Usefulness of multislice computed tomography to assess patency of coronary artery stents versus conventional coronary angiography

Health Care Monitoring and Treatment for Coronary Artery Diseases: Challenges and Issues

In-stent restenosis concerning the coronary artery refers to the blood clotting-caused re-narrowing of the blocked section of the artery, which is opened using a stent. The failure rate for stents is in the range of 10% to 15%, where they do not remain open, thereby leading to about 40% of the patients with stent implantations requiring repeat procedure within one year, despite increased risk factors and the administration of expensive medicines. Hence, today stent restenosis is a significant cause of deaths globally. Monitoring and treatment matter a lot when it comes to early diagnosis and treatment. A review of the present stent monitoring technology as well as the practical treatment for addressing stent restenosis was conducted. The problems and challenges associated with current stent monitoring technology were illustrated, along with its typical applications. Brief suggestions were given and the progress of stent implants was discussed. It was revealed that prime requisites are needed to achieve good quality implanted stent devices in terms of their size, reliability, etc. This review would positively prompt researchers to augment their efforts towards the expansion of healthcare systems. Lastly, the challenges and concerns associated with nurturing a healthcare system were deliberated with meaningful evaluations.

Comparative analysis between 64- and 320-slice spiral computed tomography in the display of coronary artery stents and diagnosis of in-stent restenosis

The aim of the present study was to compare the accuracy of 64-multi-slice spiral computed tomography (64-MSCT) and 320-MSCT in the display of coronary artery stents and diagnosis of in-stent restenosis. The data collected from the 64- and 320-MSCT coronary angiography of 93 patients following coronary artery stent implantation were retrospectively analyzed. The 64-MSCT group comprised 30 cases with 57 stents and the 320-MSCT group comprised 63 cases with 93 stents. The image quality, heart rate of the patients and the radiation effective dose (ED) they were subjected to, were compared. Furthermore, the diagnostic abilities of 64-and 320-MSCT coronary angiography for in-stent restenosis were evaluated using invasive coronary angiography results as the gold standards. Statistically significant differences were observed in the heart rate and ED of the patients from the two groups (P<0.05), but no significant difference was identified in the accuracy index (P>0.05). The sensitivity, specificity, positive and negative predictive value and accuracy of the 64-MSCT group were found to be 100% (7/7), 93.94% (31/33), 77.78% (7/9), 100% (31/31) and 95% (38/40), respectively, and those in the 320-MSCT group were found to be 100% (16/16), 95.89% (70/73), 84.21% (16/19), 100% (70/70) and 96.63% (86/89), respectively. The present findings suggest that both 64-MSCT and 320-MSCT can be used for follow-up and curative effect evaluation following coronary stent implantation; however, 320-MSCT has fewer requirements of the patients' heart rate and uses a lower radiation dose.

The utility of the combination of the corrosion cast method and post mortem MSCT scans

A careful post-mortem investigation is needed to determine the cause of death of patients bearing coronary stents and to describe complications of stent implantation. The main purpose of this study was to combine post mortem methods of CT angiography and corrosion cast preparation for the visualization of coronary stenoses, coronary stents, instent restenosis, and stent occlusion. Injection-corrosion method was combined with post-mortem MSCT angiography to characterize the pathomorphological changes after stent implantation in 6 male cadaver hearts. Multi-slice computed tomography was employed to visualize the coronary artery system. For image post processing, multiplanar reconstructions, maximal intensity projections and three dimensional reconstructions were used. This study was assessing the feasibility of post mortem MSCT for intracoronary stent evaluation. We described a method for characterization of the coronary side branch stenosis caused by stent implantation. Post mortem CT imaging proved to be a feasible and highly reproducible technique for the characterization of pathological changes in the coronary system.

CT Imaging of Coronary Stents: Past, Present, and Future

Coronary stenting became a mainstay in coronary revascularization therapy. Despite tremendous advances in therapy, in-stent restenosis (ISR) remains a key problem after coronary stenting. Coronary CT angiography evolved as a valuable tool in the diagnostic workup of patients after coronary revascularization therapy. It has a negative predictive value in the range of 98% for ruling out significant ISR. As CT imaging of coronary stents depends on patient and stent characteristics, patient selection is crucial for success. Ideal candidates have stents with a diameter of 3 mm and more. Nevertheless, even with most recent CT scanners, about 8% of stents are not accessible mostly due to blooming or motion artifacts. While the diagnosis of ISR is currently based on the visual assessment of the stent lumen, functional information on the hemodynamic significance of in-stent stenosis became available with the most recent generation of dual source CT scanners. This paper provides a comprehensive overview on previous developments, current techniques, and clinical evidence for cardiac CT in patients with coronary artery stents.

Evaluation of coronary artery in-stent restenosis by 64-section computed tomography: factors affecting assessment and accurate diagnosis

PURPOSE

To determine factors affecting the ability of 64-multislice computed tomography (MSCT) to detect, assess, and accurately diagnose significant coronary arterial in-stent restenosis (ISR).

MATERIALS AND METHODS

The institutional review board approved this study and waived informed consent. Sixty patients underwent CT coronary angiography using 64-MSCT, after implantation of coronary artery stents (n=91). We assessed diagnostic accuracy for ISR with CT in comparison with conventional coronary angiography as the gold standard, visually and with measurement of in-stent coronary lumen density. Possible factors that influenced the diagnostic performance of CT were evaluated, which included image quality (IQ), stent characteristics, and location.

RESULTS

Sixty-nine stents (75.8%) were assessable. Low IQ, location in the left circumflex coronary artery, and narrow stent diameter were associated with poor assessment (P<0.05). In stents that could be assessed, sensitivity, specificity, positive predictive value, and negative predictive value of 64-MSCT were 90.0%, 73.5%, 58.1%, and 94.7%, respectively, for significant ISR. The diagnostic accuracy in assessable stents showed a significant increase with better IQ, thinner strut thickness, and nondrug eluting stent. False-positive diagnoses of ISR by CT were explained by coronary lumen density measurements.

CONCLUSIONS

Evaluation of stents by 64-MSCT is not recommended in stents with diameters of < or = 2.75 mm or stents located at the left circumflex coronary artery. The diagnostic accuracy of 64-MSCT is affected by IQ and strut thickness in assessable stents. Significant ISR can be excluded with high reliability in selected patients.