Complications After Stent Placement for Aortic Coarctation: A Pictorial Essay of Computed Tomographic Angiography

Very long-term follow-up after aortic stenting for coarctation of the aorta

INTRODUCTION AND OBJECTIVES

Stent implantation is the preferred treatment in older children and adults with aortic coarctation (CoA). We aimed to determine the incidence of very late events after CoA stenting.

METHODS

We analyzed a cohort of CoA patients who underwent stent implantation at our center between 1993 and 2018. Patients were periodically followed up in outpatient clinics, including computed tomography (CT) and fluoroscopy assessment.

RESULTS

A total of 167 patients with CT and fluoroscopy data were included: 83 (49.7%) were aged ≤ 12 years and 46 (28%) were female. The mean clinical follow-up time was 17±8 (range 4-30) years and the mean time to CT/fluoroscopy was 11±7 years. Aortic aneurysm was present in 13% and was associated with the PALMAZ stent (OR, 3.09; 95%CI, 1.11-9.49; P=.036) and the stented length (OR, 0.94; 95%CI, 0.89-0.99; P=.039). Stent fracture was frequent (34%), but was not related to the presence of aneurysm. Stent fracture was associated with young age (OR, 3.57; 95%CI, 1.54-8.33; P=.003), male sex (OR, 4.00; 95%CI, 1.51-12.5, P=.008) and inversely with the PALMAZ stent (OR, 0.29; 95%CI, 0.12-0.67, P=.005). Reintervention was lower in adults (10%), mainly related to aneurysms. Those treated when aged ≤ 12 years had higher reintervention rates (43%) due to recoarctation somatic growth.

CONCLUSIONS

This long-term follow-up study of CoA patients treated with stenting revealed a significant incidence of late events. Reintervention rates were higher in patients treated at younger ages. Periodic imaging surveillance appears to be advisable.

A NEW RING STENT WITH GRADED GEOMETRY FOR TREATING COARCTATION OF CURVED AORTA ARTERIES

Ring stent implantation has been widely used to treat coarctation of the aorta (CoA) as an alternative to surgery. Currently adopted stents with uniform geometry may cause uneven stress distribution and high stress concentration in curved vessels, leading to in-stent restenosis (ISR). Inspired by functional graded material, here we propose a new ring-and-link stent, which has graded geometry in order to achieve a reduced peak stress when deployed in curved arteries. Numerical simulation of a single ring of the graded stent indicated that by varying the circumferential spacing of wave crest, the maximum stress exerted on the artery was reduced by as much as 27.86% in comparison with the uniform one. The effects of stent geometric parameters and artery curvature were also obtained through a parametric study. Finally, a whole stent was studied to verify the design, and a maximum stress reduction by 31.96% was achieved. In summary, the proposed graded ring stent shows great potential in clinical applications to reduce the risk of ISR.

Quantitative analysis of dynamic computed tomography angiography for the detection of endoleaks after abdominal aorta aneurysm endovascular repair: A feasibility study

Objectives

To assess the feasibility of quantitative analysis of dynamic computed tomography angiography (dCTA) for the detection of endoleaks in patients who underwent endovascular repair of abdominal aortic aneurysms (EVAR).

Material and methods

Twenty patients scheduled for contrast-enhanced CT angiography (CTA) of the abdominal aorta post-EVAR were prospectively enrolled. All patients received a standard triphasic CTA protocol, followed by an additional dCTA. The dCTA acquisition enabled reconstruction of color-coded maps depicting blood perfusion and a dCTA dataset of the aneurysm sac. Observers assessed the dCTA and dynamic CT perfusion (dCTP) images for the detection of endoleaks, establishing diagnostic confidence based on a modified 5-point Likert scale. An index was calculated for the ratio between the endoleak and aneurysm sac using blood flow for dCTP and Hounsfield units (HU) for dCTA. The Wilcoxon test compared the endoleak index and the diagnostic confidence of the observers.

Results

In total, 19 patients (18 males, median age 74 years [70.5–75.7]) were included for analysis. Nine endoleaks were detected in 7 patients using triphasic CTA as the reference standard. There was complete agreement for endoleak detection between the two techniques on a per-patient basis. Both dCTA and dCTP identified an additional endoleak in one patient. The diagnostic confidence using dCTP for detection of endoleaks was not significantly superior to dCTA (5.0 [5–5] vs. 4.5 [4–5], respectively; p = 0.11); however, dCTP demonstrated superior diagnostic confidence for endoleak exclusion compared to dCTA (1.0 [1–1] vs 1.5 [1.5–1.5], respectively; p <0.01). Moreover, the dCTP endoleak index was significantly higher than the dCTA index (18.5 [10.8–20.5] vs. 3.5 [5–2.7], respectively; p = 0.02).

Conclusions

Quantitative analysis of dCTP imaging can aid in the detection of endoleaks and demonstrates a higher endoleak detection rate than triphasic CTA, as well as a strong correlation with visual assessment of dCTA images.

Endovascular coil embolization of a complex aortic arch pseudoaneurysm following arch stenting

Pseudoaneurysm formation is a life-threatening complication of thoracic aortic stenting due to the high risk of rupture. When located in the aortic arch, anatomic features may pose difficulties in choosing the optimal treatment strategy. Here, we describe the first poststenting aortic arch pseudoaneurysm treated by endovascular coil embolization. This approach, which we performed in a multidisciplinary setting, may be a feasible alternative in patients not considered suitable for open repair or stent-grafting. As an acute pseudoaneurysm may develop and rapidly expand during the first days after aortic stenting, early follow-up imaging is preferable.

Computed tomography image quality of aortic stents in patients with aortic coarctation: a multicentre evaluation

BACKGROUND

Stents are commonly used to treat aortic coarctation. The objective of this study was to evaluate the post-implantation computed tomography (CT) image quality of different stent types used to treat aortic coarctation.

METHODS

Adult and paediatric patients with stent-treated aortic coarctation who underwent contrast-enhanced CT were retrospectively included from three tertiary care centres. CT scans were subjectively scored for image quality using a 4-point scale (1 = unacceptable; 2 = poor; 3 = good; 4 = excellent). Furthermore, the amount of stent-induced blooming artefacts was measured as the percentage of the difference between outer and inner stent diameters over the outer stent diameter.

RESULTS

A total of 35 children and 34 adults implanted with 71 stents of six different types were included. The most commonly used stent type was the Cheatham Platinum stent (52 stents, 73%). The subjective image quality of the Cheatham Platinum stents was moderate with a score of 2.0±0.8 (mean ± standard deviation) in children and 2.3±0.6 in adults. The image quality in patients with Formula stents was 2.3±1.2. The Cheatham Platinum stents induced 34-48% blooming, the Formula stents 44-55%. The image quality in patients with the less commonly used Atrium Advanta V12, IntraStent, AndraStent and Palmaz stents was scored 3 (good) to 4 (excellent) with less blooming. The electrocardiographic gating and tube voltage (kVp) did not affect image quality.

CONCLUSIONS

There is a substantial variation in CT image quality and blooming artefacts for different stent types used to treat aortic coarctation.

Association of Aortic Arch Width Assessed by Noncontrast Cardiac Computed Tomography With Cardiac Remodeling, Cardiac Function, and Atherosclerosis in a Japanese Cohort

PURPOSE

Age-related aortic changes are related to adverse cardiac remodeling and reduced cardiac function. Here, we aim to assess the correlations between aortic arch width (AAW) and left ventricular (LV) remodeling and LV function as well as coronary artery calcification (CAC).

MATERIALS AND METHODS

This retrospective study included 194 patients (ages, 67±12 y) who underwent both coronary computed tomography angiography and echocardiography. The AAW is defined as the longest width between the ascending and descending aorta on a transaxial noncontrast coronary computed tomography angiography image at the level of the pulmonary artery bifurcation. Left ventricular mass, relative wall thickness ratio, left ventricular ejection fraction, left atrial volume, and early mitral inflow velocity to mitral annular early diastolic velocity ratio (E/e') were evaluated by echocardiography. CAC was assessed by Agatston score. The relationships between AAW and echocardiography parameters were assessed, and adjusted for demographic data and cardiovascular disease risk factors by multivariate linear regression analysis.

RESULTS

AAW (mean±SD, 11.6±1.4 cm) was positively correlated with left ventricular mass (r=0.28, P<0.0001), left atrial volume (r=0.28, P<0.0001), and E/e' (r=0.21, P<0.01). These correlations remained significant after adjustment for demographic data and cardiovascular disease risk factors. There was no correlation between AAW and left ventricular ejection fraction or relative wall thickness. There was a significant difference of AAW between the groups with Agatston score <100 and those with Agatston score ≥100, and this difference persisted after adjustment for all covariates (P<0.01).

CONCLUSION

Greater AAW was significantly associated with LV remodeling and impaired function as well as advanced CAC.