Renal and Visceral Artery Configuration During the First Year of Follow-Up After Fenestrated Aortic Aneurysm Repair Using the Anaconda Stent-graft: A Prospective Longitudinal Multicenter Study With ECG-Gated CTA Scans.

OBJECTIVE: The performance of fenestrated endovascular aortic aneurysm repair (FEVAR) may be compromised by complications related to the dynamic vascular environment. The aim of this study was to analyze the behavior of FEVAR bridging stent configurations during the cardiac cycle and during follow-up to improve our understanding on treatment durability. DESIGN: Twenty-one patients presenting with complex abdominal aortic aneurysms (AAAs; 9 juxtarenal/6 pararenal/3 paravisceral/1 thoracoabdominal aortic aneurysm type IV), treated with a fenestrated Anaconda (Terumo Aortic, Inchinnan, Scotland, UK) with Advanta V12 bridging stents (Getinge, Merrimack, NH, USA), were prospectively enrolled in a multicenter observational cohort study and underwent electrocardiogram (ECG)-gated computed tomographic angiography (CTA) preoperatively, at discharge, 7-week, and 12-month follow-ups. METHODS: Fenestrated endovascular aortic aneurysm repair stability was assessed considering the following variables: branch angle as the angle between the aorta and the target artery, end-stent angle as the angle between the end of the bridging stent and the native artery downstream from it, curvature and tortuosity index (TI) to describe the bending of the target artery. Body-bridging stent stability was assessed considering bridging stent flare lengths, the distances between the proximal sealing stent-ring and fenestrations and the distance between the fenestration and first apposition in the target artery. RESULTS: Renal branch angles significantly increased after FEVAR toward a perpendicular position (right renal artery from median 60.9°, inter quartile range [IQR]=44.2-84.9° preoperatively to 94.4°, IQR=72.6-99.8°, p=0.001 at 12-month follow-up; left renal artery [LRA], from 63.7°, IQR=55.0-73.0° to 94.3°, IQR=68.2-105.6°, p<0.001), while visceral branch angles did not. The mean dynamic curvature only decreased for the LRA from preoperative (3.0, IQR=2.2-3.8 m-1) to 12-month follow-up (1.9, IQR=1.4-2.6 m-1, p=0.027). The remaining investigated variables did not seem to show any changes over time in this cohort. CONCLUSIONS: Fenestrated endovascular aortic aneurysm repair for complex AAAs using the Anaconda fenestrated stent-graft and balloon-expandable Advanta V12 bridging stents demonstrated stable configurations up to 12-month follow-up, except for increasing renal branch angles toward perpendicular orientation to the aorta, yet without apparent clinical consequences in this cohort. CLINICAL IMPACT: This study provides detailed information on the cardiac-pulsatility-induced (dynamic) and longitudinal geometry deformations of the target arteries and bridging stents after fenestrated endovascular aortic aneurysm repair (FEVAR) up to 12-month follow-up. The configuration demonstrated limited dynamic and longitudinal deformations in terms of branch angle, end-stent angle, curvature, and tortuosity index (TI), except for the increasing renal branch angles that go toward a perpendicular orientation to the aorta. Overall, the results suggest that the investigated FEVAR configurations are stable and durable, though careful consideration of increasing renal branch angles and significant geometry alterations is advised.

The influence of electrocardiogram-gated computed tomography reconstruction into 8 or 10 cardiac phases on cardiac-pulsatility-induced motion quantification of stent grafts in the aorta.

Objective: The goal of this study was to determine to what extent aortic stent graft motion quantification is comparable between electrocardiogram (ECG)-gated computed tomography (CT) scans with reconstructions into 8 and 10 cardiac phases on CT scanners from two different vendors. Methods: An experimental setup that induces motion of an aortic stent graft, according to a predefined aortic blood pressure wave, was placed in two CT scanners of different vendors. The stent graft motion was captured using an ECG-gated CT technique and quantified using dedicated analysis algorithms. The calculated motion amplitudes and total traveled path lengths of stent segmentations were compared between scans reconstructed into 8 and 10 phases and between the scanners, after validation with sensor measurements and repeated measurements. Results: No difference in motion amplitudes in z-direction (craniocaudal direction) was observed between the reconstructions into 8 and 10 phases (0.02 mm; 95% confidence interval [CI], -0.01 to 0.05 mm; P = .358). The z-amplitudes differed by 0.04 mm (95% CI, 0.01-0.07 mm; P = .003) between the different CT scanners. Path lengths differed 0.07 mm (95% CI, 0.01-to 0.13 mm; P = .013) between the reconstructions into 8 and 10 phases and 0.13 mm (95% CI, 0.06-0.17 mm; P < .001) between the different scanners. Conclusions: The motion amplitudes can accurately be compared between 8 and 10 phases and between the two scanners, without differences larger than the voxel size of 0.3 × 0.3 × 0.5 mm. Clinical motion analysis results of different ECG-gated CT scans and CT scanners can be compared up to the accuracy of the CT scan.

In Vivo Quantification of Cardiac-Pulsatility-Induced Motion Before and After Double-Branched Endovascular Aortic Arch Repair.

The Relay®Branch stent-graft (Terumo Aortic, Sunrise, FL, USA) offers a custom-made endovascular solution for complex aortic arch pathologies. In this technical note, a modified electrocardiography (ECG)-gated computed tomography (CT)-based algorithm was applied to quantify cardiac-pulsatility-induced changes of the aortic arch geometry and motion before and after double-branched endovascular repair (bTEVAR) of an aortic arch aneurysm. This software algorithm has the potential to provide novel and clinically relevant insights in the influence of bTEVAR on aortic anatomy, arterial compliance, and stent-graft dynamics.

Diagnostic accuracy of cardiac computed tomographic angiography and transesophageal echocardiography in evaluation of patients with prosthetic paravalvular leakage.

PURPOSE: Computed Tomography (CT) scan has been well addressed to provide diagnostic information for patients with prosthetic heart valve (PHV) dysfunction. However, its role in the assessment of patients with prosthetic paravalvular leakage (PVL) has not been studied thoroughly. So, this study was conducted to assess the feasibility, reproducibility, and accuracy of CT for diagnosis of prosthetic PVL using surgical findings as the reference standard. MATERIALS AND METHODS: This was a prospective cohort study that was conducted on 26 consecutive patients with suspected prosthetic PVL who underwent both transesophageal echocardiography (TEE) and 64-slice ECG-gated CT. The gold standard was the intraoperative findings. Surgery was performed on 26 patients. RESULTS: There was an excellent degree of agreement between CT and intraoperative findings for diagnosis, localization of prosthetic PVL. The perimeter of prosthetic PVL measured by CT was strongly correlated with echocardiographic severity of PVL by TEE (Spearman's Correlation Coefficient, r = .83, p = .0014). CONCLUSION: This study demonstrates that cardiac CT showed comparable diagnostic accuracy to TEE and intraoperative findings for the detection, localization, and assessment of severity of prosthetic PVL. Moreover, CT was shown to be useful in detection of other findings related to prosthetic cardiac valves.

Sinus Valsalva Aneurysm of the non-coronary cusp initially diagnosed as right ventricular thrombus: A case report.

Sinus of Valsalva aneurysms are abnormal bulges of the aortic root caused by a tissue deficiency resulting in an enlargement of the aortic root in the area between the aortic annulus and the sinotubular junction. Frequently, sinus of Valsalva aneurysms are asymptomatic. However, sinus of Valsalva aneurysms can also be potentially fatal due to their risk of rupture. We present a case of a 49-year old asymptomatic male patient with a rare image of a sinus of Valsalva aneurysm of the non-coronary cusp which was initially mistaken for a right ventricular thrombus. Surgical repair of the sinus of Valsalva aneurysm was eventually achieved by a valve sparing root replacement and the patient was discharged 7 days after surgery. This case report shows that sinus of Valsalva aneurysms are vulnerable to misdiagnosis when it is not initially suspected. Because of the potential fatality of this phenomenon we would like to underline the necessary vigilance in the diagnostic process, as sinus of Valsalva aneurysms can be missed when the physician is not aware of this potential rare diagnosis.

Single left coronary ostium with a prepulmonic right coronary artery course in a French Bulldog with congenital valvular pulmonary stenosis.

A two-year-old, male castrated, French bulldog was presented for evaluation of coronary artery anatomy before balloon valvuloplasty for severe pulmonic valve stenosis. Multidetector computed tomography angiography showed a single left coronary ostium, absent right coronary ostium, and an anomalous, prepulmonic coursing right coronary artery. Medical management was elected to avoid the attendant risk associated with intervention. This case report documented the first known case of this specific anomaly in French bulldogs. Veterinary cardiologists should be aware of the potential for this specific coronary artery anomaly in this breed, given the predilection for the development of pulmonary stenosis. Routine screening of French bulldogs for anomalous, prepulmonic coronary arteries is recommended before interventional balloon valvuloplasty.

Cine-Computed Tomography for the Evaluation of Prosthetic Heart Valve Function.

BACKGROUND: After aortic valve replacement (AVR), suspected prosthetic valve dysfunction (mechanical or biological) may arise based on echocardiographic transvalvular velocities and gradients, leading to reoperative surgical intervention being considered. Our experience has found that 4-dimensional (space and time) image reconstruction of ECG-gated computed tomography, termed cine-CT, may be helpful in such cases. We review and illustrate our experience. METHODS: Twenty-seven AVR patients operated previously by a single surgeon (who performs >100 AVRs/year) were referred for repeat evaluation of suspected aortic stenosis (AS) based on elevated transvalvular velocities and gradients. The patients were fully evaluated by cine-CT. RESULTS: In all but 2 cases, the cine-CT strikingly and visually confirmed normal leaflet function and excursion, with no valve thrombosis, restriction by pannus, or obstruction by clot. In only 2 cases did cine-CT reveal decreased mechanical valve leaflet excursion. Repeat surgery was required in only 1 case while all other patients continued clinically without cardiac events. CONCLUSIONS: Echocardiography is an extraordinarily useful tool for the evaluation of prosthetic valve function. Increased pressure recovery beyond the valve and other factors may occasionally lead to exaggerated gradients. Cine-CT is emerging as an extremely valuable tool for further evaluation of suspected prosthetic valve AS. Our experience has been extremely helpful, as is shown in the dramatically reassuring images.

Quantitative Stent Graft Motion in ECG Gated CT by Image Registration and Segmentation: In Vitro Validation and Preliminary Clinical Results.

OBJECTIVES: The dynamic endovascular environment of stent grafts may influence long term outcome after endovascular aneurysm repair (EVAR). The sealing and fixation of a stent graft to the aortic wall is challenged at every heartbeat, yet knowledge of the cardiac induced dynamics of stent grafts is sparse. Understanding the stent-artery interaction is crucial for device development and may aid the prediction of failure in the individual patient. The aim of this work was to establish quantitative stent graft motion in multiphasic electrocardiogram (ECG) gated computed tomography (CT) by image registration and segmentation techniques. METHODS: Experimental validation was performed by evaluating a series of ECG gated CT scans of a stent graft moving at different amplitudes of displacement at different virtual heart rates using a motion generating device with synchronised ECG triggering. The methodology was further tested on clinical data of patients treated with EVAR devices with different stent graft designs. Displacement during the cardiac cycle was analysed for points on the fixating stent rings, the branches or fenestrations, and the spine. RESULTS: Errors for the amplitude of displacement measured in vitro at individual points on the wire frame were at most 0.3 mm. In situ cardiac induced displacement of the devices was found to differ per location and also depended on the type of stent graft. Displacement during the cardiac cycle was greatest in a fenestrated device and smallest in a chimney graft sac anchoring endosystem, with maximum displacement varying from 0.0 to 1.4 mm. There was no substantial displacement measurable in the spine. CONCLUSIONS: A novel methodology to quantify and visualise stent graft motion in multiphasic ECG gated CT has been validated in vitro and tested in vivo. This methodology enables further exploration of in situ motion of different stent grafts and branch stents and their interaction with native vessels.

In Vitro Quantification of Gutter Formation and Chimney Graft Compression in Chimney EVAR Stent-Graft Configurations Using Electrocardiography-Gated Computed Tomography.

PURPOSE: To assess the dynamic behavior of chimney grafts during the cardiac cycle. METHODS: Three chimney endovascular aneurysm repair (EVAR) stent-graft configurations (Endurant and Advanta V12, Endurant and Viabahn, and Endurant and BeGraft) were placed in silicone aneurysm models and subjected to physiologic flow. Electrocardiography (ECG)-gated contrast-enhanced computed tomography was used to visualize geometric changes during the cardiac cycle. Endograft and chimney graft surface, gutter volume, chimney graft angulation over the center lumen line, and the D-ratio (the ratio between the lengths of the major and minor axes) were independently assessed by 2 observers at 10 time points in the cardiac cycle. RESULTS: Both gutter volumes and chimney graft geometry changed significantly during the cardiac cycle in all 3 configurations (p<0.001). Gutters and endoleaks were observed in all configurations. The largest gutter volume (232.8 mm3) and change in volume (20.7 mm3) between systole and diastole were observed in the Endurant-Advanta configuration. These values were 2.7- and 3.0-fold higher, respectively, compared to the Endurant-Viabahn configuration and 1.7- and 1.6-fold higher as observed in the Endurant-BeGraft configuration. The Endurant-Viabahn configuration had the highest D-ratio (right, 1.26-1.35; left, 1.33-1.48), while the Endurant-BeGraft configuration had the lowest (right, 1.11-1.17; left, 1.08-1.15). Assessment of the interobserver variability showed a high correlation (intraclass correlation >0.935) between measurements. CONCLUSION: Gutter volumes and stent compression are dynamic phenomena that reshape during the cardiac cycle. Compelling differences were observed during the cardiac cycle in all configurations, with the self-expanding (Endurant-Viabahn) chimney EVAR configurations having smaller gutters and less variation in gutter volume during the cardiac cycle yet more stent compression without affecting the chimney graft surface.

Surgical decision-making in aortic prosthetic valve endocarditis: the influence of electrocardiogram-gated computed tomography.

OBJECTIVES: The aim of this study was to investigate the value of electrocardiogram (ECG)-gated computed tomography (CT) in the surgical decision-making and preoperative evaluation in patients with aortic prosthetic valve endocarditis (PVE). METHODS: Sixty-eight prosthetic valves in 67 patients with aortic PVE were prospectively evaluated with ECG-gated CT and transoesophageal echocardiography (TEE). Imaging findings considered indications for surgery were as follows: (i) abscess/pseudoaneurysm formation; (ii) prosthetic valve dehiscence; (iii) valve destruction with valvular regurgitation; (iv) large vegetations (>1.5 cm). The coronary arteries were evaluated with ECG-gated CT. Clinical data including surgical reports and mortality data were collected. RESULTS: Fifty-eight of 68 cases had indication for surgery based on imaging findings (ECG-gated CT/TEE). In 8 of these cases (14%), there was indication for surgery based on CT but not on TEE findings (all had perivalvular pseudoaneurysms). In 11 cases (19%), there was indication for surgery based on TEE but not on CT findings [non-drained abscess (n = 5), prosthetic valve dehiscence (n = 4), large vegetation (n = 1), valve destruction (n = 1)]. In 31 of 32 patients with indication for preoperative coronary angiography, ECG-gated CT coronary angiography was diagnostic. In 1 patient, ECG-gated CT coronary angiography was inconclusive and invasive coronary angiography was performed. CONCLUSIONS: In patients with aortic PVE, ECG-gated CT provides additional information over TEE regarding perivalvular extension of infection, which can influence surgical decision-making. Furthermore, ECG-gated CT provides a non-invasive coronary angiogram and can in most cases replace invasive coronary angiography in the preoperative evaluation.

IMAGING DIAGNOSIS-MULTIMODALITY FINDINGS IN AN ADULT DOG WITH PRIMARY SARCOMA OF THE PULMONARY ARTERY AND MYOCARDIAL METASTASES.

Intravascular pulmonary artery sarcomas in combination with myocardial metastasis are rare in dogs. We describe the radiographic, echocardiographic, and electrocardiographic-gated (ECG-gated) computed tomographic angiography (CTA) findings in a dog with pulmonary artery sarcoma. All imaging studies demonstrated severe main pulmonary artery enlargement. Echocardiography and ECG-gated CTA revealed a mass occluding the lumen of the right pulmonary artery. In addition, CTA revealed focal left ventricular myocardial contrast enhancement and parenchymal lung changes. Postmortem examination confirmed the presence of a large thrombus associated with arteriosclerosis and an intravascular sarcoma in the right pulmonary artery with metastases to the myocardium, lungs and brain.