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Dive into the research topics where Carlos Chan is active.

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Featured researches published by Carlos Chan.


Annals of Surgery | 1993

Clinical behavior and prognostic factors of periampullary adenocarcinoma

Carlos Chan; Miguel F. Herrera; L de la Garza; L Quintanilla-Martinez; F Vargas-Vorackova; Y Richaud-Patín; L Llorente; Luis Uscanga; G Robles-Diaz; E Leon

ObjectiveThe authors evaluated the outcome and potential prognostic factors of 60 patients with surgically resected periampullary tumors. Summary Background DataPeriampullary carcinomas exhibit different clinical behaviors according to their site of origin. There are no prognostic factors for deciding the type of surgery to be used or for choosing patients with tumors that have a poor prognosis for adjuvant treatment. MethodsA retrospective review was performed of 15 clinical and pathologic variables encountered among 60 patients with periampullary tumors. Tumors were divided into four groups according to their site of origin. Kaplan-Meier survival curves of the four groups were plotted and differences were evaluated with the log-rank test. Coxs proportional hazards model was used to test for separate and combined independent predictors of disease-free survival. ResultsTwenty-nine ampullary carcinomas, 20 ductal pancreatic carcinomas, 7 distal common bile duct carcinomas, and 4 carcinomas of the periampullary duodenum were found. Five-year disease-free survival was 43%, 0%, 0%, and 75%, respectively. According to the Cox analysis, absence of neural invasion and use of adjuvant chemotherapy were significant factors for longer survival of patients with ampullary tumors. Lymphatic invasion was related to a shorter survival in patients with pancreatic carcinoma. ConclusionsFive-year disease-free survival of patients with periampullary tumors is related to tumor type. Prognosis was better for ampullary tumors if neural invasion was absent and if adjuvant chemotherapy was used. Lymphatic invasion was associated with a shorter recurrence-free survival among patients with pancreatic carcinoma.


Surgical Endoscopy and Other Interventional Techniques | 2003

Acute bile duct injury. The need for a high repair.

Miguel Angel Mercado; Carlos Chan; Héctor Orozco; Manuel Tielve; Carlos A. Hinojosa

Background: An immediate repair is considered optimal in acute biliary duct injuries; however, it may prove to be a challenge, because such repairs are usually performed on small ducts whose viability cannot always be determined. Methods: We performed a retrospective review of the charts of patients with acute bile duct injury who underwent repair at a tertiary care academic university hospital. A total of 204 patients with acute bile duct injury were seen between 1989 and 2002. Of these, 30 were repaired within minutes to hours after the injury. These patients were divided into two groups. Group I patients had a Roux-en-Y hepatojejunostomy below the hepatic junction; Group II patients had a Roux-en-Y hepatojejunostomy at the junction level. We then performed a long-term evaluation of anastomosis function in these patients, using clinical, radiological, and laboratory. Results: Twenty-eight injuries were secondary to a laparoscopy; the other two resulted from open cholecystectomies. All of the patients suffered complex injuries with complete section of the duct and substance loss (Strasberg E). There were 12 patients in group I and 18 in group II. Three cases in group I (25%) and one in group II (5%) developed anastomosis dysfunction. Mean follow-up was 56 months (range, 12–80) in group I and 52 months (range, 10–76) in group II. Two cases in group I (16%) and none in group II (0) required reoperation (p < 0.05). Conclusions: In the acute setting, complex lesions should be treated with a high bilioenteric anastomosis (at the junction level) in the first attempt at repair. Lower-level anastomoses are associated with a higher dysfunction rate and the need for radiological manipulation and reoperation. Also, stenosis of the anastomosis secondary to undetected duct ischemia in the acute repair is more frequent in low bilioenteric anastomoses.


Surgical Endoscopy and Other Interventional Techniques | 2004

Laparoscopic drainage of pancreatic pseudocysts.

A. Dávila-Cervantes; F. Gómez; Carlos Chan; P. Bezaury; G. Robles-Díaz; Luis Uscanga; M. F. Herrera

Background. Laparoscopic drainage of pancreatic pseudocysts (PPs) has been used in selected cases. The aim of this study is to analyze our results with the laparoscopic technique and to compare them with those of a cohort of patients treated by open surgery during the same time period.Patients and methods. Ten patients underwent laparoscopic drainage of PPs during a 7-year period [laparoscopic group (LG)]. The type of drainage was chosen according to the size and location of the PP. Demography, surgical details, results, and complications were analyzed and contrasted with those of 6 patients who underwent open drainage [open group (OG)].Results. All patients presented with mature PPs developed after a documented episode of acute pancreatitis. Mean age of the LG was 42 years (six males and four females). In the OG, mean age was 36 years (five males and one female). Etiology of the pancreatitis was alcoholic in eight patients, biliary in five, toxic in two, and associated with systemic lupus erythematous in one. Laparoscopic procedures included Roux-en-Y cystojejunostomy in four patients, extraluminal cystogastrostomy in four, and intraluminal cystogastrostomy in two. There were no conversions. In the OG, cystogastrostomy was performed in three patients and Roux-en-Y cystojejunostomy in three. One patient in the LG developed upper gastrointestinal bleeding the day after surgery that resolved uneventfully, one patient presented a postoperative abscess that required open drainage, and one patient presented a residual pseudocyst that was treated by endoscopy. Morbidity in the OG included a small bowel obstruction secondary to an internal hernia that required reoperation, pneumonia, and a residual pseudocyst that was treated conservatively in one patient each. At a median follow-up of 22 months (range, 1–72) all patients were asymptomatic with no evidence of recurrent disease by computed tomography scan.Conclusion. Laparoscopic drainage of PPs is feasible, safe, and effective. Results are similar to those obtained using the open technique.


Journal of Gastrointestinal Surgery | 2006

Long-term evaluation of biliary reconstruction after partial resection of segments IV and V in iatrogenic injuries.

Miguel Angel Mercado; Carlos Chan; Héctor Orozco; José Manuel Villalta; Alexandra Barajas-Olivas; Javier Eraña; Ismael Domínguez

Roux-en-Y hepatojejunostomy is the procedure of choice for biliary reconstruction after complex iatrogenic injury that is usually associated with vascular injuries and concomitant ischemia of the ducts. To avoid the ischemic component, our group routinely performs a high repair to assure an anastomosis in noninflamed, nonscarred, and nonischemic ducts. If the duct bifurcation is preserved, the Hepp-Couinaud approach for reconstruction is an excellent choice. Partial liver resection of segments IV and V allows adequate exposure of the bile duct at its bifurcation with an anterior approach of the ducts (therefore not jeopardizing the circulation), allowing a high quality anastomosis. Long-term results of bile duct reconstruction using this approach are described. Two hundred eighty-five bile duct reconstructions were done between 1989 and 2004 in a tertiary care university hospital. The first partial-segment IV resection was done in 1994; 94 cases have been reconstructed since then using this approach. All of them had a complex injury (Strasberg E1-E5), and although in many cases the bifurcation was preserved (E1-E3), a high bilioenteric anastomosis was done to facilitate the reconstruction. In 70 cases, the bifurcation was identified, and in the 24 in which the confluence was not preserved, the right and left ducts were found except in one case. In three patients, the right duct was found unsuitable for anastomosis, and a liver resection was done. In the remaining 21, an anastomosis was done using a stent (transhepatic, transanastomotic) through the right duct. According to Lillemoe’s criteria, 86 cases had good results (91%). In four of the eight remaining patients, there was the need to operate again due to the presence of an obstruction and/or cholangitis. In the rest, radiological instrumentation was done. Four of these cases have developed secondary biliary cirrhosis, two of which have died while waiting for a liver transplant, four and six years after reconstruction. Partial segments IV and V resection allows adequate exposure of the confluence and the isolated left or right hepatic ducts. Anterior exposure of the ducts allows an anastomosis in well-preserved, nonischemic, nonscarred, or noninflamed ducts. Parenchyma removal also allows the free placement of the jejunal limb, without external compression and tension, obtaining a high quality anastomosis with excellent long-term results.


American Journal of Surgery | 1996

Distal splenorenal shunt versus 10-mm low-diameter mesocaval shunt for variceal hemorrhage

Miguel Angel Mercado; Julio César Morales-Linares; Jorge Granados-García; Tito José María Gómez-Méndez; Carlos Chan; Héctor Orozco

BACKGROUND Portal hypertension surgery remains a good therapeutic choice for well selected patients with variceal bleeding. The distal splenorenal shunt (DSRS) has shown good long-term results and low-diameter shunts have emerged as an alternate choice. METHODS A prospective, controlled and not randomized study was designed to compare the DSRS (23 patients) and the low-diameter 10 mm ring reinforced PTFE mesocaval shunt (LDMCS) (22 patients) in low-risk electively operated patients (Child-Pugh A-B). The operation was selected according to the anatomical status of the veins. RESULTS Both groups were comparable. No differences were observed regarding rebleeding, operative mortality and survival. Significative differences were observed regarding encephalopathy and shunt thrombosis (higher in the LDMCS). Postoperative angiography showed better maintenance of portal blood flow in the DSRS group. CONCLUSIONS Both operations are adequate alternatives for the elective treatment of portal hypertension in low-risk patients. However, the DSRS has more advantages than the LDMCS.


Annals of Surgery | 2000

A comparative study of the elective treatment of variceal hemorrhage with β-blockers, transendoscopic sclerotherapy, and surgery : A prospective, controlled, and randomized trial during 10 years

Héctor Orozco; Miguel Angel Mercado; Carlos Chan; Erika Guillén-Navarro; Luz María López-Martínez

ObjectiveTo compare three options for the elective treatment of portal hypertension during a 10-year period. MethodsPatients included in the trial were 18 to 76 years old, had a history of bleeding portal hypertension, and had undergone no prior treatment. Treatment options were &bgr;-blockers (propranolol), sclerotherapy, and portal blood flow-preserving procedures (selective shunts and the Sugiura-Futagawa operation). ResultsA total of 119 patients were included: 40 in the pharmacology group, 46 in the sclerotherapy group,and 33 in the surgical group. The three groups showed no differences in terms of age, Child-Pugh classification, and cause of liver disease. The rebleeding rate was significantly lower in the surgical group than in the other two groups. The rebleeding rate was only 5% in the Child A surgical group, compared with 71% and 68% for the sclerotherapy and pharmacotherapy groups, respectively. Survival was better for the low-risk patients (Child A) in the three groups, but when the three options were compared, no significant difference was found. ConclusionsPortal blood flow-preserving procedures offer the lowest rebleeding rate in low-risk patients undergoing elective surgery.


Journal of Gastrointestinal Surgery | 2006

Bile duct growing factor: An alternate technique for reconstruction of thin bile ducts after iatrogenic injury

Miguel Angel Mercado; Héctor Orozco; Carlos Chan; Carlos Quezada; Alexandra Barajas-Olivas; Daniel Borja-Cacho; Norberto Sánchez-Fernández

A variant of bilioenteric anastomosis, laterolateral hepatojejunostomy, is described in which the opened anterior aspect of the common hepatic duct and left hepatic duct is anastomosed to a Roux jejunal limb. This technique is specially designed for thin, injured bile ducts in which a conventional anastomosis is difficult due to the small diameter of the ducts. A wide anastomosis is obtained, leaving the posterior wall as a conduit for bile, ensuring an adequate anastomotic diameter.


World Journal of Surgery | 2002

Application of molecular biology studies to gene therapy treatment strategies

Allen N. Gustin; Lee C. Pederson; Ryan Miller; Carlos Chan; Selwyn M. Vickers

The diagnosis of pancreatic cancer continues to produce fear in both patients and practitioners in large part owing to the likely incurability in all for whom the diagnosis is made. It is this reality that continually motivates the surgical and medical oncologists who endeavor to treat these patients. Currently, the cure rate for pancreatic cancer has improved only minimally, and the overall survival of patients remains dismal, with fewer than 5% of patients alive at 5 years and 92% of these patients dead at 2 years. This current treatment status has stimulated numerous studies endeavoring to understand the diverse mechanisms of cell growth in this tumor. Intensive investigative efforts have produced the understanding of new tumor suppressor genes such as DPC4 and an increasing understanding of tyrosine kinase receptors and signal transduction and their regulation of programmed cell death (apoptosis). Detection of these numerous genetic defects may give new insights and understanding of the highly chemo- and radioresistant nature of pancreatic cancer. These same findings also provide the basis for the development of new potential therapies for pancreatic cancer through gene therapy. This paper reviews the significant molecular biologic findings and their influence on the development of gene therapy strategies in the treatment of pancreatic adenocarcinoma.


Current Surgery | 2001

Improved reduction in pain in chronic pancreatitis with combined intraoperative celiac axis plexus block and lateral pancreaticojejunostomy.

Carlos Chan; Mario Vilatobá; Alfred A. Bartolucci; Selwyn M. Vickers

PURPOSE:Severe abdominal pain secondary to chronic pancreatitis is often multifactorial in origin. Lateral pancreaticojejunostomy (LPJ) is currently the accepted surgical treatment of choice when the main pancreatic duct is dilated. Chemical ablation of the celiac plexus for the treatment of intractable pain in chronic pancreatitis has been used without clear benefit. The aim of this study is to compare treatment outcomes of 2 groups of patients with the diagnosis of chronic pancreatitis and intractable abdominal pain (LPJ alone versus LPJ with intraoperative alcohol celiac ablation).Between 1994 and 1997, 34 patients underwent LPJ to control intractable pain secondary to chronic pancreatitis. These patients were divided into 2 groups, group 1 was LPJ only (16 patients) and group 2 was LPJ and intraoperative celiac ablation with 50% absolute alcohol (18 patients). Preoperative diagnosis and treatment criteria were similar for both groups. The clinical characteristics and outcome of both groups were retrospectively analyzed. Fisher exact test was used for statistical analysis.Demographic characteristics were similar in both groups. Pain control at short- and long-term follow-up was significantly improved in group 2 compared with group 1 (p < 0.035).Intraoperative celiac ablation in addition to LPJ appears to have a better response than does LPJ alone. Even though the number of patients is small, these results provide a basis for pursuing a prospective, randomized study to definitively answer this question.


Journal of Gastrointestinal Surgery | 2000

Comparison of ceftibuten vs. amoxicillin/clavulanic acid as antibiotic prophylaxis in cholecystectomy and/or biliary tract surgery.

Héctor Orozco; José Sifuentes-Osornio; Carlos Chan; Heriberto Medina-Franco; Florencia Vargas-Vorackova; Eduardo Prado; Jorge Arch

A randomized, comparative, prospective clinical trial was carried out at a tertiary care center to compare the efficacy of two antibiotic regimens in the prophylaxis of postoperative infection in patients undergoing biliary tract surgery. One hundred patients undergoing cholecystectomy or biliary tract exploration were randomly allocated to one of the following antibiotic regimens: the standard regimen of three doses of amoxicillin/clavulanic acid (1000/200 mg) given by intravenous infusion, or a single dose of ceftibuten (400 mg) given orally. Patients were monitored during their stay in the hospital and over a 2 week period as outpatients. Fifty adult patients were included in each group. Mean age was 49 years, and sex distribution was 82 women and 18 men. The groups were comparable in terms of demographic characteristics and comorbidity. There were no cases of postoperative infection in the ceftibuten group, but five cases of infection occurred in the amoxicillin/clavulanic acid group (P <0.05). No adverse effects were observed with either antibiotic. The treatment cost per patient was significantly lower for ceftibuten. The results indicate that ceftibuten is well tolerated and more effective than amoxicillin/clavulanic acid for prophylaxis following gallbladder and biliary tract surgery. In addition, ceftibuten has the advantage of being more cost-effective and easier to administer than amoxicillin/clavulanic acid so it could be considered as an alternative for antibiotic prophylaxis in these types of surgical procedures.

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Bernardo Franssen

Universidad Autónoma del Estado de México

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Félix Ignacio Téllez-Ávila

National Autonomous University of Mexico

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Selwyn M. Vickers

University of Alabama at Birmingham

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Luis Uscanga

French Institute of Health and Medical Research

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Alfred A. Bartolucci

University of Alabama at Birmingham

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Mario Vilatobá

University of Alabama at Birmingham

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Bernardo Franssen

Universidad Autónoma del Estado de México

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