Ryash Vather
University of Auckland
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Featured researches published by Ryash Vather.
Annals of Surgical Oncology | 2009
Ryash Vather; Tarik Sammour; Arman Kahokehr; Andrew B. Connolly; Andrew G. Hill
The most important prognostic factor in colonic cancer is the presence or absence of regional lymph nodes metastases. The aim of this study was to evaluate the relationship between 5-year mortality in the New Zealand population, and the number of nodes examined in Stage II and III colon cancers. New Zealand Cancer Registry data were retrieved for patients with colonic cancer from January 1995 to July 2003. Patients with incomplete entries, Stage I tumors, and distant metastases were excluded from analysis. Univariate and Cox regression models were used with 5-year mortality as the primary endpoint. The study identified 4309 patients. Younger age, female gender, Pacific Island descent, and right-sided tumors were associated with significantly higher lymph node retrieval. Cox regression analysis showed that the number of nodes examined was a significant predictor of 5-year mortality when age, sex, ethnicity, and site were controlled for. Five-year survival consistently improved between nodal strata until the 16-node mark, above which survival advantage was minimal. For Stage III cancers, a higher lymph node ratio was associated with a significant increase in mortality. Increased rates of nodal examination are associated with a significantly lower 5-year mortality for Stage II and III colonic cancer, but this survival advantage appears to be minimal after the 16-node mark. The lymph node ratio has been validated as a powerful predictor of survival in Stage III cancer. Our results support the current practice of harvesting and examining as many nodes as possible during attempted curative resection.BackgroundThe most important prognostic factor in colonic cancer is the presence or absence of regional lymph nodes metastases. The aim of this study was to evaluate the relationship between 5-year mortality in the New Zealand population, and the number of nodes examined in Stage II and III colon cancers.MethodsNew Zealand Cancer Registry data were retrieved for patients with colonic cancer from January 1995 to July 2003. Patients with incomplete entries, Stage I tumors, and distant metastases were excluded from analysis. Univariate and Cox regression models were used with 5-year mortality as the primary endpoint.ResultsThe study identified 4309 patients. Younger age, female gender, Pacific Island descent, and right-sided tumors were associated with significantly higher lymph node retrieval. Cox regression analysis showed that the number of nodes examined was a significant predictor of 5-year mortality when age, sex, ethnicity, and site were controlled for. Five-year survival consistently improved between nodal strata until the 16-node mark, above which survival advantage was minimal. For Stage III cancers, a higher lymph node ratio was associated with a significant increase in mortality.ConclusionsIncreased rates of nodal examination are associated with a significantly lower 5-year mortality for Stage II and III colonic cancer, but this survival advantage appears to be minimal after the 16-node mark. The lymph node ratio has been validated as a powerful predictor of survival in Stage III cancer. Our results support the current practice of harvesting and examining as many nodes as possible during attempted curative resection.
Anz Journal of Surgery | 2006
Ryash Vather; Kamran Zargar-Shoshtari; Samuel Adegbola; Andrew G. Hill
Background: Physiologic and operative severity score for the enumeration of mortality and morbidity (POSSUM), ‘Portsmouth’‐physiologic and operative severity score for the enumeration of mortality and morbidity (P‐POSSUM) and ‘Colorectal’‐physiologic and operative severity score for the enumeration of mortality and morbidity (Cr‐POSSUM) are three related scoring systems, which uses individual patient parameters to predict postoperative mortality. POSSUM overpredicts mortality in low‐risk patients and underpredicts mortality in elderly and emergency patients. P‐POSSUM was developed to compensate for these weaknesses. Cr‐POSSUM was developed specifically for colorectal surgery. We aim to establish which of these scoring systems would be most useful in an Australasian context.
The American Journal of Gastroenterology | 2010
Benjamin Loveday; Sanket Srinivasa; Ryash Vather; Anubhav Mittal; Maxim S. Petrov; Anthony R. J. Phillips; John A. Windsor
OBJECTIVES:Several clinical guidelines exist for acute pancreatitis, with varying recommendations. The aim of this study was to determine the quality of guidelines for acute pancreatitis.METHODS:A literature search identified relevant guidelines, which were then reviewed to determine their document format and scope and the presence of endorsement by a professional body. The quality of guidelines was determined using the validated Grilli, Shaneyfelt, and AGREE instruments.RESULTS:Twenty-one of the 30 guidelines analyzed were endorsed by professional bodies. Median quality scores were as follows: Grilli, 2; Shaneyfelt, 13; and AGREE, 50. Guideline quality did not improve over time. Guidelines endorsed by a professional body had higher scores than those without official endorsement. Guidelines with tables, a recommendations summary, evidence grading, and audit goals had significantly higher scores than guidelines lacking those features.CONCLUSIONS:The many clinical guidelines for acute pancreatitis range widely in quality. Guidelines developed by professional bodies, and those with tables, a recommendations summary, evidence grading, and audit goals, are of higher quality. Further research is required to determine whether guideline quality alters clinical outcomes.
Surgery | 2015
Ryash Vather; Rachel Josephson; Rebekah Jaung; Jason P. Robertson; Ian P. Bissett
BACKGROUND Management strategies for prolonged postoperative ileus (PPOI) are principally conservative and it is therefore valuable to shift attention to prevention. This study aimed to identify prospectively the perioperative risk factors for the development of PPOI and create a tool to predict its occurrence. METHODS Patients undergoing elective colorectal surgery at Auckland District Health Board between September 2012 and June 2014 were enrolled. In total, 92 variables were investigated prospectively with uniform application of a standardized definition of PPOI. Logistic regression and area under receiver operating characteristic curves (AUC) were used to generate risk stratification models. RESULTS PPOI occurred in 88 of 327 patients (26.9%). Independent predictors of PPOI were male gender (odds ratio [OR], 3.01), decreasing preoperative albumin (OR, 1.11 per g/L unit), open or converted technique (OR, 6.37 [vs laparoscopic]), increasing wound size (OR, 1.09 [per cm]), operative difficulty (OR, 1.28 [per unit on 10-point Likert scale]), operative bowel handling (OR, 1.38 [per unit on 10-point Likert scale]), red cell transfusion (OR, 1.84 [per unit]), intravenous crystalloid administration (OR, 1.55 [per liter]), and delayed first mobilization (OR, 1.39 [per day]). The I-Score assimilated preoperative and intraoperative variables to generate a score out of 6 with a 7-fold increase in risk from low-risk to high-risk strata and fair predictive capacity (AUC, 0.742; 95% CI, 0.684-0.799). CONCLUSION Independent predictors for the development of PPOI have been identified prospectively and used to construct a novel risk stratification model.
Clinical and Experimental Pharmacology and Physiology | 2014
Ryash Vather; Greg O'Grady; Ian P. Bissett; Philip G. Dinning
Postoperative ileus (POI) is an abnormal pattern of gastrointestinal motility characterized by nausea, vomiting, abdominal distension and/or delayed passage of flatus or stool, which may occur following surgery. Postoperative ileus slows recovery, increases the risk of developing postoperative complications and confers a significant financial load on healthcare institutions. The aim of the present review is to provide a succinct overview of the clinical features and pathophysiological mechanisms of POI, with final comment on selected directions for future research.Terminology used when describing POI is inconsistent, with little differentiation made between the obligatory period of gut dysfunction seen after surgery (‘normal POI’) and the more clinically and pathologically significant entity of a ‘prolonged POI’. Both normal and prolonged POI represent a fundamentally similar pathophysiological phenomenon. The aetiology of POI is postulated to be multifactorial, with principal mediators being inflammatory cell activation, autonomic dysfunction (both primarily and as part of the surgical stress response), agonism at gut opioid receptors, modulation of gastrointestinal hormone activity and electrolyte derangements. A final common pathway for these effectors is impaired contractility and motility and gut wall oedema. There are many potential directions for future research. In particular, there remains scope to accurately characterize the gastrointestinal dysfunction that underscores an ileus, development of an accurate risk stratification tool will facilitate early implementation of preventive measures and clinical appraisal of novel therapeutic strategies that target individual pathways in the pathogenesis of ileus warrant further investigation.
BJUI | 2013
Arman Kahokehr; Ryash Vather; Anthony Nixon; Andrew G. Hill
Benign prostatic hyperplasia (BPH) is the most frequent benign neoplasm in ageing men. Histological studies have shown that intraprostatic inflammatory infiltration is seen in 43–98% of BPH tissues. Preclinical investigations have shown inhibition of growth in the BPH cell line in vitro after treatment with NSAIDs. This review provides evidence that NSAIDs result in improved symptoms and urinary flow associated with BPH. Further research and larger clinical trials are needed to assess the safety and long‐term impact of NSAID use in men with BPH. From the clinical viewpoint, the development of substances that can inhibit inflammatory changes in the hyperplastic prostate may provide new treatment strategies.
Anz Journal of Surgery | 2013
Ryash Vather; Ian P. Bissett
Prolonged post‐operative ileus (PPOI) occurs in up to 25% of patients following major elective abdominal surgery. It is associated with a higher risk of developing post‐operative complications, prolongs hospital stay and confers a significant financial load on health‐care institutions. Literature outlining best‐practice management strategies for PPOI is nebulous. The aim of this text was to review the literature and provide concise evidence‐based recommendations for its management.
Annals of Surgery | 2015
Ryash Vather; Rachel Josephson; Rebekah Jaung; Arman Kahokehr; Tarik Sammour; Ian P. Bissett
OBJECTIVE To investigate the therapeutic value of Gastrografin in shortening duration of prolonged postoperative ileus (PPOI) after elective colorectal surgery. BACKGROUND Gut wall edema is central to the pathogenesis of PPOI. Hyperosmotic, orally administered, water-soluble contrast media such as Gastrografin are theoretically capable of mitigating this edema. METHODS A double-blinded, placebo-controlled, randomized trial was conducted. Participants were allocated to receive 100 mL of Gastrografin (Exposure Group) or flavored distilled water (Control Group) administered enterally. Other aspects of management were standardized. Resolution of PPOI was assessed 12-hourly. RESULTS Eighty patients were randomized equally, with 5 in the Exposure Group and 4 in the Control Group excluded from analysis. Participants were evenly matched at baseline. Mean duration of PPOI did not differ between Exposure and Control Groups (83.7 vs 101.3 hours; P = 0.191). When considering individual markers of PPOI resolution, Gastrografin did not affect time to resolution of nausea and vomiting (64.5 vs 74.3 hours; P = 0.404) or consumption of oral diet (75.8 vs 90.0 hours; P = 0.297). However, it accelerated time to flatus or stool (18.9 vs 32.7 hours; P = 0.047) and time to resolution of abdominal distension (52.8 vs 77.7 hours; P = 0.013). There were no significant differences between groups in nasogastric output; analgesia, antiemetic, or fluid requirement; complications; or length of stay. CONCLUSIONS Gastrografin is not clinically useful in shortening an episode of PPOI characterized by upper and lower gastrointestinal symptoms. It may however be of therapeutic benefit in the subset of PPOI patients who display lower gastrointestinal symptoms exclusively after surgery.
Anz Journal of Surgery | 2011
Ryash Vather; Tarik Sammour; Arman Kahokehr; Andrew B. Connolly; Andrew G. Hill
Background: The prognostic significance of lymph node evaluation is not well described for rectal cancer due to a lack of reproducibility in nodal counts and variable use of adjuvant and neoadjuvant therapy. The aim of this study was to examine the role of quantitative lymph node evaluation as an independent marker of prognosis in stage III rectal cancer.
Hpb | 2015
Michael J. J. Chu; Ryash Vather; Anthony J. R. Hickey; Anthony R. J. Phillips; Adam Bartlett
BACKGROUND Steatotic livers are vulnerable to the deleterious effects of ischaemia-reperfusion injury (IRI) that occur after hepatic surgery. Ischaemic preconditioning (IPC) has been shown to abrogate the effects of IRI in patients undergoing hepatic surgery. Experimental studies have suggested that IPC may be beneficial in steatotic livers subjected to IRI. OBJECTIVE The aim of this systematic review was to evaluate the effects of IPC on steatotic livers following hepatic IRI in experimental models. METHODS An electronic search of the OVID Medline and EMBASE databases was performed to identify studies that reported clinically relevant outcomes in animal models of hepatic steatosis subjected to IPC and IRI. RESULTS A total of 1093 articles were identified, of which 18 met the inclusion criteria. There was considerable heterogeneity in the type of animal model, and duration and type of IRI. Increased macrovesicular steatosis (> 30%) was associated with a poor outcome following IRI. Ischaemic preconditioning was found to be beneficial in > 30% steatotic livers and provided for decreased histological damage, improved liver function findings and increased survival. CONCLUSIONS Experimental evidence supports the use of IPC in steatotic livers undergoing IRI. These findings may be applicable to patients undergoing liver surgery. However, clinical studies are required to validate the efficacy of IPC in this setting.