الفهرس 
CORONARY ARTERY ANATOMYOnly 14 pages are availabe for public view
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Abstract
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n the last thirty-five years, coronary revascularization was done through catheter-based technique and there is increase in percutaneous coronary interventions performance. The most advanced technique in the percutaneous coronary interventions was the coronary stent implantation in the 1990s, which decreased the incidence of restenosis. The usage of new stents generations led to more reductions in the occurrence of restenosis, but in-stent restenosis may still occur and cause partial or complete occlusion. So we should differentiate between patients who need invasive intervention versus conservative management by a non-invasive technique.
The utility of multi–slice CT is gaining increasing acceptance as a non-invasive technique for cardiac imaging. Recent years with the new machines have demonstrated successful application of multi–slice CT angiography for the non-invasive assessment of coronary artery disease and the evaluation of coronary artery stents.
The objective of our study was to assess the role of 128-slice dual-source CT angiography as a non-invasive technique in the assessment of the patency of the coronary arteries stents.
This study included forty patients with prior coronary artery stent implantation, they underwent invasive coronary angiography as a gold standard for evaluation of the coronary artery stents. The mean age of the included patients was 58 with an age range between 40 and 73 years.
In this study forty-two coronary artery stents implanted in forty patients were involved; and assessed by MSCT angiography for follow up of their patency and underwent invasive coronary angiography.
The MSCT angiography findings in our study were, 3 stents (7.14%) were non-assessable by MSCT angiography due to heavy stent struts and narrow caliber (all of them are 2.5 mm in caliber) and proved to be patent stents by invasive coronary angiography, while the rest of 39 assessable stents the following results were found:
1. Twenty-six stents: (66.66%) were reported to be patent by MSCT and proved their patency by invasive coronary angiography.
2. Nine stents: (23%) were reported to have suspected in-stent restenosis by MSCT and the invasive coronary angiography revealed that 4 (10.25%) of them have in-stent restenosis while 5 (12.8 %) stents proved to be patent by invasive coronary angiography.
3. Four stents: (10.25%) were reported to be totally occluded by MSCT and proved their occlusion by invasive coronary angiography.
CT angiography compared to the invasive coronary angiography as a gold standard technique gave us a sensitivity of 100%, a specificity of about 83.8 %, an accuracy of about 87.1 %, PPV of 61.5 % and NPV of 100% in the assessment of coronary artery stents.
In conclusion, our study helps to identify factors that influence the assessability of coronary artery stents by 128-slice dual source CT scanner, namely, stent type and diameter. It shows that under certain conditions, the detection of in-stent restenosis might be possible with an accuracy that could permit clinical applications, but the non assessable stents role out the use of MSCT coronary angiography in unselected patients with implanted stents in coronary arteries.
Our recommendations are the following:
1- Patients must be carefully selected before undergoing MSCT angiography for assessment of in-stent restenosis.
2- MSCT angiography should consider the first-line tool for the non-invasive assessment of patients with the ability to breath-hold and achieve low heart rates as well as patients with large diameter (3 mm or more) and thin-strut, implanted stents.
3- Invasive coronary angiography should be spared for patients who needs intervention procedures.