Tejas Singh - Academia.edu (original) (raw)

Papers by Tejas Singh

Research paper thumbnail of A Systematic Review and Meta-Analysis of the Incidence and Risk Factors for Major Adverse Cardiovascular Events in Patients with Unrepaired Abdominal Aortic Aneurysms

Biomedicines

Major adverse cardiovascular events (MACE), including myocardial infarction (MI), stroke and card... more Major adverse cardiovascular events (MACE), including myocardial infarction (MI), stroke and cardiovascular death, cause substantial morbidity and mortality. This review assessed the incidence rate of MACE and the association with modifiable risk factors (diabetes, hypertension) and medication use (aspirin, statins) in patients with unrepaired abdominal aortic aneurysm (AAA). Electronic databases were searched systematically for observational studies reporting the incidence of MI, stroke or cardiovascular death in patients with unrepaired AAAs. The primary outcome was cardiovascular death reported as an incidence rate (events per 100 person-years (PY)). Fourteen studies, including 69,579 participants with a mean follow-up time of 5.4 years, were included. Meta-analysis revealed the overall incidence of cardiovascular death, MI and stroke of 2.31 per 100 PY (95% CI, 1.63–3.26; I2 = 98%), 1.65 per 100 PY (95% CI, 1.01–2.69, I2 = 88%) and 0.89 per 100 PY (95% CI, 0.53–1.48, I2 = 87.0%)...

Research paper thumbnail of Association between aortic peak wall stress and rupture index with abdominal aortic aneurysm–related events

European Radiology

Objective The aim of this study was to assess whether aortic peak wall stress (PWS) and peak wall... more Objective The aim of this study was to assess whether aortic peak wall stress (PWS) and peak wall rupture index (PWRI) were associated with the risk of abdominal aortic aneurysm (AAA) rupture or repair (defined as AAA events) among participants with small AAAs. Methods PWS and PWRI were estimated from computed tomography angiography (CTA) scans of 210 participants with small AAAs (≥ 30 and ≤ 50 mm) prospectively recruited between 2002 and 2016 from two existing databases. Participants were followed for a median of 2.0 (inter-quartile range 1.9, 2.8) years to record the incidence of AAA events. The associations between PWS and PWRI with AAA events were assessed using Cox proportional hazard analyses. The ability of PWS and PWRI to reclassify the risk of AAA events compared to the initial AAA diameter was examined using net reclassification index (NRI) and classification and regression tree (CART) analysis. Results After adjusting for other risk factors, one standard deviation increa...

Research paper thumbnail of Comparison of peak wall stress and peak wall rupture index in ruptured and asymptomatic intact abdominal aortic aneurysms

British Journal of Surgery

Background Previous studies have suggested that finite element analysis (FEA) can estimate the ru... more Background Previous studies have suggested that finite element analysis (FEA) can estimate the rupture risk of an abdominal aortic aneurysm (AAA); however, the value of biomechanical estimates over measurement of AAA diameter alone remains unclear. This study aimed to compare peak wall stress (PWS) and peak wall rupture index (PWRI) in participants with ruptured and asymptomatic intact AAAs. Methods The reproducibility of semiautomated methods for estimating aortic PWS and PWRI from CT images was assessed. PWS and PWRI were estimated in people with ruptured AAAs and those with asymptomatic intact AAAs matched by orthogonal diameter on a 1 : 2 basis. Spearman's correlation coefficient was used to assess the association between PWS or PWRI and AAA diameter. Independent associations between PWS or PWRI and AAA rupture were identified by means of logistic regression analyses. Results Twenty individuals were included in the analysis of reproducibility. The main analysis included 50 p...

Research paper thumbnail of Association of Oral Anticoagulation Prescription with Clinical Events in Patients with an Asymptomatic Unrepaired Abdominal Aortic Aneurysm

Biomedicines

Background: Most abdominal aortic aneurysms (AAA) have large volumes of intraluminal thrombus whi... more Background: Most abdominal aortic aneurysms (AAA) have large volumes of intraluminal thrombus which has been implicated in promoting the risk of major adverse events. The aim of this study was to examine the association of therapeutic anticoagulation with AAA-related events and major adverse cardiovascular events (MACE) in patients with an unrepaired AAA. Methods: Patients with an asymptomatic unrepaired AAA were recruited from four sites in Australia. The primary outcome was the combined incidence of AAA repair or AAA rupture-related mortality (AAA-related events). The main secondary outcome was MACE (the combined incidence of myocardial infarction, stroke, or cardiovascular death). The associations of anticoagulation with these outcomes were assessed using Cox proportional hazard analyses (reporting hazard ratio, HR, and 95% confidence intervals, CI) to adjust for other risk factors. Results: A total of 1161 patients were followed for a mean (standard deviation) of 4.9 (4.0) years...

Research paper thumbnail of Major amputation rates and outcomes for Aboriginal and Torres Strait Islander and non-Indigenous people in North Queensland Australia between 2000 and 2015

BMC Endocrine Disorders

Background This study estimated the incidence of major amputation for people in North Queensland,... more Background This study estimated the incidence of major amputation for people in North Queensland, Australia, examined changes in amputation rates over time and investigated survival after major amputation. Methods This was a retrospective study of patients who underwent a major amputation above the ankle between 2000 and 2015. Major amputation rates and incidence rate ratios (IRR) were calculated using census data to define the at-risk population. Associations between risk factors and calendar year with major amputation were assessed using quasipoisson regression. Kaplan-Meier survival and Cox-proportional hazard analyses estimated the incidence of and risk factors for all-cause mortality. Results The annual incidence of major amputation was estimated to be greater in Aboriginal and Torres Strait Islanders than non-Indigenous people (IRR 2.75, 95 % CI 1.92 to 3.84). After adjusting for population growth, the annual incidence of major amputations did not change significantly over tim...

Research paper thumbnail of Additional file 1: of A meta-analysis of the efficacy of allopurinol in reducing the incidence of myocardial infarction following coronary artery bypass grafting

Table S1. Diagnostic criteria for MI. Table S2. Sensitivity Analyses using the leave-one-out appr... more Table S1. Diagnostic criteria for MI. Table S2. Sensitivity Analyses using the leave-one-out approach. (DOCX 18 kb)

Research paper thumbnail of Opinions of vascular surgeons and podiatrists in Australia and New Zealand on the use of hyperbaric oxygen therapy for lower limb ulcers

BMJ Open Diabetes Research & Care, 2020

IntroductionHyperbaric oxygen therapy (HBOT) has been suggested to improve healing of lower limb ... more IntroductionHyperbaric oxygen therapy (HBOT) has been suggested to improve healing of lower limb ulcers, though the quality of available evidence is weak to moderate. This study assessed the opinions and use of HBOT by specialists treating lower limb ulcers.Research design and methodsAccredited vascular surgeons and podiatrists in Australia and New Zealand were sent an online survey via their professional organizations. The survey asked about their use and opinions of HBOT in treating lower limb ischemic, neuropathic and venous ulcers. Data were summarized with descriptive statistics. Non-parametric tests were used to compare survey results obtained from vascular surgeons and podiatrists.Results61 vascular surgeons and 40 podiatrists completed the survey. Thirty-seven specialists used HBOT for treating lower limb ulcers, with the remainder indicating they did not feel there was a role for HBOT (n=25) or did not have access to HBOT (n=39). Less than 8% of specialists indicated that H...

Research paper thumbnail of Author response to: Peak wall stress and peak wall rupture index in ruptured and asymptomatic intact abdominal aortic aneurysms

British Journal of Surgery, 2021

Research paper thumbnail of Systematic Review and Meta-Analysis of Mendelian Randomisation Analyses of Abdominal Aortic Aneurysms

Journal of Vascular Surgery, 2021

Introduction: Mendelian randomisation (MR) has been suggested to be able to overcome biases of ob... more Introduction: Mendelian randomisation (MR) has been suggested to be able to overcome biases of observational studies, but no meta-analysis is available on MR studies on abdominal aortic aneurysm (AAA). This systematic review and Meta-analysis examined the evidence of causal risk factors for AAA identified in MR studies. Methods: Publicly available databases were systematically searched for MR studies that reported any causal risk factors for AAA diagnosis. Meta-analyses were performed using random effect models and reported as odds ratio (OR) and 95% confidence intervals (CI). Study quality was assessed using a modified version of Strengthening the Reporting of Mendelian Randomisation Studies (STROBE-MR) guidelines. Results: Sixteen MR studies involving 34,050 patients with AAA and 2,205,894 controls were included. Meta-analyses suggested that one standard deviation increase in high density lipoprotein (HDL) significantly reduced (OR: 0.66, 95% CI: 0.61, 0.72) and one standard deviation increase in low density lipoprotein (LDL) significantly increased the risk (OR: 1.68, 95%, CI: 1.55, 1.82) of AAA. One standard deviation increase in triglycerides did not significantly increase the risk of AAA (OR: 1.21, 95% CI: 0.86, 1.71). Quality assessment suggested that ten and five studies were of low and moderate risk of bias respectively, with one study considered as high risk of bias. Conclusion: This meta-analysis suggests LDL and HDL are positive and negative casual risk factors for AAA.

Research paper thumbnail of Association of chronic venous disease with major adverse cardiovascular events

Journal of Vascular Surgery: Venous and Lymphatic Disorders, 2021

OBJECTIVE The aim of this study was to examine if severe chronic venous disease (CVD) was associa... more OBJECTIVE The aim of this study was to examine if severe chronic venous disease (CVD) was associated with a greater risk of major adverse cardiovascular events (MACE) than mild CVD. METHODS Participants with CVD were prospectively recruited from outpatient vascular departments at two hospitals in North Queensland, Australia. CVD severity was ascertained by vascular specialists using the Clinical, Etiological, Anatomical and Pathophysiological (CEAP) staging criteria. MACE, defined as myocardial infarction, stroke or cardiovascular death, were identified from outpatient follow-up and linked medical records. Kaplan-Meier and Cox-proportional hazard analyses were used to examine the association of CVD severity with MACE. A sub-analysis was performed in which participants with CEAP C5 and C6 (Severe CVD) were compared with participants with CEAP C2, C3 and C4 (Mild CVD). RESULTS A total of 774 participants were included and followed for a median (inter-quartile range) of 3.09 (1.09-8.14) years. Participants with CEAP C6 CVD (n=69) had a three-fold greater risk of MACE (Hazard ratio, HR 3.03, 95% confidence intervals, CI 1.02-9.03; p=0.046) compared to those with C2 CVD (n=326) after adjusting for other risk factors. Participants with severe CVD were at increased risk of MACE compared to those with mild CVD (adjusted HR 2.37, 95% CI 1.12-5.04; p=0.024). CONCLUSION Individuals with severe CVD are at increased risk of MACE compared to those with mild CVD independent of traditional risk factors. Further research is required to clarify the cause of the excess risk.

Research paper thumbnail of Topical oxygen therapy for diabetes‐related foot ulcers: A systematic review and meta‐analysis

Diabetic Medicine, 2021

IntroductionTopical oxygen therapy (TOT) has been suggested as a treatment for diabetes‐related f... more IntroductionTopical oxygen therapy (TOT) has been suggested as a treatment for diabetes‐related foot ulcer (DFU) but no prior meta‐analyses of randomised clinical trials (RCT) have been reported. This systematic review and meta‐analysis examined the randomised evidence for the benefit of TOT in healing DFU.MethodsPublicly available databases were searched for RCTs investigating the effect of TOT on wound healing in participants with a DFU. The primary outcome was ulcer healing defined as full epithelialisation. Meta‐analyses were performed using random effect models and reported as risk ratios (RR) and 95% confidence intervals (CI). Study quality and publication bias were assessed using a modified version of the Cochrane Collaboration's tool and funnel plots, respectively.ResultsSix RCTs involving 530 participants with a DFU testing TOT were included. Meta‐analysis suggested that TOT significantly increased the likelihood of ulcer healing compared to controls (Risk ratio [RR] 1....

Research paper thumbnail of Effect of Blood Pressure Lowering Drugs and Antibiotics on Abdominal Aortic Aneurysm Growth: A Systematic Review and Meta-Analysis

Journal of Vascular Surgery, 2021

Objective There is currently no medical treatment proven to limit abdominal aortic aneurysm (AAA)... more Objective There is currently no medical treatment proven to limit abdominal aortic aneurysm (AAA) progression. The aim of this systematic review and meta-analysis was to pool data from previous randomised controlled trials assessing the efficacy of blood pressure-lowering and antibiotic medications in limiting AAA growth and AAA-related events, that is, rupture or repair. Methods A systematic literature search was performed to identify randomised controlled trials that examined the efficacy of blood pressure-lowering medications or antibiotics in reducing AAA growth and AAA-related events. AAA growth (mm/year) was measured by ultrasound or computed tomography imaging. Meta-analyses were performed using random effects models. A subanalysis was conducted including trials that investigated tetracycline or macrolide antibiotics. Results Ten randomised controlled trials including 2045 participants with an asymptomatic AAA were included. Follow-up was between 18 and 63 months. Neither blood pressure-lowering medications (mean growth±SD 2.0±2.4 vs 2.3±2.7 mm/year; standardised mean difference (SMD) −0.07, 95% CI −0.19 to 0.06; p=0.288) or antibiotics (mean growth±SD 2.6±2.1 vs 2.6±2.5 mm/year; SMD −0.11, 95% CI −0.38 to 0.16; p=0.418) reduced AAA growth or AAA-related events (blood pressure-lowering medications: 92 vs 95 events; risk ratio (RR) 0.86, 95% CI 0.66 to 1.11; p=0.244; and antibiotics: 69 vs 73 events; RR 0.93, 95% CI 0.69 to 1.25; p=0.614). The subanalysis of antibiotics showed similar results. Conclusions This meta-analysis suggests that neither blood pressure-lowering medications or antibiotics limit growth or clinically relevant events in people with AAAs.

Research paper thumbnail of Lack of an effective drug therapy for abdominal aortic aneurysm

Journal of Internal Medicine, 2019

Content List-Read more articles from the symposium: "Uppsala Aortic summit".

Research paper thumbnail of Meta-analysis of clinical trials examining the benefit of structured home exercise in patients with peripheral artery disease

British Journal of Surgery, 2019

Background Supervised exercise is recommended for the management of peripheral artery disease (PA... more Background Supervised exercise is recommended for the management of peripheral artery disease (PAD); however, the uptake is limited. Structured home exercise programmes may be more feasible, but their effectiveness is unclear. This systematic review and meta-analysis examined the benefit of structured home exercise programmes for treating PAD in comparison to controls not receiving an exercise programme. Methods A literature search was conducted to identify RCTs comparing structured home exercise with controls not receiving an exercise programme among patients with PAD. To be included, studies had to report outcomes from treadmill or corridor walking tests, or objective assessment of physical activity. Inverse variance-weighted meta-analysis was performed to compare changes in maximum walking distance and intermittent claudication onset distance in treadmill tests, walking distance during a 6-min walking test, and physical activity measured using a pedometer or accelerometer. Summar...

Research paper thumbnail of Presentation and outcomes of indigenous Australians with peripheral artery disease

BMC cardiovascular disorders, Jan 16, 2018

The risk factors for peripheral artery disease (PAD) are more common in Indigenous than non-Indig... more The risk factors for peripheral artery disease (PAD) are more common in Indigenous than non-Indigenous Australians, however the presentation and outcome of PAD in Indigenous Australians has not been previously investigated. The aim of this prospective cohort study was to compare the presenting characteristics and clinical outcome of Indigenous and non-Indigenous Australians with PAD. PAD patients were prospectively recruited and followed-up since 2003 from an outpatient vascular clinic in Townsville, Australia. Presenting symptoms and risk factors in Indigenous and non-Indigenous patients were compared using Pearson's χ2 test and Mann Whitney U test. Kaplan Meier survival analysis and Cox proportional hazard analysis were used to compare the incidence of myocardial infarction (MI), stroke or death (major cardiovascular events) among Indigenous and non-Indigenous patients. Four hundred and one PAD patients were recruited, of which 16 were Indigenous and 385 were non-Indigenous Au...

Research paper thumbnail of Response to “Re: A Systematic Review and Meta-analysis of the Association Between C-reactive Protein and Major Cardiovascular Events in Patients with Peripheral Artery Disease”

European Journal of Vascular and Endovascular Surgery, 2017

Research paper thumbnail of Association between metformin prescription and growth rates of abdominal aortic aneurysms

British Journal of Surgery, 2017

Background It has been suggested that diabetes medications, such as metformin, may have effects t... more Background It has been suggested that diabetes medications, such as metformin, may have effects that inhibit abdominal aortic aneurysm (AAA) growth. The aim of this study was to examine the association of diabetes treatments with AAA growth in three patient cohorts. Methods AAA growth was studied using ultrasound surveillance in cohort 1, repeated CT in cohort 2 and more detailed repeat CT in cohort 3. Growth was estimated by the mean annual increase in maximum AAA diameter. Results A total of 1697 patients with an AAA were studied, of whom 118, 39 and 16 patients were prescribed metformin for the treatment of diabetes in cohorts 1, 2 and 3 respectively. Prescription of metformin was associated with a reduced likelihood of median or greater AAA growth in all three cohorts (cohort 1: adjusted odds ratio (OR) 0·59, 95 per cent c.i. 0·39 to 0·87, P = 0·008; cohort 2: adjusted OR 0·38, 0·18 to 0·80, P = 0·011; cohort 3: adjusted OR 0·13, 0·03 to 0·61, P = 0·010). No other diabetes treat...

Research paper thumbnail of Assessment and validation of a novel angiographic scoring system for peripheral artery disease

The British journal of surgery, Jan 31, 2017

Angiography is used routinely in the assessment of lower-limb arteries, but there are few well va... more Angiography is used routinely in the assessment of lower-limb arteries, but there are few well validated angiographic scoring systems. The aim of this study was to develop and validate a novel angiographic scoring system for peripheral artery disease. An angiographic scoring system (the ANGIO score) was developed and applied to a sample of patients from a single vascular surgical department who underwent CT angiography of the lower limbs. The reproducibility of the ANGIO score was compared with those of the Bollinger and Trans-Atlantic inter-Society Consensus (TASC) IIb systems in a series of randomly selected patients. Associations between the ANGIO score and lower-limb ischaemia, as measured by the ankle : brachial pressure index (ABPI), and outcome events (major lower-limb amputations and cardiovascular events - myocardial infarction, stroke and cardiovascular death) were assessed. Some 256 patients undergoing CT angiography were included. The interobserver reproducibility of the...

Research paper thumbnail of Association of Computed Tomographic Leg Muscle Characteristics With Lower Limb and Cardiovascular Events in Patients With Peripheral Artery Disease

Journal of the American Heart Association, 2018

Background Poor lower extremity physical performance is an independent predictor of unfavorable o... more Background Poor lower extremity physical performance is an independent predictor of unfavorable outcome in patients with peripheral artery disease ( PAD ); however, few studies have assessed muscle characteristics on imaging directly. Method and Results A novel 3‐dimensional semi‐automated protocol was developed to estimate leg muscle volume and density (mean attenuation) from computed tomography images. Patients with PAD who underwent a lower extremity computed tomography scan at a tertiary vascular surgery center were included, and were followed up using hospital records and linked data as part of a retrospective cohort study. The primary outcomes were lower limb events (major amputation or peripheral revascularization) and cardiovascular events (myocardial infarction, stroke, or cardiovascular death). Two hundred and twenty‐three patients with PAD were included (median age 69.0 years; 73% men) and followed for a median of 4.9 [2.6–7.0] years. During this time there were 99 index ...

Research paper thumbnail of A Meta-Analysis of the Efficacy of Allopurinol in Reducing the Incidence of Myocardial Infarction (MI)

Heart, Lung and Circulation, 2017

Introduction: Teratomas are the most common type of germ cell tumour in the anterior mediastinum.... more Introduction: Teratomas are the most common type of germ cell tumour in the anterior mediastinum. They are of equal distribution in both males and females with a peak incidence in young adults. Less than one per cent are malignant,

Research paper thumbnail of A Systematic Review and Meta-Analysis of the Incidence and Risk Factors for Major Adverse Cardiovascular Events in Patients with Unrepaired Abdominal Aortic Aneurysms

Biomedicines

Major adverse cardiovascular events (MACE), including myocardial infarction (MI), stroke and card... more Major adverse cardiovascular events (MACE), including myocardial infarction (MI), stroke and cardiovascular death, cause substantial morbidity and mortality. This review assessed the incidence rate of MACE and the association with modifiable risk factors (diabetes, hypertension) and medication use (aspirin, statins) in patients with unrepaired abdominal aortic aneurysm (AAA). Electronic databases were searched systematically for observational studies reporting the incidence of MI, stroke or cardiovascular death in patients with unrepaired AAAs. The primary outcome was cardiovascular death reported as an incidence rate (events per 100 person-years (PY)). Fourteen studies, including 69,579 participants with a mean follow-up time of 5.4 years, were included. Meta-analysis revealed the overall incidence of cardiovascular death, MI and stroke of 2.31 per 100 PY (95% CI, 1.63–3.26; I2 = 98%), 1.65 per 100 PY (95% CI, 1.01–2.69, I2 = 88%) and 0.89 per 100 PY (95% CI, 0.53–1.48, I2 = 87.0%)...

Research paper thumbnail of Association between aortic peak wall stress and rupture index with abdominal aortic aneurysm–related events

European Radiology

Objective The aim of this study was to assess whether aortic peak wall stress (PWS) and peak wall... more Objective The aim of this study was to assess whether aortic peak wall stress (PWS) and peak wall rupture index (PWRI) were associated with the risk of abdominal aortic aneurysm (AAA) rupture or repair (defined as AAA events) among participants with small AAAs. Methods PWS and PWRI were estimated from computed tomography angiography (CTA) scans of 210 participants with small AAAs (≥ 30 and ≤ 50 mm) prospectively recruited between 2002 and 2016 from two existing databases. Participants were followed for a median of 2.0 (inter-quartile range 1.9, 2.8) years to record the incidence of AAA events. The associations between PWS and PWRI with AAA events were assessed using Cox proportional hazard analyses. The ability of PWS and PWRI to reclassify the risk of AAA events compared to the initial AAA diameter was examined using net reclassification index (NRI) and classification and regression tree (CART) analysis. Results After adjusting for other risk factors, one standard deviation increa...

Research paper thumbnail of Comparison of peak wall stress and peak wall rupture index in ruptured and asymptomatic intact abdominal aortic aneurysms

British Journal of Surgery

Background Previous studies have suggested that finite element analysis (FEA) can estimate the ru... more Background Previous studies have suggested that finite element analysis (FEA) can estimate the rupture risk of an abdominal aortic aneurysm (AAA); however, the value of biomechanical estimates over measurement of AAA diameter alone remains unclear. This study aimed to compare peak wall stress (PWS) and peak wall rupture index (PWRI) in participants with ruptured and asymptomatic intact AAAs. Methods The reproducibility of semiautomated methods for estimating aortic PWS and PWRI from CT images was assessed. PWS and PWRI were estimated in people with ruptured AAAs and those with asymptomatic intact AAAs matched by orthogonal diameter on a 1 : 2 basis. Spearman's correlation coefficient was used to assess the association between PWS or PWRI and AAA diameter. Independent associations between PWS or PWRI and AAA rupture were identified by means of logistic regression analyses. Results Twenty individuals were included in the analysis of reproducibility. The main analysis included 50 p...

Research paper thumbnail of Association of Oral Anticoagulation Prescription with Clinical Events in Patients with an Asymptomatic Unrepaired Abdominal Aortic Aneurysm

Biomedicines

Background: Most abdominal aortic aneurysms (AAA) have large volumes of intraluminal thrombus whi... more Background: Most abdominal aortic aneurysms (AAA) have large volumes of intraluminal thrombus which has been implicated in promoting the risk of major adverse events. The aim of this study was to examine the association of therapeutic anticoagulation with AAA-related events and major adverse cardiovascular events (MACE) in patients with an unrepaired AAA. Methods: Patients with an asymptomatic unrepaired AAA were recruited from four sites in Australia. The primary outcome was the combined incidence of AAA repair or AAA rupture-related mortality (AAA-related events). The main secondary outcome was MACE (the combined incidence of myocardial infarction, stroke, or cardiovascular death). The associations of anticoagulation with these outcomes were assessed using Cox proportional hazard analyses (reporting hazard ratio, HR, and 95% confidence intervals, CI) to adjust for other risk factors. Results: A total of 1161 patients were followed for a mean (standard deviation) of 4.9 (4.0) years...

Research paper thumbnail of Major amputation rates and outcomes for Aboriginal and Torres Strait Islander and non-Indigenous people in North Queensland Australia between 2000 and 2015

BMC Endocrine Disorders

Background This study estimated the incidence of major amputation for people in North Queensland,... more Background This study estimated the incidence of major amputation for people in North Queensland, Australia, examined changes in amputation rates over time and investigated survival after major amputation. Methods This was a retrospective study of patients who underwent a major amputation above the ankle between 2000 and 2015. Major amputation rates and incidence rate ratios (IRR) were calculated using census data to define the at-risk population. Associations between risk factors and calendar year with major amputation were assessed using quasipoisson regression. Kaplan-Meier survival and Cox-proportional hazard analyses estimated the incidence of and risk factors for all-cause mortality. Results The annual incidence of major amputation was estimated to be greater in Aboriginal and Torres Strait Islanders than non-Indigenous people (IRR 2.75, 95 % CI 1.92 to 3.84). After adjusting for population growth, the annual incidence of major amputations did not change significantly over tim...

Research paper thumbnail of Additional file 1: of A meta-analysis of the efficacy of allopurinol in reducing the incidence of myocardial infarction following coronary artery bypass grafting

Table S1. Diagnostic criteria for MI. Table S2. Sensitivity Analyses using the leave-one-out appr... more Table S1. Diagnostic criteria for MI. Table S2. Sensitivity Analyses using the leave-one-out approach. (DOCX 18 kb)

Research paper thumbnail of Opinions of vascular surgeons and podiatrists in Australia and New Zealand on the use of hyperbaric oxygen therapy for lower limb ulcers

BMJ Open Diabetes Research & Care, 2020

IntroductionHyperbaric oxygen therapy (HBOT) has been suggested to improve healing of lower limb ... more IntroductionHyperbaric oxygen therapy (HBOT) has been suggested to improve healing of lower limb ulcers, though the quality of available evidence is weak to moderate. This study assessed the opinions and use of HBOT by specialists treating lower limb ulcers.Research design and methodsAccredited vascular surgeons and podiatrists in Australia and New Zealand were sent an online survey via their professional organizations. The survey asked about their use and opinions of HBOT in treating lower limb ischemic, neuropathic and venous ulcers. Data were summarized with descriptive statistics. Non-parametric tests were used to compare survey results obtained from vascular surgeons and podiatrists.Results61 vascular surgeons and 40 podiatrists completed the survey. Thirty-seven specialists used HBOT for treating lower limb ulcers, with the remainder indicating they did not feel there was a role for HBOT (n=25) or did not have access to HBOT (n=39). Less than 8% of specialists indicated that H...

Research paper thumbnail of Author response to: Peak wall stress and peak wall rupture index in ruptured and asymptomatic intact abdominal aortic aneurysms

British Journal of Surgery, 2021

Research paper thumbnail of Systematic Review and Meta-Analysis of Mendelian Randomisation Analyses of Abdominal Aortic Aneurysms

Journal of Vascular Surgery, 2021

Introduction: Mendelian randomisation (MR) has been suggested to be able to overcome biases of ob... more Introduction: Mendelian randomisation (MR) has been suggested to be able to overcome biases of observational studies, but no meta-analysis is available on MR studies on abdominal aortic aneurysm (AAA). This systematic review and Meta-analysis examined the evidence of causal risk factors for AAA identified in MR studies. Methods: Publicly available databases were systematically searched for MR studies that reported any causal risk factors for AAA diagnosis. Meta-analyses were performed using random effect models and reported as odds ratio (OR) and 95% confidence intervals (CI). Study quality was assessed using a modified version of Strengthening the Reporting of Mendelian Randomisation Studies (STROBE-MR) guidelines. Results: Sixteen MR studies involving 34,050 patients with AAA and 2,205,894 controls were included. Meta-analyses suggested that one standard deviation increase in high density lipoprotein (HDL) significantly reduced (OR: 0.66, 95% CI: 0.61, 0.72) and one standard deviation increase in low density lipoprotein (LDL) significantly increased the risk (OR: 1.68, 95%, CI: 1.55, 1.82) of AAA. One standard deviation increase in triglycerides did not significantly increase the risk of AAA (OR: 1.21, 95% CI: 0.86, 1.71). Quality assessment suggested that ten and five studies were of low and moderate risk of bias respectively, with one study considered as high risk of bias. Conclusion: This meta-analysis suggests LDL and HDL are positive and negative casual risk factors for AAA.

Research paper thumbnail of Association of chronic venous disease with major adverse cardiovascular events

Journal of Vascular Surgery: Venous and Lymphatic Disorders, 2021

OBJECTIVE The aim of this study was to examine if severe chronic venous disease (CVD) was associa... more OBJECTIVE The aim of this study was to examine if severe chronic venous disease (CVD) was associated with a greater risk of major adverse cardiovascular events (MACE) than mild CVD. METHODS Participants with CVD were prospectively recruited from outpatient vascular departments at two hospitals in North Queensland, Australia. CVD severity was ascertained by vascular specialists using the Clinical, Etiological, Anatomical and Pathophysiological (CEAP) staging criteria. MACE, defined as myocardial infarction, stroke or cardiovascular death, were identified from outpatient follow-up and linked medical records. Kaplan-Meier and Cox-proportional hazard analyses were used to examine the association of CVD severity with MACE. A sub-analysis was performed in which participants with CEAP C5 and C6 (Severe CVD) were compared with participants with CEAP C2, C3 and C4 (Mild CVD). RESULTS A total of 774 participants were included and followed for a median (inter-quartile range) of 3.09 (1.09-8.14) years. Participants with CEAP C6 CVD (n=69) had a three-fold greater risk of MACE (Hazard ratio, HR 3.03, 95% confidence intervals, CI 1.02-9.03; p=0.046) compared to those with C2 CVD (n=326) after adjusting for other risk factors. Participants with severe CVD were at increased risk of MACE compared to those with mild CVD (adjusted HR 2.37, 95% CI 1.12-5.04; p=0.024). CONCLUSION Individuals with severe CVD are at increased risk of MACE compared to those with mild CVD independent of traditional risk factors. Further research is required to clarify the cause of the excess risk.

Research paper thumbnail of Topical oxygen therapy for diabetes‐related foot ulcers: A systematic review and meta‐analysis

Diabetic Medicine, 2021

IntroductionTopical oxygen therapy (TOT) has been suggested as a treatment for diabetes‐related f... more IntroductionTopical oxygen therapy (TOT) has been suggested as a treatment for diabetes‐related foot ulcer (DFU) but no prior meta‐analyses of randomised clinical trials (RCT) have been reported. This systematic review and meta‐analysis examined the randomised evidence for the benefit of TOT in healing DFU.MethodsPublicly available databases were searched for RCTs investigating the effect of TOT on wound healing in participants with a DFU. The primary outcome was ulcer healing defined as full epithelialisation. Meta‐analyses were performed using random effect models and reported as risk ratios (RR) and 95% confidence intervals (CI). Study quality and publication bias were assessed using a modified version of the Cochrane Collaboration's tool and funnel plots, respectively.ResultsSix RCTs involving 530 participants with a DFU testing TOT were included. Meta‐analysis suggested that TOT significantly increased the likelihood of ulcer healing compared to controls (Risk ratio [RR] 1....

Research paper thumbnail of Effect of Blood Pressure Lowering Drugs and Antibiotics on Abdominal Aortic Aneurysm Growth: A Systematic Review and Meta-Analysis

Journal of Vascular Surgery, 2021

Objective There is currently no medical treatment proven to limit abdominal aortic aneurysm (AAA)... more Objective There is currently no medical treatment proven to limit abdominal aortic aneurysm (AAA) progression. The aim of this systematic review and meta-analysis was to pool data from previous randomised controlled trials assessing the efficacy of blood pressure-lowering and antibiotic medications in limiting AAA growth and AAA-related events, that is, rupture or repair. Methods A systematic literature search was performed to identify randomised controlled trials that examined the efficacy of blood pressure-lowering medications or antibiotics in reducing AAA growth and AAA-related events. AAA growth (mm/year) was measured by ultrasound or computed tomography imaging. Meta-analyses were performed using random effects models. A subanalysis was conducted including trials that investigated tetracycline or macrolide antibiotics. Results Ten randomised controlled trials including 2045 participants with an asymptomatic AAA were included. Follow-up was between 18 and 63 months. Neither blood pressure-lowering medications (mean growth±SD 2.0±2.4 vs 2.3±2.7 mm/year; standardised mean difference (SMD) −0.07, 95% CI −0.19 to 0.06; p=0.288) or antibiotics (mean growth±SD 2.6±2.1 vs 2.6±2.5 mm/year; SMD −0.11, 95% CI −0.38 to 0.16; p=0.418) reduced AAA growth or AAA-related events (blood pressure-lowering medications: 92 vs 95 events; risk ratio (RR) 0.86, 95% CI 0.66 to 1.11; p=0.244; and antibiotics: 69 vs 73 events; RR 0.93, 95% CI 0.69 to 1.25; p=0.614). The subanalysis of antibiotics showed similar results. Conclusions This meta-analysis suggests that neither blood pressure-lowering medications or antibiotics limit growth or clinically relevant events in people with AAAs.

Research paper thumbnail of Lack of an effective drug therapy for abdominal aortic aneurysm

Journal of Internal Medicine, 2019

Content List-Read more articles from the symposium: "Uppsala Aortic summit".

Research paper thumbnail of Meta-analysis of clinical trials examining the benefit of structured home exercise in patients with peripheral artery disease

British Journal of Surgery, 2019

Background Supervised exercise is recommended for the management of peripheral artery disease (PA... more Background Supervised exercise is recommended for the management of peripheral artery disease (PAD); however, the uptake is limited. Structured home exercise programmes may be more feasible, but their effectiveness is unclear. This systematic review and meta-analysis examined the benefit of structured home exercise programmes for treating PAD in comparison to controls not receiving an exercise programme. Methods A literature search was conducted to identify RCTs comparing structured home exercise with controls not receiving an exercise programme among patients with PAD. To be included, studies had to report outcomes from treadmill or corridor walking tests, or objective assessment of physical activity. Inverse variance-weighted meta-analysis was performed to compare changes in maximum walking distance and intermittent claudication onset distance in treadmill tests, walking distance during a 6-min walking test, and physical activity measured using a pedometer or accelerometer. Summar...

Research paper thumbnail of Presentation and outcomes of indigenous Australians with peripheral artery disease

BMC cardiovascular disorders, Jan 16, 2018

The risk factors for peripheral artery disease (PAD) are more common in Indigenous than non-Indig... more The risk factors for peripheral artery disease (PAD) are more common in Indigenous than non-Indigenous Australians, however the presentation and outcome of PAD in Indigenous Australians has not been previously investigated. The aim of this prospective cohort study was to compare the presenting characteristics and clinical outcome of Indigenous and non-Indigenous Australians with PAD. PAD patients were prospectively recruited and followed-up since 2003 from an outpatient vascular clinic in Townsville, Australia. Presenting symptoms and risk factors in Indigenous and non-Indigenous patients were compared using Pearson's χ2 test and Mann Whitney U test. Kaplan Meier survival analysis and Cox proportional hazard analysis were used to compare the incidence of myocardial infarction (MI), stroke or death (major cardiovascular events) among Indigenous and non-Indigenous patients. Four hundred and one PAD patients were recruited, of which 16 were Indigenous and 385 were non-Indigenous Au...

Research paper thumbnail of Response to “Re: A Systematic Review and Meta-analysis of the Association Between C-reactive Protein and Major Cardiovascular Events in Patients with Peripheral Artery Disease”

European Journal of Vascular and Endovascular Surgery, 2017

Research paper thumbnail of Association between metformin prescription and growth rates of abdominal aortic aneurysms

British Journal of Surgery, 2017

Background It has been suggested that diabetes medications, such as metformin, may have effects t... more Background It has been suggested that diabetes medications, such as metformin, may have effects that inhibit abdominal aortic aneurysm (AAA) growth. The aim of this study was to examine the association of diabetes treatments with AAA growth in three patient cohorts. Methods AAA growth was studied using ultrasound surveillance in cohort 1, repeated CT in cohort 2 and more detailed repeat CT in cohort 3. Growth was estimated by the mean annual increase in maximum AAA diameter. Results A total of 1697 patients with an AAA were studied, of whom 118, 39 and 16 patients were prescribed metformin for the treatment of diabetes in cohorts 1, 2 and 3 respectively. Prescription of metformin was associated with a reduced likelihood of median or greater AAA growth in all three cohorts (cohort 1: adjusted odds ratio (OR) 0·59, 95 per cent c.i. 0·39 to 0·87, P = 0·008; cohort 2: adjusted OR 0·38, 0·18 to 0·80, P = 0·011; cohort 3: adjusted OR 0·13, 0·03 to 0·61, P = 0·010). No other diabetes treat...

Research paper thumbnail of Assessment and validation of a novel angiographic scoring system for peripheral artery disease

The British journal of surgery, Jan 31, 2017

Angiography is used routinely in the assessment of lower-limb arteries, but there are few well va... more Angiography is used routinely in the assessment of lower-limb arteries, but there are few well validated angiographic scoring systems. The aim of this study was to develop and validate a novel angiographic scoring system for peripheral artery disease. An angiographic scoring system (the ANGIO score) was developed and applied to a sample of patients from a single vascular surgical department who underwent CT angiography of the lower limbs. The reproducibility of the ANGIO score was compared with those of the Bollinger and Trans-Atlantic inter-Society Consensus (TASC) IIb systems in a series of randomly selected patients. Associations between the ANGIO score and lower-limb ischaemia, as measured by the ankle : brachial pressure index (ABPI), and outcome events (major lower-limb amputations and cardiovascular events - myocardial infarction, stroke and cardiovascular death) were assessed. Some 256 patients undergoing CT angiography were included. The interobserver reproducibility of the...

Research paper thumbnail of Association of Computed Tomographic Leg Muscle Characteristics With Lower Limb and Cardiovascular Events in Patients With Peripheral Artery Disease

Journal of the American Heart Association, 2018

Background Poor lower extremity physical performance is an independent predictor of unfavorable o... more Background Poor lower extremity physical performance is an independent predictor of unfavorable outcome in patients with peripheral artery disease ( PAD ); however, few studies have assessed muscle characteristics on imaging directly. Method and Results A novel 3‐dimensional semi‐automated protocol was developed to estimate leg muscle volume and density (mean attenuation) from computed tomography images. Patients with PAD who underwent a lower extremity computed tomography scan at a tertiary vascular surgery center were included, and were followed up using hospital records and linked data as part of a retrospective cohort study. The primary outcomes were lower limb events (major amputation or peripheral revascularization) and cardiovascular events (myocardial infarction, stroke, or cardiovascular death). Two hundred and twenty‐three patients with PAD were included (median age 69.0 years; 73% men) and followed for a median of 4.9 [2.6–7.0] years. During this time there were 99 index ...

Research paper thumbnail of A Meta-Analysis of the Efficacy of Allopurinol in Reducing the Incidence of Myocardial Infarction (MI)

Heart, Lung and Circulation, 2017

Introduction: Teratomas are the most common type of germ cell tumour in the anterior mediastinum.... more Introduction: Teratomas are the most common type of germ cell tumour in the anterior mediastinum. They are of equal distribution in both males and females with a peak incidence in young adults. Less than one per cent are malignant,