronchial injury in five patients (8.2%). The mortality was 27.9%. Nine patients (14.8%) underwent pneumonectomy: eight died of intractable hemorrhagic shock during thoracotomy despite rapid control of pulmonary hemorrhage: one died of sepsis. Eleven patients (18.0%) underwent lobectomy: six (54.5%) died of concomitant injuries. Thirty-six patients (59.0%) underwent pneumonorrhaphy: one died of concomitant injuries. Five (8.2%) patients underwent tracheobronchial repair: one died of concomitant injuries. Pneumonectomy was uniformly fatal and should be a procedure of last resort in the treatment of pulmonary injury, as lobectomy and pneumonorraphy are better tolerated by these critically ill patients.

Bronchi↗

Failure of glycogen depletion to improve left ventricular function of the rabbit heart after hypothermic ischemic arrest.

We tested the hypothesis that depletion of glycogen prior to myocardial ischemia diminishes lactate buildup and improves functional recovery on reperfusion in the isolated rabbit heart. Cardiac glycogen was reduced either by substituting N2 for O2 in the perfusate or by perfusion with substrate-free solution, before the onset of ischemia. Hearts were subjected to either 30 minutes of normothermic (37 degrees C) or 60 minutes of hypothermic (4 degrees C) ischemia followed by 30 minutes of reperfusion with oxygenated Krebs-Henseleit buffer. Function was assessed by measuring peak left ventricular pressure at end-diastolic pressures ranging from 0 to 20 mm Hg. N2 perfusion for 15 minutes lowered myocardial glycogen by 60% and decreased ATP and phosphocreatine (p less than 0.001). Glycogen depletion did not decrease lactate accumulation during ischemia, but it impaired recovery with reperfusion (-46%, p less than 0.05). N2 perfusion for 5 minutes also reduced glycogen by 60%, but energy-rich phosphates were not reduced and functional recovery was still impaired (-40%, p less than 0.05). Perfusion with substrate-free medium diminished glycogen by 33% (p less than 0.05). Although lactate accumulation was significantly reduced (-45%, p less than 0.05), recovery following reperfusion was not improved. The results suggest that preservation of glycogen stores, but not the prevention of lactate buildup during ischemia, is beneficial for the recovery of function with reperfusion.

Animals↗

Improved recovery of cardiac function after hypothermic ischemic storage with ouabain.

We investigated the hypothesis that ouabain would reduce energy expenditure in the hypothermic, ischemic heart by inhibiting membrane-bound sodium/potassium-activated adenosine triphosphatase and lead to improved function on reperfusion. Additionally, we compared ouabain with another potential adjunct, the calcium channel blocker verapamil. The isolated rabbit heart was used as a model, and three experimental groups were studied after 1, 6, 12, and 24 hours of 4 degrees C ischemia. Hearts in group I were stored in a standard high potassium solution; hearts in groups II and III were stored in the same solution supplemented with verapamil (2 mg/L) and ouabain (3 mg/L), respectively. After ischemia, all hearts were reperfused for 45 minutes on a modified Langendorff apparatus, and left ventricular function was measured before freeze-clamping the heart for metabolite determination. At 1 and 6 hours, hearts in all groups functioned well, but the group III hearts had higher levels of adenosine triphosphate, phosphocreatine, total adenine nucleotides, and glycogen. After 12 hours of ischemia, function was significantly better in group III hearts (p less than 0.01) compared with that of hearts in groups I and II. Group III hearts also exhibited higher levels of high energy phosphates and glycogen. After 24 hours of storage, all hearts functioned poorly, and there was a marked decline in measured metabolites. Although we could show no improvement with the addition of verapamil, ventricular function was improved after storage in a high potassium hypothermic solution containing ouabain. Because ouabain inhibits the hydrolysis of adenosine triphosphate by sodium/potassium-activated adenosine triphosphatase, this result suggests that the glycoside maintains energy-rich phosphates necessary for optimal resumption of cardiac function.

Adenine Nucleotides↗

Factors affecting outcome of coronary reperfusion with intracoronary streptokinase in acute myocardial infarction.

Aggressive interventional therapy in acute myocardial infarction (AMI) is expensive, time-consuming and not without significant risk. To determine which patients are most likely to benefit from such therapy, the effects of patient age, reperfusion success, admission left ventricular (LV) function, infarct location, admission clinical class, time from onset of pain to reperfusion and admission electrocardiographic findings on the outcome of coronary reperfusion in AMI were assessed in 292 prospectively studied, sequential patients from August 1980 to January 1984. Two hundred ten patients received intracoronary streptokinase (SK) therapy on admission and 82 patients, who either refused the protocol or met exclusion criteria, served as control subjects. Patients older than 65 years showed little improvement in 1-year mortality risk and no significant improvement in LV function during hospitalization after treatment with intracoronary SK. The remaining patients, 178 treated with SK and 48 control, were well matched and served as the basis for further comparisons. In this subgroup of patients, reperfusion success was associated with improved survival and LV function (mortality rate 3%, vs 17% in control subjects; increase in ejection fraction [EF] 18% vs 4%). Patients with an EF of less than 45% on admission showed a 21 +/- 30% increase in EF, compared with an increase in control subjects of 8 +/- 19%, and a lower 1-year mortality rate than controls (6% vs 21%, p = 0.01). Patients with anterior AMI had a significant increase in EF in the SK group (22 +/- 31%) and lower mortality compared with control subjects (5% vs 25%, p = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Biochemical consequences of protein depletion in the rabbit heart.

We showed previously that cardiac function was depressed in rabbits subjected to 6 weeks of protein depletion and was restored after 4 weeks of protein refeeding. To identify nutritional or metabolic factors that underlie cardiac dysfunction, we assessed the nutritional status and myocardial content of energy-providing substrates in three groups of rabbits: group I served as control; group II was fed a protein-free diet; and group III was fed a protein-free diet and then repleted. Animal weights were 2.73 +/- 0.22 kg in group I, 1.92 +/- 0.28 kg in group II, and 2.78 +/- 0.12 kg in group III. Serum albumin concentrations decreased from 3.70 +/- 0.12 g/dl in group I to 2.81 +/- 0.10 g/dl in group II, and returned to normal (3.71 +/- 0.11 g/dl) in group III. The heart weights; myocardial contents of water, nitrogen (N), total fat, and glycogen; skeletal muscle N concentrations; and liver N contents were measured. Protein depletion produced a reduction in total cardiac mass due to decreased nitrogen and glycogen contents, but there was an increased fat content. Comparison with other organs suggests that cardiac muscle plays a role in energy homeostasis, undergoing glycogenolysis and proteolysis similar to those of liver and skeletal muscle. Protein repletion restored normal mass of the heart, but not of the liver. We conclude that adequate nutrition may be important in maintaining cardiac function.

Animals↗

Atrial rupture in a child from cardiac massage by his parent.

A 4-year-old boy presented with a single seizure following a viral syndrome. He had a pericardial effusion on admission, and this increased suddenly on the third day of hospitalization, producing cardiac tamponade. After blood was aspirated from the child's pericardial cavity, the father revealed that he performed cardiac massage on his son following the seizure. A laceration of the right atrium was repaired at operation, and the boy made a good recovery. Cardiopulmonary resuscitation by lay persons is not without hazard, and patients with such a history should be watched carefully for the possibility of damage to intrathoracic structures.

Cardiac Tamponade↗

Peripheral pulmonary artery aneurysm in a patient with limited respiratory reserve: controlled resection using cardiopulmonary bypass.

Pulmonary artery aneurysms are rare lesions for which operative management is not frequently undertaken. When operation is indicated, central lesions involving the pulmonary trunk, right main pulmonary artery, or left main pulmonary artery are repaired using cardiopulmonary bypass. Peripheral aneurysms in segmental intrapulmonary arteries have been managed most frequently by lobectomy, but occasionally by aneurysmectomy and pulmonary arterial repair. We used cardiopulmonary bypass for peripheral pulmonary aneurysmectomy in a patient with limited respiratory reserve because he had undergone prior contralateral bilobectomy; this allowed controlled resection while preserving a maximal amount of pulmonary parenchyma.

Adult↗

Successful aortocoronary bypass in osteogenesis imperfecta.

Cardiovascular abnormalities are infrequently documented in osteogenesis imperfecta, one of a group of hereditary, generalized connective tissue disorders. A patient with osteogenesis imperfecta is described with mitral valve prolapse, significant coronary artery disease and a coronary artery aneurysm. The latter two cardiac defects are apparently rare in this disease. The option of surgery was carefully considered with regard to technical feasibility and potential deterioration of the graft anastomoses. Although successful aortocoronary bypass surgery had not been previously reported in osteogenesis imperfecta, this patient received such surgery with therapeutic benefit. Therefore, coronary artery vascularization should be considered as a safe and effective treatment modality for patients with osteogenesis imperfecta and coexisting coronary atherosclerosis.

Adult↗

The management of aortoduodenal fistula by in situ replacement of the infected abdominal aortic graft.

Conventional surgical wisdom dictates the complete removal of infected abdominal aortic graft, oversewing of the aorta, and restoration of lower limb bloodflow by extra-anatomic bypass grafting. Dissatisfied with this approach because of the high incidence of local complications, mortality, and loss of limb, 20 patients with secondary aortoduodenal fistula had duodenal repair, excision of the old graft, and placement of a new graft in the same location. A similar technique was used in three patients with erosion of an aortic graft into the jejunum. Length of follow-up averaged 5.2 years, and was more than 1 year in each instance. Of the eighteen patients who survived the repair, three have had early recurrent rupture or false aneurysm of the proximal aortic anastomosis, with consequent death in two, but fifteen patients (83%) have had no further related problem. There was no loss of limb. Use of greater omentum as a protective barrier seemed helpful. Optimal antibiotic usage, and the idea that varying degrees of graft infection require different approaches, require further definition. In conclusion, in situ graft replacement is the correct operative strategy in this challenging group of patients.

Aorta, Abdominal↗