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Biomedical subjects

Omer Aziz

Publications and source records attributed to Omer Aziz.

At least 19 recordsLinked to original sources
PubMed2007

Multi-detector computed tomography in coronary artery bypass graft assessment: a meta-analysis.

Multi-detector computed tomography (MDCT) has become an alternative to coronary angiography in diagnosis of graft occlusion and stenosis after coronary artery bypass. A literature search was performed for studies comparing angiography to 8-slice, 16-slice, and 64-slice MDCT in the assessment of coronary grafts. In assessing occlusion, 14 studies produced pooled sensitivity of 97.6%, specificity of 98.5%, diagnostic odds ratio of 934.2, area under the curve of 0.996, and Q* of 0.977. Ninety-six percent of all grafts were visualized for occlusion assessment. Beta blockers, symptomatic status, and postoperative period did not significantly affect diagnostic performance. Stenosis assessment produced sensitivity of 88.7% and specificity of 97.4%. Eighty-eight percent of patent grafts could be assessed for stenosis. The diagnostic accuracy of MDCT approaches angiography for diagnosing graft occlusion and stenosis in patients with venous and arterial coronary bypass grafts. Our findings show that cardiac surgeons will need to interpret MDCT images of both native and grafted vessels soon in preparation for primary or re-do coronary bypass grafting procedures.

Coronary Angiography↗
PubMed2006

Laparoscopic versus open surgery for rectal cancer: a meta-analysis.

BACKGROUND: Laparoscopic rectal cancer surgery aims to provide patients with curative resection while minimizing postoperative morbidity and mortality. This study used meta-analytical techniques to compare laparoscopic and open surgery as the primary treatment for patients with rectal cancer with regard to short-term and long-term outcomes. METHODS: A literature search was performed on all studies between 1993 and 2004 comparing laparoscopic and open surgery for rectal cancer. Subgroup analysis was performed on patients undergoing abdominoperineal excision of the rectum. The following end points were evaluated: operative outcomes, postoperative recovery, and early and late adverse events. RESULTS: Twenty studies matched the selection criteria and reported on 2071 subjects, of whom 909 (44%) underwent laparoscopic and 1162 (56%) underwent open surgery for rectal cancer. Time to stomal function (weighted mean difference [WMD], -1.52; 95% confidence interval [95% CI], -2.20, -1.01), first bowel movement (WMD, -.72; 95% CI, -1.21, -.22), feeding solids (WMD, -.92; 95% CI, -1.35, -.50), and length of hospital stay (WMD, -2.67; 95% CI, -3.81, -1.54) were all significantly reduced after laparoscopic surgery. In patients who underwent abdominoperineal excision of the rectum, wound infection (odds ratio, .15; 95% CI, .03, .73) and requirement for postoperative parenteral analgesia (WMD, -.63; 95% CI, -1.22, -.04) were also significantly reduced. There was no difference between groups in the extent of oncological clearance. CONCLUSIONS: Laparoscopic rectal cancer surgery results in an earlier postoperative recovery and a resected specimen that is oncologically comparable to open surgery. Results from randomized trials reporting long-term outcomes such as cancer recurrence (local and metastatic) and 5-year survival are eagerly awaited.

Clinical Trials as Topic↗
PubMed2006

Minimally invasive conduit harvesting: a systematic review.

Minimally invasive conduit harvesting techniques for coronary artery bypass grafting have developed over the past decade, aiming to reduce the morbidity and recovery time associated with the procedure, whilst preserving the quality of the conduit. Two types of commonly harvested free conduits include the great saphenous vein and the radial artery. Although much research has focussed on comparing less invasive and conventional harvest techniques, there is at present no consensus on the areas where one technique is superior to the other. Aspects of conduits that deserve appreciation when comparing minimally invasive and open harvesting techniques include wound healing at the harvest site, the macroscopic, histological and functional quality of the conduit, but perhaps most importantly its long-term angiographic patency. This paper aims to review the literature comparing minimally invasive and conventional conduit harvesting techniques for coronary artery bypass grafting, with regard to the previously mentioned factors. A literature search of Medline, Ovid, Embase and Cochrane databases was used to identify comparative studies published between 1997 and 2005. Outcomes of interest included: wound infection, non-infective healing disturbances, post-operative pain, neurological disturbance, mobility, patient satisfaction, conduit quality (macroscopic, histological and functional) and long-term conduit patency. A scoring system was applied and used to grade the quality of the evidence, based on which a recommendation of it being 'good' (Grade A), 'fair' (Grade B), or 'insufficient' (Grade C) was made. Results showed that there was 'good' evidence to suggest that wound infection and non-infective complications are reduced with minimally invasive harvest as compared to conventional vein harvest. The evidence suggesting that post-operative pain and mobilisation is reduced after minimally invasive vein harvest and that once harvested, the conduits are macroscopically comparable to conventional ones, is only 'fair'. Finally, although initial reports are encouraging, there is at present insufficient evidence to comment on whether minimally invasive radial artery harvesting is better than that of conventional open surgery. Wounds from minimally invasively harvested venous conduits appear to be less prone to complications although more comparative evidence on conduit quality and long-term patency is eagerly awaited.

Coronary Artery Bypass↗
PubMed2006

Laparoscopic vs. open surgery for diverticular disease: a meta-analysis of nonrandomized studies.

PURPOSE: This study was designed to compare outcomes between laparoscopic and open surgery for patients with diverticular disease by using meta-analytic techniques. METHODS: Comparative studies published between 1996 and 2004 of open vs. laparoscopic surgery for diverticular disease were included. The end points that were evaluated are operative and functional outcomes and adverse events. A random effects model was used during analysis of these outcomes; heterogeneity was assessed and sensitivity analysis was performed to account for bias in patient selection. RESULTS: Twelve nonrandomized studies, incorporating 19,608 patients, were included in the analysis. One study with 18,444 patients accounted for 94.5 percent of the total sample. Laparoscopic surgery resulted in reduced infective (odds ratio, 0.61; P = 0.01), pulmonary (odds ratio, 0.4; P < 0.001), gastrointestinal tract (odds ratio, 0.75; P = 0.03), and cardiovascular complications (odds ratio, 0.28; P = 0.0008) with no significant heterogeneity. Operative time was longer with laparoscopic surgery (weighted mean difference, 67.59; P = 0.04), and length of stay was significantly shorter (weighted mean difference, -3.81; P < 0.0001); however, these outcomes demonstrated significant heterogeneity. These results remained significant throughout all the sensitivity analyses except when evaluating high-quality studies (when the study with 18,444 patients was excluded), in which only blood loss and length of stay were significantly in favor of the laparoscopic group. CONCLUSIONS: The results for patients selected for laparoscopic surgery compared with open surgery for diverticular disease are equivalent with a potential reduction in complications and hospital stay. Laparoscopic surgery for diverticular disease performed by appropriately experienced surgeons in the elective setting may be safe and feasible; because of the potential of significant bias arising from the included studies, a randomized, controlled trial is recommended.

Adult↗
PubMed2006

Primary resection with anastomosis vs. Hartmann's procedure in nonelective surgery for acute colonic diverticulitis: a systematic review.

PURPOSE: This study compares primary resection with anastomosis and Hartmann's procedure in an adult population with acute colonic diverticulitis. METHODS: Comparative studies published between 1984 and 2004 of primary resection with anastomosis vs. Hartmann's procedure were included. The primary end point was postoperative mortality. Secondary end points included surgical and medical morbidity, operative time, and length of postoperative hospitalization. Random effects model was used and sensitivity analysis was performed. RESULTS: Fifteen studies, including 963 patients (57 percent primary resection with anastomoses, 43 percent Hartmann's procedures), were analyzed. Overall mortality was significantly reduced with primary resection and anastomosis (4.9 vs. 15.1 percent; odds ratio = 0.41). Subgroup analysis of trials matched for emergency operations showed significantly decreased mortality with primary resection and anastomosis (7.4 vs. 15.6 percent; odds ratio = 0.44). No significant difference in mortality was observed in trials matched for severity of peritonitis Hinchey > 2 (14.1 vs. 14.4 percent; odds ratio = 0.85). Sensitivity analysis did not reveal significant heterogeneity between the studies for the primary outcome. CONCLUSIONS: Patients selected for primary resection and anastomosis have a lower mortality than those treated by Hartmann's procedure in the emergency setting and comparable mortality under conditions of generalized peritonitis (Hinchey > 2). The retrospective nature of the included studies allows for a considerable degree of selection bias that limits robust and clinically sound conclusions. This analysis highlights the need for high-quality randomized trials comparing the two techniques.

Acute Disease↗
PubMed2006

Laparoscopic versus open appendectomy in children: a meta-analysis.

OBJECTIVE: This study aims to use meta-analysis to compare laparoscopic and open appendectomy in a pediatric population. SUMMARY BACKGROUND DATA: Meta-analysis is a statistical tool that can be used to evaluate the literature in both qualitative and quantitative ways, accounting for variations in characteristics that can influence overall estimate of outcomes of interest. Meta-analysis of laparoscopic versus open appendectomy in a pediatric population has not previously been performed. METHODS: Comparative studies published between 1992 and 2004 of laparoscopic versus open appendectomy in children were included. Endpoints were postoperative pyrexia, ileus, wound infection, intra-abdominal abscess formation, operative time, and postoperative hospital stay. RESULTS: Twenty-three studies including 6477 children (43% laparoscopic, 57% open) were included. Wound infection was significantly reduced with laparoscopic versus open appendectomy (1.5% versus 5%; odds ratio [OR] = 0.45, 95% confidence interval [CI], 0.27-0.75), as was ileus (1.3% versus 2.8%; OR = 0.5, 95% CI, 0.29-0.86). Intra-abdominal abscess formation was more common following laparoscopic surgery, although this was not statistically significant. Subgroup analysis of randomized trials did not reveal significant difference between the 2 techniques in any of the 4 complications. Operative time was not significantly longer in the laparoscopic group, and postoperative stay was significantly shorter (weighted mean difference, -0.48; 95% CI, -0.65 to -0.31). Sensitivity analysis identified lowest heterogeneity when only randomized studies were considered, followed by prospective, recent, and finally large studies. CONCLUSIONS: The results of this meta-analysis suggest that laparoscopic appendectomy in children reduces complications. However, we also see the need for further high-quality randomized trials comparing the 2 techniques, matched not only for age and sex but also for obesity and severity of appendicitis.

Appendectomy↗
PubMed2005

Handheld computers and the 21st century surgical team: a pilot study.

BACKGROUND: The commercial development and expansion of mobile phone networks has led to the creation of devices combining mobile phones and personal digital assistants, which could prove invaluable in a clinical setting. This pilot study aimed to look at how one such device compared with the current pager system in facilitating inter-professional communication in a hospital clinical team. METHODS: The study looked at a heterogeneous team of doctors (n = 9) working in a busy surgical setting at St. Mary's Hospital in London and compared the use of a personal digital assistant with mobile phone and web-browsing facilities to the existing pager system. The primary feature of this device being compared to the conventional pager was its use as a mobile phone, but other features evaluated included the ability to access the internet, and reference data on the device. A crossover study was carried out for 6 weeks in 2004, with the team having access to the personal digital assistant every alternate week. The primary outcome measure for assessing efficiency of communication was the length of time it took for clinicians to respond to a call. We also sought to assess the ease of adoption of new technology by evaluating the perceptions of the team (n = 9) to personal digital assistants, by administering a questionnaire. RESULTS: Doctors equipped with a personal digital assistant rather than a pager, responded more quickly to a call and had a lower of failure to respond rate (RR: 0.44; 95%CI 0.20-0.93). Clinicians also found this technology easy to adopt as seen by a significant reduction in perceptions of nervousness to the technology over the six-week study period (mean (SD) week 1: 4.10 (SD 1.69) vs. mean (SD) week 6: 2.20 (1.99); p = 0.04). CONCLUSION: The results of this pilot study show the possible effects of replacing the current hospital pager with a newer, more technologically advanced device, and suggest that a combined personal digital assistant and mobile phone device may improve communication between doctors. In the light of these encouraging preliminary findings, we propose a large-scale clinical trial of the use of these devices in facilitating inter-professional communication in a hospital setting.

Attitude of Health Personnel↗
PubMed2005

A comparison of open vs. laparoscopic abdominal rectopexy for full-thickness rectal prolapse: a meta-analysis.

PURPOSE: Using meta-analytical techniques, this study was designed to compare open and laparoscopic abdominal procedures used to treat full-thickness rectal prolapse in adults. METHODS: Comparative studies published between 1995 and 2003, cited in the literature of open abdominal rectopexy vs. laparoscopic abdominal rectopexy, were used. The primary end points were recurrence and morbidity, and the secondary end points assessed were operative time and length of hospital stay. A random effect model was used to aggregate the studies reporting these outcomes, and heterogeneity was assessed. RESULTS: Six studies, consisting of a total of 195 patients (98 open and 97 laparoscopic) were included. Analysis of the data suggested that there is no significant difference in recurrence and morbidity between laparoscopic abdominal rectopexy and open abdominal rectopexy. Length of stay was significantly reduced in the laparoscopic group by 3.5 days (95 percent confidence interval, 3.1-4; P < 0.01), whereas the operative time was significantly longer in this group, by approximately 60 minutes (60.38 minutes; 95 percent confidence interval, 49-71.8). CONCLUSIONS: Laparoscopic abdominal rectopexy is a safe and feasible procedure, which may compare equally with the open technique with regards to recurrence and morbidity and favorably with length of stay. However large-scale randomized trials, with comparative, sound methodology are still needed to ascertain detailed outcome measures accurately.

Adult↗
PubMed2005

Does minimally invasive vein harvesting technique affect the quality of the conduit for coronary revascularization?

The effect of minimally invasive great saphenous vein harvest on patient morbidity (wound infection and other healing disturbances) has been extensively investigated, yet its impact on the quality of the venous conduit is less well known. This study aims to review the literature with regard to macroscopic quality, postoperative myocardial infarction rates, and angiographic patency of the minimally invasive versus conventionally harvested vein using meta-analytic techniques where appropriate. Results suggest that conduits are comparable in macroscopic quality with minimally invasively harvested veins requiring more repairs prior to grafting. Postoperative myocardial infarction rates were not significantly different between groups, which is supported by the limited evidence on angiographic patency.

Coronary Artery Bypass↗
PubMed2005

Do technical parameters affect the diagnostic accuracy of virtual bronchoscopy in patients with suspected airways stenosis?

PURPOSE: Virtual bronchoscopy has gained popularity over the past decade as an alternative investigation to conventional bronchoscopy in the diagnosis, grading and monitoring of airway disease. The effect of technical parameters on diagnostic outcome from virtual bronchoscopy has not been determined. This meta-analysis aims to estimate accuracy of virtual compared to conventional bronchoscopy in patients with suspected airway stenosis, and evaluate the influence of technical parameters. MATERIALS AND METHODS: A MEDLINE search was used to identify relevant published studies. The primary endpoint was the "correct diagnosis" of stenotic lesions on virtual compared to conventional bronchoscopy. Secondary endpoints included the effects of the technical parameters (pitch, collimation, reconstruction interval, rendering method, and scanner type), and date of publication on the diagnostic accuracy of virtual bronchoscopy. RESULTS: Thirteen studies containing 454 patients were identified. Meta-analysis showed good overall diagnostic performance with 85% calculated pooled sensitivity (95% CI 77-91%), 87% specificity (95% CI 81-92%) and area under the curve (AUC) of 0.947. Subgroups included collimation of 3mm or more (AUC 0.948), pitch of 1 (AUC 0.955), surface rendering technique (AUC 0.935), and reconstruction interval of more than 1.25 mm (AUC 0.914). There was no significant difference in accuracy accounting for publication date, scanner type or any of the above variables. Weighted regression analysis confirmed none of these variables could significantly account for study heterogeneity. CONCLUSION: Virtual bronchoscopy performs well in the investigation of patients with suspected airway stenosis. Overall sensitivity and specificity and diagnostic odds ratio for diagnosis of airway stenosis were high. The effects of pitch, collimation, reconstruction interval, rendering technique, scanner type, and publication date on diagnostic accuracy were not significant.

Airway Obstruction↗
PubMed2005

Haemostasis using a ready-to-use collagen sponge coated with activated thrombin and fibrinogen.

Adequate haemostasis is an important part of any surgical procedure, but particularly so in the case of visceral organ surgery where apparently insignificant ooze can ultimately result in significant haemorrhage and coagulopathy. To achieve haemorrhage control, the surgeon may use conventional techniques (eg, suture ligation, diathermy, and swab compression), but failing this has the option of using physical coagulation tools (eg, the argon beam coagulator) and haemostasis adjuncts (eg, fibrin glues and collagen sheets). Advances in manufacturing have led to development of several other haemostatic products including absorbable gelatin sponges, cyanoacrylates, and polymer-based adhesives. One such product consists of a fixed, ready-to-use equine collagen sponge coated with human thrombin and fibrinogen. It may be applied directly to the bleeding surface, without the need for preparation or reconstitution. This chapter reviews the published evidence and compares its use to other classes of haemostasis adjuncts across a range of surgical specialties, namely hepatic, splenic, thoracic, vascular, and minimally invasive surgery. It also aims to highlight the apparent advantages and limitations of the fibrinogen and thrombin-coated collagen sponge compared to other commercially available haemostasis adjuncts, and identify potential applications for the product.

Animals↗
PubMed2004

Apical suction device facilitating off-pump bypass for recurrent coarctation: case report.

Apical suction devices to perform complete surgical revascularization without cardiopulmonary bypass have been recently introduced in cardiac surgical practice. We have increasingly explored the possibility of using these devices to perform other procedures on a beating heart that have previously necessitated the need for cardiopulmonary bypass. We present a case of recurrent coarctation in which an ascending-to-abdominal aorta bypass graft was successfully facilitated by the use of an apical suction device. The surgical technique and advantages and disadvantages of this method are highlighted.

Adult↗
PubMed2004

Do off-pump techniques reduce the incidence of postoperative atrial fibrillation in elderly patients undergoing coronary artery bypass grafting?

BACKGROUND: Atrial fibrillation is the most common postoperative complication in patients undergoing coronary artery bypass grafting (CABG) with advancing age having been shown to have a significant association with its incidence. This study aims to assess whether off-pump coronary artery bypass (OPCAB) reduces the incidence of atrial fibrillation in elderly patients. METHODS: A meta-analysis of all observational studies reporting a comparison between the two techniques in elderly patients (> 70 years) between 1999-2003 was performed. The primary outcome of interest was the incidence of postoperative atrial fibrillation. The quality of each study was evaluated by examining three items: patient selection, matching of the off-pump and cardiopulmonary bypass patient groups, and assessment of outcome. Meta-regression analysis was undertaken to see the effects of study size and quality on the calculated odds ratio. RESULTS: Eight studies fulfilled our inclusion criteria, all of which were nonrandomized. In total the studies identified 3017 subjects, of which 764 had off-pump surgery (25%) and 2253 underwent cardiopulmonary bypass (75%). Meta-analysis showed that after off-pump surgery there was a significantly lower incidence of postoperative atrial fibrillation in these patients (odds ratio 0.70, 95% confidence interval [CI] 0.56-0.89). Meta-regression analysis including study characteristics did not show any associations affecting the calculated odds ratio of atrial fibrillation. CONCLUSIONS: Our study demonstrates a reduced incidence of postoperative atrial fibrillation in an elderly population with off-pump as compared with cardiopulmonary bypass techniques. We appreciate, however, that our statistical analysis uses nonrandomized published data and that the results must be treated with caution. If this finding is confirmed by a large-scale randomized trial, it has significant implications on the operative strategy employed for this patient group.

Aged↗
PubMed2004

Does off-pump coronary artery bypass reduce the incidence of post-operative atrial fibrillation? A question revisited.

Atrial fibrillation (AF) is the most common post-operative complication in patients undergoing coronary artery bypass grafting, with an increased incidence associated with advancing age. This study aims to determine whether off-pump coronary artery bypass (OPCAB) reduces the incidence of AF in a generalized population (mean age <70 years). A meta-analysis was performed including all randomised and propensity score matched non-randomised studies published between 2001 and 2003 reporting a comparison between the two techniques in a generalised patient group (average age <70 years). The primary outcome of interest was post-operative AF. Sensitivity analysis was performed to evaluate consistency of the calculated treatment effect. Fourteen studies fulfilled our inclusion criteria, including a total of 16,505 subjects. The incidence of AF was 19% (1612/8265) in the off-pump group versus 24% (1976/8240) in the on-pump group. When considering only the 11 randomised studies (2207 subjects), we found a significant reduction in the incidence of post-operative AF in the off-pump group using a random-effect model (odds ratio (OR)=0.60, 95% confidence interval (CI)=0.45-0.82, and chi-square of heterogeneity=18.02, P=0.05). Sensitivity analysis highlighted one randomised study causing funnel plot asymmetry, exclusion of which resulted in a significant reduction in the incidence of post-operative AF in the off-pump group (OR=0.71, 95% CI=0.57-0.90), with a non-significant heterogeneity of 3.91 (P=0.92). When only studies of high quality were considered (898 patients), no significant difference was seen between on and off-pump groups (OR=0.78, 95% CI=0.57-1.07, and heterogeneity=0.53, P=0.91). This may be due to small number of patients in this group. Our results suggest that although OPCAB surgery may reduce the incidence of post-operative AF in a generalised population (age <70 years) this finding is not clearly supported by high quality randomised trials. Although previous evidence suggests that the incidence of post-operative AF is reduced in an elderly population (>70 years) with off-pump surgery, our results show that the evidence is less clear in a younger population group. The question of whether off-pump surgery in this patient group results in a lower rate of post-operative AF remains to be answered by further high quality randomised research.

Adult↗
PubMed2004

Are wound healing disturbances and length of hospital stay reduced with minimally invasive vein harvest? A meta-analysis.

Minimally invasive great saphenous vein harvest for coronary artery bypass grafting aims to reduce post-operative leg-wound related morbidity. In a meta-analysis of randomised trials we have shown leg wound infection rates to be significantly lower in patients undergoing minimally invasive harvest. This study aims to use meta-analysis to compare the two techniques with regards to non-infective wound healing disturbances (NIWHD) (wound drainage, haematoma, dehiscence, necrosis, need for surgical debridement, and seroma formation). A meta-analysis of all studies published between 1995 and 2002 reporting a comparison between the two techniques was performed. Primary outcomes of interest were the six wound healing disturbances mentioned above and length of hospital stay. Heterogeneity was assessed using graphical exploration and sensitivity analysis with subgroup analysis. Twenty-seven studies published between 1997 and 2002 matched our selection criteria, with a combined total of 4953 subjects, of which 2442(49%) underwent minimally invasive harvest and 2511(51%) underwent conventional surgery. When considering only randomised studies, the total number of non-infective wound disturbances was lower in minimally invasive (4%) as compared to the conventional (13%) group (random effect OR 0.24, CI 0.16-0.38). Similar results were found when only fully matched studies were considered. The absolute risk reduction when comparing the two techniques was calculated to be 0.10, which translates to a number of patients needed to treat of 10. Length of stay was significantly reduced in the minimally invasive group in comparison to the conventional group (random effect weighted mean difference of -1.04, CI -1.92 to -0.16). Our results suggest that NIWHD all reduced with minimally invasive harvest techniques. Despite the limitations of this meta-analysis, we feel we have once again illustrated an important link between minimally invasive great saphenous vein harvest and improved tissue healing when compared to conventional open surgery. This has the potential to reduce wound-related morbidity, infection, post-operative pain, length of hospital stay, and re-admission rate.

Coronary Artery Bypass↗