Constitutive Modeling of Porcine Coronary Arteries Using Designed Experiments

2003 ◽  
Vol 125 (2) ◽  
pp. 274-279 ◽  
Author(s):  
Stacey A. Dixon ◽  
Russell G. Heikes ◽  
Raymond P. Vito
Keyword(s):  
Coronary Artery ◽  
Internal Pressure ◽  
Coronary Arteries ◽  
Axial Strain ◽  
Constitutive Models ◽  
Parameter Study ◽  
Dependent Variables ◽  
Measured Force ◽  
The Difference ◽  
Constitutive Parameters

The development of new coronary artery constitutive models is of critical importance in the design and analysis of coronary replacement grafts. In this study, a two-parameter logarithmic complementary energy function, with normalized measured force and internal pressure as the independent variables and strains as the dependent variables, was developed for healthy porcine coronary arteries. Data was collected according to an experimental design with measured force ranging from 9.8 to 201 mN and internal pressure ranging from 0.1 to 16.1 kPa (1 to 121 mmHg). Comparisons of the estimated constitutive parameters showed statistically significant differences between the left anterior descending [LAD] and right coronary artery [RCA], but no differences between the LAD and left circumflex [LCX] or between the LCX and RCA. Point-by-point strain comparisons confirm the findings of the model parameter study and isolate the difference to the axial strain response. Average axial strains for the LAD, LCX, and RCA are 0.026±0.009,0.015±0.005, and 0.011±0.009, respectively, at all physiologic loads, suggesting that the axial strains in the LAD are significantly higher than in the other regions.

scholarly journals Reduced order numerical modeling for calibration of complex constitutive models in powder pressing simulations

2017 ◽  
Vol 49 (3) ◽  
pp. 331-345
Author(s):  
Shwetank Pandey ◽  
Vladimir Buljak ◽  
Igor Balac
Keyword(s):  
Ceramic Powder ◽  
Constitutive Models ◽  
Industrial Applications ◽  
Reduced Order ◽  
Discrepancy Function ◽  
Numerical Instabilities ◽  
Powder Pressing ◽  
Cap Model ◽  
The Difference ◽  
Constitutive Parameters

Numerical simulations of different ceramic production phases often involve complex constitutive models, with difficult calibration process, relying on a large number of experiments. Methodological developments, proposed in present paper regarding this calibration problem can be outlined as follows: assessment of constitutive parameters is performed through inverse analysis procedure, centered on minimization of discrepancy function which quantifies the difference between measurable quantities and their computed counterpart. Resulting minimization problem is solved through genetic algorithms, while the computational burden is made consistent with constraints of routine industrial applications by exploiting Reduced Order Model (ROM) based on proper orthogonal decomposition. Throughout minimization, a gradual enrichment of designed ROM is used, by including additional simulations. Such strategy turned out to be beneficial when applied to models with a large number of parameters. Developed procedure seems to be effective when dealing with complex constitutive models, that can give rise to non-continuous discrepancy function due to the numerical instabilities. Proposed approach is tested and experimentally validated on the calibration of modified Drucker-Prager CAP model, frequently adopted for ceramic powder pressing simulations. Assessed values are compared with those obtained by traditional, time-consuming tests, performed on pressed green bodies.

Abstract 4225: Periadventitial Adipose Tissue Inflammation Assessed By 64-slice Computed Tomography Is Associated With Coronary Artery Atherosclerosis

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
masaaki konishi ◽  
Seigo Sugiyama ◽  
Takeshi Nakaura ◽  
Kazuo Awai ◽  
Yasuyuki Yamashita ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Adipose Tissue ◽  
Coronary Artery ◽  
Coronary Arteries ◽  
Subcutaneous Fat ◽  
Adipose Tissues ◽  
Pericardial Fat ◽  
The Mean ◽  
The Difference ◽  
Ct Density

Background It has become increasingly evident that adipose tissue is a multifunctional organ that produces and secretes various paracrine and endocrine factors. Periadventitial cardiac adipose tissue (PCAT), which exists closely around coronary arteries, is now recognized as a rich source of a number of bioactive molecules. There have been some reports that highlight local chronic inflammation of PCAT as a potential contributing factor to the pathogenesis of coronary artery disease (CAD) and adipose tissue with inflammation is known to have high density in computed tomography (CT). We assessed CT density of adipose tissues to evaluate the inflammatory activity and investigated the association between PCAT inflammation and CAD. Methods and results We assessed the CT density of periadventitial adipose tissues in consecutive 69 patients suspected of CAD ( 51% men, 65 ± 11 years) using 64-slice CT. By using the image scanned for coronary CT angiography, adipose tissue and presence of CAD (>75% organic stenosis) were confirmed in the same scan. We measured CT density of PCAT around the proximal right coronary artery (Coronary-PCAT), pericardial fat apart from coronary arteries (between ascending and descending aorta as the control site; Cont-PCAT), and thoracic subcutaneous fat. In each of these sites, the CT density measurements in two or more regions of interest were randomly performed and the mean value was recorded. The mean of CT density was −81 ± 11 Hounsfield Unit (HU) in Coronary-PCAT, −99±11HU in Cont-PCAT, −103±7HU in the subcutaneous fat, which were significantly different values (p < 0.01). The difference of CT density between Coronary-PCAT and the Cont-PCAT was significantly greater in patients with CAD (n = 30) than those without CAD (n=39) (22±16 versus 16±10 HU, p < 0.05) but the difference between Cont-PCAT and subcutaneous fat was not related to the presence of CAD (6 ± 12 versus 3 ± 14 HU, p = 0.22). Conclusions Coronary-PCAT had significantly higher CT density than the Cont-PCAT and subcutaneous fat. The difference of CT density between Coronary-PCAT and Cont-PCAT was significantly greater in patients with CAD than non-CAD patients. The inflammatory actively of local PCAT rather than whole pericardial fat may implicate in the development of CAD.

scholarly journals Is myocardial bridge more frequently detected on radial access coronary angiography?

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Oktay Şenöz ◽  
Zeynep Yapan Emren
Keyword(s):  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Coronary Angiography ◽  
Coronary Arteries ◽  
Conventional Coronary Angiography ◽  
Myocardial Bridge ◽  
Femoral Access ◽  
Radial Access ◽  
The Difference ◽  
Artery Disease

Abstract Background Although the incidence of myocardial bridge (MB) has been defined in different femoral access conventional coronary angiography (FACCA) studies, the frequency of MB on radial access coronary angiography (RACA) is unknown. The aim of this study was to determine the difference in the incidence of MB between patients undergoing RACA and FACCA. Method A total of 2500 consecutive patients who underwent RACA and a total of 1455 consecutive patients who underwent FACCA were retrospectively investigated to detect the presence of MB. The incidences of the groups were calculated separately and compared. The clinical and angiographic features of the patients with MB were analyzed. Results MB was detected at an incidence of 10.2%, in 255/2500 patients who underwent RACA, and 1.8% in 27/1455 patients who underwent FACCA (p < 0.001). In both RACA and FACCA patients, the most involved coronary artery was the left anterior descending artery (LAD) (86.9% and 93.1%) and the mid-segment (84.9% and 88.9%) was the most affected section. Co-involvement of multiple coronary arteries by MB was 7.8% in patients who underwent RACA and 7.4% in patients who underwent FACCA. Coronary artery disease (CAD) was determined in 111 (35.7%) of the coronary arteries with MB, of which 81.9% were proximal to the MB. No significant CAD was detected in any of the vessels of 69.8% (178/255) of the patients who underwent RACA for different clinical indications. Conclusion These data demonstrated that the incidence of myocardial bridge able to be detected on RACA was much higher than FACCA.

Heparin from Intestine and Lung Source Administered in Large Dose to Dogs with Acute Myocardial Ischemia

1978 ◽  
Vol 40 (02) ◽  
pp. 407-417
Author(s):  
Michael J Saliba ◽  
Richard J Pavalec
Keyword(s):  
Coronary Artery ◽  
Myocardial Ischemia ◽  
Adenosine Triphosphate ◽  
Intestinal Mucosa ◽  
Large Dose ◽  
Acute Myocardial Ischemia ◽  
Ischemic Myocardium ◽  
Atp Levels ◽  
Initial Control ◽  
The Difference

SummaryIntestinal mucosa heparin (IMH) and beef lung heparin (BLH) were infused into dogs subjected to myocardial ischemia by intermittent coronary artery occlusions. The IMH was from a mixture of beef, sheep, and pig intestinal mucosa. Initial control occlusion and recovery was followed by a second occlusion with 60,000 units of IMH or BLH added. Electrocardiographic S-T segment elevations (ST) were measured acutely. There were no significant differences in ST in non-ischemic myocardium before occlusions or with occlusions. In ischemic myocardium, IMH significantly lowered control ST 84% in amount (t = 6.1 p <0.00005), and 76% in number (t = 11.6 p <0.00001). BLH lowered control ST a significant, lesser, 36% in amount (t = 3.6 p <0.008), and 35% in number (t = 3.2 p <0.01). The difference between IMH and BLH in ischemic myocardium was a significant 48% in amount (t = 4.0 p <0.0007), and 41% in number (t = 2.0 p <0.06). Myocardial adenosine triphosphate (ATP) levels were assayed after 90 min. ATP levels were 31% higher in both ischemic and non-ischemic myocardium in IMH-treated dogs than in BLH- treated. It was concluded that IMH and BLH are functionally different, and IMH was significantly more effective.

Quantification of Coronary Artery Stenosis with 16-Slice MSCT in Patients before CABG Surgery: Comparison to Standard Invasive Coronary Angiography

2005 ◽  
Vol 8 (1) ◽  
pp. 42 ◽  
Author(s):  
C. Probst ◽  
A. Kovacs ◽  
C. Schmitz ◽  
W. Schiller ◽  
H. Schild ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Coronary Angiography ◽  
Coronary Arteries ◽  
Artery Bypass ◽  
Invasive Coronary Angiography ◽  
Bypass Graft ◽  
Heart Association ◽  
Artery Stenosis ◽  
Vessel Disease ◽  
Selective Coronary Angiography

Objective: Invasive, selective coronary angiography is the gold standard for evaluation of coronary artery disease (CAD) and degree of stenosis. The purpose of this study was to compare 3-dimensional (3D) reconstructed 16-slice multislice computed tomographic (MSCT) angiography and selective coronary angiography in patients before elective coronary artery bypass graft (CABG) procedure. Methods: Sixteen-slice MSCT scans (Philips Mx8000 IDT) were performed in 50 patients (42 male/8 female; mean age, 64.44 8.66 years) scheduled for elective CABG procedure. Scans were retrospectively electrocardiogram-gated 3D reconstructed. The images of the coronary arteries were evaluated for stenosis by 2 independent radiologists. The results were compared with the coronary angiography findings using the American Heart Association segmental classification for coronary arteries. Results: Four patients (8%) were excluded for technical reasons. Thirty-eight patients (82.6%) had 3-vessel disease, 4 (8.7 %) had 2-vessel disease, and 4 (8.7%) had an isolated left anterior descending artery stenosis. In the proximal segments all stenoses >50% (56/56) were detected by MSCT; medial segment sensitivity was 97% (73/75), specificity 90.3%; distal segment sensitivity was 90.7% (59/65), specificity 77%. Conclusion: Accurate quantification of coronary stenosis greater than 50% in the proximal and medial segments is possible with high sensitivity and specificity using the new generation of 16-slice MSCTs. There is still a tendency to overestimate stenosis in the distal segments. MSCT seems to be an excellent diagnostic tool for screening patients with possible CAD.

Congenital Left Main Coronary Artery to Coronary Sinus Fistula

2011 ◽  
Vol 14 (4) ◽  
pp. 255 ◽  
Author(s):  
Fotios A. Mitropoulos ◽  
Meletios A. Kanakis ◽  
Periklis A. Davlouros ◽  
George Triantis
Keyword(s):  
Coronary Artery ◽  
Coronary Arteries ◽  
Coronary Sinus ◽  
Left Main Coronary Artery ◽  
Coronary Artery Fistula ◽  
Left Main ◽  
Coronary Fistula ◽  
Excellent Outcome ◽  
Surgical Ligation ◽  
Congenital Coronary Artery Fistula

Congenital coronary artery fistula is an extremely rare anomaly that may involve any of the coronary arteries and any of the cardiac chambers. We report the case of a 14-year-old female patient with a symptomatic congenital coronary fistula starting from the left main coronary artery and draining to the coronary sinus. The patient underwent surgical ligation of the fistula and had an excellent outcome.

Coronary artery embolism in a patient with mechanical heart valve and normal coronary arteries (clinical case)

2019 ◽  
Vol 17 (2) ◽  
pp. 153-157
Author(s):  
A. Z. Sharafeev ◽  
◽  
A. F. Khalirakhmanov ◽  
A. I. Alkhazurov ◽  
E. A. Gaziev ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Heart Valve ◽  
Coronary Arteries ◽  
Clinical Case ◽  
Mechanical Heart Valve ◽  
Normal Coronary Arteries ◽  
Artery Embolism ◽  
Coronary Artery Embolism

Gender Differences in Non-Obstructive Coronary Artery Disease

2020 ◽  
Vol 26 ◽  
Author(s):  
Maria Bergami ◽  
Marialuisa Scarpone ◽  
Edina Cenko ◽  
Elisa Varotti ◽  
Peter Louis Amaduzzi ◽  
...  
Keyword(s):  
Coronary Artery Disease ◽  
Gender Differences ◽  
Heart Disease ◽  
Coronary Artery ◽  
Ischemic Heart Disease ◽  
Coronary Arteries ◽  
Obstructive Coronary Artery Disease ◽  
Ischemic Heart ◽  
Current Evidence ◽  
Artery Disease

: Subjects affected by ischemic heart disease with non-obstructive coronary arteries constitute a population that has received increasing attention over the past two decades. Since the first studies with coronary angiography, female patients have been reported to have non-obstructive coronary artery disease more frequently than their male counterparts, both in stable and acute clinical settings. Although traditionally considered a relatively infrequent and low-risk form of myocardial ischemia, its impact on clinical practice is undeniable, especially when it comes to infarction, where the prognosis is not as benign as previously assumed. Unfortunately, despite increasing awareness, there are still several questions left unanswered regarding diagnosis, risk stratification and treatment. The purpose of this review is to provide a state of the art and an update on current evidence available on gender differences in clinical characteristics, management and prognosis of ischemic heart disease with non-obstructive coronary arteries, both in the acute and stable clinical setting.

scholarly journals Quantitative evaluation and comparison of coronary artery characteristics by 3D coronary volume reconstruction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yongcheol Kim ◽  
Jonathan James Hyett Bray ◽  
Benjamin Waterhouse ◽  
Alexander Gall ◽  
Georgia May Connolly ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Coronary Angiography ◽  
Coronary Arteries ◽  
Intraclass Correlation ◽  
Quantitative Coronary Angiography ◽  
Volume Estimation ◽  
Diabetic Patients ◽  
Volume Reconstruction ◽  
3 Dimensional ◽  
Inter Observer Variability

AbstractNon-atherosclerotic abnormalities of vessel calibre, aneurysm and ectasia, are challenging to quantify and are often overlooked in qualitative reporting. Utilising a novel 3-dimensional (3D) quantitative coronary angiography (QCA) application, we have evaluated the characteristics of normal, diabetic and aneurysmal or ectatic coronary arteries. We selected 131 individuals under 50 years-of-age, who had undergone coronary angiography for suspected myocardial ischaemia between 1st January 2011 and 31st December 2015, at the Bristol Heart Institute, Bristol, UK. This included 42 patients with angiographically normal coronary arteries, 36 diabetic patients with unobstructed coronaries, and 53 patients with abnormal coronary dilatation (aneurysm and ectasia). A total of 1105 coronary segments were analysed using QAngio XA 3D (Research Edition, Medis medical imaging systems, Leiden, The Netherlands). The combined volume of the major coronary arteries was significantly different between each group (1240 ± 476 mm3 diabetic group, 1646 ± 391 mm3 normal group, and 2072 ± 687 mm3 abnormal group). Moreover, the combined coronary artery volumes correlated with patient body surface area (r = 0.483, p < 0.01). Inter-observer variability was assessed and intraclass correlation coefficient of the total coronary artery volume demonstrated a low variability of 3D QCA (r = 0.996, p < 0.001). Dedicated 3D QCA facilitates reproducible coronary artery volume estimation and allows discrimination of normal and diseased vessels.

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