ORCID Profile
0000-0001-8752-2941
Current Organisations
James Cook University
,
University of Sydney
,
The University of Newcastle
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Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-10-2018
Abstract: There is no drug therapy for abdominal aortic aneurysm ( AAA ). FAME‐2 (Fenofibrate in the Management of Abdominal Aortic Aneurysm 2) was a placebo‐controlled randomized trial designed to assess whether administration of 145 mg of fenofibrate/d for 24 weeks favorably modified circulating markers of AAA. Patients with AAA s measuring 35 to 49 mm and no contraindication were randomized to fenofibrate or identical placebo. The primary outcome measures were the differences in serum osteopontin and kallistatin concentrations between groups. Secondary analyses compared changes in the circulating concentration of AAA ‐associated proteins, and AAA growth, between groups using multivariable linear mixed‐effects modeling. A total of 140 patients were randomized to receive fenofibrate (n=70) or placebo (n=70). By the end of the study 3 (2.1%) patients were lost to follow‐up and 18 (12.9%) patients had ceased trial medication. A total of 85% of randomized patients took ≥80% of allocated tablets and were deemed to have complied with the medication regimen. Patients’ allocated fenofibrate had expected reductions in serum triglycerides and estimated glomerular filtration rate, and increases in serum homocysteine. No differences in serum osteopontin, kallistatin, or AAA growth were observed between groups. Administering 145 mg/d of fenofibrate for 24 weeks did not significantly reduce serum concentrations of osteopontin and kallistatin concentrations, or rates of AAA growth in this trial. The findings do not support the likely benefit of fenofibrate as a treatment for patients with small AAA s. URL : www.anzctr.org.au . Unique identifier: ACTRN 12613001039774.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 19-03-2019
Abstract: Hypertension is an important risk factor for cardiovascular events in patients with peripheral artery disease however, optimal blood pressure targets for these patients are poorly defined. This study investigated the association between systolic blood pressure ( SBP ) and cardiovascular events in a prospectively recruited patient cohort with peripheral artery disease. A total of 2773 patients were included and were grouped according to SBP at recruitment (≤120 mm Hg, n=604 121–140 mm Hg, n=1065 and mm Hg, n=1104). Adjusted Cox proportional hazards analyses suggested that patients with SBP ≤120 mm Hg were at greater risk of having a major cardiovascular event (myocardial infarction, stroke, or cardiovascular death) than patients with SBP of 121–140 mm Hg (adjusted hazard ratio, 1.36 95% CI, 1.08–1.72 P =0.009). Patients with SBP mm Hg had an adjusted hazard ratio of 1.23 (95% CI, 1.00–1.51 P =0.051) of major cardiovascular events compared with patients with SBP of 121–140 mm Hg. These findings were similar in sensitivity analyses only including patients receiving antihypertensive medications or focused on patients with a minimum of 3 months of follow‐up. This cohort study suggests that patients with peripheral artery disease and SBP ≤120 mm Hg are at increased risk of major cardiovascular events. The findings suggest caution in intensive SBP lowering in this patient group.
Publisher: Frontiers Media SA
Date: 03-05-2022
Abstract: The benefit of controlling cardiovascular risk factors in slowing the progression of small abdominal aortic aneurysm (AAA) is controversial. This study investigated the association of optimal blood pressure control at entry with the growth of small AAA. A total of 1,293 patients with initial AAA diameter & mm were followed by a median 5 (inter-quartile range, IQR, 3–7) ultrasound scans for a median of 3.6 years (IQR 1.8, 5.3). Optimal blood pressure control was defined as blood pressure ≤140/90 mmHg at recruitment. The association of optimal blood pressure control at entry with AAA growth was assessed using linear mixed effects models adjusted for established risk factors of AAA growth and factors which were unequally distributed among the blood pressure groups. Optimal blood pressure control at entry was not significantly associated with AAA growth. In the risk factor adjusted model the mean difference in AAA growth between blood pressure groups was 0.04 mm/year (95% CI −0.20, 0.13 p = 0.65). The results were similar in sensitivity analyses excluding outliers or focused on systolic or diastolic blood pressure alone. This observational study suggests that optimal blood pressure control at entry is not associated with slower AAA growth.
Publisher: Springer Science and Business Media LLC
Date: 20-01-2016
Publisher: Springer Science and Business Media LLC
Date: 17-06-2015
Publisher: MDPI AG
Date: 29-08-2022
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.EJVS.2018.07.035
Abstract: Currently there is no drug therapy for abdominal aortic aneurysm (AAA) and most previous investigations have focused on imaging rather than clinical outcomes. The aim of this study was to assess whether AAA related clinical events were lower in patients prescribed metformin. This was a prospective cohort observational study performed in three cities in Australia, which was designed to study risk factors for clinical events not simply to focus on metformin. Patients with an asymptomatic unrepaired AAA of any diameter ≥30 mm were recruited from hospital outpatient clinics and surveillance programs run at four centres. The main outcome was the requirement for AAA repair or AAA related mortality (AAA events). The association between metformin prescription and AAA events was assessed using Kaplan-Meier analysis and Cox proportional hazard analysis. Patients (1,080) with a mean (SD) initial AAA diameter of 46.1 (11.3) mm were followed for a mean (SD) of 2.5 (3.1) years until an AAA event (n = 454), death (n = 176), loss to follow up (n = 128), or completion of current follow up (n = 322). Patients with diabetes who were prescribed metformin (adjusted HR 0.63, 95% CI 0.44-0.93), but not patients with diabetes who were not prescribed metformin (adjusted HR 1.15, 95% CI 0.83-1.59), had a lower incidence of AAA events compared with those without diabetes. Findings were similar in sensitivity analyses restricted to patients with an initial AAA diameter ≤50 mm and patients with a minimum follow up of six months before an AAA event. These findings suggest that clinically important AAA events may be reduced in patients with diabetes who are prescribed metformin, but not those with diabetes receiving other treatments. A randomised controlled trial is needed to definitively test whether metformin reduces AAA related clinical events in patients with small AAAs who do not have diabetes.
Publisher: Society for Neuroscience
Date: 24-07-2013
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 17-03-2020
Abstract: The aim of this study was to assess the relationship between serum lipoprotein (a) (Lp[a]) concentration and the requirement for peripheral artery disease ( PAD ) operations or incidence of major adverse cardiovascular events. A total of 1472 people with PAD presenting with intermittent claudication (n=355), abdominal aortic aneurysm (n=989) or critical limb ischemia (n=128) were prospectively recruited from 4 outpatient clinics in Australia. Lp(a) was measured in serum s les collected at recruitment using an immunoassay. Participants were followed for a median (interquartile range) of 2.4 (0.1–6.1) years to record requirement for any PAD operation, defined to include any open or endovascular PAD intervention (lower limb peripheral revascularization, abdominal aortic aneurysm repair, other aneurysm repair, or carotid artery revascularization). Myocardial infarctions, strokes, and deaths were also recorded. The association of Lp(a) with events was assessed using Cox proportional hazard analysis adjusting for traditional risk factors. Participants with Lp(a) ≥30 mg/dL had a greater requirement for any PAD operation (hazard ratio, 1.20, 95% CI , 1.02–1.41) and lower limb peripheral revascularization alone ( hazard ratio 1.33, 95% CI , 1.06–1.66) but no increased risk of major adverse cardiovascular events or all‐cause mortality. Lp(a) ≥50 mg/dL and a 40 mg/dL increase in Lp(a) were also associated with an increased risk of lower limb peripheral revascularization alone but not with other outcomes. In participants with PAD referred for hospital management those with high Lp(a) had greater requirement for lower limb peripheral revascularization but Lp(a) was not consistently associated with other clinical events.
Publisher: Elsevier BV
Date: 02-2022
DOI: 10.1016/J.AVSG.2021.06.038
Abstract: Depression is associated with an increased risk of cardiovascular events but its association with abdominal aortic aneurysm (AAA) progression is unknown. This study examined if a diagnosis of depression was association with more rapid AAA growth. Patients with small AAA measuring between 30 and 50 mm were recruited from surveillance programs at 4 Australian centres. Maximum AAA diameter was measured by ultrasound imaging using a standardised and reproducible protocol to monitor AAA growth. Depression was defined from medical records of treatment for depression at recruitment. Linear mixed effects modelling was performed to examine the independent association of depression with AAA growth. A propensity matched sub-analysis was performed. A total of 574 participants were included of whom 73 (12.7%) were diagnosed with depression. Participants were followed with a median of 3 (Inter-quartile range (IQR): 2, 5) ultrasound scans for a median of 2.1 (IQR: 1.1, 3.5) years. The unadjusted model suggested that annual AAA growth was non-significantly reduced (mean difference: -0.3 mm/year 95% confidence interval (CI): -0.7, 0.2 P = 0.26) in participants with a diagnosis of depression compared to other participants. After adjustment for covariates, depression was not significantly associated with AAA growth (mean difference: -0.3 mm/year 95% CI: -0.8, 0.2 P = 0.27). Findings were similar in the propensity matched sub-analysis. Sensitivity analyses investigating the impact of initial AAA diameter and follow up on the association of depression with AAA growth found no interaction. This study suggested that depression was not associated with faster AAA growth.
Publisher: Elsevier BV
Date: 05-2019
Publisher: Public Library of Science (PLoS)
Date: 26-08-2009
Publisher: Elsevier BV
Date: 10-2022
DOI: 10.1016/J.EJVS.2022.07.042
Abstract: This study was an unplanned exploratory analysis of a subset of participants from the Telmisartan in the Management of Abdominal Aortic Aneurysm (TEDY) trial. It aimed to assess the efficacy of the angiotensin 1 receptor blocker telmisartan in reducing abdominal aortic aneurysm (AAA) peak wall stress (PWS) and peak wall rupture index (PWRI) among in iduals with small AAAs. Participants with AAAs measuring 35 - 49 mm in maximum diameter were randomised to receive telmisartan 40 mg or identical placebo in the TEDY trial. Participants who had computed tomography angiography performed at entry and at least one other time point during the trial (12 or 24 months) were included in the current study. Orthogonal AAA diameter, PWS, and PWRI were measured using previously validated methods. The annual change in PWS and PWRI from baseline was compared between participants allocated telmisartan or placebo using linear mixed effects models. These models were either unadjusted or adjusted for risk factors that were different in the groups at entry (p < .100) or systolic blood pressure (SBP) at one year. Of the 207 participants recruited to TEDY, 124 were eligible for inclusion in this study. This study included 65 and 59 participants from the telmisartan and placebo groups, respectively. The PWS and PWRI were not significantly different in the two groups at baseline. Participants allocated telmisartan had a slower annual increase in PWS (-4.19 95% CI -8.24, -0.14 kPa/year p = .043) and PWRI (-0.014 95% CI -0.026, -0.001 p = .032) compared with those allocated placebo after adjusting for risk factors. After adjustment for SBP at one year, telmisartan did not significantly reduce annual increases in PWS or PWRI. The findings of this study suggest that telmisartan limits the rate of increase in PWS and PWRI of small AAAs by reducing blood pressure.
Publisher: Springer Science and Business Media LLC
Date: 16-11-2017
Publisher: Oxford University Press (OUP)
Date: 26-06-2021
DOI: 10.1002/BJS.10587
Abstract: 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. 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. 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 treatment was significantly associated with AAA growth in any cohort. These findings suggest a potential role for metformin in limiting AAA growth.
Publisher: Springer Science and Business Media LLC
Date: 10-03-2023
DOI: 10.1007/S00330-023-09488-1
Abstract: 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. 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. After adjusting for other risk factors, one standard deviation increase in PWS (hazard ratio, HR, 1.56, 95% confidence intervals, CI 1.19, 2.06 p = 0.001) and PWRI (HR 1.74, 95% CI 1.29, 2.34 p 0.001) were associated with significantly higher risks of AAA events. In the CART analysis, PWRI was identified as the best single predictor of AAA events at a cut-off value of 0.562. PWRI, but not PWS, significantly improved the classification of risk of AAA events compared to the initial AAA diameter alone. PWS and PWRI predicted the risk of AAA events but only PWRI significantly improved the risk stratification compared to aortic diameter alone. • Aortic diameter is an imperfect measure of abdominal aortic aneurysm (AAA) rupture risk. • This observational study of 210 participants found that peak wall stress (PWS) and peak wall rupture index (PWRI) predicted the risk of aortic rupture or AAA repair. • PWRI, but not PWS, significantly improved the risk stratification for AAA events compared to aortic diameter alone.
No related grants have been discovered for Michael Bourke.