Technical Pitfalls for Fenestrated-Branched Endovascular Aortic Repair Following PETTICOAT.

PURPOSE: The Provisional Extension to Induce Complete Attachment Technique (PETTICOAT) uses a bare-metal stent to scaffold the true lumen in patients with acute or subacute aortic dissections. While it is designed to facilitate remodeling, some patients with chronic post-dissection thoracoabdominal aortic aneurysms (TAAAs) require repair. This study describes the technical pitfalls of fenestrated-branched endovascular aortic repair (FB-EVAR) in patients who underwent prior PETTICOAT repair. TECHNIQUE: We report 3 patients with extent II TAAAs who had prior bare-metal dissection stents treated by FB-EVAR. Two patients required maneuvers to reroute the aortic guidewire, which was initially placed in-between stent struts. This was recognized before the deployment of the fenestrated-branched device. A third patient had difficult advancement of the celiac bridging stent due to a conflict of the tip of the stent delivery system into one of the stent struts, requiring to redo catheterization and pre-stenting with a balloon-expandable stent. There were no mortalities and target-related events after a follow-up of 12 to 27 months. CONCLUSION: FB-EVAR following the PETTICOAT is infrequent, but technical difficulties should be recognized to prevent complications from the inadvertent deployment of the fenestrated-branched stent-graft component in-between stent struts. CLINICAL IMPACT: The present study highlights a few maneuvers to prevent or overcome possible complications during endovascular repair of chronic post-dissection thoracoabdominal aortic aneurysm following PETTICOAT. The main problem to be recognized is the placement of the aortic wire beyond one of the struts of the existing bare-metal stent. Moreover, encroachment of catheters or the bridging stent delivery system into the stent struts may potentially cause difficulties.

Imaging characteristics of acute type A aortic dissection and candidacy for repair with ascending aortic endografts.

BACKGROUND: Acute type A aortic dissection (ATAD) remains associated with substantial short-term mortality, and despite increasing rates of surgical repair, as many as 10% to 20% of patients do not undergo surgery because of comorbidities and dissection-related complications. For patients unable to undergo open repair, previous attempts at endovascular treatment of ATAD used devices originally designed for deployment in the descending thoracic aorta. Industry has begun to support early investigational devices meant specifically for placement within the ascending aorta. We evaluated relevant aortic parameters to examine which patients may be candidates for repair with an ascending aortic endograft. METHODS: We reviewed 100 consecutive patients in our institutional ATAD database with contrast-enhanced computed tomography imaging on an Aquarius iNtuition workstation (TeraRecon, San Mateo, Calif), using curved planar reformatting (vessel tracking) and orthogonal views for measurements. We compared relevant aortic measurements against proposed criteria for future ascending endografts, including various landing zone diameters and intimal tear distances from the distal coronary ostium. RESULTS: Of the 100 patients examined, 39% had proximal intimal tears located outside the tubular ascending aorta. In all, 30% were excluded on the basis of either the presence of a prosthetic aortic valve or significant aortic insufficiency, and 6% were excluded on the basis of the presence of patent coronary artery bypass grafts from the ascending aorta. Many patients had multiple exclusion criteria, and based on various proposed criteria, overall candidacy ranged from 2% to 23%. If a maximum landing zone diameter of 42 mm and intimal tears as little as 20 mm distal to the distalmost coronary were considered treatable, only 8% of patients would have been candidates compared with 20% candidacy if aortic diameters up to 46 mm and intimal tears as little as 10 mm distal to the distalmost coronary were considered treatable. The most frequent single cause for exclusion was inadequacy of the proximal landing zone. Iliofemoral vascular access was also assessed and deemed adequate in >90% of cases. CONCLUSIONS: A minority of patients suffering ATAD would currently qualify for ascending aortic endografting on the basis of anatomic criteria alone. Future device designs should take into account these common anatomic exclusion criteria so that more versatile devices may be developed and commercially available to treat a larger number of patients.

Segmentation of acute stroke infarct core using image-level labels on CT-angiography.

Acute ischemic stroke is a leading cause of death and disability in the world. Treatment decisions, especially around emergent revascularization procedures, rely heavily on size and location of the infarct core. Currently, accurate assessment of this measure is challenging. While MRI-DWI is considered the gold standard, its availability is limited for most patients suffering from stroke. Another well-studied imaging modality is CT-Perfusion (CTP) which is much more common than MRI-DWI in acute stroke care, but not as precise as MRI-DWI, and it is still unavailable in many stroke hospitals. A method to determine infarct core using CT-Angiography (CTA), a much more available imaging modality albeit with significantly less contrast in stroke core area than CTP or MRI-DWI, would enable significantly better treatment decisions for stroke patients throughout the world. Existing deep-learning-based approaches for stroke core estimation have to face the trade-off between voxel-level segmentation / image-level labels and the difficulty of obtaining large enough samples of high-quality DWI images. The former occurs when algorithms can either output voxel-level labeling which is more informative but requires a significant effort by annotators, or image-level labels that allow for much simpler labeling of the images but results in less informative and interpretable output; the latter is a common issue that forces training either on small training sets using DWI as the target or larger, but noisier, dataset using CT-Perfusion (CTP) as the target. In this work, we present a deep learning approach including a new weighted gradient-based approach to obtain stroke core segmentation with image-level labeling, specifically the size of the acute stroke core volume. Additionally, this strategy allows us to train using labels derived from CTP estimations. We find that the proposed approach outperforms segmentation approaches trained on voxel-level data and the CTP estimation themselves.

Early Feasibility of Endovascular Repair of Distal Aortic Arch Aneurysms Using Patient-Specific Single Retrograde Left Subclavian Artery Branch Stent Graft.

OBJECTIVE: To describe the feasibility and outcomes of endovascular repair of distal aortic arch aneurysms using a patient-specific stent graft with a pre-loaded single retrograde left subclavian artery (LSA) branch stent graft. METHODS: We reviewed the clinical data and outcomes of consecutive patients enrolled in an ongoing prospective, non-randomized physician-sponsored investigational device exemption study to evaluate the outcomes of endovascular aortic arch repair using patient-specific arch branch stent grafts (William Cook Europe, Bjaeverskov, Denmark) between 2019 and 2022. All patients received a design with triple-wide scallop and a single retrograde LSA branch with a pre-loaded catheter. RESULTS: There were five male patients with median age of 77 years old (72-80) treated using the single LSA branch stent graft. Technical success was achieved in all patients. Median operating time, fluoroscopy time, and total radiation dose area product were 103 (78-134) minutes, 26 (19-39) minutes, and 123 (71-270) mGy.cm2, respectively. There were no 30-day or in-hospital mortality, neurological or other major adverse events (MAEs). During median follow-up of 21 (20-27) months, all patients were alive with patent LSA branches, except for one who died of COVID-19 complications. There was no branch instability or secondary interventions. CONCLUSION: This early feasibility study demonstrates successful endovascular repair of distal aortic arch aneurysms using a patient-specific stent graft with single retrograde LSA branch without technical failures, mortality or neurological events. Larger clinical experience and longer follow-up are needed to determined effectiveness of this approach in patients who need endovascular repair with proximal extension into Zone 2.

Technical pitfalls and proposed modifications of instructions for use for endovascular aortic aneurysm repair using the Gore Excluder conformable device in angulated and short landing zones.

We describe a case of an abdominal aortic aneurysm (AAA) and angulated proximal neck treated with a Gore Excluder conformable endoprosthesis and show relevant technical pitfalls in the deployment of the graft main body. An 82-year-old man presented with a 71-mm asymptomatic AAA with an angulated infrarenal proximal neck (75°) and was referred to our unit. The patient was treated with a 26-mm Gore Excluder conformable device, which was deployed slightly above the renal arteries after precatheterization of the lowest renal artery. The graft was then repositioned with support of the introducer sheath and a stiff guide wire. The proximal sealing zone was ballooned before the endograft delivery system was retrieved to avoid distal migration. Technical success was achieved. The patient was discharged with no complications. No type Ia endoleak was present on the 6-month computed tomography scan. Endovascular treatment of an AAA with a severe angulated proximal neck can be effective with a conformable stent graft if technical measures are used during deployment of the main body to optimize the seal.

Total Transfemoral Percutaneous Endovascular Aortic Arch Repair Using 3-Vessel Inner Branch Stent-Graft.

Endovascular repair has been introduced to decrease the morbidity and mortality associated with open surgical repair of aortic arch pathology. We illustrate total percutaneous transfemoral approach with a 3-vessel inner branch stent-graft to treat aortic arch aneurysm. (Level of Difficulty: Advanced.).

Diffusion tensor tractography of the mammillothalamic tract in the human brain using a high spatial resolution DTI technique.

The mammillary bodies as part of the hypothalamic nuclei are in the central limbic circuitry of the human brain. The mammillary bodies are shown to be directly or indirectly connected to the amygdala, hippocampus, and thalami as the major gray matter structures of the human limbic system. Although it is not primarily considered as part of the human limbic system, the thalamus is shown to be involved in many limbic functions of the human brain. The major direct connection of the thalami with the hypothalamic nuclei is known to be through the mammillothalamic tract. Given the crucial role of the mammillothalamic tracts in memory functions, diffusion tensor imaging may be helpful in better visualizing the surgical anatomy of this pathway noninvasively. This study aimed to investigate the utility of high spatial resolution diffusion tensor tractography for mapping the trajectory of the mammillothalamic tract in the human brain. Fifteen healthy adults were studied after obtaining written informed consent. We used high spatial resolution diffusion tensor imaging data at 3.0 T. We delineated, for the first time, the detailed trajectory of the mammillothalamic tract of the human brain using deterministic diffusion tensor tractography.

Revealing the cerebello-ponto-hypothalamic pathway in the human brain.

The cerebellum is shown to be involved in some limbic functions of the human brain such as emotion and affect. The major connection of the cerebellum with the limbic system is known to be through the cerebello-hypothalamic pathways. The consensus is that the projections from the cerebellar nuclei to the limbic system, and particularly the hypothalamus, or from the hypothalamus to the cerebellar nuclei, are through multisynaptic pathways in the bulbar reticular formation. The detailed anatomy of the pathways responsible for mediating these responses, however, is yet to be determined. Diffusion tensor imaging may be helpful in better visualizing the surgical anatomy of the cerebello-ponto-hypothalamic (CPH) pathway. This study aimed to investigate the utility of high-spatial-resolution diffusion tensor tractography for mapping the trajectory of the CPH tract in the human brain. Fifteen healthy adults were studied. We delineated, for the first time, the detailed trajectory of the CPH tract of the human brain in fifteen normal adult subjects using high-spatial-resolution diffusion tensor tractography. We further revealed the close relationship of the CPH tract with the optic tract, temporo-pontine tract, amygdalofugal tract and the fornix in the human brain.