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Biomedical subjects

W A Williamson

Publications and source records attributed to W A Williamson.

At least 19 recordsLinked to original sources
PubMed1995

The role of coronary revascularization in recipients of an implantable cardioverter-defibrillator.

The impact of adjuvant coronary revascularization was studied in a group of 138 recipients of an implantable cardioverter-defibrillator, all of whom had ischemic heart disease as the cause of their arrhythmias. Patients chosen for revascularization had more severe anatomic, symptomatic, or physiologic evidence of active ischemia. There were no operative deaths among 23 patients who actually underwent coronary artery bypass combined with cardioverter-defibrillator implantation; however, operative mortality by the intention-to-treat principle was 8% (2/25). Total cardiac survival was better for patients who underwent revascularization than for those patients who had "high-risk" characteristics and did not undergo revascularization. Stratified subgroup analysis demonstrated significant survival advantages favoring revascularization in patients with three-vessel or left main coronary artery disease, class III or IV angina, and an ejection fraction greater than 25%. Multivariate analysis revealed that low ejection fraction and left main coronary artery disease were independent predictors of decreased survival.

Adult↗
PubMed1995

Transvenous versus transthoracic cardioverter-defibrillator implantation. A comparative analysis of morbidity, mortality, and survival.

The hypothesis that transvenous implantation of a cardioverter-defibrillator is associated with less morbidity than use of a transthoracic approach was investigated in a retrospective series of 146 patients. None of these patients had concomitant heart procedures, and the preoperative characteristics of the two groups were similar. When analyzed by actual technique used (transvenous, 57 patients; transthoracic, 89 patients) and by the intention-to-treat method (transvenous, 65 patients, 8 of whom actually underwent thoracotomy; thoracotomy, 81 patients), transvenous implantation was associated with a lower incidence of postoperative respiratory complications and atrial fibrillation. Total cardiac mortality and freedom from sudden cardiac death in the transvenous and transthoracic groups were comparable at 2 years.

Aged↗
PubMed1994

Efficacy of short term versus long term tube thoracostomy drainage before tetracycline pleurodesis in the treatment of malignant pleural effusions.

BACKGROUND: A study was undertaken to compare the efficacy of short term tube thoracostomy drainage with standard tube thoracostomy drainage before instillation of tetracycline for sclerotherapy of malignant pleural effusions. METHODS: The study consisted of a randomised clinical trial in a sequential sample of 25 patients with malignant pleural effusions documented cytopathologically. Fifteen patients were randomly assigned to group 1 (standard protocol) and 10 to group 2 (short term protocol). Patients in group 1 had tube thoracostomy suction drainage until radiological evidence of lung re-expansion was obtained and the amount of fluid drained was < 150 ml/day, before tetracycline (1.5 g) was instilled. The chest tube was removed when the amount of fluid drained after instillation was < 150 ml/day. Patients in group 2 also had suction drainage, but the tetracycline (1.5 g) was instilled when the chest radiograph showed the lung to be re-expanded and the effusion drained, which was usually within 24 hours. The chest tube was removed the next day. RESULTS: The response to tetracycline sclerotherapy in the two groups was the same (80%) but the duration of chest tube drainage was significantly shorter for patients in group 2 (median two days) than for those in group 1 (median seven days). CONCLUSIONS: The duration of chest tube drainage before sclerotherapy for malignant pleural effusions need not be influenced by the amount of fluid drained daily but by radiographic evidence of fluid evacuation and lung re-expansion. Shorter duration of drainage will reduce the length of hospital stay without sacrificing the efficacy of pleurodesis.

Adult↗
PubMed1993

Infection of implantable cardioverter defibrillator systems: a preventable complication?

In a consecutive series of 164 patients undergoing primary implantation of an implantable cardioverter defibrillator (ICD), two patients died in the hospital (1.2%) and early system infection developed in one patient requiring explantation of the device (0.61%). Late infection developed in one additional patient (0.61%) 7 months after transvenous ICD implantation, and was thought to be due to a recent intravascular catheterization. Symptomatic generator pocket hematomas developed in three patients, two of which were treated by simple evacuation and one with temporary generator explanation and subsequent reimplantation of the unit in a new pocket. No infection developed in these three patients during follow-up. Generator erosion without obvious system infection developed in a fourth patient. Guidelines for the prevention of infection in ICD systems are presented.

Defibrillators, Implantable↗
PubMed1992

Mediastinal goiters. The need for an aggressive approach.

We reviewed the cases of 52 patients with substernal goiters to examine clinical presentation, workup, technique of removal, malignancy, and outcome. Half of the patients were asymptomatic; half had at least one compressive symptom. Chest film was the most used; computed tomography or magnetic resonance imaging was by far the most useful study. Thyroid scans often failed to show the intrathoracic goiter. Fine-needle aspiration was not helpful because of the gland's inaccessibility. Seventeen percent (nine) of the thyroids showed malignancy, 21% (11) including incidental papillary carcinomas. These were not identified by duration of goiter, symptoms, or fine-needle aspiration. Except for lymphomas, prognosis was good after resection. Removal was almost always accomplished via cervical incision, with low morbidity and no deaths. The threat of compression, the substantial chance of malignancy, and the safety of resection mean that the presence of substernal goiter is an indication for surgery.

Academic Medical Centers↗
PubMed1992

Current concepts concerning the nature and treatment of Barrett's esophagus and its complications.

Current concepts regarding the nature and the treatment of Barrett's esophagus and its complications are reviewed. The columnar-lined lower esophagus is being increasingly recognized as an acquired condition caused by gastroesophageal reflux. Many patients are asymptomatic. Barrett's esophagus occurs in about 10% to 15% of patients with reflux esophagitis. The diagnosis depends on endoscopy and biopsy. Complications are common and include ulceration, stricture, dysplasia, and adenocarcinoma. Esophagitis, ulceration, and stricture can usually be treated medically. Surgical approaches are discussed for patients whose condition is refractory to medical therapy. The premalignant nature of Barrett's epithelium is well recognized, and strategies for surveillance and resection are discussed. Survival after resection of adenocarcinoma in Barrett's esophagus is not appreciably different from that of other carcinomas. Surveillance with endoscopy offers the best chance for early detection and cure.

Barrett Esophagus↗
PubMed1992

Subfascial implantation of implantable cardioverter defibrillator generator.

The automatic cardioverter defibrillator generator is a relatively large unit, which has most often been implanted in a subcutaneous pocket. In a consecutive series of 120 primary implantations, we employed a subrectus fascia pocket that has resulted in a cosmetically superior result with a 0.8% incidence of system infection. The technique of subfascial implantation is described.

Electric Countershock↗
PubMed1992

Pulmonary venous infarction.

Pulmonary venous infarction, although rare, can develop in patients with the various pathologic conditions outlined. The triad of cough, dyspnea, and hemoptysis should raise clinical suspicion. The venous phase of pulmonary arteriography is the best way to document pulmonary venous obstruction, although MR imaging may also prove useful in the future. Treatment of patients with pulmonary venous infarction should be determined on the basis of the obstructing pathologic findings. Antibiotic therapy is important, as evidenced by the early experimental experience with this condition. It may be the only treatment available to patients with idiopathic fibrosing mediastinitis. Pulmonary resection, however, can be accomplished when a localized obstructing lesion is identified.

Animals↗
PubMed1992

Pulmonary venous infarction secondary to squamous cell carcinoma.

This type of pulmonary venous infarction has not been previously reported, namely: pulmonary vein obstruction from squamous cell carcinoma. Furthermore, this case is unique in that the characteristic pathologic vascular changes observed with pulmonary venous infarction were contrasted with a noninfarcted upper lobe that was removed from the same patient one year later.

Carcinoma, Squamous Cell↗
PubMed1992

Barrett's ulcer: a surgical disease?

Between 1973 and 1990, 285 patients with Barrett's esophagus were treated at the Lahey Clinic. Of these patients, 73 had adenocarcinoma in Barrett's esophagus either when first seen or while under surveillance. Of the remaining 212 patients with benign Barrett's esophagus, 30 had endoscopic evidence of a Barrett's ulcer, for a prevalence of 14%. Initial treatment consisted of aggressive medical therapy, including H2 antagonists and antacids as well as the usual dietary and antireflux measures. In 2 to 4 months, 27 patients underwent repeat endoscopy. Continued endoscopic evaluation in this group totaled 109 patient-years, with a range of 2 months to 13 years (median 2.3 years). Complete healing occurred in 23 of the 27 patients (85%) in 2 to 14 months (median 4 months). Recurrent ulcers developed in seven patients, and these ulcers healed with further medical therapy in five patients. Antireflux procedures were performed in four of six patients with nonhealing Barrett's ulcers, 1 to 1.5 cm in size, and all healed. Two patients refused to have an operation. In our experience, the majority of Barrett's ulcers heal with medical therapy. We reserve surgical intervention for otherwise suitable candidates for operation when no evidence of healing is found within 4 months of medical therapy or for the complications of Barrett's ulcer, namely, perforation, uncontrollable hemorrhage, or malignant degeneration, which were not encountered in this series.

Adenocarcinoma↗
PubMed1991

Barrett's esophagus. Prevalence and incidence of adenocarcinoma.

Between January 1973 and January 1989, 241 patients with Barrett's esophagus were treated at the Lahey Clinic Medical Center, Burlington, Mass. Of these patients, 65 presented with adenocarcinoma in Barrett's esophagus for a prevalence rate of 27%. Of 176 patients followed up for a total of 497 patient-years, adenocarcinoma developed in five patients for an incidence of one per 99 patient-years. The development of adenocarcinoma during endoscopic surveillance 1, 2, 2, 4, and 10 years after the initial diagnosis of Barrett's esophagus emphasizes the importance of long-term endoscopic and histologic surveillance. All five patients had severe dysplasia before adenocarcinoma developed. Yearly endoscopic follow-up examination is recommended for all patients with Barrett's esophagus unless mild dysplastic changes are found, in which case surveillance should be increased. Patients with severe dysplasia who are otherwise acceptable candidates for operation should be advised to have esophageal resection.

Adenocarcinoma↗
PubMed1990

Effect of antireflux operation on Barrett's mucosa.

Regression of Barrett's epithelium after antireflux operations remains a controversial topic. We evaluated the effect of antireflux procedures in patients with Barrett's esophagus on the regression of columnar epithelium and dysplasia and its potential protective effect on the subsequent development of carcinoma. Of the 241 patients with Barrett's esophagus treated at the Lahey Clinic from 1973 to 1989, 37 patients underwent an antireflux operation. Regression was defined as histological evidence of regenerating squamous mucosa that completely or partially replaced the columnar epithelium. Improvement in lower esophageal sphincter pressure to 12 mm Hg or greater occurred in 19 of 26 patients (73%) who had perioperative manometry. Symptomatic relief of esophagitis occurred in 34 of 37 patients (92%). Four patients had partial regression with regenerating squamous mucosa juxtaposed with areas of columnar epithelium. Carcinoma developed in 3 of 37 patients (8.1%). One patient had recurrence of severe symptoms of reflux esophagitis before development of carcinoma. Patients with Barrett's esophagus who have undergone a successful antireflux operation with symptomatic relief and evidence of improvement in lower esophageal sphincter pressures rarely show regression of Barrett's mucosa and may still be at risk for development of carcinoma. Therefore, the indications for antireflux operation in Barrett's esophagus should remain the same as for other patients with gastroesophageal reflux, but yearly endoscopic and histological surveillance should be continued postoperatively.

Adult↗
PubMed1981

Retrocecal appendicitis.

The clinical presentation of 105 cases of retrocecal appendicitis was reviewed. Thirty-six percent of the patients had the classic appendicitis scenario of periumbilical pain localizing to the right lower quadrant, accompanied by anorexia, nausea and vomiting, and tenderness and guarding in the right lower quadrant. The remaining 64 percent had subtle variations of this presentation. Retrocecal appendicitis did not have a distinctive clinical pattern in our series. Twelve of the 105 retrocecal appendices were also retroperitoneal. The diagnosis was delayed in four patients and two had flank pain. Five of the twelve appendices were either gangrenous or perforated. Although the number of patients is small, we conclude that the traditional type of retrocecal appendicitis can occur in the retroperitoneal subgroup but that his anatomic variation is infrequent. The incidence in our series was 2.5 percent.

Adolescent↗
PubMed1978

Impairment of the immune response to vaccination after acute malaria.

Children with acute malaria were vaccinated with Salmonella typhi and meningococcal vaccines at varying times after the onset of their illness. The immune response to both vaccines was depressed when they were given on the day of presentation at hospital. Immune responsiveness to S. typhi vaccine was rapidly regained after treatment, but a month after the attack the immune response to meningococcal vaccine was still impaired.

Acute Disease↗
PubMed1978

A study of the role of immunological factors in the pathogenesis of the anaemia of acute malaria.

Children with acute Plasmodium falciparum malaria and anemia were investigated to see if immunological factors could be implicated in the pathogenesis of their anaemia. Direct Coombs tests using an anti-whole immunoglobulin antiserum were negative in all 12 children tested but two had positive tests with antisera to C3b and C3d. Low plasma levels of C3 and C4 were found but these were not significantly different from values found in a group of children with acute malaria who were not anaemic. Serum levels of immune complexes were normal at the time of their presentation at hospital with anaemia but were elevated one month later. Incubation of group O rhesus-negative red cells in a serum pool obtained from children with acute malaria and anaemia did not cause enhanced haemolysis or reduce their survival time on injection into mice. Splenic uptake of red cells was, however, significantly enhanced. We conclude that the anaemia of acute malaria is due mainly to destruction of red cells by malaria parasites and to enhanced erythrophagocytosis of normal cells.

Acute Disease↗
PubMed1978

Water supply and nutritional status in rural northern Nigeria.

A high incidence of protein energy malnutrition (PEM) was found in a community survey of preschool children in rural northern Nigeria among whom gastro-enteritis is common. Wasting (less than 80% Weight/Height) was more common (37.9%) among those with scanty, unprotected water supplies than in those with copious protected water (10.2%) whereas the incidence of stunting (less than 90% Height/Age)) was similar. Severe coliform contaminatin of all water sources was demonstrable. Even higher numbers of coliforms in foods sampled suggests that other factors related to water supply may be more important than water purity in the genesis of the PEM/gastro-enteritis complex.

Body Height↗