Heart failure (HF) and diabetes (DM) are a lethal combination. The current armamentarium of anti-diabetic agents has been shown to be less efficacious and sometimes even harmful in diabetic patients ...with concomitant cardiovascular disease, especially HF. Sodium glucose linked co-transporter type 2 (SGLT2) inhibitors are a new class of anti-diabetic agent that has shown potentially beneficial cardiovascular effects such as pre-load and after load reduction through osmotic diuresis, blood pressure reduction, reduced arterial stiffness and weight loss. This has been supported by the recently published EMPA-REG trial which showed a striking 38 and 35 % reduction in cardiovascular death and HF hospitalisation respectively.
The REFORM trial is a novel, phase IV randomised, double blind, placebo controlled clinical trial that has been ongoing since March 2015. It is designed specifically to test the safety and efficacy of the SLGT2 inhibitor, dapagliflozin, on diabetic patients with known HF. We utilise cardiac-MRI, cardio-pulmonary exercise testing, body composition analysis and other tests to quantify the cardiovascular and systemic effects of dapagliflozin 10 mg once daily against standard of care over a 1 year observation period. The primary outcome is to detect the change in left ventricular (LV) end systolic and LV end diastolic volumes. The secondary outcome measures include LV ejection fraction, LV mass index, exercise tolerance, fluid status, quality of life measures and others.
This trial will be able to determine if SGLT2 inhibitor therapy produces potentially beneficial effects in patients with DM and HF, thereby replacing current medications as the drug of choice when treating patients with both DM and HF. Trial registration Clinical Trials.gov: NCT02397421. Registered 12th March 2015.
Current distance measurement techniques for pulse wave velocity (PWV) calculation are susceptible to intercenter variability. The aim of this study was to derive and validate a formula for this ...distance measurement. Based on carotid femoral distance in 1183 whole-body magnetic resonance angiograms, a formula was derived for calculating distance. This was compared with distance measurements in 128 whole-body magnetic resonance angiograms from a second study. The effects of recalculation of PWV using the new formula on association with risk factors, disease discrimination, and prediction of major adverse cardiovascular events were examined within 1242 participants from the multicenter SUMMIT study (Surrogate Markers of Micro- and Macrovascular Hard End-Points for Innovative Diabetes Tools) and 825 participants from the Caerphilly Prospective Study. The distance formula yielded a mean error of 7.8 mm (limits of agreement =−41.1 to 56.7 mm; P<0.001) compared with the second whole-body magnetic resonance angiogram group. Compared with an external distance measurement, the distance formula did not change associations between PWV and age, blood pressure, or creatinine (P<0.01) but did remove significant associations between PWV and body mass index (BMI). After accounting for differences in age, sex, and mean arterial pressure, intercenter differences in PWV persisted using the external distance measurement (F=4.6; P=0.004), whereas there was a loss of between center difference using the distance formula (F=1.4; P=0.24). PWV odds ratios for cardiovascular mortality remained the same using both the external distance measurement (1.14; 95% confidence interval, 1.06–1.24; P=0.001) and the distance formula (1.17; 95% confidence interval, 1.08–1.28; P<0.001). A population-derived automatic distance calculation for PWV obtained from routinely collected clinical information is accurate and removes intercenter measurement variability without impacting the diagnostic utility of carotid–femoral PWV.Hypertension is published on behalf of the American Heart Association, Inc., by Wolters Kluwer Health, Inc. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited.
Purpose
Haemodialysis access-induced distal ischaemia (HAIDI) is a significant
complication of vascular access creation, and has traditionally been
difficult to manage without loss of access. Current ...treatment options
include ligation, banding, distal revascularisation with interval ligation
(DRIL), proximalisation of the arterial inflow (PAI) and revision using
distal flow (RUDI). The purpose of this review was to evaluate the
effectiveness of the different surgical techniques in the treatment of
HAIDI.
Methods
Electronic databases were searched for studies assessing surgical techniques
in the treatment of HAIDI in accordance with PRISMA. The primary outcome for
the study was symptomatic relief for each technique, defined within each
study. Secondary outcomes included comparison of early thrombosis rates
following each different procedure.
Results
Following strict inclusion/exclusion criteria by two reviewers, twenty-seven
studies of surgical interventions were included and divided into subgroups
for banding, DRIL, PAI and RUDI procedures. Both DRIL and banding procedures
were found to have high rates of symptomatic relief. In addition, the DRIL
has a significantly lower rate of early thrombosis than banding although the
more recent papers seem to suggest that early thrombosis is less of a
problem in banding. PAI and RUDI showed some promise but there were too few
studies to be able to make any clear conclusions.
Conclusions
All four procedures have high success rate in relieving ischaemic symptoms
with the DRIL procedure having a significantly better vascular access
patency rate than other techniques, although further well designed studies
are required to compare all four surgical techniques.
The current study aims to computationally evaluate the effect of right upper arm position on the geometric and hemodynamic characteristics of the brachial artery (BA) and cephalic vein (CV) and, ...furthermore, to present in detail the methodology to characterise morphological and hemodynamical healthy vessels. Ten healthy volunteers were analysed in two configurations, the supine (S) and the prone (P) position. Lumen 3D surface models were constructed from images acquired from a non‐contrast MRI sequence. Then, the models were used to numerically compute the physiological range of geometric (n = 10) and hemodynamic (n = 3) parameters in the BA and CV. Geometric parameters such as curvature and tortuosity, and hemodynamic parameters based on wall shear stress (WSS) metrics were calculated with the use of computational fluid dynamics. Our results highlight that changes in arm position had a greater impact on WSS metrics of the BA by altering the mean and maximum blood flow rate of the vessel. Whereas, curvature and tortuosity were found not to be significantly different between positions. Inter‐variability was associated with antegrade and retrograde flow in BA, and antegrade flow in CV. Shear stress was low and oscillatory shear forces were negligible. This data suggests that deviations from this state may contribute to the risk of accelerated intimal hyperplasia of the vein in arteriovenous fistulas. Therefore, preoperative conditions coupled with post‐operative longitudinal data will aid the identification of such relationships.
This study highlighted that changes in arm position had a greater impact on wall shear stress metrics of the brachial artery by altering the mean and maximum blood flow rate. Whereas, curvature and tortuosity were found not to be significantly different between positions. Moreover, the image‐based computational fluid dynamics analysis highlighted an inter‐variability of shear stress metrics within a small sample of healthy subjects which lead to the postulation that deviations from homeostatic conditions will modulate remodelling rather than exceeding a global threshold.
Common carotid intima media thickness (CIMT) and ankle brachial pressure index (ABPI) are used as surrogate marker of atherosclerosis, and have been shown to correlate with arterial stiffness, ...however their correlation with global atherosclerotic burden has not been previously assessed. We compare CIMT and ABPI with atheroma burden as measured by whole body magnetic resonance angiography (WB-MRA).
50 patients with symptomatic peripheral arterial disease were recruited. CIMT was measured using ultrasound while rest and exercise ABPI were performed. WB-MRA was performed in a 1.5T MRI scanner using 4 volume acquisitions with a divided dose of intravenous gadolinium gadoterate meglumine (Dotarem, Guerbet, FR). The WB-MRA data was divided into 31 anatomical arterial segments with each scored according to degree of luminal narrowing: 0 = normal, 1 = <50%, 2 = 50-70%, 3 = 70-99%, 4 = vessel occlusion. The segment scores were summed and from this a standardized atheroma score was calculated.
The atherosclerotic burden was high with a standardised atheroma score of 39.5±11. Common CIMT showed a positive correlation with the whole body atheroma score (β 0.32, p = 0.045), however this was due to its strong correlation with the neck and thoracic segments (β 0.42 p = 0.01) with no correlation with the rest of the body. ABPI correlated with the whole body atheroma score (β -0.39, p = 0.012), which was due to a strong correlation with the ilio-femoral vessels with no correlation with the thoracic or neck vessels. On multiple linear regression, no correlation between CIMT and global atheroma burden was present (β 0.13 p = 0.45), while the correlation between ABPI and atheroma burden persisted (β -0.45 p = 0.005).
ABPI but not CIMT correlates with global atheroma burden as measured by whole body contrast enhanced magnetic resonance angiography in a population with symptomatic peripheral arterial disease. However this is primarily due to a strong correlation with ilio-femoral atheroma burden.
Purpose
The purpose of this investigation was to evaluate human Thiel-embalmed cadavers with the addition of extracorporeal driven ante-grade pulsatile flow in the aorta as a model for simulation ...training in interventional techniques and endovascular device testing.
Materials and Methods
Three human cadavers embalmed according to the method of Thiel were selected. Extracorporeal pulsatile ante-grade flow of 2.5 L per min was delivered directly into the aorta of the cadavers via a surgically placed connection. During perfusion, aortic pressure and temperature were recorded and optimized for physiologically similar parameters. Pre- and post-procedure CT imaging was conducted to plan and follow up thoracic and abdominal endovascular aortic repair as it would be in a clinical scenario. Thoracic endovascular aortic repair (TEVAR) and endovascular abdominal repair (EVAR) procedures were conducted in simulation of a clinical case, under fluoroscopic guidance with a multidisciplinary team present.
Results
The Thiel cadaveric aortic perfusion model provided pulsatile ante-grade flow, with pressure and temperature, sufficient to conduct a realistic simulation of TEVAR and EVAR procedures. Fluoroscopic imaging provided guidance during the intervention. Pre- and post-procedure CT imaging facilitated planning and follow-up evaluation of the procedure.
Conclusion
The human Thiel-embalmed cadavers with the addition of extracorporeal flow within the aorta offer an anatomically appropriate, physiologically similar robust model to simulate aortic endovascular procedures, with potential applications in interventional radiology training and medical device testing as a pre-clinical model.
Carotid-femoral pulse wave velocity (cf-PWV) and aortic PWV measured using MRI (MRI-PWV) show good correlation, but with a significant and consistent bias across studies. The aim of the current study ...was to evaluate whether the differences between cf.-PWV and MRI-PWV can be accounted for by inaccuracies of currently used distance measurements.
One hundred fourteen study participants were recruited into one of 4 groups: Type 2 diabetes melltus (T2DM) with cardiovascular disease (CVD) (n = 23), T2DM without CVD (n = 41), CVD without T2DM (n = 25) and a control group (n = 25). All participants underwent cf.-PWV, cardiac MRI and whole body MR angiography(WB-MRA). 90 study participants also underwent aortic PWV using MRI. cf.-PWV
was performed using a SphygmoCor device (Atcor Medical, West Ryde, Australia). The true intra-arterial pathlength was measured using the WB-MRA and then used to recalculate the cf.-PWV
to give a cf.-PWV
.
Distance measurements were significantly lower on WB-MRA than on external tape measure (mean diff = -85.4 ± 54.0 mm,p < 0.001). MRI-PWV was significantly lower than cf.-PWV
(MRI-PWV = 8.1 ± 2.9 vs. cf.-PWV
= 10.9 ± 2.7 ms
,p < 0.001). When cf.-PWV was recalculated using the inter-arterial distance from WB-MRA, this difference was significantly reduced but not lost (MRI-PWV = 8.1 ± 2.9 ms
vs. cf.-PWV
9.1 ± 2.1 ms
, mean diff = -0.96 ± 2.52 ms
,p = 0.001). Recalculation of the PWV increased correlation with age and pulse pressure.
Differences in cf.-PWV and MRI PWV can be predominantly but not entirely explained by inaccuracies introduced by the use of simple surface measurements to represent the convoluted arterial path between the carotid and femoral arteries.
Abstract Purpose Device tracking is crucial for interventional MRI (iMRI) because conventional device materials do not contribute to the MR signal, may cause susceptibility artifacts and are ...generally invisible if moved out of the scan plane. A robust method for wireless tracking and dynamic guidance of interventional devices equipped with wirelessly connected resonant circuits (wRC) is presented. Methods The proposed method uses weak spatially-selective excitation pulses with very low flip angle (0.3°), a Hadamard multiplexed tracking scheme and employs phase-field dithering to obtain the 3D position of a wRC. RF induced heating experiments (ASTM protocol) and balloon angioplasties of the iliac artery were conducted in a perfused vascular phantom and three Thiel soft-embalmed human cadavers. Results Device tip tracking was interleaved with various user-selectable fast pulse sequences receiving a geometry update from the tracking kernel in less than 30 ms. Integrating phase-field dithering significantly improved our tracking robustness for catheters with small diameters (4–6 French). The volume root mean square distance error was 2.81 mm (standard deviation: 1.31 mm). No significant RF induced heating (< 0.6 °C) was detected during heating experiments. Conclusion This tip tracking approach provides flexible, fast and robust feedback loop, intuitive iMRI scanner interaction, does not constrain the physician and delivers very low specific absorption rates. Devices with wRC can be exchanged during a procedure without modifications to the iMRI setup or the pulse sequence. A drawback of our current implementation is that position information is available for a single tracking coil only. This was satisfactory for balloon angioplasties of the iliac artery, but further studies are required for complex navigation and catheter shapes before animal trials and clinical application.
Increased left ventricular mass index (LVMI) is associated with mortality in end-stage renal disease. LVMI regression may improve outcomes. Allopurinol has reduced LVMI in randomized controlled ...trials in chronic kidney disease, diabetes, and ischemic heart disease. This study investigated whether allopurinol would regress LVMI in hemodialysis patients.
This was a randomized placebo-controlled double-blind multicenter trial funded by the British Heart Foundation (PG/12/72/29743). A total of 80 patients undergoing regular maintenance hemodialysis were recruited from NHS Tayside, NHS Greater Glasgow and Clyde and NHS Ayrshire and Arran in Scotland, UK. Participants were randomly assigned on a 1:1 ratio to 12 months of therapy with allopurinol 300 mg or placebo after each dialysis session. The primary outcome was change in LVMI, as assessed by cardiac magnetic resonance imaging (CMRI) at baseline and 12 months. Secondary outcomes were change in BP, flow-mediated dilation (FMD), augmentation indices (AIx), and pulse wave velocity (PWV).
A total of 53 patients, with a mean age of 58 years, completed the study and had CMRI follow-up data for analysis. Allopurinol did not regress LVMI (change in LVMI: placebo +3.6 ± 10.4 g/m2; allopurinol: +1.6 ± 11 g/m2; P = 0.49). Allopurinol had no demonstrable effect on BP, FMD, AIx, or PWV.
Compared with placebo, treatment with allopurinol did not regress LVMI in this trial.
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