A Completely Endovascular Solution for Transcatheter Aortic Valve Implantation Embolisation and Inversion into the Aortic Arch

Introduction: Transcatheter aortic valve implantation (TAVI) has evolved into the preferred alternative to surgical valve replacement for severe aortic valve stenosis with high surgical risk. With expanding indications, life threatening complications including transcatheter aortic valve embolisation and inversion (TAVEI), in which the valve dislodges, inverts, and migrates caudally, may increase concomitantly. Report: An 80 year old male with severe aortic valve stenosis underwent balloon expandable transcatheter aortic valve implantation (TAVI). Valve embolisation into the aortic arch inverted the bioprothesis, excluding the option of fixation in the descending aorta. Through-valve thoracic endovascular aortic repair (TEVAR) was performed after bifemoral snaring using a through-and-through wire technique and pulling the valve into the descending aorta. Discussion: TAVI is emerging as the preferred treatment for severe aortic valve stenosis and comes with unique procedural complications, such as life threatening transcatheter aortic valve embolisation and inversion (TAVEI). Although some authors prefer treating embolisation of a non-inverted balloon expandable valve into the aorta by using the valvuloplasty balloon to pull the valve distally and fixing it in the descending aorta, this risks further expansion of the valve and consequently fixing it in an undesirable position and is not possible if the valve inverts. Downstream placement of the valve by snaring with a guiding catheter covering/protecting a through-and-through wire technique, combined with through-valve TEVAR, provides a new bail out strategy for this serious complication and may reduce TAVEI associated mortality and morbidity

Results of the Anaconda endovascular graft in abdominal aortic aneurysm with a severe angulated infrarenal neck

Objective: Proximal neck anatomy of an abdominal aortic aneurysm (AAA), especially a severe angulated neck of more than 60 degrees, predicts adverse outcome in endovascular aneurysm repair. In the present study, we evaluate the feasibility of the use of the Anaconda endovascular graft (Vascutec, Terumo, Inchinnan, Scotland) for treating infrarenal AAA with a severe angulated neck (>60 degrees) and report the midterm outcomes. Methods: In total, nine Dutch hospitals participated in this prospective cohort study. From December 2005 to January 2011, a total of 36 AAA patients, 30 men and six women, were included. Mean and median follow-up were both 40 months. Results: Mean infrarenal neck angulation was 82 degrees. Successful deployment was reached in 34 of 36 patients. Primary technical success was achieved in 30 of 36 patients (83%). There was no aneurysm-related death. Four-year primary clinical success was 69%. In the first year, eight clinical failures were reported including four leg occlusions which could be solved using standard procedures. After the first year, three patients with additional failures occurred; two of them were leg occlusions. Four patients needed conversion to open AAA exclusion. In six of 36 patients, one or more reinterventions were necessary. Three of them were performed for occlusion of one Anaconda leg and two were for occlusion of the body. Conclusions: The use of the Anaconda endovascular graft in AAA with a severe angulated infrarenal neck is feasible but has its side effects. Most clinical failures occur in the first year. Thereafter, few problems occur, and midterm results are acceptable. Summarizing the present experiences, we conclude that open AAA repair is still a preferable option in patients with challenging aortic neck anatomy and fit for open surgery

Image fusion of LM-MRI and MRA for endovascular interventions

Peripheral arterial occlusive disease can be treated with endovascular interventions. These interventions are currently intraoperatively guided by fluoroscopy. A possible alternative is LF-MRI, but the current image quality of low-field (LF) MRI may not be sufficient. The purpose of this study is to evaluate the possibility of image fusion of LF-MRI with preoperative MRA to improve the image quality. To test this, LF-MRI and 3T MRI images were made of a healthy test subject. These images were registrated using manual landmark detection. The result was a visually successful registration image of LF-MRI and anatomical MRI, which shows the possibility of manual image registration

In vivo geometry of the kissing stent and covered endovascular reconstruction of the aortic bifurcation configurations in aortoiliac occlusive disease

Objectives Various configurations of kissing stent (KS) configurations exist and patency rates vary. In response the covered endovascular reconstruction of the aortic bifurcation configuration was designed to minimize mismatch and improve outcome. The aim of the current study is to compare geometrical mismatch of kissing stent with the covered endovascular reconstruction of the aortic bifurcation configuration in vivo. Methods Post-operative computed tomographic data and patient demographics from 11 covered endovascular reconstruction of the aortic bifurcation and 11 matched kissing stent patients were included. A free hand region of interest and ellipse fitting method were applied to determine mismatch areas and volumes. Conformation of the stents to the vessel wall was expressed using the D-ratio. Results Patients were mostly treated for Rutherford category 2 and 3 (64%) with a lesion classification of TASC C and D in 82%. Radial mismatch area and volume for the covered endovascular reconstruction of the aortic bifurcation group was significantly lower compared to the kissing stent configuration ( P &lt; 0.05). The D-ratio did not significantly differ between groups. Measurements were performed with good intra-class correlation. There were no significant differences in the post-procedural aortoiliac anatomy. Conclusions The present study shows that radial mismatch exists in vivo and that large differences in mismatch exist, in favour of the covered endovascular reconstruction of the aortic bifurcation configuration. Future research should determine if the decreased radial mismatch results in improved local flow profiles and subsequent clinical outcome. </jats:sec

Twenty-Four Hour Tonometry in Patients Suspected of Chronic Gastrointestinal Ischemia

Background and aims: Gastrointestinal tonometry is currently the only clinical diagnostic test that enables identification of symptomatic chronic gastrointestinal ischemia. Gastric exercise tonometry has proven its value for detection of ischemia in this patients group, but has its disadvantages. Earlier studies with postprandial tonometry gave unreliable results. In this study we challenged (again) the use of postprandial tonometry in patients suspected of gastrointestinal ischemia. Methods: Patients suspected for chronic gastrointestinal ischemia had standard diagnostic work up, including gastric exercise tonometry and 24-h tonometry using standard meals. Results: Thirty-three patients were enrolled in the study. Chronic gastrointestinal ischemia was diagnosed in 17 (52%) patients. The 24-h tonometry correctly predicted the presence of ischemia in 13/17 patients, and absence of ischemia in 15/16 patients. Conclusions: The use of 24-h tonometry after meals in patients suspected of gastrointestinal ischemia seems feasible, with promising accuracy for the detection of ischemia

Investigating the potential of low concentrations of iron-oxide contrast agents at low magnetic field strengths for the purpose of MR guided interventions

Iron-oxide contrast agents might prove valuable in endovascular interventions at low-field MRI because their relaxivities are more favorable at lower field strengths, but still maintaining and generating positive contrast. Differences between a range concentrations of a gadolinium-based and a super paramagnetic iron-oxide (SPIO) contrast agent were compared both in simulations and experimentally on 0.25T using three different MR sequences. Optimal contrast for all sequences was found around 0.15mM for the SPIO agent and for concentrations higher than 7.0mM for the gadolinium agent. The use of low concentration SPIOs therefore is more beneficial for imaging at low magnetic field strengths than gadolinium-based contrast agents

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. : Clinical Relevance: This in vitro experiment showed that the motion amplitudes of stent grafts during the cardiac cycle can accurately be compared between electrocardiogram-gated computed tomography (CT) scans reconstructed into either 8 or 10 phases and between scanners of different manufacturers, without differences larger than the voxel size of 0.3 × 0.3 × 0.5 mm. In other words, clinical motion analysis of stent grafts using different retrospective electrocardiogram-gated CT scans and CT scanners of different manufacturers can be compared up to the accuracy of the CT scan

Incidence and predictive factors for endograft limb patency of the fenestrated Anaconda endograft used for complex endovascular aneurysm repair

Objective: In the present study, we have described the incidence, risk factors, and outcomes of treatment of limb occlusion for patients who had undergone treatment of complex thoracoabdominal aortic aneurysms with the fenestrated Anaconda endograft (Terumo Aortic, Inchinnan, UK). Methods: Between June 2010 and May 2018, 335 patients had undergone elective fenestrated aortic aneurysm repair at 11 participating centers using the fenestrated Anaconda endograft with a median follow-up of 14.3 months (interquartile range, 27.4 months). The primary outcome measure was freedom from limb occlusion. The secondary outcome measures were freedom from limb-related reintervention, secondary patency, and the risk factors associated with limb occlusion. Results: Of the 335 patients, 30 (9.0%) had presented with limb occlusion during follow-up with a freedom from limb occlusion rate of 98.5%, 91.2%, and 81.7% at 30 days and 1 and 5 years, respectively. In 87% of the cases, no obvious cause for limb occlusion was documented. Primary occlusion had occurred within 30 days in 36.7% and within 1 year in 80.0%. Of the 30 patients, 23 (77%) had undergone an occlusion-related reintervention and 7 (23.3%) had been treated conservatively. The freedom from limb occlusion-related reintervention at 30 days and 1 and 5 years was 97.8%, 93.2%, and 88.6%, respectively. Secondary patency was 91.3% after 1 month and 86.2% after 1 and 5 years. Female sex (odds ratio [OR], 3.27; 95% confidence interval [CI], 1.28-8.34; P = .01) was a statistically significant predictor for limb occlusion. A greater proportion of thrombus in the aneurysm sac appeared to be protective for limb occlusion (0% vs 50%: OR, 0.08; 95% CI, 0.020.38; P = .00), as did iliac angulation (OR, 0.99; 95% CI, 0.98-1.00; P = .04). Conclusions: Limb occlusion remains a significant impediment of endograft durability for patients treated with the fenestrated Anaconda endograft, especially for female patients. In contrast, a high aneurysmal thrombus load and a high degree of iliac angulation appeared to be protective for limb occlusion, for which no obvious cause could be identified