Geometric and Hemodynamic Evaluation of 3-Dimensional Reconstruction Techniques for the Assessment of Coronary Artery Wall Shear Stress in the Setting of Clinical Disease Progression

Author(s):  
Lucas H. Timmins ◽  
Jin Suo ◽  
Parham Eshtehardi ◽  
Saurabh S. Dhawan ◽  
Michael C. McDaniel ◽  
...  

Myocardial infarction and sudden cardiac death are usually due to the rapid progression of previously non-flow limiting atherosclerotic plaques that transform to an unstable (i.e., vulnerable) phenotype. Despite considerable advances in medical therapies and treatment modalities for coronary artery disease (CAD), there is no accurate method to predict the site of abrupt lesion progression that can lead to an acute coronary event. Wall shear stress (WSS) has not only been implicated in the development of CAD, but also in its rapid progression [1]. Recent data from our laboratory indicates significant plaque progression in areas of low WSS (<10 dynes/cm2), plaque regression in regions of physiologic WSS (10–25 dynes/cm2), and phenotypic transformation towards an unstable lesion in regions of high WSS (>25 dynes/cm2) [2].


Author(s):  
Jin Suo ◽  
Michael McDaniel ◽  
Parham Eshtehardi ◽  
Saurabh S. Dhawan ◽  
Lucas H. Timmins ◽  
...  

The high resolution of optical coherence tomography (OCT) may offer improved description of luminal surfaces and intimal thickening in human coronary arteries by comparison to other imaging modalities, such as intravascular ultrasound (IVUS). We investigated the left anterior descending (LAD) coronary artery of a patient using both OCT and IVUS methods and found an asymmetrical distribution of intimal thickness (IT) around the lumen circumference in the OCT images, whereas the IVUS images showed a lumen with no asymmetry in IT. We reconstructed a 3D coronary artery model from the OCT slices that represented the morphological details of local luminal surfaces accurately and used this to simulate the pulsatile flow field in the model employing computational fluid dynamics (CFD). The pulsatile wall shear stress (WSS) distribution on the LAD surface was derived, and time-averaged WSS was computed. The data for IT and WSS distributions in the LAD segment were compared, and a linear inverse relationship between IT and WSS was found; higher WSS (> 25±5 dynes per square centimeter) favors thinner intima (< 0.12±0.05 millimeters) and lower WSS (< 12±5 dynes per square centimeter) favors thicker intima (> 0.33±0.05 millimeters). The enhanced spatial resolution of OCT offers an improved imaging technique for developing CFD models and assessing early atherosclerosis in patients with coronary artery disease.





2017 ◽  
Vol 14 (127) ◽  
pp. 20160972 ◽  
Author(s):  
Lucas H. Timmins ◽  
David S. Molony ◽  
Parham Eshtehardi ◽  
Michael C. McDaniel ◽  
John N. Oshinski ◽  
...  

Although experimental studies suggest that low and oscillatory wall shear stress (WSS) promotes plaque transformation to a more vulnerable phenotype, this relationship has not been examined in human atherosclerosis progression. Thus, the aim of this investigation was to examine the association between oscillatory WSS, in combination with WSS magnitude, and coronary atherosclerosis progression. We hypothesized that regions of low and oscillatory WSS will demonstrate progression towards more vulnerable lesions, while regions exposed to low and non-oscillatory WSS will exhibit progression towards more stable lesions. Patients ( n = 20) with non-flow-limiting coronary artery disease (CAD) underwent baseline and six-month follow-up angiography, Doppler velocity and radiofrequency intravascular ultrasound (VH-IVUS) acquisition. Computational fluid dynamics models were constructed to compute time-averaged WSS magnitude and oscillatory WSS. Changes in VH-IVUS-defined total plaque and constituent areas were quantified in focal regions (i.e. sectors; n = 14 235) and compared across haemodynamic categories. Compared with sectors exposed to low WSS magnitude, high WSS sectors demonstrated regression of total plaque area ( p < 0.001) and fibrous tissue ( p < 0.001), and similar progression of necrotic core. Sectors subjected to low and oscillatory WSS exhibited total plaque area regression, while low and non-oscillatory WSS sectors demonstrated total plaque progression ( p < 0.001). Furthermore, compared with low and non-oscillatory WSS areas, sectors exposed to low and oscillatory WSS demonstrated regression of fibrous ( p < 0.001) and fibrofatty ( p < 0.001) tissue and similar progression of necrotic core ( p = 0.82) and dense calcium ( p = 0.40). Herein, we demonstrate that, in patients with non-obstructive CAD, sectors subjected to low and oscillatory WSS demonstrated regression of total plaque, fibrous and fibrofatty tissue, and progression of necrotic core and dense calcium, which suggest a transformation to a more vulnerable phenotype.





2018 ◽  
Vol 11 (20) ◽  
pp. 2072-2080 ◽  
Author(s):  
Arnav Kumar ◽  
Olivia Y. Hung ◽  
Marina Piccinelli ◽  
Parham Eshtehardi ◽  
Michel T. Corban ◽  
...  


Author(s):  
Lucas H. Timmins ◽  
David S. Molony ◽  
Parham Eshtehardi ◽  
Michael C. McDaniel ◽  
John N. Oshinski ◽  
...  

Natural history data on clinical coronary artery disease (CAD) indicates that there is a critical need to prospectively identify rapidly progressing and vulnerable coronary lesions that may cause potentially fatal acute coronary events [1]. Recent prospective clinical investigations have evaluated the value of wall shear stress (WSS) as a prognostic marker for identifying rapidly progressing coronary lesions [2,3]. Data indicate that low WSS is associated with significant plaque progression, while regions of high WSS are associated with plaque regression and phenotypic transformation towards a more vulnerable lesion. While these studies provided unprecedented data on the role of hemodynamic-induced mechanical forces in lesion dynamics, they were limited by a lack of focal understanding of the association between WSS and plaque progression. Specifically, despite the understanding that WSS and plaque progression are heterogeneous around the artery’s circumference, in each image slice WSS values were spatially averaged around the circumference and correlated with average values for changes in virtual histology-intravascular ultrasound (VH-IVUS) defined plaque constituent areas.





2014 ◽  
Vol 43 (1) ◽  
pp. 94-106 ◽  
Author(s):  
Lucas H. Timmins ◽  
David S. Molony ◽  
Parham Eshtehardi ◽  
Michael C. McDaniel ◽  
John N. Oshinski ◽  
...  


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