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Keywords:
Cardiac, Cardiovascular system, CT-Angiography, CT, Comparative studies, Computer Applications-Detection, diagnosis, Image verification
Authors:
H. Eom, D. H. Yang, Y.-H. Kim, J. Kwon, J.-H. Roh, J.-W. Kang, T.-H. Lim; Seoul/KR
DOI:
10.1594/ecr2015/C-1924
Conclusion
The major findings of the study were 1) post-bifurcation stent morphology could be demonstrated on dual source CT which correlated well with micro-CT findings 2) Unexpected findings such as floating strut (44%),
unintended gap (22%) and the eccentric location (11%) of crushed segment was observed in post-bifurcation stents.
Several bench studies have demonstrated post-bifurcation stent morphology including crushed struts,
jailed SB ostium,
or gaps in stent coverage using micro-CT (16-18).
Also,
intravascular ultrasound and optical computed tomography have been widely used to visualize morphological characteristics of stent struts (19,20).
General idea of optional SB stenting has been proved to show not much benefit compared to provisional SB stenting in randomized controlled studies (3-5,7).
The limitation of these studies is that the effect of post-bifurcation stent morphology on patient outcome has not been evaluated.
Future study evaluating the significance of post-bifurcation morphological changes in correlation with clinical prognosis might be done and the findings of our study might be put into practice.
Regarding the outcome,
computational fluid dynamic simulations to evaluate flow-related processes leading to in-stent restenosis are being conducted (21,22).
Further study on post-bifurcation stent morphology and local hemodynamic changes could be helpful in understanding the clinical impact of post-bifurcation stent morphology.
Clinical significance of morphological changes of the post-bifurcation stent is yet unclear,
but characteristic such as the length and location of crushed segment,
the presence of floating strut or unintended gap might potentially affect patient outcome.
As shown in our study,
coronary CT angiography could be useful in not only evaluating luminal patency but also morphological changes that could be potentially related to adverse clinical outcome after percutaneous coronary intervention.
Also,
patients showing unfavorable post-bifurcation stent morphology on coronary CT angiography could be more closely observed than the others to prevent undesirable events.
However,
current appropriate use criteria for cardiac CT does not include patient after percutaneous coronary intervention (23).
Several limitations of our study should be mentioned.
1) Even though we tried to simulate coronary bifurcation lesion,
the silicone tube was not an anthropomorphic cardiac phantom and the phantom did not have features of atherosclerosis.
It could have influenced the stent deployment.
Also when the calcified plaque sets in plaque shifting phenomenon could take place and moreover it could be difficult to separate crushed segment or floating strut from calcified plaque.
2) We did not use intraluminal iodine contrast agent unlike coronary CT angiography.
However,
by applying the appropriate window width and center,
this setting would not hinder the interpretation of the images in practice.
3) The number of phantoms was small.
In conclusion,
the morphology of the post-bifurcation stent on dual source CT correlated well with that of micro-CT in the coronary artery phantom.
Coronary CT angiography may be a feasible method for the evaluation of stent morphology in patients who underwent bifurcation stenting.