Coronary stent assessment on multidetector computed tomography: Source and predictors of image distortion

Long-term prognostic impact of non-invasive follow-up with computed tomography angiography in patients with left main coronary artery stenting

BACKGROUND

Left main coronary artery (LMCA) stenting is an evolving technique. Whether follow-up computed tomography angiography (CTA) might have clinical impact in these patients is controversial. The aim of present study is to compare clinical outcomes of patients with LMCA stenting followed with CTA versus patients with conventional clinical follow-up.

METHODS

From 2003 to 2014 all consecutive patients with unprotected LMCA stenosis treated with single DES implantation were prospectively included. Since 2009 all patients underwent CTA at 6-month after LMCA stenting. Therefore, the non-CTA group included all patients treated from 2003 to 2009 and the CTA group included patients treated from 2009 to 2014. Patients with 6-month cardiac events, renal dysfunction or atrial fibrillation were excluded. All patients underwent at least 2-year clinical follow-up. The primary endpoint was a composite of cardiac death, nonfatal myocardial infarction, and LMCA revascularization.

RESULTS

A total of 236 patients were included (119 in the non-CTA and 117 in the CTA group). Nine event-free patients presented with in-stent restenosis as assessed by CTA at 6 months; 5 had angiographic confirmation and were revascularized. At 2 years, the primary end-point was observed in 15.1% and 7.3% of patients of the non-CTA and CTA groups, respectively (P=0.07). All-cause mortality was higher in the non-CTA group (8.4% vs. 2.6%; P=0.05). Euroscore and CTA were found independent predictors of the primary end-point in the multivariate analysis.

CONCLUSIONS

Elective 6-month CTA after LMCA stenting is associated with better outcomes compared to conventional clinical follow-up.

Geographic miss with aorto-ostial coronary stent implantation: insights from high-resolution coronary computed tomography angiography

AIMS

Accurate positioning of aorto-ostial coronary stents is challenging. Coronary CT angiography (CCTA) allows detailed imaging of the coronary sinuses and implanted stents. We utilised CCTA to evaluate the accuracy of aorto-ostial stenting and to assess the efficacy of conventional angiography for guiding these procedures.

METHODS AND RESULTS

We analysed 256-row CCTA scans in 23 patients who had undergone aorto-ostial stenting. Optimal stent positioning was defined as presence of the entire circumference of the proximal stent edge within an aorto-ostial landing zone (AOLZ), located within 1 mm of the aorto-ostial plane. Geographic miss was diagnosed when at least a section of the proximal stent edge was located proximal or distal to the AOLZ. CCTA findings were compared with review of the conventional two-dimensional implantation angiogram (two experienced operators). By CCTA, the entire circumference of the proximal stent edge was located within the AOLZ in only three (13%) cases, with geographic miss in the remainder. Conversely, conventional coronary angiography suggested complete lesion coverage to be present in 95% of cases and optimal location of the proximal stent edge within the AOLZ in 76%.

CONCLUSIONS

Geographic miss was common in aorto-ostial stenting and was underestimated by conventional two-dimensional angiography.

Intra-arterial DynaCT angiography: an alternative tool to assess the patency of intracranial stent lumen

OBJECTIVE

The aim of this retrospective study was to assess the clinical utility of intra-arterial DynaCT angiographic imaging for the evaluation of intracranial stent patency.

METHODS

Between July 2011 and May 2014, 35 patients with symptomatic intracranial atherosclerotic stenosis (ICAS) were treated with percutaneous transluminal angioplasty and stents. All were evaluated with intra-arterial DynaCT angiographic imaging during the operations and follow-up. All images were further processed with three different kernels (sharp, normal, or smooth).

RESULTS

Thirty-six stents were implanted into the parent arteries. DynaCT provided "good" quality images (median score of 2 or 3 on a 5-point scale) with minimal artifact interference as rated by observers blind to treatment history and other imaging results. The median subjective visibility score was highest (3) using the sharp kernel.

CONCLUSIONS

DynaCT with sharp kernel image processing achieved good visualization of luminal patency following intracranial stents.

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 middle cerebral artery stents using multidetector row CT angiography in vivo study: comparison of the three different kernels

BACKGROUND

There are very few reports assessing middle cerebral artery (MCA) stents using multidetector computed tomography (MDCT).

PURPOSE

To assess MCA stents using multidetector CT angiography (CTA) in vivo evaluation: the differences in the CTA results according to the three different kernels.

MATERIAL AND METHODS

We retrospectively evaluated 27 MCA stents from 26 patients who underwent CTA with 16- and 64-slice MDCT after percutaneous transluminal angioplasty and stenting (PTAS). By CTA, using medium-smooth kernel (B30), medium-sharp kernel (B50), and sharp kernel (B60), the lumen diameter, artificial luminal narrowing (ALN), and subjective visibility score of the stented vessels were evaluated. The subjective visibility score ranged from 1 (poor quality) to 5 (excellent) using a five-point scale.

RESULTS

There were excellent inter-observer agreements for the lumen diameter measurements (P < 0.001). The mean diameter of the stented vessels was 2.10 ± 0.31 mm on digital subtraction angiography (DSA), 0.93 ± 0.20 mm on CTA using B30, 1.18 ± 0.27 mm on CTA using B50, and 1.29 ± 0.29 mm on CTA using B60. The mean ALN was 55.7 ± 6.0% on CTA using B30, 43.8 ± 7.5% on CTA using B50, and 38.7 ± 8.3% on CTA using B60. CTA with higher kernels had a smaller ALN than images with smaller kernels. The median subjective visibility score on the CTA using B50 was 3, which was higher than for the other kernels. The differences in the lumen diameter, ALN, and the subjective visibility score of the stented vessels on CTA using the three different kernels was statistically significant (P < 0.001).

CONCLUSION

The sharp kernel was better to assess the lumen diameter and ALN, but was inferior to the medium-sharp kernel for in-stent evaluation due to high image-to-noise. CTA with medium-sharp kernel showed good lumen visibility and acceptable ALN for MCA stents. This could therefore be a non-invasive, readily applicable clinical method for assessing MCA stent patency after stent placement.

Coming of age: coronary computed tomography angiography

Technical development has substantially improved diagnostic performance of coronary computed tomography angiography (CCTA). A large number of studies have addressed proof of concept, feasibility, and clinical robustness of this noninvasive diagnostic technique, and most have consistently described the ability of CCTA to reliably rule out significant coronary artery stenosis. Clinical evidence supports the significant role of CCTA in an increasing number of scenarios, including the detection of coronary disease in symptomatic patients who are at intermediate risk and evaluation of coronary revascularization procedures. After initial feasibility testing, the scientific evaluation of CCTA now points toward analyzing prognosis, outcome, and cost-effectiveness of this noninvasive diagnostic tool. In this article, appropriate clinical indications, diagnostic performance, current clinical applications, prognostic value, and cost-effectiveness of CCTA are reviewed.

Incremental value and safety of oral ivabradine for heart rate reduction in computed tomography coronary angiography

BACKGROUND

Heart rate (HR) reduction is essential to achieve optimal image quality and diagnostic accuracy with computed tomography coronary angiography (CTCA). Administration of ivabradine could be an attractive alternative to beta-blockade to reduce HR.

METHODS

One-hundred-twenty-three patients referred for CTCA were prospectively enrolled. Patients were divided in two groups depending on the absence or presence of chronic beta-blockade treatment. Within the two groups patients were randomized to either no additional premedication or oral ivabradine for 5 days prior to CTCA. In presence of chronic beta-blockade therapy it was shifted to atenolol 50mg twice a day for 5 days prior to CTCA. HR and blood pressure were assessed at admission (T0), immediately before CTCA (T1) and during CTCA (T2). The target HR was <65 bpm.

RESULTS

Ivabradine significantly reduced HR during CTCA. Mean relative HR reduction was 15% for controls, 12% for chronic beta-blockade, 19% for ivabradine and 24% for both chronic beta-blockade and ivabradine at T2 (p for trend <0.001). The rate of patients who reached the target HR at T2 was 83% in controls, 71% with chronic beta-blockade, 97% with ivabradine and 97% with both (p for trend <0.05). The percentage of patients that needed additional IV beta-blockade at T1 decreased from 69% to 40% with ivabradine and 30% with both (p for trend <0.05).

CONCLUSIONS

Ivabradine is safe and effective in increasing the rate of patients at target HR and in reducing the need for additional IV beta-blockade in patients referred for CTCA.