Trapping and P2-P3 Posterior Inferior Cerebellar Artery Reanastomosis for Treatment of a Ruptured Fusiform Aneurysm: Application of Fourth-Generation Technique: 2-Dimensional Operative Video

Aneurysms of the posterior inferior cerebellar artery (PICA) represent the second most common posterior circulation aneurysm and commonly have complex morphology. Various bypass options exist for PICA aneurysms,1-6 depending on their location relative to brainstem perforators and the vertebral artery, and the presence of nearby donor arteries. We present a case of a man in his late 40s who presented with 3 d of severe headache. He was found to have a fusiform right P2-segment PICA aneurysm. Preoperative angiogram demonstrated the aneurysm and a redundant P3 caudal loop that came in close proximity to the healthy P2 segment proximal to the aneurysm. The risks and benefits of the procedure were discussed with the patient, and they consented for a right far lateral approach craniotomy with partial condylectomy for trapping of the aneurysm with bypass. The aneurysm was trapped proximally and distally. The P3 was transected just distal to the aneurysm and brought toward the proximal P2 segment, facilitated by a lack of perforators on this redundant distal artery. An end-to-side anastomosis was performed. Postoperative angiogram demonstrated exclusion of the aneurysm and patent bypass. The patient recovered well and remained without any neurological deficit at 6-mo follow-up. This case demonstrates the use of a “fourth-generation”5,7,8 bypass technique. These techniques represent the next innovation beyond third-generation intracranial-intracranial bypass. In this type 4B reanastomosis bypass, an unconventional orientation of the arteries was used. Whereas reanastomosis is typically performed end-to-end, the natural course of these arteries and the relatively less-mobile proximal P2 segment made end-to-side the preferred option in this case. Fourth-generation bypass techniques open up more configurations for reanastomosis, using the local anatomy to the surgeon's advantage. The patient consented to the described procedure and consented to the publication of their image.

Abstract P563: Prognosis Driven Definition of Carotid Near-Occlusion With Full Collapse

Introduction: Carotid near-occlusion is a severe carotid stenosis causing distal artery collapse of varying degree. Near-occlusion is often divided into a “full collapse” group with a threadlike distal lumen, and the often overlooked “without full collapse” group with a normal-appearing, albeit small, distal lumen. By this division by appearance, symptomatic near-occlusion with full collapse has been reported to have worse short-term prognosis than those without full collapse, no other division has been assessed for prognosis. The aim of this study was to assess if a measurement based definition of full collapse might improve prognostic discrimination. Methods: 99 consecutive patients with symptomatic near-occlusion diagnosed on CT-angiography were included. The risk of preoperative recurrent ipsilateral ischemic stroke within 28 days of presenting event was assessed with Kaplan-Meier analysis, censoring at revascularization. We assessed residual stenosis diameter, distal ICA diameter, ICA-ratio (side-to-side), and ICA-ECA ratio as risk markers. Results: By appearance, the 28-day risk of stroke tended to be higher for full collapse (27%, 11/42) than without full collapse (11%, 6/57), p=0.054 (figure). The best new definition of full collapse was distal ICA diameter ≤2.0 mm and/or ICA ratio ≤0.47. 10 patients were reclassified by this new definition compared to appearance definition, 5 in each direction. By the new definition, 28-day risk of stroke was higher in full collapse (34%, 14/42) than without full collapse (5%, 3/57), p<0.001 (fig 1B). Conclusions: Compared to the appearance based definition, our new definition of separating near-occlusions into with and without full collapse yields similar groups sizes but better prognostic discrimination. This new definition could be used as inclusion criteria in future treatment trials.

Glue Embolization of Adrenal Artery Pseudoaneurysm: Case Series with Review of Literature

Mortality rates for pseudoaneurysm (PSA) rupture are high and immediate intervention in the form of embolization can be life saving for the patient. Adrenal artery PSAs are rare with scarce references in literature. These arteries are small in caliber and require modification of the cannulation techniques for endovascular access. In situations, where the distal artery cannot be cannulated or the ostium cannot be negotiated, and percutaneous direct needle puncture (PDNP) techniques can be used. We discuss two patients with adrenal artery PSA that presented to us and their successful embolization with N-butyl cyanoacrylate through endovascular and PDNP techniques along with relevant review of the literature.

Susceptibility to high-altitude pulmonary edema is associated with increased pulmonary arterial stiffness during exercise

High-altitude pulmonary edema (HAPE), a reversible form of capillary leak, is a common consequence of rapid ascension to high altitude and a major cause of death related to high-altitude exposure. Individuals with a prior history of HAPE are more susceptible to future episodes, but the underlying risk factors remain uncertain. Previous studies have shown that HAPE-susceptible subjects have an exaggerated pulmonary vasoreactivity to acute hypoxia, but incomplete data are available regarding their vascular response to exercise. To examine this, seven HAPE-susceptible subjects and nine control subjects (HAPE-resistant) were studied at rest and during incremental exercise at sea level and at 3,810 m altitude. Studies were conducted in both normoxic (inspired Po2 = 148 Torr) and hypoxic (inspired Po2 = 91 Torr) conditions at each location. Here, we report an expanded analysis of previously published data, including a distensible vessel model that showed that HAPE-susceptible subjects had significantly reduced small distal artery distensibility at sea level compared with HAPE-resistant control subjects [0.011 ± 0.001 vs. 0.021 ± 0.002 mmHg−1; P < 0.001). Moreover, HAPE-susceptible subjects demonstrated constant distensibility over all conditions, suggesting that distal arteries are maximally distended at rest. Consistent with having increased distal artery stiffness, HAPE-susceptible subjects had greater increases in pulmonary artery pulse pressure with exercise, which suggests increased proximal artery stiffness. In summary, HAPE-susceptible subjects have exercise-induced increases in proximal artery stiffness and baseline increases in distal artery stiffness, suggesting increased pulsatile load on the right ventricle. NEW & NOTEWORTHY In comparison to subjects who appear resistant to high-altitude pulmonary edema, those previously symptomatic show greater increases in large and small artery stiffness in response to exercise. These differences in arterial stiffness may be a risk factor for the development of high-altitude pulmonary edema or evidence that consequences of high-altitude pulmonary edema are long-lasting after return to sea level.

Atherosclerotic ICA stenosis coinciding with ICA asymmetry associated with Circle of Willis variations can mimic near-occlusion

Differentiating carotid near-occlusion (tight atherosclerotic stenosis causing distal artery size reduction) from conventional stenosis is the first step when grading carotid stenoses with NASCET method. The internal carotid artery (ICA) can be asymmetrically associated with Circle of Willis variations. When such ICA asymmetry coincides with stenosis, it may mimic near-occlusion. We studied ICA anatomical variant prevalence in 4042 consecutive CTA exams from all indications, 53 excluded due to carotid occlusion, 814 with any ≥ 50% steno-occlusive disease intra- or extracranially, 3228 without. Of the 3989 included cases, 568 (14%) had ICA asymmetry, of which 335 (59%) were from associated with Circle of Willis variations. Of 3228 patients without ≥ 50% stenosis or other steno-occlusive disease intra- and extracranially; 257 (8.0%) demonstrated ICA asymmetry associated with Circle of Willis variations, equally common among sexes and age unrelated and most frequently attributed to an ipsilateral A1 hypoplasia/aplasia, less often attributed to large contralateral posterior communicating artery. As ICA asymmetry associated with Circle of Willis variations are common, caution should be exercised diagnosing near-occlusion on asymmetry alone.

Delayed Cerebral Infarction is Systematically Associated with a Cerebral Vasospasm of Large Intracranial Arteries

BACKGROUND Whether delayed cerebral infarction (DCIn) after aneurysmal subarachnoid hemorrhage (aSAH) is driven by large artery vasospasm is still controversial. OBJECTIVE To study the association between DCIn and vasospasm by using quantitative assessment of vasospasm up to distal arteries with time and territorial-based correlation. METHODS Clinical and imaging data of 392 patients with aSAH treated at our center between 2012 and 2017 were reviewed. DCIn was defined as any cerebral infarction occurring within 3 to 21 d after ictus and not related to other specific cause. In patients with DCIn, vasospasm was assessed within 24 h around DCIn for each cerebral artery up to the end of the 2nd segments. DCIn and vasospasm analyses were blinded. RESULTS DCIn was found in 11% of patients (inter-rater k = 0.90, computed tomography (CT)-scan = 100%, follow-up MRI = 91%). Vasospasm was quantified in 258 artery territories including 66 with and 192 without DCIn (DSA = 93%, computed tomography angiography = 7%). Vasospasm was more severe in DCIn than in non-DCIn territories (60% [55-69] vs 20% [0-50], P < .001). Vasospasm was associated with DCIn in a “dose-dependent” manner (P for trend = .022). Every DCIn territory had a vasospasm ≥ 50%, including 39% only of distal artery segments. Only 9% of non-DCIn territories had vasospasm ≥ vasospasm in DCIn territories. CONCLUSION The necessary association between severe vasospasm and DCIn in our study brings additional arguments in favor of large artery vasospasm (especially of distal segments) as a major determinant of DCIn and a potential therapeutic target.

Carotid near-occlusion can be identified with ultrasound by low flow velocity distal to the stenosis

Background Most carotid near-occlusions are indistinguishable from conventional ≥ 50% stenosis on ultrasound, demonstrating high peak systolic velocity (PSV) in the stenosis. Purpose To study whether the velocity distal to the stenosis can separate high PSV near-occlusion from conventional ≥ 50% stenosis. Material and Methods We included patients with ≥ 50% carotid stenosis with high PSV (≥125 cm/s), examined with both computed tomography angiography (CTA) and ultrasound within 30 days, and a distal velocity measurement was performed. Based on CTA, cases were divided into three groups: conventional stenosis; near-occlusion without full collapse (NwoC; normal-appearing albeit small distal artery); and near-occlusion with full collapse (NwC; threadlike distal artery). Distal Doppler ultrasound flow velocities were compared between these groups. Results Sixty patients were included: 33 patients with conventional stenosis; 20 patients with NwoC; and seven patients with NwC. Mean distal PSV was 93, 63, and 21 cm/s ( P < 0.001) and mean distal end-diastolic velocity was 30, 24, and 5 cm/s ( P < 0.001), respectively. A distal PSV < 50 cm/s was 63% sensitive and 94% specific for separating both types of near-occlusion from conventional stenosis. Conclusion In high PSV carotid stenoses, the distal velocity was lower in near-occlusions than conventional carotid stenosis. Distal velocities warrant further investigation in diagnostic studies.

Autogenous forearm loop arteriovenous fistula creation

Introduction: Arteriovenous fistula is a lifeline for end-stage kidney disease patients on dialysis. The quality of the vein and artery to be used plays a crucial role in attaining a functioning, reliable and long-lasting arteriovenous fistula. The aim of the study is to present an alternative for haemodialysis access to preserve the upper arm vasculature for future use – the forearm loop arteriovenous fistula. Methods: From October 2015 to September 2016, 202 patients with chronic kidney disease (CKD), stages 4 and 5, underwent arteriovenous fistula creation at the Universiti Sains Malaysia Hospital, Malaysia. Nine patients, with severe atherosclerosis of the distal artery, but with satisfactory veins, underwent forearm loop arteriovenous fistula creation. Maturation of the fistula was based on the classification by the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI). Results: All nine patients who underwent forearm loop arteriovenous fistula have had diabetes mellitus for more than 10 years. Only one fistula failed to mature within 6 weeks. Two arteriovenous fistulas thrombosed at 3 and 5 months, respectively, after the commencement of haemodialysis. However, the other six matured fistulas are still functioning well after a year of regular usage. Conclusions: Distal forearm arteries in diabetics may be severely atherosclerotic. Forearm loop arteriovenous fistula can be considered as the primary access for cases decided as inconvenient for fistula creation due to severe occlusive atherosclerotic disease of the forearm arteries; in order to preserve upper arm veins for future access procedures.

Rare use of twin Solitaire® stents in the double waffle-cone technique for endovascular treatment of a wide-necked bifurcation aneurysm

Endovascular treatment of wide-necked bifurcation aneurysms may be challenging. The waffle-cone technique can be used in these aneurysms in case of acute angulation between parent artery and distal artery of the aneurysm. Solitaire® stent (Ev3, Irvine, CA, USA) has the significant advantage of mitigating the potential complication risks. This study reports the second case in the literature in which endovascular treatment of a wide-necked bifurcation aneurysm with the double waffle-cone technique by using twin Solitaire® stents proved to be successful.