Baseline carotid intima-media complex echogenicity associates with the 3-year progression of intima-media thickness

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Region Vasterbotten Central ALF and the Swedish Research Council

Background

Echogenicity of the intima-media (IM) complex and progression of carotid intima media thickness (cIMT) have both separately been demonstrated to predict cardiovascular disease (CVD). However, it is unknown if the IM echogenicity reflects arterial wall remodelling associated with increased progression of cIMT.

Purpose

The aim of this study was to evaluate if the baseline echogenicity of the IM-complex measured by ultrasound is associated with cIMT progression over a 3-year follow-up period.

Methods

Ultrasound images from baseline and 3-year follow-up performed for the randomised controlled trial ‘Visualization of asymptomatic atherosclerotic disease for optimum cardiovascular prevention’ (VIPVIZA) were included in this study (n: 3154). Participants were 40, 50 or 60 years old at baseline and had at minimum one traditional risk factor for CVD to be included in the VIPVIZA study. Measurements of mean cIMT were made at baseline and in the 3-year follow-up in the distal 1 cm of the common carotid artery at standardised angles bilaterally. Echogenicity of the IM-complex was determined by greyscale median (IM-GSM), automatically calculated from the B-mode ultrasound images. Associations between IM-GSM at baseline and the 3-year progression of cIMT were investigated using linear regression models, and stratified by sex, age and VIPVIZA study group (intervention versus control). In addition, adjusted analysis for traditional risk factors was also performed. All analysis was carried out on left and right sides separately.

Results

The unadjusted analysis showed associations between baseline IM-GSM with the 3-year progression of cIMT (p<0.001 for both left and right sides, Figure 1). The association between IM-GSM and cIMT was statistically significant bilaterally in both male and female participants and on comparison of VIPVIZA study subgroups. When stratifying by age group, the association between baseline IM-GSM and cIMT progression was present among 40 (p<0.001) and 60 year olds (p<0.001), but not among 50 years old (p=0.906) in the left side. In the right CCA the association was significant among 40 years old (p=0.047), but not for 50 and 60 years (p=0.106 and 0.067, respectively). Adjustments for traditional risk factors did not alter the estimated relationship between baseline IM-GSM and 3-year cIMT progression.

Conclusion

Baseline ultrasound echogenicity of the IM-complex is associated with the 3-year progression of cIMT among a middle-aged population with subclinical atherosclerosis. Echogenicity of the IM-complex may serve to identify arterial wall remodelling reflecting progressive atherosclerotic disease and could be a valuable tool in future CVD prevention.

Reduced progression of carotid intima media thickness by pictorial presentation of subclinical atherosclerosis 3-year follow-up from VIPVIZA a randomized controlled trial

Background

Reduced progression of carotid intima media thickness (cIMT) and atherosclerotic plaque assessed by carotid ultrasound has been reported in pharmacological intervention studies. We have previously provide evidence for improved primary prevention of cardiovascular diseases by pictorial presentation of subclinical atherosclerosis severity based on reduction in traditional risk scores in 1-year follow-up.

Purpose

We aimed to investigate if pictorial presentation of subclinical atherosclerosis severity affected cIMT and plaque progression over a 3-year follow-up period in comparison with a routine primary prevention program.

Methods

Visualization of asymptomatic atherosclerotic disease for optimum cardiovascular prevention (VIPVIZA) study is a population-based, randomized controlled trial with blinded evaluators (PROBE design). Participants aged 40, 50 and 60 years were enrolled from a prevention program within the routine primary care. Carotid ultrasound examinations were made at baseline and at 3-year follow-up (n: 3154). The ultrasound examinations included standardized measurements of cIMT in the far wall of common carotid artery at predefined angles due to Meijer's arc. Used angles was 240 degrees for left-mean-cIMT and 120 degrees for right-mean-cIMT. Detection of plaque was based on Mannheim consensus and plaque prevalence was evaluated as absent, unilateral or bilateral plaques. Total plaque area (TPA) was a sum of plaque areas and measured off-line form the longitudinal 2D B-mode images. At baseline, the intervention group (n: 1575) and their primary care physicians received a pictorial presentation describing the severity of subclinical atherosclerosis with graphs and colored figures based on measured cIMT and plaque prevalence (Figure 1). The control group with respective physician (n: 1579) did not receive any information about ultrasound results. The bilateral, left and right mean cIMT, plaque prevalence and TPA at 3-year follow-up were compared between groups. Analysis was performed by analysis of covariance and ordinal proportional odds models. Bonferroni correction was applied to account for multiple comparisons, each individual test was performed using α = 0.01.

Results

Reduced cIMT progression in the intervention group was found in left-mean-cIMT with an estimated group difference of −0.011 mm (p=0.001). Estimated group difference of right- and bilateral-mean-cIMT were both −0.005 mm (p=0.223 and 0.036, respectively) (Figure 2). No significant difference between groups was found for plaque prevalence or TPA.

Conclusion

Intervention by pictorial presentation of subclinical atherosclerotic severity reduced the progression of cIMT in comparison with a traditional cardiovascular preventive program only. This was largely driven by changes in the left carotid artery. Long-term follow-up will be required to elucidate if the intervention will have a protective effect on future risk of cardiovascular events.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The Heart Foundation of Northern Sweden, Västerbotten County Council. Figure 1Figure 2

Pictorial information about subclinical atherosclerosis reduces the CVD risk: Results from the VIPVIZA RCT

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Region Västerbotten and the Swedish Research Council

Background

The VIPVIZA trial has previously shown beneficial effects on cardiovascular disease (CVD) risk scores 1 year after sending pictorial information of carotid ultrasound imaging (Picture 1) to individuals and their physicians

Purpose

To investigate whether the beneficial effects on CVD-risk observed at 1-year were sustained over three years 

Methods

VIPVIZA is a pragmatic prospective open-label randomized controlled trial with blinded evaluators performed within a CVD prevention programme integrated in the regular primary health care in Västerbotten County, Sweden. Individuals aged 40, 50 or 60 years old with one CVD risk factor were enrolled and randomised 1:1 to intervention (n = 1749, pictorial information about subclinical atherosclerosis provided to participants and physicians, Picture 1) or control group(n = 1783, no information to participants or physicians). Intervention participants also recieved a follow-up phone call and the corresponding physicians written guideline-based information about the clinical significance of carotid ultrasound results. Participants were examined at baseline (2013-2016), after one and at three years

Results

A significant beneficial effect on cardiovascular risk was observed at the 3-year follow-up; Framingham Risk Score (FRS) was 13.38 for the intervention group and 14.08 for the control group(p = 0.047) and SCORE was 1.69 vs. 1.82(p = 0.022) respectively. The 3-year results adjusted for sex and educational level showed significant differences between the intervention and control group in FRS, SCORE, P-Total-Cholesterol, P-LDL-Cholesterol and waist circumference in favour of the intervention group. Analysis by sex showed difference in differences(DID) in FRS for men -1.19(95% CI -2.01 to -0.37) and -0.50(95% CI -0.93 to -0.07) for women and in SCORE for men -0.20(95% CI -0.33 to -0.06) and -0.08 (95% CI -0.13 to -0.04) for women, between the two groups over 3 years. Similarly, there were significant differences in DID in all educational groups. Further stratification by baseline FRS and SCORE risk category, showed a beneficial pattern of the intervention in all risk groups, however the DID at the 3-year follow-up was statistically significant only in the intermediate risk group for both FRS -1.34(95% CI -2.13 to -0.56) and SCORE -0.19(95% CI -0.32 to -0.05)

Conclusions

This study provides evidence of sustained effects over three years of pictorial information of subclinical carotid atherosclerosis on the reduction of cardiovascular risk regardless of sex and educational level. Importantly, a statistically significant intervention effect was seen in the intermediate risk group, where the majority of CVD events occur. Visualization of subclinical atherosclerosis may be one way to approach individuals at intermediate risk of CVD, a group where sufficient prevention is often overlooked. However, further studies are needed to investigate the intervention effect on hard end points as CVD-events and death.

Abstract Figure. Picture 1

P3430Classification of pronounced subclinical atherosclerosis: deep learning approach of carotid intima media ultrasound images is superior to clinical risk factors

Background

Carotid ultrasound measurements of subclinical atherosclerosis is extensively used in the research field of cardiovascular disease. Increased intima media thickness (IMT) and plaque detection have predictive value for cardiovascular events when added to traditional risk factors. However, among studies different protocols for measuring IMT (projections, mean or max values and sites) are used and methodological difficulties of plaque detection, together result in conflicting results. Recently, Deep Learning image driven classification methods, has been successfully applied in several medical imaging applications. Here we hypothesize that ultrasound image texture of the intima media complex accurately reflects the disease burden without the need to measure IMT values or detect plaques.

Purpose

To evaluate classification accuracy of ultrasound based deep learning approach of the intima media complex image compared to traditional risk factors for participants with no vs pronounced subclinical atherosclerosis.

Methods

Subjects from the VIPVIZA study (Visualization of asymptomatic atherosclerotic disease for optimum cardiovascular prevention, n: 3532, 40, 50 and 60 year old, 53% women) were selected for analysis. Bilateral carotid ultrasound examinations were performed according to a standardized protocol. Subjects were categorized in two groups as 1) pronounced subclinical atherosclerosis (n: 401) – bilateral plaques and estimated vascular age 10 years older, or 2) No subclinical atherosclerosis (n: 592) – no plaques and estimated ordinary vascular age. Traditional risk factors for the participants were estimated by the SCORE risk chart. A 1-cm wide region of the distal common carotid artery intima media complex was automatically segmented from the original B-mode images. The images were fed to a Deep Learning model, convolution neural network (CNN), trained using transfer learning model with 60% training data set and 40% evaluation data set. Classification performance was quantified using accuracy of ROC analysis.

Results

The mean age was 58 and 56 years in groups 1 and 2, respectively (with 43% and 56% women, respectively). The mean SCORE was 1.74 in group 1 and 1.09 in group 2. Classification based on SCORE had an area under the curve of 0.69 with an accuracy of 38%. The Deep learning approach had an area under the curve of 0.89 with an accuracy of 78%.

Intima media image based classification

Conclusion

The results shows that ultrasound image texture of the intima media with Deep Learning approach can be used to detect pronounced disease without explicit measurement of IMT values or detection of plaques. With hard end-points, the approach could be used for risk stratification of subclinical atherosclerosis.

Acknowledgement/Funding

Västerbotten County Council, Swedish Research Council, Heart and Lung Foundation, Carl Bennet Ltd, Sweden.

P3416Bilateral carotid intima media thickness (cIMT) and plaque measurements was stronger associated with cardiovascular risk factors than unilateral measurements. Results from the VIPVIZA trial

Background

Clinical risk factors of cardiovascular diseases (CVD) are related to atherosclerosis and cIMT and plaque are signs of early atherosclerosis. However, associations between risk factors and ultrasound variables are not fully established and comparison between studies is hampered by different imaging protocols. There is limited data regarding study population characteristics and ultrasound measurements differ regarding arterial bed, projections, and plaque definitions and inclusion

Purpose

1/ To describe the distribution of asymptomatic atherosclerosis as assessed by carotid ultrasound in a middle-aged population at low/intermediate risk of CVD. 2/ To investigate the associations between clinical risk factors and a set of ultrasound variables

Method

Bilateral carotid ultrasound examinations were performed according to a standardized protocol in 3532 healthy VIPVIZA-participants with at least one conventional CVD risk factor. CIMT was measured in the distal far wall of CCA, 240o and 210o left and 150o and 120o right side, based on Meijer arch. For each angle, mean and max IMT was measured in a 10 mm segment. Plaques were identified according to the Mannheim consensus. Socio-economic data was also recorded.

Associations between the risk factors and the set of ultrasound variables were quantified by a partial least squares (PLS) regression. A new compound ultrasound variable was computed, PLS UL, bya combining all IMT variables and plaque using the weights of the first PLS component. In a second step, to estimate how much risk factors explained the variability of the ultrasound results, associations between risk factors and both PLS UL and single cIMT variables and plaque were determined using step-wise linear regression modelling

Results

Mean age was 55.6 and 55.8 years among men and women (52.7% women), 13% were smokers in both sexes, and 50.8% and 39.3%, respectively, had carotid plaque. Mean of mean cIMT was 0.68 mm vs 0.64 mm (p<0.001), and max cIMT was 0.90 mm vs 0.82 mm (p<0.001), respectively. Overall, cIMT was slightly higher in the left compared to the right carotid.

All ultrasound variables had similar univariate associations with clinical risk factors, positive associations for all risk factors except physical activity, fruit and vegetable consumption, education and HDL-cholesterol.

The strongest association between risk factors and ultrasound variables was found with PLS UL (R2=23%), compared to single cIMT variables (R2=14–18%) and plaque (R2=15%). The pattern was similar in both sexes with most risk factors shared between the sexes. The association with factors and PLS UL was stronger among 40-year olds (R2=22%) than among 50- and 60-year olds (R=12%)

Conclusion

A combination of ultrasound variables are stronger associated to CVD risk factors than plaque or a single CIMT measurement. The pattern is similar in men and women. These findings are relevant for development of a consensus for cIMT measurements

Acknowledgement/Funding

Västerbotten County Council, the Swedish Research Council, the Heart and Lung Foundation, the Swedish Society of Medicin, Carl Bennet Ltd, Sweden

Automated Measurement of Patient-Specific Tibial Slopes from MRI

Background: Multi-planar proximal tibial slopes may be associated with increased likelihood of osteoarthritis and anterior cruciate ligament injury, due in part to their role in checking the anterior-posterior stability of the knee. Established methods suffer repeatability limitations and lack computational efficiency for intuitive clinical adoption. The aims of this study were to develop a novel automated approach and to compare the repeatability and computational efficiency of the approach against previously established methods. Methods: Tibial slope geometries were obtained via MRI and measured using an automated Matlab-based approach. Data were compared for repeatability and evaluated for computational efficiency. Results: Mean lateral tibial slope (LTS) for females (7.2°) was greater than for males (1.66°). Mean LTS in the lateral concavity zone was greater for females (7.8° for females, 4.2° for males). Mean medial tibial slope (MTS) for females was greater (9.3° vs. 4.6°). Along the medial concavity zone, female subjects demonstrated greater MTS. Conclusion: The automated method was more repeatable and computationally efficient than previously identified methods and may aid in the clinical assessment of knee injury risk, inform surgical planning, and implant design efforts.

A novel 3D approach for determination of frontal and coronal plane tibial slopes from MR imaging

BACKGROUND

The proximal tibia is geometrically complex, asymmetrical, and variable, is heavily implicated in arthrokinematics of the knee joint, and thus a contributor to knee pathologies such as non-contact anterior cruciate ligament injury. Medial, lateral, and coronal tibial slopes are anatomic parameters that may increase predisposition to knee injuries, but the extent to which each contributes has yet to be fully realized. Previously, two-dimensional methods have quantified tibial slopes, but more reliable 3D methods may prove advantageous.

AIMS

(1) to explore the reliability of two-dimensional methods, (2) to introduce a novel three-dimensional measurement approach, and (3) to compare data derived from traditional and novel methods.

METHODS

Medial, lateral, and coronal tibial slope geometry from both knees (left and right) of one subject were obtained via magnetic resonance images and measured by four trained observers from two-dimensional views. The process was repeated via three-dimensional approaches and data evaluated for intra- and inter-rater reliability.

RESULTS

The conventional method presented a weaker Intraclass Correlation Coefficient (ICC) for the measured slopes (ranging from 0.43 to 0.81) while the resultant ICC for the proposed method indicated greater reliability (ranging from 0.84 to 0.97). Statistical analysis supported the novel approach for production of more reliable and repeatable results for tibial slopes.

CONCLUSIONS

The novel three-dimensional method for calculating tibial plateau slope may be more reliable than previously established methods and may be applicable in assessment of susceptibility to osteoarthritis, as part of anterior cruciate ligament injury risk assessment, and in total knee implant design.

Real-time feedback during drop landing training improves subsequent frontal and sagittal plane knee kinematics

BACKGROUND

Although neuromuscular training featuring visual feedback may benefit modification of anterior cruciate ligament injury-risk linked knee kinematics, wide-spread clinical intervention has been limited to date. This study evaluated the effects of a Microsoft Kinect-based feedback system for modification of drop vertical jump knee kinematics traditionally consistent with predisposition to non-contact anterior cruciate ligament injury in female athletes. We hypothesized that a four-week feedback training protocol would increase peak knee flexion angle and frontal plane valgus-correlated knee separation distance during drop jump landing performance.

METHODS

Twenty-four female athletes were randomly divided equally into control or Kinect-based feedback groups. Subjects were pre-screened for peak knee flexion angle and minimum knee separation distance during drop landing and later performed twenty 31cm drop landings three days per week for four weeks. The feedback group received Kinect-based visual feedback, while controls did not. Kinematics were re-assessed immediately following the end of the training period.

FINDINGS

The feedback group increased peak knee flexion and experienced a greater improvement in peak knee flexion. The feedback group improved normalized knee separation distance with greater improvement in post-training peak knee separation distance as compared with controls.

INTERPRETATION

Kinect-based feedback training significantly improved drop vertical jump knee kinematics associated with non-contact anterior cruciate ligament injury. The Kinect-based feedback approach demonstrates promise for mitigating non-contact anterior cruciate ligament injury predisposing knee biomechanics in female athletes within the clinical environment.

Prediction of contact mechanics in metal-on-metal Total Hip Replacement for parametrically comprehensive designs and loads

Manufacturers and investigators of Total Hip Replacement (THR) bearings require tools to predict the contact mechanics resulting from diverse design and loading parameters. This study provides contact mechanics solutions for metal-on-metal (MoM) bearings that encompass the current design space and could aid pre-clinical design optimization and evaluation. Stochastic finite element (FE) simulation was used to calculate the head-on-cup contact mechanics for five thousand combinations of design and loading parameters. FE results were used to train a Random Forest (RF) surrogate model to rapidly predict the contact patch dimensions, contact area, pressures and plastic deformations for arbitrary designs and loading. In addition to widely observed polar and edge contact, FE results included ring-polar, asymmetric-polar, and transitional categories which have previously received limited attention. Combinations of design and load parameters associated with each contact category were identified. Polar contact pressures were predicted in the range of 0-200 MPa with no permanent deformation. Edge loading (with subluxation) was associated with pressures greater than 500 MPa and induced permanent deformation in 83% of cases. Transitional-edge contact (with little subluxation) was associated with intermediate pressures and permanent deformation in most cases, indicating that, even with ideal anatomical alignment, bearings may face extreme wear challenges. Surrogate models were able to accurately predict contact mechanics 18,000 times faster than FE analyses. The developed surrogate models enable rapid prediction of MoM bearing contact mechanics across the most comprehensive range of loading and designs to date, and may be useful to those performing bearing design optimization or evaluation.

Effects of IL-1β-Blocking Therapies in Type 2 Diabetes Mellitus: A Quantitative Systems Pharmacology Modeling Approach to Explore Underlying Mechanisms

Recent clinical studies suggest sustained treatment effects of interleukin-1β (IL-1β)–blocking therapies in type 2 diabetes mellitus. The underlying mechanisms of these effects, however, remain underexplored. Using a quantitative systems pharmacology modeling approach, we combined ex vivo data of IL-1β effects on β-cell function and turnover with a disease progression model of the long-term interactions between insulin, glucose, and β-cell mass in type 2 diabetes mellitus. We then simulated treatment effects of the IL-1 receptor antagonist anakinra. The result was a substantial and partly sustained symptomatic improvement in β-cell function, and hence also in HbA1C, fasting plasma glucose, and proinsulin–insulin ratio, and a small increase in β-cell mass. We propose that improved β-cell function, rather than mass, is likely to explain the main IL-1β–blocking effects seen in current clinical data, but that improved β-cell mass might result in disease-modifying effects not clearly distinguishable until >1 year after treatment.

Linkage of nicotine dependence and smoking behavior on 10q, 7q and 11p in twins with homogeneous genetic background

The significant worldwide health burden introduced by tobacco smoking highlights the importance of studying the genetic determinants of smoking behavior and the key factor sustaining compulsive smoking, that is, nicotine dependence (ND). We have here addressed the genetic background of smoking in a special study sample of twins, harmonized for early life events and specifically ascertained for smoking from the nationwide twin cohort of the genetically unique population of Finland. The twins and their families were carefully examined for extensive phenotype profiles and a genome-wide scan was performed to identify loci behind the smoking status, ND and the comorbid phenotype of ND and alcohol use in 505 individuals from 153 families. We replicated previous linkage findings on 10q (max logarithm of the odds (LOD) 3.12) for a smoker phenotype, and on 7q and 11p (max LOD 2.50, and 2.25, respectively) for the ND phenotype. The loci linked for ND also showed evidence for linkage for the comorbid phenotype. Our study provides confirmatory evidence for the involvement of these genome regions in the genetic etiology of smoking behavior and ND and for the first time associates drinking and smoking to a shared locus on 10q.

Limited utility of the phenylephrine-nitroprusside sigmoid curve method of measuring baroreflex function after myocardial infarction

BACKGROUND

Conventional testing of baroreflex function with phenylephrine bolus injection measures reflex vagal tone.

OBJECTIVE

To evaluate an alternative pharmacological method of baroreflex testing, which might provide more comprehensive evaluation of the baroreflex function in patients with uncomplicated myocardial infarction.

METHODS

Forty-eight patients, aged 59 +/- 7 years, were evaluated 5-7 days after myocardial infarction and after 6 weeks of rehabilitation. Baroreflex testing was performed with 10-14 incremental injections of nitroprusside and phenylephrine. The peak heart rate and blood pressure point from each injection were fitted to a four parameter (upper plateau, lower plateau, gain and median blood pressure) sigmoid logistic function. The baroreflex sensitivity (BRS) was also measured by conventional linear analysis of the response of the R-R interval to the initial rise in systolic blood pressure induced by phenylephrine bolus injection.

RESULTS

Non-linear curve fitting of four logistic curve parameters was possible for results from 91% of tests; in the remaining tests the upper plateau was held constant at the maximum heart-rate response to allow estimation of the other three parameters. When all four parameters had been estimated, the gain parameter could not be precisely determined (the coefficient of variation of the gain parameter was 85 +/- 10%). The upper (R = 0.72, P < 0.001) and lower plateaux (R = 0.76, P < 0.001) were strongly related to the resting heart rate and weakly related to measures of heart-rate variability. There was also a significant inverse correlation between the lower plateau and the BRS (R = -0.57, P < 0.001). The gain parameter was not related to the BRS or any measure of the heart-rate variability. After 6 weeks' rehabilitation there was a significant decrease in the lower plateau (from 54 +/- 2 to 48 +/- 1 beats/min, P < 0.001), an increase in BRS (from 9.4 +/- 0.8 to 12.1 +/- 0.8 ms/mmHg, P < 0.001) and no change in the other three sigmoid curve parameters.

CONCLUSIONS

Non-linear curve fitting of the heart-rate-blood-pressure relationship for patients after myocardial infarction is feasible but technical limitations and the lack of correlation between the gain parameter and other measures of autonomic function suggest that this method has limited usefulness. The lower plateau is related strongly to the BRS; both are vagal measures of cardiac autonomic function.

Dangerous alcoholics. Personality varieties in aggressive and suicidally inclined subjects

Alcoholics registered as dangerous to others were compared, by means of a health questionnaire and individual testing, with a suicidally inclined group and non-dangerous alcoholic controls. Dangerous subjects reported conspicuously few nervous complaints, whereas the suicidal group was characterized by a broad spectrum of symptoms including paranoid, depressive and aggressive feelings as well as tiredness and irritability. Intellectually they were found to be rather verbal. The controls formed an intermediate group as to the variables applied. The results tend to confirm a hypothesis of a psychopathic-neurotic continuum as a major differentiating factor between the groups.