Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Angus C.W. Chan is active.

Publication


Featured researches published by Angus C.W. Chan.


The New England Journal of Medicine | 2000

Effect of intravenous omeprazole on recurrent bleeding after endoscopic treatment of bleeding peptic ulcers.

James Y. Lau; Joseph J.Y. Sung; Kenneth Lee; Man-Yee Yung; Simon K. Wong; Justin C. Wu; Francis K.L. Chan; Enders K. Ng; Joyce H. S. You; Cw Lee; Angus C.W. Chan; S.C.Sydney Chung

BACKGROUND After endoscopic treatment of bleeding peptic ulcers, bleeding recurs in 15 to 20 percent of patients. METHODS We assessed whether the use of a high dose of a proton-pump inhibitor would reduce the frequency of recurrent bleeding after endoscopic treatment of bleeding peptic ulcers. Patients with actively bleeding ulcers or ulcers with nonbleeding visible vessels were treated with an epinephrine injection followed by thermocoagulation. After hemostasis had been achieved, they were randomly assigned in a double-blind fashion to receive omeprazole (given as a bolus intravenous injection of 80 mg followed by an infusion of 8 mg per hour for 72 hours) or placebo. After the infusion, all patients were given 20 mg of omeprazole orally per day for eight weeks. The primary end point was recurrent bleeding within 30 days after endoscopy. RESULTS We enrolled 240 patients, 120 in each group. Bleeding recurred within 30 days in 8 patients (6.7 percent) in the omeprazole group, as compared with 27 (22.5 percent) in the placebo group (hazard ratio, 3.9; 95 percent confidence interval, 1.7 to 9.0). Most episodes of recurrent bleeding occurred during the first three days, which made up the infusion period (5 in the omeprazole group and 24 in the placebo group, P<0.001). Three patients in the omeprazole group and nine in the placebo group underwent surgery (P=0.14). Five patients (4.2 percent) in the omeprazole group and 12 (10 percent) in the placebo group died within 30 days after endoscopy (P=0.13). CONCLUSIONS After endoscopic treatment of bleeding peptic ulcers, a high-dose infusion of omeprazole substantially reduces the risk of recurrent bleeding.


The New England Journal of Medicine | 1999

Endoscopic retreatment compared with surgery in patients with recurrent bleeding after initial endoscopic control of bleeding ulcers.

James Y. Lau; Joseph J.Y. Sung; Yuk-hoi Lam; Angus C.W. Chan; Enders K. Ng; Danny W.H. Lee; Francis K.L. Chan; Roamy Suen; S.C.Sydney Chung

Background and Methods After endoscopic treatment to control bleeding of peptic ulcers, bleeding recurs in 15 to 20 percent of patients. In a prospective, randomized study, we compared endoscopic retreatment with surgery after initial endoscopy. Over a 40-month period, 1169 of 3473 adults who were admitted to our hospital with bleeding peptic ulcers underwent endoscopy to reestablish hemostasis. Of 100 patients with recurrent bleeding, 7 patients with cancer and 1 patient with cardiac arrest were excluded from the study; 48 patients were randomly assigned to undergo immediate endoscopic retreatment and 44 were assigned to undergo surgery. The type of operation used was left to the surgeon. Bleeding was considered to have recurred in the event of any one of the following: vomiting of fresh blood, hypotension and melena, or a requirement for more than four units of blood in the 72-hour period after endoscopic treatment. Results Of the 48 patients who were assigned to endoscopic retreatment, 35 had long-term...


BMJ | 1997

Randomised comparison between adrenaline injection alone and adrenaline injection plus heat probe treatment for actively bleeding ulcers

Sydney Sc Chung; James Y. Lau; Joseph J.Y. Sung; Angus C.W. Chan; C. W. Lai; Enders K. Ng; Francis K.L. Chan; My Yung; A. K. C. Li

Abstract Objective: To compare endoscopic adrenaline injection alone and adrenaline injection plus heat probe for the treatment of actively bleeding peptic ulcers. Design: Randomised prospective study of patients admitted with actively bleeding peptic ulcers. Setting: One university hospital. Subjects: 276 patients with actively bleeding ulcers detected by endoscopy within 24 hours of admission: 136 patients were randomised to endoscopic adrenaline injection alone and 140 to adrenaline injection plus heat probe treatment. Main outcome measures: Initial endoscopic haemostasis; clinical rebleeding; requirement for operation; requirement for blood transfusion; hospital stay, ulcer healing at four weeks; and mortality in hospital. Results: Initial haemostasis was achieved in 131/134 patients (98%) who received adrenaline injection alone and 135/136 patients (99%) who received additional heat probe treatment (P = 0.33). Outcome as measured by clinical rebleeding (12 v 5), requirement for emergency operation (14 v 8), blood transfusion (2 v 3 units), hospital stay (4 v 4 days), ulcer healing at four weeks (79.1% v 74%), and in hospital mortality (7 v 8) were not significantly different in the two groups. In the subgroup of patients with spurting haemorrhage 8/27 (29.6%; 14.5% to 50.3%) patients from the adrenaline injection alone group and 2/31 (6.5%; 1.1% to 22.9%) patients from the dual treatment group required operative intervention. The relative risk of this was lower in the dual treatment group (0.17; 0.03 to 0.87). Hospital stay was significantly shorter in the dual treatment group than the adrenaline injection alone group (4 v 6 days, P = 0.01). Conclusion: The addition of heat probe treatment after endoscopic adrenaline injection confers an advantage in ulcers with spurting haemorrhage. Key messages Endoscopic injection of adrenaline alone is effective in stopping bleeding peptic ulcers Further bleeding after adrenaline injection alone, however, occurs in 15-20% of patients, and the addition of heat probe thermocoagulation may improve permanent haemostasis and therefore patient outcome When compared with adrenaline injection alone the dual treatment significantly reduced the requirement for operative intervention and the length of hospital stay in the subgroup of patients with spurting ulcer haemorrhage In the endoscopic treatment of spurting ulcer haemorrhage heat probe thermocoagulation should be added after adrenaline injection


Journal of Hepato-biliary-pancreatic Sciences | 2013

TG13 diagnostic criteria and severity grading of acute cholecystitis (with videos)

Masamichi Yokoe; Tadahiro Takada; Steven M. Strasberg; Joseph S. Solomkin; Toshihiko Mayumi; Harumi Gomi; Henry A. Pitt; O. James Garden; Seiki Kiriyama; Jiro Hata; Toshifumi Gabata; Masahiro Yoshida; Fumihiko Miura; Kohji Okamoto; Toshio Tsuyuguchi; Takao Itoi; Yuichi Yamashita; Christos Dervenis; Angus C.W. Chan; Wan Yee Lau; Avinash Nivritti Supe; Giulio Belli; Serafin C. Hilvano; Kui Hin Liau; Myung-Hwan Kim; Sun Whe Kim; Chen Guo Ker

Since its publication in 2007, the Tokyo Guidelines for the management of acute cholangitis and cholecystitis (TG07) have been widely adopted. The validation of TG07 conducted in terms of clinical practice has shown that the diagnostic criteria for acute cholecystitis are highly reliable but that the definition of definite diagnosis is ambiguous. Discussion by the Tokyo Guidelines Revision Committee concluded that acute cholecystitis should be suspected when Murphy’s sign, local inflammatory findings in the gallbladder such as right upper quadrant abdominal pain and tenderness, and fever and systemic inflammatory reaction findings detected by blood tests are present but that definite diagnosis of acute cholecystitis can be made only on the basis of the imaging of ultrasonography, computed tomography or scintigraphy (HIDA scan). These proposed diagnostic criteria provided better specificity and accuracy rates than the TG07 diagnostic criteria. As for the severity assessment criteria in TG07, there is evidence that TG07 resulted in clarification of the concept of severe acute cholecystitis. Furthermore, there is evidence that severity assessment in TG07 has led to a reduction in the mean duration of hospital stay. As for the factors used to establish a moderate grade of acute cholecystitis, such as leukocytosis, ALP, old age, diabetes, being male, and delay in admission, no new strong evidence has been detected indicating that a change in the criteria used in TG07 is needed. Therefore, it was judged that the severity assessment criteria of TG07 could be applied in the updated Tokyo Guidelines (TG13) with minor changes. TG13 presents new standards for the diagnosis, severity grading and management of acute cholecystitis.Free full-text articles and a mobile application of TG13 are available via http://www.jshbps.jp/en/guideline/tg13.html.


Surgical Endoscopy and Other Interventional Techniques | 1997

Comparison of two-dimensional vs three-dimensional camera systems in laparoscopic surgery

Angus C.W. Chan; S. C. S. Chung; Anthony P.C. Yim; James Y. Lau; Enders K. Ng; A. K. C. Li

AbstractBackground: The lack of depth perception and spatial orientation in video vision are the drawbacks of laparoscopic surgery. The advent of a three-dimensional camera system enables surgeons to regain binocular vision and may be advantageous in complex laparoscopic procedures. Methods: We prospectively studied two groups of surgeons (with and without experiences in laparoscopic surgery) who performed a designated standardized laparoscopic task using a two-dimensional camera system (Olympus OTV-S4) vs a three-dimensional camera system (Baxter-V. Mueller VS7700) and compared their time performances. Results: The results suggested that only experience in laparoscopic surgery had significant effect on individuals performance. We could not demonstrate any superiority of the 3D system over the 2D system. However, two-thirds of the surgeons commented that the depth perception did improve. Conclusions: With further refinement of the technology, the 3D system may improve its potential in laparoscopic surgery.


Journal of Gastrointestinal Surgery | 2005

Multicenter prospective randomized trial comparing standard esophagectomy with chemoradiotherapy for treatment of squamous esophageal cancer: early results from the Chinese University Research Group for Esophageal Cancer (CURE).

Philip W. Chiu; Angus C.W. Chan; S. F. Leung; H.T. Leong; Kwok-Hung Kwong; Micheal K. W. Li; Alex C.M. Auyeung; S. C. S. Chung; Enders K. Ng

We conducted a prospective randomized trial to compare the efficacy and survival outcome by chemoradiation with that by esophagectomy as a curative treatment. From July 2000 to December 2004, 80 patients with potentially resectable squamous cell carcinoma of the mid or lower thoracic esophagus were randomized to esophagectomy or chemoradiotherapy. A two-or three-stage esophagectomy with two-field dissection was performed. Patients treated with chemoradiotherapy received continuous 5-.uorouracil infusion (200 mg/m2/day) from day 1 to 42 and cisplatin (60 mg/m2) on days 1 and 22. The tumor and regional lymphatics were concomitantly irradiated to a total of 50–60 Gy.Tumor response was assessed by endoscopy, endoscopic ultrasonography, and computed tomography scan. Salvage esophagectomy was performed for incomplete response or recurrence. Forty-four patients received standard esophagectomy, whereas 36 were treated with chemoradiotherapy. Median follow-up was 16.9 months. The operative mortality was 6.8%. The incidence of postoperative complications was 38.6%. No difference in the early cumulative survival was found between the two groups (RR = 0.89; 95% confidence interval, 0.37-2.17; log-rank test P =0.45). There was no difference in the disease-free survival. Patients treated with surgery had a slightly higher proportion of recurrence in the mediastinum, whereas those treated with chemoradiation sustained a higher proportion of recurrence in the cervical or abdominal regions. Standard esophagectomy or chemoradiotherapy offered similar early clinical outcome and survival for patients with squamous cell carcinoma of the esophagus. The challenge lies in the detection of residue disease after chemoradiotherapy.


Annals of Surgery | 2000

Eradication of Helicobacter pylori prevents recurrence of ulcer after simple closure of duodenal ulcer perforation: randomized controlled trial.

Enders K. Ng; Yuk-hoi Lam; Joseph J.Y. Sung; My Yung; Kin-Wang To; Angus C.W. Chan; Danny W.H. Lee; Bonita K.B. Law; James Y. Lau; Thomas K. W. Ling; W. Y. Lau; S.C.Sydney Chung

OBJECTIVE In this randomized trial, the authors sought to determine whether eradication of Helicobacter pylori could reduce the risk of ulcer recurrence after simple closure of perforated duodenal ulcer. BACKGROUND DATA Immediate acid-reduction surgery has been strongly advocated for perforated duodenal ulcers because of the high incidence of ulcer relapse after simple patch repair. Although H. pylori eradication is now the standard treatment of uncomplicated and bleeding peptic ulcers, its role in perforation remains controversial. Recently a high prevalence of H. pylori infection has been reported in patients with perforations of duodenal ulcer. It is unclear whether eradication of the bacterium confers prolonged ulcer remission after simple repair and hence obviates the need for an immediate definitive operation. METHODS Of 129 patients with perforated duodenal ulcers, 104 (81%) were shown to be infected by H. pylori. Ninety-nine H. pylori-positive patients were randomized to receive either a course of quadruple anti-helicobacter therapy or a 4-week course of omeprazole alone. Follow-up endoscopy was performed 8 weeks, 16 weeks (if the ulcer did not heal at 8 weeks), and 1 year after hospital discharge for surveillance of ulcer healing and determination of H. pylori status. The endpoints were initial ulcer healing and ulcer relapse rate after 1 year. RESULTS Fifty-one patients were assigned to the anti-Helicobacter therapy and 48 to omeprazole alone. Nine patients did not undergo the first follow-up endoscopy. Of the 90 patients who did undergo follow-up endoscopy, 43 of the 44 patients in the anti-Helicobacter group and 8 of the 46 in the omeprazole alone group had H. pylori eradicated; initial ulcer healing rates were similar in the two groups (82% vs. 87%). After 1 year, ulcer relapse was significantly less common in patients treated with anti-Helicobacter therapy than in those who received omeprazole alone (4.8% vs. 38.1%). CONCLUSIONS Eradication of H. pylori prevents ulcer recurrence in patients with H. pylori-associated perforated duodenal ulcers. Immediate acid-reduction surgery in the presence of generalized peritonitis is unnecessary.


Journal of Hepato-biliary-pancreatic Sciences | 2013

TG13 surgical management of acute cholecystitis

Yuichi Yamashita; Tadahiro Takada; Steven M. Strasberg; Henry A. Pitt; Dirk J. Gouma; O. James Garden; Markus W. Büchler; Harumi Gomi; Christos Dervenis; John A. Windsor; Sun Whe Kim; Eduardo De Santibanes; Robert Padbury; Xiao-Ping Chen; Angus C.W. Chan; Sheung Tat Fan; Palepu Jagannath; Toshihiko Mayumi; Masahiro Yoshida; Fumihiko Miura; Toshio Tsuyuguchi; Takao Itoi; Avinash Nivritti Supe

BackgroundLaparoscopic cholecystectomy is now accepted as a surgical procedure for acute cholecystitis when it is performed by an expert surgeon. There are several lines of strong evidence, such as randomized controlled trials (RCTs) and meta-analyses, supporting the introduction of laparoscopic cholecystectomy for patients with acute cholecystitis. The updated Tokyo Guidelines 2013 (TG13) describe the surgical treatment for acute cholecystitis according to the grade of severity, the timing, and the procedure used for cholecystitis in a question-and-answer format using the evidence concerning surgical management of acute cholecystitis.Methods and materialsForty-eight publications were selected for a careful examination of their full texts, and the types of surgical management of acute cholecystitis were investigated using this evidence. The items concerning the surgical management of acute cholecystitis were the optimal surgical treatment for acute cholecystitis according to the grade of severity, optimal timing for the cholecystectomy, surgical procedure used for cholecystectomy, optimal timing of the conversion of cholecystectomy from laparoscopic to open surgery, and the complications of laparoscopic cholecystectomy.ResultsThere were eight RCTs and four meta-analyses concerning the optimal timing of the cholecystectomy. Consequently, it was found that cholecystectomy is preferable early after admission. There were three RCTs and two meta-analyses concerning the surgical procedure, which concluded that laparoscopic cholecystectomy is preferable to open procedures. Literature concerning the surgical treatment according to the grade of severity could not be quoted, because there have been no publications on this topic. Therefore, the treatment was determined based on the general opinions of professionals.ConclusionSurgical management of acute cholecystitis in the updated TG13 is fundamentally the same as in the Tokyo Guidelines 2007 (TG07), and the concept of a critical view of safety and the existence of extreme vasculobiliary injury are added in the text to call the surgeon’s attention to the need to reduce the incidence of bile duct injury.Free full-text articles and a mobile application of TG13 are available via http://www.jshbps.jp/en/guideline/tg13.html.


Clinical & Experimental Allergy | 1997

Comparison of the ISAAC video questionnaire (AVQ 3.0) with the ISAAC written questionnaire for estimating asthma associated with bronchial hyperreactivity

C. K. W. Lai; Joseph K.W. Chan; Angus C.W. Chan; Gary W.K. Wong; A. Ho; Dominic K.L. Choy; Joseph Lau; R. Leung

Background A standardized protocol is essential for international comparisons of asthma prevalence and severity. The International Study of Asthma and Allergies in Childhood (ISAAC) used a standardized written questionnaire (WQ) and a video questionnaire (AVQ3.0) to survey the prevalence and severity of asthma in 13–14‐year‐old schoolchildren in different countries.


Gastrointestinal Endoscopy | 1997

Stigmata of hemorrhage in bleeding peptic ulcers: an interobserver agreement study among international experts ☆ ☆☆ ★

James Y. Lau; Joseph J.Y. Sung; Angus C.W. Chan; Grace W.Y. Lai; Joseph Lau; Enders K. Ng; S.C.Sydney Chung; A. K. C. Li

BACKGROUND Stigmata of hemorrhage predict rebleeding and outcome of patients with bleeding peptic ulcers. There are variabilities in reported incidences of stigmata and their respective rebleeding risks. We sought to study the interobserver agreement among experts. METHODS Between June 1994 and July 1994, 100 consecutive patients with bleeding peptic ulcers underwent videoendoscopy within 24 hours of their admissions. An edited videotape of these ulcers was compiled and sent to an international panel of 14 experts. They independently rated these ulcers exclusively into one of the six categories: spurting, oozing, nonbleeding visible vessel, adherent clot, flat pigmented spot, or clean based. Agreement between any two experts was expressed by a kappa estimate (kappa). Agreements over individual stigmata and a composite kappa estimate (kappa(w)) signifying overall agreement were also computed. RESULTS Out of the possible 91 pairwise kappa estimates among 14 experts, 35 (38.5%) were less than or equal to 0.40, indicating poor agreement. None of the kappa estimates was greater than 0.75. Composite kappa estimates for individual stigmata were as follows: spurting kappa = 0.664, oozing kappa = 0.420, nonbleeding visible vessel kappa = 0.342, adherent clot kappa = 0.426, flat pigmented spot kappa = 0.393, and clean-based ulcer kappa = 0.371. The weighted kappa estimate was 0.426. CONCLUSION Agreement between experts was poor in more than a third of occasions. Although the overall interobserver agreement was fair (0.4 < kappa < 0.75), agreements for nonbleeding visible vessels, flat pigmented spots, and clean-based ulcers were poor.

Collaboration


Dive into the Angus C.W. Chan's collaboration.

Top Co-Authors

Avatar

Enders K. Ng

The Chinese University of Hong Kong

View shared research outputs
Top Co-Authors

Avatar

S. C. S. Chung

The Chinese University of Hong Kong

View shared research outputs
Top Co-Authors

Avatar

A. K. C. Li

The Chinese University of Hong Kong

View shared research outputs
Top Co-Authors

Avatar

Danny W.H. Lee

The Chinese University of Hong Kong

View shared research outputs
Top Co-Authors

Avatar

James Y. Lau

The Chinese University of Hong Kong

View shared research outputs
Top Co-Authors

Avatar

Joseph J.Y. Sung

The Chinese University of Hong Kong

View shared research outputs
Top Co-Authors

Avatar

Simon K. Wong

The Chinese University of Hong Kong

View shared research outputs
Top Co-Authors

Avatar

James F. Griffith

The Chinese University of Hong Kong

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Steven M. Strasberg

Washington University in St. Louis

View shared research outputs
Researchain Logo
Decentralizing Knowledge