PubMed Health⌕ Search

Biomedical subjects

Richard C K Wong

Publications and source records attributed to Richard C K Wong.

At least 19 recordsLinked to original sources

Endoscopic Doppler ultrasound versus endoscopic stigmata-directed management of acute peptic ulcer hemorrhage: a multimodel cost analysis.

Recurrent bleeding from acute peptic ulcer hemorrhage is problematic. Studies have shown that Doppler ultrasound (DOP-US) is useful in decreasing rebleeding. We analyzed associated costs and outcomes to better define the role of DOP-US versus Conventional (Forrest classification endoscopic stigmata) in the management of acute peptic ulcer bleeding. Two separate decision analyses were constructed. Recurrent bleeding, failed esophagogastroduodenoscopy (EGD) hemostasis, complications, and surgery rates were derived from medical literature. Costs were based on Medicare data. DOP-US is preferred over Conventional in acute peptic ulcer bleeding with average cost savings per patient ranging from 853 dollars (decision-tree modeling) to 1,160 dollars (Monte Carlo simulation). High-dose intravenous proton-pump inhibitors lowered rates of recurrent bleeding for both Conventional and DOP-US, resulting in a lower but still persistent average cost savings per patient for DOP-US (decision-tree modeling = 328 dollars, Monte Carlo simulation = 560 dollars). This decision analyses identified DOP-US as the preferred cost-minimizing strategy in acute peptic ulcer hemorrhage. Results of cost analyses were most dependent on hospitalization costs and recurrent bleeding rates.

Acute Disease↗

Accuracy of endoscopic optical coherence tomography in the detection of dysplasia in Barrett's esophagus: a prospective, double-blinded study.

BACKGROUND: Endoscopic optical coherence tomography (EOCT) is a high-resolution, cross-sectional tissue-imaging technique that provides microscopic morphologic information. EOCT should detect dysplasia in Barrett's epithelium, but this has not been established in a prospective blinded study. This study evaluated the accuracy of EOCT for the diagnosis and the exclusion of dysplasia in patients with Barrett's esophagus. METHODS: A 2.4-mm diameter EOCT probe was modified for use with a cap-fitted, two-channel endoscope. Pairs of EOCT image streams and jumbo biopsy specimens were obtained. Endoscopy/EOCT procedures were performed by 4 endoscopists who separately reviewed the EOCT digital images for the absence or the presence of dysplasia (low grade, high grade, or cancer) for each biopsy specimen obtained. The endoscopists were blinded to the interpretation of the pathology. An experienced pathologist blinded to the endoscopic/EOCT findings evaluated each biopsy for the absence or the presence of dysplasia. The setting of the study was a major academic medical center. Adult patients with documented Barrett's esophagus greater than 2 cm were included in the study. The main outcome measurement was the accuracy of EOCT in the detection of dysplasia in patients with Barrett's esophagus. RESULTS: A total of 314 usable EOCT image stream/biopsy pairs were obtained in 33 patients. By using histology as the standard, the performance of EOCT was sensitivity, 68%; specificity, 82%; positive predictive value, 53%; negative predictive value, 89%; and diagnostic accuracy, 78%. Diagnostic accuracy for the 4 endoscopists ranged from 56% to 98%. Limitations of the study were the variability in endoscopists' accuracy rates, difficulty in real-time interpretation, and the need for refined criteria of dysplasia by EOCT imaging. CONCLUSIONS: The current EOCT system has an accuracy of 78% for the detection of dysplasia in patients with Barrett's esophagus. EOCT could be used to target biopsies to areas of Barrett's epithelium with a higher probability for the presence of dysplasia. However, further modifications, including increased resolution and identification of further potential OCT characteristics of dysplasia, are needed before EOCT can be used clinically.

Adult↗

The yield of bleeding scans in acute lower gastrointestinal hemorrhage.

GOALS/BACKGROUND: Previous studies have demonstrated low yield and conflicting results as to the ability of technetium-99m labeled red blood cell (TRBC) scintigraphy to accurately localize the site of bleeding in acute lower gastrointestinal hemorrhage. Our objective was to evaluate the accuracy of TRBC scintigraphy in clinical day-to-day practice at our institution and to determine predictors of a positive test. METHODS: A retrospective medical records review of all patients who underwent TRBC scintigraphy over a 5-year period was conducted at a single academic medical center. The site of bleeding found on TRBC scintigraphy was correlated with the endoscopic, angiographic, surgical, and pathologic findings in each patient. RESULTS: A total of 127 scans were performed in 115 patients. Forty-nine scans were positive (39%) and 78 were negative (61%). Forty-two patients had further evaluation after a positive scan, and the bleeding site was confirmed to be accurate in 20 of 42 patients (48%). A contradictory bleeding site was found in 5 of 49 positive scans (10%). Patients transfused greater than 2 units of packed red blood cells within 24 hours preceding the TRBC scan were twice as likely to have a positive scan (64%) than those transfused 2 units or less (32%) (P = 0.002). Multivariate analysis demonstrated that the number of units of blood transfused within 24 hours prior to the TRBC scan and the lowest recorded hematocrit were significantly different between patients with positive and negative scans. There was no difference in the rate of endoscopy between patients with a positive or negative scan result. CONCLUSIONS: TRBC scintigraphy has a relatively low yield in the evaluation of acute lower gastrointestinal bleeding. Objective selection criteria such as number of units of packed red blood cells transfused prior to obtaining the scan may increase the overall yield.

Acute Disease↗

Does prophylactic pancreatic stent placement reduce the risk of post-ERCP acute pancreatitis? A meta-analysis of controlled trials.

BACKGROUND: Impaired drainage of the pancreatic duct is one of the possible triggers for post-ERCP acute pancreatitis. The aim of this meta-analysis was to determine whether temporary stent placement across the main pancreatic-duct orifice lowers the frequency of post-ERCP acute pancreatitis in patients at high risk for this complication. METHODS: Two reviewers systematically identified prospective studies that (1) compared the risk of post-ERCP acute pancreatitis in patients with pancreatic stent placement vs. no stent placement and (2) included patients at high risk of developing this complication. Studies were assessed for methodologic quality and variations in execution and design. Frequency and severity of post-ERCP acute pancreatitis were the primary outcomes evaluated. RESULTS: Five trials involving 481 patients were selected. Of the 481, 55 (11.4%) patients developed pancreatitis after ERCP. Patients in the no stent group had 3-fold higher odds of developing pancreatitis compared with the stent group (15.5% vs. 5.8%; OR 3.2: 95% CI[1.6, 6.4]). Number needed to treat analysis showed that one in every 10 patients (95% CI[6,18]) could be expected to benefit from pancreatic-duct stent placement. CONCLUSIONS: Prophylactic temporary stent placement across the main pancreatic-duct orifice reduces the risk of post-ERCP acute pancreatitis in patients at risk for developing this complication.

Acute Disease↗

Success and shortcomings of a clinical care pathway in the management of acute nonvariceal upper gastrointestinal bleeding.

OBJECTIVES: Acute nonvariceal upper gastrointestinal (GI) bleeding is the most common medical emergency encountered by gastroenterologists resulting in high patient morbidity and cost. We sought to establish if a GI bleeding clinical care pathway could improve the quality and cost effectiveness of inpatient medical care. METHODS: A disease management program for acute upper GI bleeding was established. Length of stay, time to endoscopy, utilization of potentially unnecessary radiological tests, acid suppression, and cost of care were compared between patients pre- and postinitiation of GI bleeding pathway guidelines. RESULTS: The instituted GI bleeding management program significantly reduced the use of intravenous H2-blockade from 65.3% to 47.7% (p = 0.002). The use of radiological tests, time to endoscopy, and length of hospital of stay were unchanged. There was a trend toward a reduction in total cost and variable direct cost per patient admitted with acute upper GI bleeding, from $5,381 to $4,627 and from $2,269 to $1,952, respectively. CONCLUSION: A clinical care pathway may affect the management of acute upper GI bleeding and reduce costs. However, there are significant limitations and barriers to the overall effectiveness of such a pathway in actual clinical practice.

Acute Disease↗

Prediction of outcome in acute lower-gastrointestinal haemorrhage based on an artificial neural network: internal and external validation of a predictive model.

BACKGROUND: Models based on artificial neural networks (ANN) are useful in predicting outcome of various disorders. There is currently no useful predictive model for risk assessment in acute lower-gastrointestinal haemorrhage. We investigated whether ANN models using information available during triage could predict clinical outcome in patients with this disorder. METHODS: ANN and multiple-logistic-regression (MLR) models were constructed from non-endoscopic data of patients admitted with acute lower-gastrointestinal haemorrhage. The performance of ANN in classifying patients into high-risk and low-risk groups was compared with that of another validated scoring system (BLEED), with the outcome variables recurrent bleeding, death, and therapeutic interventions for control of haemorrhage. The ANN models were trained with data from patients admitted to the primary institution during the first 12 months (n=120) and then internally validated with data from patients admitted to the same institution during the next 6 months (n=70). The ANN models were then externally validated and direct comparison made with MLR in patients admitted to an independent institution in another US state (n=142). FINDINGS: Clinical features were similar for training and validation groups. The predictive accuracy of ANN was significantly better than that of BLEED (predictive accuracy in internal validation group for death 87% vs 21%; for recurrent bleeding 89% vs 41%; and for intervention 96% vs 46%) and similar to MLR. During external validation, ANN performed well in predicting death (97%), recurrent bleeding (93%), and need for intervention (94%), and it was superior to MLR (70%, 73%, and 70%, respectively). INTERPRETATION: ANN can accurately predict the outcome for patients presenting with acute lower-gastrointestinal haemorrhage and may be generally useful for the risk stratification of these patients.

Acute Disease↗

Prospective evaluation of 4-mm diameter endoscopes for esophagoscopy in sedated and unsedated patients.

BACKGROUND: Unsedated esophagoscopy with small-diameter endoscopes is generally well tolerated but of limited sensitivity for the diagnosis of esophageal mucosal disease. This study evaluated the sensitivity of esophagoscopy performed with new 4-mm diameter prototype battery-powered and video endoscopes. Patient tolerance for an unsedated examination with the 4-mm endoscopes was assessed and the performance characteristics of the battery-powered and video 4-mm endoscopes were compared. METHODS: Patients referred for EGD were recruited to undergo an additional examination with a 4-mm endoscope. A prototype 60-cm long, 4-mm diameter battery-powered fiberoptic esophagoscope was used in the first 24 patients and a prototype 60-cm long, 4-mm diameter video esophagoscope in the next 27 patients. Examiners who were unaware of patient history and procedure indications recorded esophageal findings, ease of intubation, optical quality (5-point visual scale), and time for examination of the esophagus and then recorded esophageal findings after the standard EGD. RESULTS: The sensitivity, specificity, and accuracy for identification of Barrett's esophagus was 100%; overall sensitivity, accuracy, and specificity for detecting esophageal lesions were, respectively, 91%, 98%, and 99%. Patient tolerance (assessed by symptom scores for choking, pain, and discomfort) and acceptability of unsedated esophagoscopy with the 4-mm diameter instruments were significantly better than in a historical group of patients examined with a 3-mm diameter endoscope. The optical quality of video endoscope was rated as superior to that of battery-powered endoscope, and esophageal examination was performed significantly quicker with the video versus the battery-powered endoscope (68 vs. 137 seconds; p = 0.001). CONCLUSIONS: Unsedated esophagoscopy with 4-mm diameter endoscopes may be an alternative to EGD for screening for Barrett's esophagus. Given the current state of endoscopic technology, a minimum diameter of 4 mm is required for satisfactory esophageal imaging.

Barrett Esophagus↗

Criteria for the diagnosis of dysplasia by endoscopic optical coherence tomography.

BACKGROUND: Endoscopic optical coherence tomography provides images of the GI mucosa and submucosa in microscopic detail. It is unknown whether endoscopic optical coherence tomography can reliably detect dysplasia. Colon polyps were used as a model to determine whether dysplasia in GI tissue has characteristic optical coherence tomography imaging features. METHODS: Endoscopic optical coherence tomography images of colon polyps and normal colon tissue were obtained at colonoscopy. In real time, endoscopists compared tissue organization and light scattering for polyps and normal mucosa with endoscopic optical coherence tomography. Imaged polyps were removed and evaluated histopathologically. Organization and light scattering, as assessed by endoscopic optical coherence tomography at colonoscopy, were compared for adenomas versus hyperplastic polyps. A computer program also quantified and compared the degree of light scattering for hyperplastic polyps and adenomas. RESULTS: A total of 44 polyps were imaged in 24 patients (30 adenomas, 14 hyperplastic polyps). Endoscopic optical coherence tomography images of adenomas had significantly less structure (p = 0.0005) and scattered light to a lesser degree than hyperplastic polyps (p = 0.0007). Hyperplastic polyps were significantly closer in organization (p = 0.0003) and light scattering (p = 0.0006) to normal mucosa as compared with adenomas. By digital image analysis, the light-scattering property of hyperplastic polyps was closer to normal mucosa compared with adenomas (14.86 vs. 45.81; p = 0.0001). CONCLUSIONS: Real-time endoscopic optical coherence tomography imaging differentiated adenomas, hyperplastic polyps, and normal colon tissue. By using the colon adenoma as a model, the endoscopic optical coherence tomography characteristics of dysplasia are loss of tissue organization and reduced light scattering.

Adenoma↗

Effectiveness of open-access endoscopy in routine primary-care practice.

BACKGROUND: Direct referral of patients for endoscopic procedures without prior consultation (open-access endoscopy) has become commonplace. However, the effect of open-access endoscopy on the care of patients in routine clinical practice has not been studied. METHODS: The impact of open-access endoscopy was examined in 168 consecutive patients referred from 8 primary-care practices to our tertiary hospital-based endoscopy center. The effectiveness of open-access endoscopy was assessed by review of office medical records at the primary-care practice sites for a minimum follow-up period of 6 months. Outcome measures evaluated included postprocedure communication between primary-care physician and patient, primary-care physician adherence to postprocedure recommendations, and the need for subsequent diagnostic evaluation and/or consultation. RESULTS: The mean age of the 168 patients was 60 years; 56 (33%) underwent EGD and 112 (67%) had colonoscopy; 65% were from hospital-based practices and 35% from community practices. The indication(s) for 77% of the procedures met American Society for Gastrointestinal Endoscopy guidelines for the appropriate use of endoscopy. An office follow-up was noted for 82% of patients after the open-access procedure. Discussion of results was documented in 61% of the patient charts. Compliance with diagnostic and therapeutic recommendations was documented, respectively, in 75% and 90% of patient charts. A follow-up GI consultation was requested for only 7% of the patients. CONCLUSION: Open-access endoscopy in the primary-care setting is effective to the extent that subsequent GI consultations are rare and the level of compliance with endoscopist recommendations is high. However, documentation of communication of the results of endoscopy with the patient can be improved.

Aged↗

Visualization of subsurface blood vessels by color Doppler optical coherence tomography in rats: before and after hemostatic therapy.

BACKGROUND: The ability to visualize subsurface blood vessels and measure flow may be useful in certain experimental and clinical settings. METHODS: Color Doppler optical coherence tomography was used to visualize and measure blood flow in subsurface vessels in vivo in a rat skin flap model. Local "hemostatic" interventions (epinephrine or sclerosant injection, heat probe, and laser) were then applied and imaging was repeated. The skin flap was evaluated histologically. RESULTS: Subsurface blood vessels were easily visualized in cross-section, and vessel diameter and bidirectional blood flow velocity were readily measured. Color Doppler optical coherence tomography demonstrated that flow was significantly reduced after epinephrine injection and became undetectable after the other interventions. This correlated with pathologic evidence of vessel damage in all interventions, except for epinephrine injection. Although vessel response was as predicted to most interventions, the response to epinephrine was only temporary, and limited application of heat alone from the heat probe halted flow without visually apparent surface injury. CONCLUSIONS: Color Doppler optical coherence tomography provides high-resolution, cross-sectional flow imaging in subsurface blood vessels. Color Doppler optical coherence tomography is potentially a better technique for the study of existing and new hemostatic intervention in the laboratory. Potential future clinical applications include monitoring of the response to hemostatic modalities.

Animals↗

Accuracy of a narrow-diameter battery-powered endoscope in sedated and unsedated patients.

BACKGROUND: Esophagoscopy with a portable battery-powered endoscope could provide a safe, inexpensive, and minimally invasive way to screen for Barrett's esophagus or esophageal varices. The use of such an instrument in an unsedated fashion has not been previously evaluated. METHODS: Patients referred for an EGD were recruited to undergo an additional examination with the battery-powered endoscope before EGD. In phase 1, (n = 42) patients received conscious sedation before the battery-powered endoscopic examination. In phase 2, (n = 56) patients were not sedated and were given the option of a peroral (n = 43) or transnasal (n = 13) endoscopy. Examiners were blinded to patient history and procedure indications. Esophageal findings, ease of intubation, optical quality, and patient comfort for the battery-powered endoscope and standard EGD were recorded by the endoscopist. RESULTS: Ninety-eight patients (60 men, 38 women, mean age 53 years) were recruited. The sensitivity for detecting Barrett's esophagus, esophageal tumors, and esophageal varices was 54.5%, 66.7%, and 80%, respectively. Ease of intubation and patient comfort as perceived by the endoscopist were not significantly different between the battery-powered endoscope and EGD. Optical quality was ranked as less than 4 (on a 5-point scale with 5 = standard EGD and 1 = poor) in 42% of battery-powered endoscopic examinations. There were no complications. CONCLUSION: The accuracy of esophageal examination with a 3.1-mm endoscope is substantially inferior to standard EGD. Thus, the battery-powered endoscope would not be useful for screening patients for Barrett's esophagus or varices unless improvements in optical quality and visualization are made.

Adult↗

A prospective evaluation of outcome in patients referred for PEG placement.

BACKGROUND: PEG feeding is not recommended for short-term use because the 30-day mortality after PEG placement is substantial. The primary aim of this study was to prospectively identify factors predictive of survival in patients referred for PEG placement. METHODS: All patients for whom gastroenterology consultation was sought for feeding PEG placement were prospectively studied. Demographic data, Charlson comorbidity index, and functional status were recorded at entry. After PEG placement, patients were followed for up to 12 months. RESULTS: Of the 67 patients for whom consultation was requested, 58 were eligible for the study and 50 underwent PEG placement. The 7-day and 30-day mortality rates in the PEG placement group were 4% and 20%, respectively. In multivariate analysis, only the Charlson index > or =4 was associated with decreased survival time (relative hazard = 2.9: 95% CI [1.20, 7.21], p = 0.019). Median survival in patients with Charlson comorbidity index > or =4 was significantly shorter than that in patients with Charlson index < 4 (p = 0.013). CONCLUSIONS: A Charlson comorbidity index > or =4 was significantly associated with shorter patient survival after initial consultation. Careful consideration of predictive factors of survival may improve patient selection for feeding PEG placement.

Aged↗

Patient tolerance and acceptance of unsedated ultrathin esophagoscopy.

BACKGROUND: Unsedated endoscopy has not gained wide acceptance in the United States. Factors that may predict tolerance and acceptance of unsedated endoscopy are ill defined. METHODS: Outpatients referred for standard EGD were recruited to undergo unsedated ultrathin esophagoscopy (UUE) with a new 3.1-mm battery-powered esophagoscope before sedated EGD. They rated preprocedure and postprocedure anxiety levels with the Profile of Mood States Tension/Anxiety subscale (POMS-SF T/A). They also rated symptoms and overall acceptability and listed procedural preference between EGD and UUE. Patients who refused UUE noted a reason for refusal and also completed the anxiety questionnaire. RESULTS: Fifty-two of 98 patients recruited agreed to participate, and underwent both UUE and EGD. Patients who refused UUE were significantly more anxious (mean anxiety score, 8.2 vs. 4.5, p < 0.005). Participants reported no significant difference between preprocedural (4.6 vs. 5.3) or postprocedural (3.5 vs. 2.6) anxiety for UUE versus standard EGD. After undergoing both procedures, only 46% stated they would prefer UUE to EGD in the future. Patients who chose the peroral approach were more likely to prefer UUE than those who chose the transnasal approach (58% vs. 23%, p = 0.02). CONCLUSIONS: Patient acceptance of unsedated endoscopy even with an ultrathin instrument is limited. Anxiety assessment by the POMS-SF T/A can identify patients willing to undergo UUE. Patients who choose transoral UUE may be more willing to repeat the procedure.

Adult↗