Ethnic Differences in Carotid Intima Media Thickness and Plaque Presence - The HELIUS study.

Introduction In the Netherlands, the prevalence of cardiovascular diseases (CVD) is higher among South-Asian Surinamese and lower among Moroccans compared to the Dutch. Traditional risk factors for atherosclerotic CVD do not fully explain these disparities. We aim to assess ethnic differences in plaque presence and intima media thickness (cIMT) and explore to which extent these differences are explained by traditional risk factors. Methods We used cross-sectional data from a subgroup of participants enrolled in the multi-ethnic population-based HEalthy Life In an Urban Setting (HELIUS) study who underwent carotid ultrasonography. Logistic and linear regression models were built to assess ethnic differences in plaque presence and cIMT with the Dutch population as reference. Additional models were created to adjust for socioeconomic status, body height and cardiovascular risk factors. Results Of the 3022 participants, 1183, 1051 and 790 individuals were of Dutch, South-Asian Surinamese and Moroccan descent. Mean age was 60.9 years (SD 8.0), 52.8% was female. Compared to the Dutch, we found lower odds for plaque presence in Moroccans (0.77, 95% CI 0.62; 0.95) and no significant differences between the South-Asian Surinamese and Dutch population (0.91, 95% CI 0.76; 1.10). After adjustment for CVD risk factors, we found a lower plaque presence in South-Asian Surinamese (0.63, 95% CI 0.48; 0.82). In both Moroccan and South-Asian Surinamese individuals, adjustment for socioeconomic status did not materially change the results. cIMT was lower in South-Asian Surinamese compared to the Dutch (-17.9 µm, 95% CI -27.9; -7.9) and partly explained by ethnic differences in body height as South-Asian Surinamese individuals were, on average, shorter than the Dutch population. No differences in cIMT between Moroccans and Dutch were found. Conclusions cIMT and plaque prevalence differ between ethnic groups independent of CVD risk. Lower plaque prevalence in Moroccans was partly attributable to a lower prevalence of traditional CVD risk factors, while body height was an important contributor to differences in cIMT in South-Asians. This study emphasizes the need for ethnic-specific cut-off values for plaque presence and cIMT.

Vascular risk factors and staging of atherosclerosis in patients and controls: The Norwegian Stroke in the Young Study.

Objectives: We studied the prevalence of vascular risk factors (RFs) among 385 ischaemic stroke patients ⩽60 years and 260 controls, and their association with atherosclerosis in seven vascular areas. Methods: History of cardiovascular events (CVE), hypertension, diabetes mellitus (DM), dyslipidaemia, pack-years of smoking (PYS), alcohol, and physical inactivity were noted. Blood pressure, body mass index (BMI), waist-hip ratio (WHR), lipid profile, epicardial adipose tissue (EAT), visceral abdominal adipose tissue (VAT), and subcutaneous abdominal adipose tissue were measured. Numeric staging of atherosclerosis was done by standardized examination of seven vascular areas by right and left carotid and femoral intima-media thickness, electrocardiogram, abdominal aorta plaques, and the ankle-arm index. All results were age and sex-adjusted. Poisson regression analysis was applied. Results: At age ⩽49 years at least one RF was present in 95.6% patients versus 90.0% controls. Compared to controls, male patients and middle-aged female patients showed no significant differences. Young female patients compared to young female controls had a higher burden of RFs (94.3% vs 88.6%, p = 0.049). Poisson regression analysis combined for patients and controls, adjusted for age and sex, showed numeric staging of atherosclerosis associated with age, prior CVE, hypertension, DM, dyslipidaemia, PYS, alcohol, BMI, WHR, EAT, VAT, and an increased number of risk factors. Adjusted for all risk factors, numeric staging of atherosclerosis was associated with increasing age, hypertension, DM, PYS, and BMI. Conclusion: Vascular risk factors are highly prevalent in young- and middle-aged patients and controls, and are predictors of established atherosclerosis at study inclusion. Focus on main modifiable vascular RFs in primary prevention, and early and aggressive secondary treatment of patients are necessary to reduce further progression of atherosclerosis.

Prevalence of atherosclerosis and association with 5-year outcome: The Norwegian Stroke in the Young Study.

Objectives: We studied the prevalence of atherosclerosis among ischaemic stroke patients ≤60 years and controls at the time of the index stroke, and its association with occurrence of new cardiovascular events (CVEs) and mortality at a 5-year follow-up. Methods: Prevalent atherosclerosis was assessed for 385 patients and 260 controls in seven vascular areas by electrocardiogram (ECG), ankle-arm index (AAI) and measurement of right and left carotid and femoral intima-media thickness (cIMT and fIMT) and abdominal aorta plaques (AAP). Clinical end-points were any new CVE (stroke, angina, myocardial infarction or peripheral arterial disease) or death from any cause at 5-year follow-up. All results were sex- and age-adjusted; logistic regression and Cox proportional hazards models were applied. Results: Young patients ≤49 years had prevalent atherosclerosis in 1/2 of males and 1/3 of females. Compared with controls, young female patients showed significantly higher prevalent atherosclerosis, p = 0.024. Ischaemic ECG and mean cIMT were higher in young and middle-aged female patients (p = 0.044, p = 0.020, p = 0.023 and p <0.001, respectively). Mean fIMT was higher in middle-aged female patients (p <0.001). Cardiovascular events were associated with ischaemic ECG; AAI ≤0.9, fIMT ≥0.9 mm and increased number of areas with atherosclerosis (NAA) among patients, and with AAP, cIMT ≥0.9 mm, fIMT ≥0.9 mm and NAA among controls. Mortality was associated with higher age, ischaemic ECG and NAA among patients, and cIMT ≥0.9 mm among controls. Conclusion: Atherosclerosis is highly prevalent even in young stroke patients. Some areas and increasing NAA are associated with CVEs and death.

Segment-specific association of carotid-intima-media thickness with cardiovascular risk factors - findings from the STAAB cohort study.

BACKGROUND: The guideline recommendation to not measure carotid intima-media thickness (CIMT) for cardiovascular risk prediction is based on the assessment of just one single carotid segment. We evaluated whether there is a segment-specific association between different measurement locations of CIMT and cardiovascular risk factors. METHODS: Subjects from the population-based STAAB cohort study comprising subjects aged 30 to 79 years of the general population from Würzburg, Germany, were investigated. CIMT was measured on the far wall of both sides in three different predefined locations: common carotid artery (CCA), bulb, and internal carotid artery (ICA). Diabetes, dyslipidemia, hypertension, smoking, and obesity were considered as risk factors. In multivariable logistic regression analysis, odds ratios of risk factors per location were estimated for the endpoint of individual age- and sex-adjusted 75th percentile of CIMT. RESULTS: 2492 subjects were included in the analysis. Segment-specific CIMT was highest in the bulb, followed by CCA, and lowest in the ICA. Dyslipidemia, hypertension, and smoking were associated with CIMT, but not diabetes and obesity. We observed no relevant segment-specific association between the three different locations and risk factors, except for a possible interaction between smoking and ICA. CONCLUSIONS: As no segment-specific association between cardiovascular risk factors and CIMT became evident, one simple measurement of one location may suffice to assess the cardiovascular risk of an individual.

Protocol and quality assurance for carotid imaging in 100,000 participants of UK Biobank: development and assessment.

Background Ultrasound imaging is able to quantify carotid arterial wall structure for the assessment of cerebral and cardiovascular disease risks. We describe a protocol and quality assurance process to enable carotid imaging at large scale that has been developed for the UK Biobank Imaging Enhancement Study of 100,000 individuals. Design An imaging protocol was developed to allow measurement of carotid intima-media thickness from the far wall of both common carotid arteries. Six quality assurance criteria were defined and a web-based interface (Intelligent Ultrasound) was developed to facilitate rapid assessment of images against each criterion. Results and conclusions Excellent inter and intra-observer agreements were obtained for image quality evaluations on a test dataset from 100 individuals. The image quality criteria then were applied in the UK Biobank Imaging Enhancement Study. Data from 2560 participants were evaluated. Feedback of results to the imaging team led to improvement in quality assurance, with quality assurance failures falling from 16.2% in the first two-month period examined to 6.4% in the last. Eighty per cent had all carotid intima-media thickness images graded as of acceptable quality, with at least one image acceptable for 98% of participants. Carotid intima-media thickness measures showed expected associations with increasing age and gender. Carotid imaging can be performed consistently, with semi-automated quality assurance of all scans, in a limited timeframe within a large scale multimodality imaging assessment. Routine feedback of quality control metrics to operators can improve the quality of the data collection.

Burden of carotid artery atherosclerosis in Chinese adults: Implications for future risk of cardiovascular diseases.

Background Population-based studies of ultrasound measures of carotid atherosclerosis are informative about future risks of cardiovascular disease. Design Cross-sectional studies of carotid artery atherosclerosis in 24,822 Chinese adults from the China Kadoorie Biobank and 2579 Europeans from the UK Biobank. Methods Mean intima-media thickness of the common carotid arteries and presence of carotid artery plaque were examined in the China Kadoorie Biobank study. The carotid intima-media thickness (cIMT) findings in Chinese (mean age 59 years) were compared with a European population (mean age 62 years). Results Overall, the mean cIMT in Chinese was 0.70 mm (SD 0.16) and increased with age by 0.08 mm (SE 0.008) per 10-years older age. About 31% of the Chinese had carotid plaques and the prevalence varied 10-fold with age (6% at 40-49 to 63% at 70-89 years) and four-fold by region (range, 14%-57%). After adjustment for age, sex and region, plaque prevalence was higher in smokers than in non-smokers (36% vs. 28%) and two-fold higher in individuals with systolic blood pressure ≥160 mmHg than those with systolic blood pressure <120 mmHg (44% vs. 22%) in the China Kadoorie Biobank study. Mean cIMT was similar in the younger Chinese and European adults, but increased more steeply with age in the Chinese ( p = 0.002). Conclusions About one-third of Chinese adults had carotid plaques. The rate of progression of carotid atherosclerosis with age was more extreme in the Chinese compared with the European population, highlighting the need for more intensive strategies for cardiovascular disease prevention in China.

Carotid Intima-media Thickness Measurements: Relations with Atherosclerosis, Risk of Cardiovascular Disease and Application in Randomized Controlled Trials.

Advances in the field of carotid ultrasound have been incremental, resulting in a steady decrease in measurement variability. Improvements in edge detection algorithms point toward increasing automation of CIMT measurements. The major advantage of CIMT is that it is completely noninvasive and can be repeated as often as required. It provides a continuous measure since all subjects have a measurable carotid wall. It is also relatively inexpensive to perform, and the technology is widely available. A graded relation between raising LDL cholesterol and increased CIMT is apparent. Increased CIMT has been shown consistently to relate the atherosclerotic abnormalities elsewhere in the arterial system. Moreover, increased CIMT predicts future vascular events in both populations from Caucasian ancestry and those from Asian ancestry. Furthermore, lipid­lowering therapy has been shown to affect CIMT progression within 12­18 months in properly designed trials with results congruent with clinical events trials. In conclusion, when one wants to evaluate the effect of a pharmaceutical intervention that is to be expected to beneficially affect atherosclerosis progression and to reduce CV event risk, the use of CIMT measurements over time is a valid, suitable, and evidence­based choice.

The Norwegian Stroke in the Young Study (NOR-SYS): rationale and design.

BACKGROUND: Ischemic stroke in young adults is a major health problem being associated with a higher vascular morbidity and mortality compared to controls, and a stroke recurrence rate of 25% during the first decade. The assumed cause of infarction and the detected risk factors determine the early- and long-term treatment. However, for many patients the cause of stroke remains unknown. Risk factor profile and etiology differ in young and elderly ischemic stroke patients, and atherosclerosis is the determined underlying condition in 10 to 15%. However, subclinical atherosclerosis is probably more prevalent and may go unrecognized. METHODS/DESIGN: NOR-SYS is a prospective long-term research program. Standardized methods are used for anamnestic, clinical, laboratory, imaging, and ultrasound data collection in ischemic stroke patients aged ≤60 years, their partners and joint adult offspring. The ultrasound protocol includes the assessment of intracranial, carotid and femoral arteries, abdominal aorta, and the estimation of VAT. To date, the study is a single centre study with approximately 400 patients, 250 partners and 350 adult offspring expected to be recruited at our site. DISCUSSION: NOR-SYS aims to increase our knowledge about heredity and the development of arterial vascular disease in young patients with ischemic stroke and their families. Moreover, optimization of diagnostics, prophylaxis and early intervention are major targets with the intention to reduce stroke recurrence and other clinical arterial events, physical disability, cognitive impairment and death.

Asymmetrical distribution of atherosclerosis in the carotid artery: identical patterns across age, race, and gender.

BACKGROUND: Small autopsy studies and clinical practice indicated that carotid atherosclerosis develops in an asymmetrical helical pattern coinciding with regions of low shear stress. We investigated the distribution of carotid atherosclerosis as determined by maximum carotid intima-media thickness (CIMT), to assess if we could confirm this atherosclerotic configuration across various populations with different cardiovascular risk. METHODS AND RESULTS: We used the individual baseline CIMT data from 3364 subjects from four recent international multicentre randomized controlled trials in which the carotid artery was systematically examined using the same ultrasound protocol and method to quantify CIMT. For each subject, circumferential information on the maximum CIMT of the left and right carotid arteries was obtained for the common carotid, bifurcation, and internal carotid artery segments. In each segment (common, bifurcation, internal), mixed modelling was used to study the differences in CIMT between angles, sides, gender, age, race, and studies. Each segment showed a different circumferential CIMT pattern. In all segments there were statistically significant differences between maximum CIMT across circumferential angles (p < 0.001); on average CIMT was highest in the posteromedial wall of the bifurcation and internal carotid segments and in the anterolateral wall of the common carotid segment. This asymmetric circumferential pattern was found to be identical in men and women, in young and old age, in different race groups, and across the studies. CONCLUSIONS: We confirmed the asymmetrical helix-like distribution of atherosclerosis in the carotid arteries and expand the evidence by showing that the atherosclerotic configuration is similar across populations with different vascular risks and across gender, age, and race. This has implications for future design of carotid ultrasound studies, as the angle of insonation is an important predictor of maximum CIMT.

The use of plaque score measurements to assess changes in atherosclerotic plaque burden induced by lipid-lowering therapy over time: the METEOR study.

AIM: To evaluate whether plaque scoring measurements are able to track changes in atherosclerotic plaque burden over time and to study whether this is affected by lipid-lowering therapy. METHODS: Data used were from METEOR (Measuring Effects on Intima-Media Thickness: an Evaluation Of Rosuvastatin), a randomized controlled trial of rosuvastatin 40 mg among 984 low-risk patients with modest carotid intima-media thickening (CIMT). In this analysis, duplicate ultrasound images from 12 carotid sites were collected at the baseline and end of the study from 495 European patients and were evaluated for plaque presence and severity. Plaques were scored from near and far walls of the 12 sites (0= none; 1= minimal; 2= moderate; 3= severe) and plaque scores (PS) were combined into two summary measures for each examination. The MeanMaxPS is the mean over the 12 carotid sites of the maximum score at each site and the MaxMaxPS reflects the most severe lesion at any site. RESULTS: Baseline MeanMaxPS and MaxMaxPS were 0.31 (SD: 0.20) and 1.15 (SD: 0.51), respectively. Changes in MeanMaxPS and MaxMaxPS significantly differed between rosuvastatin and placebo (mean difference: -0.03 [SE: 0.01; p =0.016] and -0.09 [SE: 0.04; p =0.027], respectively). In contrast to rosuvastatin, which demonstrated no change from the baseline, placebo showed significant progression in MeanMaxPS and MaxMaxPS (p =0.002; both). CONCLUSION: The plaque-scoring method proved capable of assessing the change in atherosclerotic plaque burden over time and proved useful to evaluate lipid-lowering in asymptomatic individuals with a low risk of cardiovascular disease and subclinical atherosclerosis.

Striking increases in carotid artery wall thickness in healthy subjects.

BACKGROUND: Atherosclerosis has long been thought to develop over time in a linear manner from gradual wall thickening to advanced thick lesions. However, evidence has emerged indicating a phasic rather than linear progression with time. A major reason for this non-linear pattern appears to be the occurrence of hemorrhages in the arterial wall, although data on this issue are still scarce. We studied the occurrence of temporarily impressive thickenings of the carotid arterial wall in a cohort of healthy postmenopausal women who were followed up for 3 years with regular carotid ultrasound examinations. METHODS: The women were the European participants of a randomized placebo-controlled trial into the effect of hormone replacement therapy on progression of carotid intima-media thickness (CIMT). For a period of 3 years, the women underwent a standardized carotid ultrasound protocol every 6 months. Common, bifurcation and internal carotid segments were scanned on both sides, stored on videotape, and the near and far wall CIMT was measured on defined angles and segments, also in areas of plaque. Adverse events were routinely recorded. At the completion of the study, all segment-specific measurements were evaluated for outliers. Images were retrieved from videotape and evaluated whether the outlier resulted from a real morphological change or 'measurement error'. RESULTS: The 509 healthy postmenopausal women, free from previous symptomatic cardiovascular disease, underwent 3,812 carotid ultrasound scans during the study, and 44,924 carotid segments were evaluated. In 203 segments of 188 participants outliers were observed. True morphological changes were found in 12 participants, equivalent to a 3-year risk of 2.4%. These changes did not give rise to clinical symptoms. In the 6 women of whom we had follow-up measurements, the changes were reversed within 6-12 months. CONCLUSION: We observed acute increases in CIMT among 2.4% of healthy postmenopausal European women followed for 3 years. When assuming these were the result of vessel wall hemorrhages, our findings add to the body of evidence suggesting that vessel wall hemorrhages contribute to atherosclerosis development and also appear to occur clinically silent.

Effect of carotid angioplasty and stenting on duplex velocity measurements in a porcine model.

PURPOSE: To evaluate if there are any differences in duplex ultrasound velocity measurements between native and stented carotid arteries using duplex ultrasound in an animal model. METHODS: The common carotid artery of 5 pigs was exposed bilaterally (10 arteries). Diameters and velocities were measured by ultrasound in the proximal, mid, and distal native artery at the intended site of stent implantation. Measurements were repeated after bilateral stent placement (Wallstent versus Precise) under angiographic control. Outcomes of native versus stented arteries and Wallstent versus Precise were statistically compared. RESULTS: Angiographic measurements matched well with duplex-measured diameters. The mean proximal stent diameter (3.5+/-0.5 mm) was significantly smaller than the native proximal artery diameter (4.2+/-0.4 mm, p = 0.004), mostly due to narrowing of the Wallstent diameter to 3.2+/-0.5 mm (p = 0.009). Proximal, mid, and distal segments of the Wallstents were narrower than those of the Precise stent, and associated peak systolic velocities (PSV) were higher at the 3 locations versus the Precise stent, although the differences were not statistically significant. Wallstent PSVs were higher than in the native artery at the proximal, mid, and distal segments, respectively; again, the differences were not statistically significant. CONCLUSION: Stent placement caused anatomical and hemodynamic alterations. Narrowings and associated increased velocities were noted. Such alterations, however, were stent-type dependent and did not justify a general approach to new velocity criteria indiscriminately applied to all stents.

Ultrasound mini-transducer with malleable handle for coronary artery surgery.

PURPOSE: A 13 MHz epicardial ultrasound mini-transducer (15 x 9 x 6 mm) with a custom made malleable handling tool was evaluated to assess the coronary artery and anastomosis on all sides of the heart. DESCRIPTION: On indication, in 8 patients undergoing coronary artery bypass surgery on the arrested heart, 8 coronary arteries as well as 27 coronary anastomoses were scanned. EVALUATION: The malleable handle was easily adjusted, and all sides of the heart were accessible for scanning with the mini-transducer. Based on intraoperative scanning, the anastomotic site was altered (n = 4), an additional coronary artery was grafted (n = 2), and the left anterior descending coronary artery was identified after incorrect conventional selection of the diagonal branch (n = 1). No anastomosis construction errors were detected. In one anastomosis, a calcified plaque was seen in the outflow corner. CONCLUSIONS: The epicardial ultrasound mini-transducer with its malleable handle allowed successful visualization and assessment of the coronary arteries and anastomoses on all sides of the heart. Ultrasound information greatly aided in intraoperative decision making that resulted in anastomotic site changes and prevented grafting of the wrong vessel.

Quality assessment of distal S(2)AS connector anastomosis by 13 MHz epicardial ultrasound.

OBJECTIVE: During application of a distal coronary bypass connector, we employed 13 MHz epicardial ultrasound to evaluate quantitative caliper measurements for vessel size matching and to assess anastomosis quality after connector deployment. METHODS: Two S(2)AS connector anastomoses were constructed on ex vivo pressure-perfused porcine hearts. Epicardial ultrasound measurements of the connector ring and anastomosis were compared to intravascular ultrasound measurement and cast dimensions. In 21 pigs, anastomotic sites with internal diameter of 2.25-3.0mm (internal mammary artery, IMA) and 1.8-2.2mm (left anterior descending coronary artery, LAD) were selected using external caliper and epicardial ultrasound measurements. Anastomoses were visualized and assessed intraoperatively (beating heart, n=21) and at 3 and 6 months' follow-up (explanted heart, n=10 each). RESULTS: Epicardial ultrasound underestimated connector dimension by < or =5% versus intravascular ultrasound and deviated < or =13% from cast dimensions for other anastomotic measurements. Caliper estimates of internal IMA and LAD diameter differed from ultrasound by -3+/-6% and -2+/-7% (mean+/-SD), respectively. Intraoperatively, the anastomotic orifice was flawless in all animals. It remained fully patent at 3 and 6 months by ultrasound, which was confirmed by histology. The connector to LAD percentage diameter stenosis changed from -12+/-5% intraoperatively to -1+/-7% at 3 months and from -5+/-6% intraoperatively to -16+/-13% at 6 months, in the growing pig model. CONCLUSIONS: In the pig, external caliper measurements provided a reliable quantitative estimate of inner graft and coronary diameter for connector size matching. Epicardial 13 MHz ultrasound is a promising method to assess coronary anastomosis quality even when connector metal is present.

Detection of construction errors in ex vivo coronary artery anastomoses by 13-MHz epicardial ultrasonography.

OBJECTIVE: Intraoperative detection of suboptimal coronary anastomoses allows revision before chest closure. We evaluated an epicardial 13-MHz ultrasound minitransducer as a means to detect three different coronary anastomosis construction errors. METHODS: In total, 120 internal thoracic artery-to-coronary artery anastomoses were constructed correctly (n = 60) or incorrectly (n = 60) with one technical error: suture crossover, purse-string or deep toe stitch (n = 20 each). Anastomoses were performed on ex vivo pressure-perfused porcine (96 anastomoses) and human hearts (24 anastomoses). Two blinded observers scanned and scored the anastomoses with epicardial ultrasonography. In 24 human and 24 porcine anastomoses, angiograms were made of 24 correct and 24 incorrect anastomoses and scored by two other blinded observers. Angioscopy and cast injection served as a reference. RESULTS: Overall, 119 of 120 anastomoses were accurately scored as correct or incorrect within a median of 67 seconds (8-381 seconds) by both observers (sensitivity 0.98, specificity 1.00, kappa 1.00 (1.00, 1.00, and 1.00 in angiography subset, respectively). One deep toe stitch that induced outflow corner stenosis was spotted by both observers but regarded as insignificant and thus inaccurately scored as correct. In 5 anastomoses, unintended irregularities were detected. By angiography, anastomoses were accurately scored with a sensitivity of 0.75 and a specificity of 0.81 ( P < .001 vs ultrasonography) and kappa of 0.54. Angioscopy and cast confirmed ultrasonographic findings and did not reveal irregularities other than detected by ultrasonography. CONCLUSION: Ex vivo epicardial 13-MHz ultrasonography allowed rapid and accurate evaluation of coronary anastomoses and detected technical construction errors with higher sensitivity and specificity than angiography.

Geometry assessment of coronary artery anastomoses with construction errors by epicardial ultrasound.

OBJECTIVE: There is concern about the quality of the distal anastomosis in off-pump coronary artery bypass grafting. We investigated the impact of specific construction errors on anastomotic geometry using epicardial ultrasound. METHODS: Twelve ex vivo pressure perfused porcine and five isolated post-mortem human hearts were used to construct 35 internal mammary artery to coronary artery anastomoses, either without (n = 7) or with a standardized construction error (oversutured toe, oversutured heel, cross-over or purse string; each error, n = 7). The anastomotic geometry was visualized and measured by a 13 MHz ultrasound mini-transducer. Impression cast material was used to validate anastomotic geometry. RESULTS: All 28 errors were visualized properly. Two unintended construction abnormalities were observed. In the porcine heart, the ratio of anastomotic orifice area and outflow corner area was 1.3+/-0.2 (mean+/-standard deviation) in the control group and reduced in the error groups: oversutured toe, 0.6+/-0.2 (P = 0.001 oversutured heel, 0.9+/-0.2 (P = 0.037); cross-over, 0.4+/-0.2 (P < 0.001); purse string, 0.3+/-0.2 (P < 0.001). None of the errors reduced the area of the inflow or outflow corner itself compared to the recipient coronary artery. In the human heart, all construction errors as well as wall plaque were visualized properly. In all anastomoses, ultrasound geometry corresponded to cast geometry. CONCLUSIONS: Ex vivo, epicardial 13 MHz ultrasound enabled accurate visualization and assessment of four different construction errors in the coronary anastomosis. All errors reduced the area of the anastomotic orifice, but not the inflow or outflow corner.

Endoscopic localization and assessment of coronary arteries by 13 MHz epicardial ultrasound.

BACKGROUND: In totally endoscopic coronary artery bypass grafting the target coronary artery is difficult to locate and assess. We explored the capacity of a high-frequency epicardial ultrasound mini-transducer (Aloka, Tokyo, Japan) to endoscopically locate and assess the left anterior descending (LAD), third obtuse marginal (OM3), and right posterior descending (RDP) coronary arteries. METHODS: In eight pigs, the LAD, OM3, and RDP were endoscopically exposed. The mini-transducer was manipulated by the "da Vinci" telemanipulation system (Intuitive Surgical, Inc, Mountain View, CA) over the unstabilized and stabilized epicardium to identify the target artery, obtain a scout scan, and both transverse and longitudinal images. RESULTS: In both unstabilized and stabilized conditions, the LAD and RDP were identified within a median of 29 seconds. In stabilized conditions, assessment was complete in 112 seconds (92 to 205) (median with range) for the LAD and 140 seconds (54 to 197) for the RDP. Stabilization of the OM3 was required for identification (16 [5 to 60]) and assessment (111 [82 to 225]). Overall identification was correct in 23 of 24 arteries. The OM branches and RDP became fully exposed endoscopically with stroke volume (SV) and mean arterial pressure (MAP) remaining at 67% +/- 11% (mean +/- standard error of the mean) and 70% +/- 5% of baseline values, respectively. Scanning itself did not augment the decrease in SV and MAP significantly. CONCLUSIONS: After proper endoscopic exposure and stabilization, robot-assisted epicardial ultrasound scanning enabled endoscopic identification and assessment of major coronary arteries within a median of 169 seconds per artery. Exposure, stabilization, and scanning were accompanied by an acceptable drop in stroke volume and mean arterial pressure.

Robot-assisted 13 MHz epicardial ultrasound for endoscopic quality assessment of coronary anastomoses.

In totally endoscopic coronary artery bypass surgery, intra-operative assessment of anastomotic quality is needed. We evaluated the endoscopic application of epicardial ultrasound to visualize the coronary anastomosis and detect a construction error. In 8 pigs (71-78kg), 16 internal mammary artery to left anterior descending coronary artery anastomoses were constructed conventionally, either correctly (n=8) or incorrectly with a suture cross-over construction error (n=8). A 13MHz mini-transducer (15x9x6mm) was introduced through a port and manipulated by the 'da Vinci' system. The chest was re-opened and scanning repeated manually. Postoperatively, macroscopic inspection served as reference and the intra-operative ultrasound images were scored as 'correct' or 'construction error' by two blinded observers. All anastomoses were scored accurately by both observers. One anastomosis constructed to be correct was scored as construction error, due to narrowing of the outflow corner and anastomotic orifice. Ultrasound images corresponded with macroscopic inspection. Closed-chest scan time was about 1.5 times longer than open-chest scan time, 176s (88-464) (median, range) versus 125s (75-314) (P=0.01), respectively. Closed-chest epicardial 13MHz ultrasound scanning required a median of 3min and enabled discrimination between correctly and incorrectly constructed coronary anastomoses.

The Osteoporosis Prevention and Arterial effects of tiboLone (OPAL) study: design and baseline characteristics.

The Osteoporosis Prevention and Arterial effects of tiboLone (OPAL) trial is a three-arm, randomized, placebo-controlled, double-blind study to determine the effect of tibolone 2.5 mg (Org OD 14) and continuous combined conjugated equine estrogens plus medroxyprogesterone acetate (0.625 mg/2.5 mg respectively) on progression of intima-media thickness of the carotid arteries and bone mineral density of the lumbar vertebrae and proximal femur in postmenopausal women. A total of 866 healthy postmenopausal women were recruited in six U.S. centers and five European centers. Duplicate carotid ultrasound examinations of the common carotid artery, the carotid bifurcation, and the internal carotid artery were performed at baseline. Single measurements of bone mineral density of the lumbar vertebrae and proximal femur were obtained at baseline. After randomization, ultrasound examinations were repeated every 6 months for 36 months following baseline, with a duplicate examination at the end of the study. Bone mineral density was measured every 12 months throughout the trial. The primary outcome is change in mean common carotid intima-media thickness (CIMT), defined as the average of the intima-media thickness measurements performed circumferentially at predefined angles for the near and far wall of 10-mm segments of the right and left distal common carotid arteries. Unique new features of the OPAL study are the specifically developed OPAL ultrasound protocol, yielding highly reproducible CIMT measurements, and the use of two experienced core laboratories for CIMT readings (one in the United States and one in Europe) with one common quality assurance and control program. The OPAL study is a large, placebo-controlled trial evaluating the effects of tibolone, as well as one of the first large randomized studies to determine the effects of continuous combined estrogen-progestin therapy on carotid atherosclerosis in healthy postmenopausal women. The OPAL study results are expected to complement other studies on atherosclerosis progression in healthy postmenopausal women.