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Dive into the research topics where Warren A. Williamson is active.

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Featured researches published by Warren A. Williamson.


The Annals of Thoracic Surgery | 1996

Screening Carotid Ultrasonography and Risk Factors for Stroke in Coronary Artery Surgery Patients

Richard S. D'Agostino; Lars G. Svensson; Deborah J. Neumann; Husam H. Balkhy; Warren A. Williamson; David M. Shahian

BACKGROUND The role of noninvasive carotid artery screening in relation to other clinical variables in identifying patients at increased risk of stroke after coronary artery bypass grafting was examined. METHODS Preoperative, intraoperative, and postoperative clinical data were prospectively collected for 1,835 consecutive patients undergoing first-time isolated coronary artery bypass grafting between March 1990 and July 1995, 1,279 of whom had screening carotid ultrasonography. All patients with postoperative neurologic events were identified and reviewed in detail. Average patient age was 65.3 years (range, 33 to 92 years), and 9.3% (171 patients) had a prior permanent stroke or transient ischemic attack. Hospital and 30-day mortality was 2.2% (41 patients). Forty-five patients (2.5%) had a transient or permanent postoperative neurologic event. The data were analyzed by stepwise logistic regression to determine the independent predictors of both significant carotid stenosis and stroke. RESULTS On multivariate analysis, the clinical predictors of significant carotid stenosis were age (p < 0.0001), diabetes (p = 0.0123), female sex (p = 0.0026), left main coronary stenosis greater than 60% (p < 0.0001), prior stroke or transient ischemic attack (p = 0.0008), peripheral vascular disease (p = 0.0001), prior vascular operation (p = 0.0068), and smoking (p < 0.0001). When all variables were evaluated for those patients who underwent noninvasive carotid artery screening, the independent predictors of postoperative neurologic event were prior stroke or transient ischemic attack (p < 0.0001), peripheral vascular disease (p = 0.0037), postinfarction angina pectoris (p = 0.0319), postoperative atrial fibrillation (p = 0.0014), carotid stenosis greater than 50% (p = 0.0029), cardiopulmonary bypass time (p = 0.0006), significant aortic atherosclerosis (p = 0.0054), postoperative amrinone or epinephrine use (p = 0.0054), and left ventricular ejection fraction less than 0.30 (p = 0.0744). CONCLUSIONS The etiology of postoperative stroke is multifactorial. Selective use of carotid ultrasonography is of value in identifying patients who are at greater risk of postoperative stroke independent of other variables and should be considered before coronary artery bypass grafting, particularly in patients with a history of neurologic event or peripheral vascular disease.


The Journal of Thoracic and Cardiovascular Surgery | 1997

Esophagogastrectomy for carcinoma of the esophagus and cardia: A comparison of findings and results after standard resection in three consecutive eight-year intervals with improved staging criteria

F. Henry Ellis; Gerald J. Heatley; M.J. Krasna; Warren A. Williamson; Karoly Balogh

OBJECTIVE A review of findings and results after standard resection for carcinoma of the esophagus and cardia without neoadjuvant therapy was done to provide a basis for comparison with current reports of radical resection and neoadjuvant therapy. METHODS A 24-year experience on one surgical service with 454 operations for carcinoma of the esophagus and cardia was reviewed. A comparison of findings and results in three consecutive 8-year intervals was analyzed, and new staging criteria were developed and compared with those currently favored by the American Joint Committee on Cancer. RESULTS From January 1, 1970, to January 1, 1994, 454 patients with carcinoma of the esophagus or cardia underwent operation, of whom 408 (90%) had esophagogastrectomy with a 30-day mortality rate of 2.5% and an additional hospital mortality rate of 1.2%. Of the 121 complications (30.7%), 71 (18%) were major and 50 (12.7%) were minor. Cardiovascular complications predominated. The overall 5-year survival was 24.7%, with a 33.7% survival after complete resections in the most recent interval under study. Palliation of dysphagia was achieved in nearly 80% of patients who survived the operation. During the three intervals under review, resectability, mortality, and complication rates remained constant. The percentages of left thoracotomies and transhiatal resections increased, and there was a decrease in thoracoabdominal incisions. The percentages of patients with Barretts esophagus and stage 0 and I tumors increased. The percentage of complete resections (R0) increased, whereas that for resections with residual microscopic tumor (R1) decreased, and there was no change in the percentage of patients with residual gross tumor after resection (R2). Modified WNM staging criteria are proposed that provide better prognostic stratification of the disease than those currently favored by The American Joint Committee on Cancer. CONCLUSIONS Standard esophagogastrectomy is applicable in 90% of patients with operable carcinoma of the esophagus or cardia, with consistently low mortality and morbidity rates and satisfactory palliation of dysphagia. The 5-year survival (24.7% overall) remains suboptimal, but the current figure for complete resections (33.7%) is encouraging. There is a need for revision of the current American Joint Committee on Cancer staging criteria.


The Annals of Thoracic Surgery | 1990

Effect of antireflux operation on Barrett's mucosa

Warren A. Williamson; F. Henry Ellis; S. Peter Gibb; David M. Shahian; H. Thomas Aretz

Regression of Barretts epithelium after antireflux operations remains a controversial topic. We evaluated the effect of antireflux procedures in patients with Barretts 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 Barretts 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 Barretts esophagus who have undergone a successful antireflux operation with symptomatic relief and evidence of improvement in lower esophageal sphincter pressures rarely show regression of Barretts mucosa and may still be at risk for development of carcinoma. Therefore, the indications for antireflux operation in Barretts esophagus should remain the same as for other patients with gastroesophageal reflux, but yearly endoscopic and histological surveillance should be continued postoperatively.


The Annals of Thoracic Surgery | 1993

Paraesophageal hiatal hernia: Is an antireflux procedure necessary?

Warren A. Williamson; F. Henry Ellis; John M. Streitz; David M. Shahian

Between January 1970 and October 1992, 119 patients underwent 126 repairs of a paraesophageal hiatal hernia at the Lahey Clinic. Seven patients with a recurrent hernia required reoperation. Of the procedures, 19 (15%) included an antireflux procedure because of severe reflux symptoms and objective evidence of reflux demonstrated by grade 2 esophagitis on endoscopy, manometric evidence of a hypotensive lower esophageal sphincter pressure (< or = 10 mm Hg), positive results on 24-hour pH monitoring, or all three methods. Follow-up ranged from 6 months to 18 years with a median of 61.5 months, and the results of 115 operations were analyzed. Symptomatic results were good to excellent after 96 (83.5%) of these 115 operations. Thirteen symptomatic paraesophageal hernias recurred in 12 patients (one recurrence per 58 patient-years of follow-up). Severe reflux symptoms accompanied by endoscopic evidence of esophagitis developed in 2 patients who had not undergone an antireflux procedure at the time of repair of the hernia. We conclude that an antireflux procedure is rarely required in patients undergoing repair of a paraesophageal hiatal hernia and should be employed only when objective evidence of reflux is seen preoperatively.


Thorax | 1994

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

Andrew G. Villanueva; Anthony W. Gray; David M. Shahian; Warren A. Williamson; John F. Beamis

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.


Journal of The American College of Surgeons | 1998

Cancer of the esophagus and cardia: does age influence treatment selection and surgical outcomes?

F. Henry Ellis; Warren A. Williamson; Gerald J. Heatley

BACKGROUND Some physicians believe that an aggressive surgical approach for the management of cancer of the esophagus and cardia is unwise in elderly patients because of allegedly higher rates of mortality and morbidity and lower rates of survival than those associated with younger patients. We have long advocated an aggressive surgical approach regardless of the patients age and have reviewed our experience to determine whether age was a factor influencing treatment and outcomes. STUDY DESIGN From January 1, 1970 to January 1, 1997, 505 patients with cancer of the esophagus or cardia underwent operations by one surgical team using standard surgical techniques. One hundred forty-seven patients (29.1%) were 70 years of age or older and 358 patients (70.9%) were under 70 years of age. Their records and clinicopathologic features were reviewed and compared. RESULTS The two groups were similar regarding the location of tumors. Tumor cell types were similar except for adenocarcinomas in Barretts esophagus, which were less common in the older group (15.6% versus 24%; p=0.046). Surgical procedures were similar, as were the rates of resectability and the percentages of R0 resections. The hospital mortality rate was higher in the elderly patients but not significantly so, and the rates of major and minor complications combined were comparable. The differences in postresection pathologic staging were not significant. Satisfactory palliation of dysphagia was comparable between the groups, as were actuarial 5-year survival rates (24.1% of the elderly patients versus 22.4% of the younger patients). CONCLUSIONS Age should not be a limiting factor in using an aggressive surgical approach for the management of cancer of the esophagus or cardia in patients aged 70 years or older. Such an approach can be performed as safely as in younger patients, with comparable rates of palliation and survival.


The Annals of Thoracic Surgery | 1996

Applications of statistical quality control to cardiac surgery

David M. Shahian; Warren A. Williamson; Lars G. Svensson; Joseph D. Restuccia; Richard S. D'Agostino

BACKGROUND Although originally developed for use in manufacturing statistical quality control techniques may be applicable to other frequently performed, standardized processes. METHODS We employed statistical quality control charts (X- s, p, and u) to analyze perioperative morbidity and mortality and length of stay in 1,131 nonemergent, isolated, primary coronary bypass operations conducted within a 17-quarter time period. RESULTS The incidence of the most common adverse outcomes, including death, myocardial infarction, stroke, and atrial fibrillation, appeared to follow the laws of statistical fluctuation and were in statistical control. Postoperative bleeding, leg-wound infection, and the summation of total and major complications were out of statistical control in the early quarters of the study period but showed progressive improvement, as did postoperative length of stay. CONCLUSIONS The incidence of morbidity and mortality after primary, isolated, nonemergent coronary bypass operations may be described by standard models of statistical fluctuation. Statistical quality control may be a valuable method to analyze the variability of these adverse postoperative events over time, with the ultimate goal of reducing that variability and producing better outcomes.


The Journal of Thoracic and Cardiovascular Surgery | 1996

Objective assessment of gastroesophageal reflux after short esophagomyotomy for achalasia with the use of manometry and pH monitoring

John M. Streitz; F. Henry Ellis; Warren A. Williamson; Michael E. Glick; Johannes A. Aas; Robert L. Tilden

The role of an antireflux procedure as an adjunct to esophagomyotomy for achalasia remains a subject of controversy. Little objective documentation exists of this operations effect on sphincteric competence and the degree of postoperative gastroesophageal reflux. This report of esophageal manometry and 24-hour pH monitoring on 14 patients with esophageal achalasia whom we had previously treated by a short esophagomyotomy without an antireflux procedure provides such documentation. Esophagomyotomy reduced lower esophageal sphincter pressure by 12% to 71% (mean 41%) from a preoperative mean of 26.7 mm Hg to a postoperative mean of 14.6 mm Hg. The number of postoperative episodes of acid reflux per patient in 24 hours was fewer than 29 (normal < 49) in 13 patients, with a median of 12 episodes for the entire group. Esophageal acid exposure, measured as percentage of total time with pH less than 4.0 (normal < 4.5%), was below 4.5% in 10 patients, six of whom had values less than 1%. Among the four patients with values greater than 4.5%, only one had a temporal correlation of symptoms with an episode of acid reflux. Multivariate analysis showed that esophageal acid exposure time correlated only with the level of residual lower esophageal sphincter pressure during the relaxation phase of deglutition. A pressure less than 8 mm Hg was predictive of normal acid contact time (p < 0.001). Mean lower esophageal sphincter pressure, percent reduction in lower esophageal sphincter amplitude, postoperative vector volume, and length of the lower esophageal sphincter did not significantly correlate with amount of esophageal acid exposure. We conclude that a short esophagomyotomy without an antireflux procedure results in a competent lower esophageal sphincter in most patients. Increased esophageal acid exposure, when it occurs, is due to slow clearance of esophageal acid from relatively few reflux episodes and is more likely to occur when there is a high residual pressure during deglutition after myotomy. These findings suggest that the addition of an antireflux procedure to a short esophagomyotomy would not be expected to improve clinical results.


The Annals of Thoracic Surgery | 1992

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

John M. Streitz; Warren A. Williamson; F. Henry Ellis

Current concepts regarding the nature and the treatment of Barretts 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. Barretts 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 Barretts epithelium is well recognized, and strategies for surveillance and resection are discussed. Survival after resection of adenocarcinoma in Barretts esophagus is not appreciably different from that of other carcinomas. Surveillance with endoscopy offers the best chance for early detection and cure.


Pacing and Clinical Electrophysiology | 1993

Infection of Implantable Cardioverter Defibrillator Systems: A Preventable Complication?

David M. Shahian; Warren A. Williamson; David Martin; Ferdinand J. Venditti

In a consecutive series of 164 patients undergoing primary implantation of an impJantable cardioverter defibrillator (ICD), two patients died in the hospital (1.2%) and early system infection developed in one patient requiring expJantation 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 explantation 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.

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F. Henry Ellis

Beth Israel Deaconess Medical Center

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John M. Streitz

Beth Israel Deaconess Medical Center

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