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Dive into the research topics where Simon A. Zanati is active.

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Featured researches published by Simon A. Zanati.


Gastroenterology | 2011

Endoscopic mucosal resection outcomes and prediction of submucosal cancer from advanced colonic mucosal neoplasia.

Alan Moss; Michael J. Bourke; Stephen J. Williams; Luke F. Hourigan; Gregor J. Brown; William Tam; Rajvinder Singh; Simon A. Zanati; Robert Chen; Karen Byth

BACKGROUND & AIMS Large sessile colonic polyps usually are managed surgically, with significant morbidity and potential mortality. There have been few prospective, intention-to-treat, multicenter studies of endoscopic mucosal resection (EMR). We investigated whether endoscopic criteria can predict invasive disease and direct the optimal treatment strategy. METHODS The Australian Colonic Endoscopic (ACE) resection study group conducted a prospective, multicenter, observational study of all patients referred for EMR of sessile colorectal polyps that were 20 mm or greater in size (n=479, mean age, 68.5 y; mean lesion size, 35.6 mm). We analyzed data on lesion characteristics and procedural, clinical, and histologic outcomes. Multiple logistic regression analysis identified independent predictors of EMR efficacy and recurrence of adenoma, based on findings from follow-up colonoscopy examinations. RESULTS Risk factors for submucosal invasion were as follows: Paris classification 0-IIa+c morphology, nongranular surface, and Kudo pit pattern type V. The most commonly observed lesion (0-IIa granular) had a low rate of submucosal invasion (1.4%). EMR was effective at completely removing the polyp in a single session in 89.2% of patients; risk factors for lack of efficacy included a prior attempt at EMR (odds ratio [OR], 3.8; 95% confidence interval, 1.77-7.94; P=.001) and ileocecal valve involvement (OR, 3.4; 95% confidence interval, 1.20-9.52; P=.021). Independent predictors of recurrence after effective EMR were lesion size greater than 40 mm (OR, 4.37; 95% confidence interval, 2.43-7.88; P<.001) and use of argon plasma coagulation (OR, 3.51; 95% confidence interval, 1.69-7.27; P=.0017). There were no deaths from EMR; 83.7% of patients avoided surgery. CONCLUSIONS Large sessile colonic polyps can be managed safely and effectively by endoscopy. Endoscopic assessment identifies lesions at increased risk of containing submucosal cancer. The first EMR is an important determinant of patient outcome-a previous attempt is a significant risk factor for lack of efficacy.


Gut | 2015

Long-term adenoma recurrence following wide-field endoscopic mucosal resection (WF-EMR) for advanced colonic mucosal neoplasia is infrequent: results and risk factors in 1000 cases from the Australian Colonic EMR (ACE) study

Alan Moss; Stephen J. Williams; Luke F. Hourigan; Gregor J. Brown; William Tam; Rajvinder Singh; Simon A. Zanati; Nicholas G. Burgess; Rebecca Sonson; Karen Byth; Michael J. Bourke

Objective Wide-field endoscopic mucosal resection (WF-EMR) is an alternative to surgery for treatment of advanced colonic mucosal neoplasia up to 120 mm in size, but has been criticised for its potentially high recurrence rates. We aimed to quantify recurrence at 4 months (early) and 16 months (late) following successful WF-EMR and identify its risk factors and clinical significance. Design Ongoing multicentre, prospective, intention-to-treat analysis of sessile or laterally spreading colonic lesions ≥20 mm in size referred for WF-EMR to seven academic endoscopy units. Surveillance colonoscopy (SC) was performed 4 months (SC1) and 16 months (SC2) after WF-EMR, with photographic documentation and biopsy of the scar. Results 1134 consecutive patients were enrolled when 1000 successful EMRs were achieved, of whom 799 have undergone SC1. 670 were normal. Early recurrent/residual adenoma was present in 128 (16.0%, 95% CI 13.6% to 18.7%). One case was unknown. The recurrent/residual adenoma was diminutive in 71.7% of cases. On multivariable analysis, risk factors were lesion size >40 mm, use of argon plasma coagulation and intraprocedural bleeding. Of 670 with normal SC1, 426 have undergone SC2, with late recurrence present in 17 cases (4.0%, 95% CI 2.4% to 6.2%). Overall, recurrent/residual adenoma was successfully treated endoscopically in 135 of 145 cases (93.1%, 95% CI 88.1% to 96.4%). If the initial EMR was deemed successful and did not contain submucosal invasion requiring surgery, 98.1% (95% CI 96.6% to 99.0%) were adenoma-free and had avoided surgery at 16 months following EMR. Conclusions Following colonic WF-EMR, early recurrent/residual adenoma occurs in 16%, and is usually unifocal and diminutive. Risk factors were identified. Late recurrence occurs in 4%. Overall, recurrence was managed endoscopically in 93% of cases. Recurrence is not a significant clinical problem following WF-EMR, as with strict colonoscopic surveillance, it can be managed endoscopically with high success rates. Trial registration number: NCT01368289.


The American Journal of Gastroenterology | 2005

Given capsule endoscopy in celiac disease: evaluation of diagnostic accuracy and interobserver agreement.

Rima Petroniene; Elena Dubcenco; Jeffrey P. Baker; Clifford A Ottaway; Shou-Jiang Tang; Simon A. Zanati; Cathy Streutker; Geoffrey W. Gardiner; Ralph Warren

BACKGROUND AND AIMS:Capsule endoscopy (CE) has been increasingly used for diagnosing diseases of the small bowel. It is an attractive technique for assessing celiac disease (CD) because it is noninvasive and provides a close and magnified view of the mucosa of the entire small bowel. In this study, we evaluated the accuracy of CE and interobserver agreement in recognizing villous atrophy (VA) using histopathology as the reference. We also explored the extent of small bowel involvement with CD and the relationship between the length of the affected bowel and the clinical presentation.METHODS:Ten CD patients with histologically proven VA and the same number of controls were subjected to CE. Four, blinded to histology findings, investigators (two with and two without prestudy CE experience) were asked to diagnose VA on CE images.RESULTS:Based on assessment of all four investigators, the overall sensitivity, specificity, PPV, and NPV of CE in diagnosing VA were 70%, 100%, 100%, and 77%, respectively. The sensitivity and the specificity of the test was 100% when the reports of experienced capsule endoscopists only were analyzed. The interobserver agreement was perfect (κ= 1.0) between investigators with prestudy CE experience and poor (κ= 0.2) between the investigators who had limited prestudy exposure to CE. Celiac patients with extensive small bowel involvement had typical symptoms of malabsorption (diarrhea, weight loss) as opposed to mild and nonspecific symptoms in patients whose disease was limited to the proximal small bowel. CE was tolerated well by all study participants with 95% reporting absence of any discomfort.CONCLUSIONS:Although based on a small sample size, the study suggests that CE may be useful in assessing patients with CD. Familiarity with CE technology appears to be a critical factor affecting the accuracy of the test. Larger studies are warranted to more precisely define the advantages and limitations of CE in CD.


Clinical Gastroenterology and Hepatology | 2014

Risk Factors for Intraprocedural and Clinically Significant Delayed Bleeding After Wide-field Endoscopic Mucosal Resection of Large Colonic Lesions

Nicholas G. Burgess; Andrew J. Metz; Stephen J. Williams; Rajvinder Singh; William Tam; Luke F. Hourigan; Simon A. Zanati; Gregor J. Brown; Rebecca Sonson; Michael J. Bourke

BACKGROUND & AIMS Wide-field endoscopic mucosal resection (WF-EMR) of large sessile colonic polyps is a safe and cost-effective outpatient treatment. Bleeding is the main complication. Few studies have examined risk factors for bleeding during the procedure (intraprocedural bleeding [IPB]) or after it (clinically significant post-endoscopic bleeding [CSPEB]). We investigated factors associated with IPB and CSPEB in a large prospective study. METHODS We analyzed data from WF-EMRs of sessile colorectal polyps ≥ 20 mm in size (mean size, 35.5 mm), which were performed on 1172 patients (mean age, 67.8 years) from June 2008-March 2013 at 7 tertiary hospitals as part of the Australian Colonic Endoscopic Resection Study. Data were collected on characteristics of patients and lesions, along with outcomes of procedures and clinical and histologic analyses. Independent predictors of IPB and CSPEB were identified by multiple logistic regression analysis. RESULTS Of the patients studied, 133 (11.3%) had IPB. Independent predictors included increasing lesion size (odds ratio, 1.24/10 mm; P < .001), Paris endoscopic classification of 0-IIa + Is (odds ratio, 2.12; P = .004), tubulovillous or villous histology (odds ratio, 1.84; P = .007), and study institutions that performed the procedure on fewer than 75 patients (odds ratio, 3.78; P < .001). All IPB was successfully controlled endoscopically. IPB prolonged procedures and was associated with early recurrence (relative risk, 1.68; P = .011). Seventy-three patients (6.2%) had CSPEB. On multivariable analysis, CSPEB was associated with proximal colon location (odds ratio, 3.72; P < .001), use of an electrosurgical current not controlled by a microprocessor (odds ratio, 2.03; P = .038), and IPB (odds ratio, 2.16; P = .016). Lesion size and comorbidities did not predict CSPEB. CONCLUSIONS In a prospective study of patients undergoing WF-EMR of large sessile colonic polyps, IPB is associated with larger lesions, lesion histology, and Paris endoscopic classification of type 0-IIa + Is. IPB prolongs the duration of the procedure, is a marker for recurrence, and is associated with CSPEB. CSPEB occurs most frequently in the proximal colon and less when current is controlled by a microprocessor.


Gastrointestinal Endoscopy | 2008

Endoscopic cryotherapy for the management of gastric antral vascular ectasia.

Sarah Cho; Simon A. Zanati; Elaine Yong; Maria Cirocco; Paul P. Kortan; Gary May; Norman E. Marcon

BACKGROUND Gastric antral vascular ectasia (GAVE) is an uncommon but clinically significant cause of chronic GI bleeding. OBJECTIVE To assess the efficacy and safety of cryotherapy for endoscopic treatment of GAVE. DESIGN Patients received 3 sessions of endoscopic cryotherapy at 3-week to 6-week intervals and had a follow-up endoscopy 4 weeks thereafter. They were followed prospectively in terms of clinical and endoscopic response. SETTING Tertiary-care center, between October 2004 and April 2006. PATIENTS The patients were 43 to 89 years of age, with a diagnosis of GAVE and documented iron deficiency anemia. Eight patients had a history of overt GI bleeding. Eight patients (67%) had previously been treated with argon plasma coagulation (APC) (median 6 sessions, range 1-10 sessions) and failed to respond or had a recurrence. RESULTS Twelve patients were enrolled. Six patients (50%) had a complete response, and 6 patients had a partial response. The mean number of units of blood transfused in the period of 3 months before cryotherapy and during the period of follow-up of 3 months was 4.6 and 1.7 units, respectively. An increased mean Hb level, from 9.9 to 11.3 g/dL, was noted. The average duration of the cryotherapy was 5 minutes (range 1-15 minutes). In 32 of 36 cryotherapy treatment sessions performed (89%), it was technically possible to treat more than 90% of GAVE lesions. There were no immediate cryotherapy-related complications, and none of the patients required admission after the procedure. LIMITATIONS A pilot study from a single center. CONCLUSIONS Endoscopic cryotherapy is a safe and effective treatment for GAVE. It appears to be effective, even for GAVE refractory to APC therapy. Optimal cryogen, delivery device, and treatment protocols are yet to be determined.


Clinical Gastroenterology and Hepatology | 2016

Cost Analysis of Endoscopic Mucosal Resection vs Surgery for Large Laterally Spreading Colorectal Lesions

Mahesh Jayanna; Nicholas G. Burgess; Rajvinder Singh; Luke F. Hourigan; Gregor J. Brown; Simon A. Zanati; Alan Moss; James Lim; Rebecca Sonson; Stephen J. Williams; Michael J. Bourke

BACKGROUND & AIMS Large laterally spreading lesions (LSL) in the colon and rectum can be safely and effectively removed by endoscopic mucosal resection (EMR). However, many patients still undergo surgery. Endoscopic treatment may be more cost effective. We compared the costs of endoscopic versus surgical management of large LSL. METHODS We performed a prospective, observational, multicenter study of consecutive patients referred to 1 of 7 academic hospitals in Australia for the management of large LSL (≥ 20 mm) from January 2010 to December 2013. We collected data on numbers of patients undergoing EMR, actual endoscopic management costs (index colonoscopy, hospital stay, adverse events, and first surveillance colonoscopy), characteristics of patients and lesions, outcomes, and adverse events, and findings from follow-up examinations 14 days, 4-6 months, and 16-18 months after treatment. We compared data from patients who underwent EMR with those from a model in which all patients underwent surgery without any complications. Event-specific costs, based on Australian refined diagnosis-related group codes, were used to estimate average cost per patient. RESULTS EMR was performed on 1489 lesions (mean size, 36 mm) in 1353 patients (mean age, 67 years; 52.1% male). Total costs involved in the endoscopic management of large LSL were US


Gut | 2017

Endoscopic mucosal resection for large serrated lesions in comparison with adenomas: a prospective multicentre study of 2000 lesions

Maria Pellise; Nicholas G. Burgess; Nicholas Tutticci; Luke F. Hourigan; Simon A. Zanati; Gregor J. Brown; Rajvinder Singh; Stephen J. Williams; Spiro C. Raftopoulos; Donald Ormonde; Alan Moss; Karen Byth; Heok P'Ng; Hema Mahajan; Duncan McLeod; Michael J. Bourke

6,316,593 and total inpatient hospitalization length of stay was 1180 days. The total cost predicted for the surgical management group was US


Gut | 2016

Clinical and endoscopic predictors of cytological dysplasia or cancer in a prospective multicentre study of large sessile serrated adenomas/polyps

Nicholas G. Burgess; Maria Pellise; Kavinderjit S. Nanda; Luke F. Hourigan; Simon A. Zanati; Gregor J. Brown; Rajvinder Singh; Stephen J. Williams; Spiro C. Raftopoulos; Donald Ormonde; Alan Moss; Karen Byth; Heok P'Ng; Duncan McLeod; Michael J. Bourke

16,601,502, with a total inpatient hospitalization length of stay of 4986 days. Endoscopic management produced a potential total cost saving of US


The American Journal of Gastroenterology | 2016

Prediction of clinically significant bleeding following wide-field endoscopic resection of large sessile and laterally spreading colorectal lesions: A clinical risk score

Farzan F. Bahin; Khalid N. Rasouli; Karen Byth; Luke F. Hourigan; Rajvinder Singh; Gregor J. Brown; Simon A. Zanati; Alan Moss; Spiro C. Raftopoulos; Stephen J. Williams; Michael J. Bourke

10,284,909; the mean cost difference per patient was US


Journal of Biophotonics | 2014

Diffuse reflectance spectroscopy in Barrett’s Esophagus: developing a large field-of-view screening method discriminating dysplasia from metaplasia

Alexandre Douplik; Simon A. Zanati; Guennadi Saiko; Catherine Streutker; Maxim Loshchenov; Desmond C. Adler; Sarah Cho; Dean Chen; Maria Cirocco; Norman E. Marcon; John Fengler; Brian C. Wilson

7602 (95% confidence interval,

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Luke F. Hourigan

Princess Alexandra Hospital

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Spiro C. Raftopoulos

Sir Charles Gairdner Hospital

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Alan C. Moss

Beth Israel Deaconess Medical Center

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