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A Chak

Publications and source records attributed to A Chak.

At least 73 records · Page 4Linked to original sources
PubMed1997

Endosonographic differentiation of benign and malignant stromal cell tumors.

BACKGROUND: Endosonography (EUS) is a valuable technique for diagnosing gastrointestinal stromal cell tumors. However, EUS features that are predictive of malignancy in these tumors have not been defined. METHODS: Videotapes and photographs of EUS examinations performed prior to surgical resection of 35 stromal cell tumors (9 malignant) were blindly reviewed by a single examiner. EUS features associated with malignancy were determined. Interobserver agreement in interpreting these features was then measured among a panel of five expert endosonographers who judged EUS videotapes of 35 resected stromal cell tumors (10 malignant). RESULTS: Stepwise logistic regression analysis demonstrated that tumor size (diameter > 4 cm), irregular extraluminal border, echogenic foci, and cystic spaces were independently associated with malignancy in stromal cell tumors (p < 0.05). Interobserver agreement for irregular extraluminal border, echogenic foci, and cystic spaces, as measured by mean kappa statistic, was 0.43, 0.39, and 0.28, respectively. For the five experts, the sensitivity for detecting malignancy ranged between 80% to 100% when at least two of the three features were judged to be present. The likelihood of finding malignancy ranged between 0% to 11% for the experts when all three features were judged absent. CONCLUSIONS: Tumor size and certain EUS features are useful for predicting malignancy in stromal cell tumors. Absence of these features indicates benign disease. Agreement among experts in interpreting these EUS features is fair to moderate.

Diagnosis, Differential↗
PubMed1997

Lack of gender and racial differences in surgery and mortality in hospitalized Medicare beneficiaries with bleeding peptic ulcer.

OBJECTIVE: Determine the relation of race and gender to outcome from bleeding peptic ulcer. DESIGN: Retrospective cohort study. SETTING: All acute care hospitals in the United States. PATIENTS: A 100% sample of hospitalized Medicare beneficiaries older than 64 years (n = 82,868) with a primary discharge diagnosis of peptic ulcer with hemorrhage. MEASUREMENTS AND MAIN RESULTS: Surgical treatment was performed in 6.9% of patients, 30-day mortality was 8.5%, and average length of stay was 9.4 days. Surgery was somewhat more common in men than women (7.3% vs 6.5%, p < .001), and in whites than African Americans (6.9% vs 6.3%, p < .001), but neither race nor gender was associated with surgery in multivariable analysis adjusting for potentially confounding factors. Mortality rates were similar in African Americans and whites (8.5%), and somewhat higher in men than women (10.7% vs 9.3%, p < .001). In multivariable analysis, there was no difference in mortality across gender and racial groups. Although unadjusted and adjusted lengths of stay were longer for African Americans and shorter for men, the differences were modest (i.e., 16% increase and 6% decrease in multivariable analysis, respectively, p < .0001). CONCLUSIONS: In this national sample, there is no significant gender or racial difference in therapy and outcome for patients with hemorrhagic peptic ulcer. The findings raise the possibility that studies that have shown race and gender differences in management of coronary artery disease and cancer may not be generalizable to other common diagnoses.

Black or African American↗
PubMed1996

Clinical implications of endoscopic ultrasound: the American Endosonography Club Study.

BACKGROUND: Despite increased clinical use of endoscopic ultrasound (EUS), there are little data regarding complications of EUS or its impact on patient management. METHODS: A prospective multicenter study was completed to evaluate clinical outcomes of EUS. Before each EUS examination the endosonographer recorded further theoretical patient management plans as if EUS was unavailable. After the EUS, endosonographers recorded actual management plans based on EUS results. The actual management plan after EUS was compared to the theoretical management before EUS. Complications were assessed in short-term follow-up. RESULTS: Four hundred twenty-eight subjects were enrolled. Of subjects able to be evaluated, EUS changed the treatment plan in 74%. Management changes of major importance occurred in 120 patients (31% of subjects able to be evaluated) and included decisions regarding surgery (62 patients), decisions regarding nonsurgical invasive management (36 patients), and decisions regarding further follow-up (22 patients). When there was a change in management, the change was to less costly, risky, or invasive management in 55%, to more costly/risky/invasive in 37%, and to equally costly/risky/invasive in 8%. Short-term follow-up was completed in 81% of subjects, with six complications identified (1.7%). Three complications were mild, two were moderate, one severe, and none fatal. CONCLUSIONS: (1) Changes in management plan may occur in the majority of patients based on EUS results. (2) The management changes are often of major importance with regard to health care costs and safety, and are more often in the direction of less costly, risky, and invasive management. (3) EUS is safe in experienced hands.

Adolescent↗
PubMed1996

Methylene blue selectively stains intestinal metaplasia in Barrett's esophagus.

BACKGROUND: Specialized columnar epithelium in Barrett's esophagus resembles gastric intestinal metaplasia, which selectively stains with methylene blue. METHODS: We prospectively evaluated the safety, accuracy, reproducibility, cost, and diagnostic yield of methylene blue-directed biopsy in detecting specialized columnar epithelium and dysplasia in Barrett's esophagus. We performed upper endoscopy with methylene blue-directed biopsy and obtained 236 large cup biopsy specimens (145 stained, 91 unstained) from 14 patients with Barrett's esophagus of any length (Group 1) and 12 control patients. Biopsy specimens were independently examined by two pathologists unaware of the endoscopic results. RESULTS: Methylene blue stained specialized columnar epithelium in 18 of the 26 patients, including those with intramucosal carcinoma (1), high-grade dysplasia (1), and indefinite/low-grade dysplasia (6). Methylene blue staining pattern, which was focal in 72% and diffuse in 28% of patients, was reproduced in 8 patients who had repeat staining within 4 weeks. The overall accuracy of methylene blue staining for detecting specialized columnar epithelium was 95%. The diagnostic yield of methylene blue staining for specialized columnar epithelium in "control" patients was 42%. The risk for dysplasia in stained biopsy specimens was greater than in unstained ones (odds ratio 17.7, p = .0004). CONCLUSIONS: Methylene blue mucosal staining is a safe, inexpensive, reproducible, and highly accurate method of diagnosing specialized columnar epithelium in Barrett's esophagus.

Barrett Esophagus↗
PubMed1996

Prospective assessment of colonoscopic intubation skills in trainees.

INTRODUCTION: The American Society for Gastrointestinal Endoscopy recommends a minimum of 100 supervised colonoscopies prior to assessment of technical competence. To establish a measurable standard for competence and to assess this recommendation, performance of colonoscopies at a university hospital was studied. METHODS: Colonoscopic preparation, surgical history, medication usage, technical maneuvers, extent of colon intubated, success rate, and cecal intubation time were prospectively monitored for first-year trainees, second-year trainees, and attendings. RESULTS: Excluding patients with poor preparations or colonic resections, 496 colonoscopies were studied. First-year trainees (n = 5) required attending assistance in 73 of 79 (92%) procedures. Second-year trainees (n = 7), who had performed a mean of 123 colonoscopies prior to the study, required attending assistance in 37 of 102 (36.3%) procedures. Attendings (n = 7) successfully intubated the cecum in 297 of 315 (94.3%) colonoscopies in a median time of 10.5 minutes. Second-year trainees were less successful than attendings in cecal intubation (success rate = 84%, p < 0.05), and required more time (median = 14.5 minutes, p < 0.01). More technical maneuvers were performed, and a lesser extent of colon was intubated, during trainee colonoscopies. CONCLUSIONS: We propose a 90% success rate and a median cecal intubation time of less than 15 minutes as reasonable standards for measuring technical competence. Trainees do not achieve this standard after the performance of 100 supervised colonoscopies.

Cecum↗
PubMed1996

Care of patients with upper gastrointestinal hemorrhage in academic medical centers: a community-based comparison.

BACKGROUND & AIMS: A common perception among purchasers is that academic medical centers are inefficient and overutilize technology; however, little empirical information exists. The aim of this study was to compare treatment and outcomes of patients with upper gastrointestinal hemorrhage admitted to major teaching hospitals and other hospitals in a large metropolitan area. METHODS: Data on 3801 consecutive eligible patients admitted to five major teaching hospitals and 25 other hospitals from 1991 to 1993 were obtained by review of medical records. Admission severity of illness was measured using validated multivariable models. RESULTS: Rates of upper endoscopy were somewhat lower among the 1004 patients discharged from fellowship hospitals, compared with the other 2797 patients (82.9% vs. 85.6%; P < 0.05), and the use of other procedures was similar. Although patients admitted to fellowship hospitals tended to have a higher severity of illness, both unadjusted (6.3 +/- 9.0 vs. 7.1 +/- 7.5 days; P < 0.01) and risk-adjusted length of stay were somewhat shorter. Mortality rates were similar between hospitals, and patients admitted to fellowship hospitals were somewhat less likely to be transfused. CONCLUSIONS: In patients with upper gastrointestinal hemorrhage, teaching hospitals do not appear to provide inefficient care or overutilize expensive treatments when compared with community facilities. These findings are noteworthy at a time when viability of academic centers and fellowship training is threatened.

Academic Medical Centers↗
PubMed1996

Endoscopic ultrasonography.

Optimal treatment of gastric carcinoma requires accurate staging as there are marked differences in the prognosis of early and advanced gastric cancer which influence the decision for surgical resection versus nonsurgical palliation. Endoscopic ultrasonography (EUS), by virtue of its considerable accuracy, has become the method of choice for regional staging of gastric cancer. EUS is unique in its ability to image the gastric wall as a 5-layer structure that correlates with actual histological layers. Thus, tumor depth can be imaged very precisely. Peritumor inflammation is the most common cause for overstaging by EUS; difficulty in determining tumor involvement of, but not through, the subserosa is another important reason for inaccurate staging. EUS is able also to detect small lymph nodes in the perigastric region. Although assessment of malignancy in nodes can be difficult, ultrasound-guided fine needle aspiration cytology appears to be an accurate method to determine lymph node status. Surgery remains the standard treatment for gastric cancer, but new methods of endoscopic resection combined with high-frequency ultrasound may hold promise for future treatment of early gastric cancer. In addition to current radial and sector scanning instruments, recently introduced high-frequency ultrasound probes enhance the diagnostic possibilities of this technology.

Biopsy, Needle↗
PubMed1996

Clinical variables associated with colorectal cancer on colonoscopy: a prediction model.

OBJECTIVES: We prospectively evaluated the ability of various indications for colonoscopy to predict colorectal cancer. METHODS: Indications and findings were prospectively recorded for 1223 consecutive colonoscopies performed during an 18-month period at a University Hospital. Colonoscopies performed on 981 patients for indications which included colorectal cancer in the differential diagnosis were included in the study. A group of 653 patients was randomly selected to derive a model predictive of colorectal cancer at colonoscopy; the remaining 328 patients were used to validate the model. RESULTS: Colorectal cancer was found in 44/981 patients (4.5%). Univariate analysis of the derivation set showed that age > 55, occult bleed, anemia, iron deficiency, weight loss, and abnormal CT scan were associated with finding colorectal cancer at colonoscopy in the derivation set, p < 0.05. History of polyps was negatively associated with finding colorectal cancer. Stepwise selection was used to develop a predictive model by using three independent variables-age > 55, iron deficiency, and weight loss. Assigning a score of 1 to each variable, cancer was present in 0% [95% confidence intervals (CI), 0-0.6%], 5.3% (95% CI, 2.3-8.3%), and 17.9% (95% CI, 4.8-31%) of patients in the validation sample with a score of 0, 1, and > or = 2, respectively (p < 0.001 by chi2 for trend). The model was predictive of finding colorectal cancer at colonoscopy, independent of the location or stage of the cancer. CONCLUSIONS: Age, iron deficiency, and weight loss are important independent predictors of colorectal cancer in patients referred for colonoscopy.

Aged↗
PubMed1995

Prognosis of esophageal cancers preoperatively staged to be locally invasive (T4) by endoscopic ultrasound (EUS): a multicenter retrospective cohort study.

BACKGROUND: Endosonography is a significant advance in the preoperative staging (TNM classification) of esophageal cancer. Its accuracy for evaluating depth of tumor invasion is over 80%. METHODS: A multicenter retrospective cohort study of patients with esophageal carcinomas defined to be invasive (T4) by endosonography was performed to compare the survival of surgically and nonsurgically treated patients. Median survival time, overall mortality, and Kaplan-Meier survival curves were compared by treatment group. Univariate and Cox regression analysis were used to evaluate the effects of various prognostic factors and treatment on the risk of death. RESULTS: A total of 79 patients were studied. The surgical group (Group I, n = 42) was significantly younger and had more distal tumors (adenocarcinomas) than the nonsurgical group (Group II, n = 37). Endosonography was significantly more accurate than CT scanning in identifying tumor invasion (87.5% versus 43.8%, respectively, p = .0002). Overall mortality rate was not significantly different between treatment groups; 59.5% of the surgical group and 64.9% of the nonsurgical group were dead at follow-up (p = 0.65). Similarly, the median survival times of Group I and Group II patients were similar (5.2 and 7.0 months, respectively, p = 0.50). Survival curves for the two groups were almost overlapping (log rank test, p = 0.84). Even after adjusting for age, histologic diagnosis, tumor location, and regional lymph node status, surgical treatment did not significantly influence survival (p = 0.24). CONCLUSIONS: Endosonography accurately identifies patients with invasive T4 tumors who have a poor prognosis. This prognosis is independent of mode of therapy.

Adenocarcinoma↗
PubMed1995

Duplex Doppler endosonography in the diagnosis of splenic vein, portal vein, and portosystemic shunt thrombosis.

BACKGROUND/AIMS: Endoscopic ultrasonography is a promising procedure for imaging mesenteric vascular structures. METHODS: Duplex and color Doppler endosonography were used to prospectively evaluate 20 asymptomatic paid volunteers. Subsequently, 11 patients with nondiagnostic transabdominal ultrasound and suspected thrombosis of the splenic and/or portal veins or a portosystemic shunt were evaluated with duplex endosonography. The final diagnosis was based on CT, angiography, and/or surgery or autopsy findings in 9 of 11 patients. RESULTS: In normal volunteers, mesenteric vessel flow velocities and diameters were similar to previously described values. In 10 of the 11 patients with failed transabdominal ultrasound, duplex endosonography was able to provide the correct diagnosis (accuracy of ultrasound 0% versus EUS 91%, p < .001). Mean portal vein diameter was greater in the patient group than in the normal volunteers (18.5 mm versus 10.7 mm, p < .001) and all of the normal volunteers had a portal vein diameter less than 13 mm. No complications were experienced. CONCLUSION: Duplex endosonography allows visualization of the intra-abdominal vasculature and can be considered when transabdominal ultrasound is nondiagnostic in patients with suspected thrombosis of their splenic vein, portal vein, or portosystemic shunt. EUS is able to identify indirect findings of portal hypertension including portal vein enlargement and venous collaterals.

Adult↗
PubMed1993

Traveler's diarrhea.

A variety of infectious enteric pathogens (bacterial, viral, and protozoal) can lead to a systemic diarrheal illness in international travelers traveling from industrialized countries to developing areas of the world. Many of the agents that lead to this syndrome have been identified, and their mode of transmission has been defined. Prophylactic measures are advisable, and effective treatment options are available. This article also discusses issues important in the management of patients who develop a chronic diarrheal illness after travel.

Diarrhea↗