Browse

You are looking at 1 - 10 of 28 items for

  • Refine by Access: all x
  • By Author: Krings, Timo x
  • By Author: Krings, Timo x
Clear All
Open access

Intraoperative intraarterial indocyanine green video-angiography for disconnection of a perimedullary arteriovenous fistula: illustrative case

Youngkyung Jung, Antti Lindgren, Syed Uzair Ahmed, Ivan Radovanovic, Timo Krings, and Hugo Andrade-Barazarte

BACKGROUND

Intraarterial (IA) indocyanine green (ICG) angiography is an intraoperative imaging technique offering special and temporal characterization of vascular lesions with very fast dye clearance. The authors’ aim is to demonstrate the use of IA ICG angiography to aid in the surgical treatment of a perimedullary thoracic arteriovenous fistula (AVF) in a hybrid operating room (OR).

OBSERVATIONS

A 31-year-old woman with a known history of spinal AVF presented with 6 weeks of lower-extremity weakness, gait imbalance, and bowel/bladder dysfunction. Magnetic resonance imaging revealed an extensive series of flow voids across the thoracic spine, most notably at T11–12. After partial embolization, she was taken for surgical disconnection in a hybrid OR. Intraoperative spinal digital subtraction angiography was performed to identify feeding vessels. When the target arteries were catheterized, 0.05 mg of ICG in 2 mL of saline was injected, and the ICG flow in each artery was recorded using the microscope. With an improved surgical understanding of the contributing feeding arteries, the authors achieved complete in situ disconnection of the AVF.

LESSONS

IA ICG angiography can be used in hybrid OR settings to illustrate the vascular anatomy of multifeeder perimedullary AVFs and confirm its postoperative disconnection with a fast dye clearance.

Free access

Recognition of the variant type of spinal dural arteriovenous fistula: a rare but important consideration

Sean T. O’Reilly, Eef Jacobus Hendriks, Marie-Christine Brunet, Ze’ev Itsekson, Rabab Al Shahrani, Ronit Agid, Patrick Nicholson, Karel terBrugge, Ivan Radovanovic, and Timo Krings

OBJECTIVE

Spinal dural arteriovenous fistulas (SDAVFs) typically represent abnormal shunts between a radiculomeningeal artery and radicular vein, with the point of fistulization classically directly underneath the pedicle of the vertebral body, at the dural sleeve of the nerve root. However, SDAVFs can also develop in atypical locations or have more than one arterial feeder, which is a variant of SDAVF. The aim of this study was to describe the incidence and multidisciplinary treatment of variant SDAVFs in a single-center case series.

METHODS

Following institutional review board approval, the authors retrospectively analyzed their prospectively maintained database of patients with SDAVFs who presented between 2008 and 2020. For all patients, spinal digital subtraction angiograms were reviewed and variant SDAVFs were identified. Variant types of SDAVFs were defined as cases in which the fistulous point was not located underneath the pedicle. Patient demographics, angiographic features, clinical outcomes, and treatment modalities were assessed.

RESULTS

Of 59 patients with SDAVFs treated at the authors’ institution, 4 patients (6.8%) were identified as having a variant location of the shunt zone, pinpointed on the dura mater at the intervertebral level, further posteriorly within the spinal canal. In 3 cases (75%), a so-called bimetameric arterial supply was demonstrated.

CONCLUSIONS

Recognition of the variant type of SDAVF is crucial for management, as correct localization of the fistulous point and bimetameric supply are critical for successful surgical disconnection, preventing delay in achieving definitive treatment.

Free access

Feasibility of robot-assisted neuroendovascular procedures

Vitor Mendes Pereira, Patrick Nicholson, Nicole M. Cancelliere, Xiao Yu Eileen Liu, Ronit Agid, Ivan Radovanovic, and Timo Krings

OBJECTIVE

Geographic factors prevent equitable access to urgent advanced neuroendovascular treatments. Robotic technologies may enable remote endovascular procedures in the future. The authors performed a translational, benchtop-to-clinical study to evaluate the in vitro and clinical feasibility of the CorPath GRX Robotic System for robot-assisted endovascular neurointerventional procedures.

METHODS

A series of bench studies was conducted using patient-specific 3D-printed models to test the system’s compatibility with standard neurointerventional devices, including microcatheters, microwires, coils, intrasaccular devices, and stents. Optimal baseline setups for various procedures were determined. The models were further used to rehearse clinical cases. Subsequent to these investigations, a prospective series of 6 patients was treated using robotic assistance for complex, wide-necked intracranial saccular aneurysms between November 2019 and February 2020. The technical success, incidence of periprocedural complications, and need for conversion to manual procedures were evaluated.

RESULTS

The ideal robotic setup for treatment of both anterior and posterior circulation aneurysms was determined to consist of an 80-cm guide catheter with a 115-cm-long intermediate catheter, a microcatheter between 150 and 170 cm in length, and a microwire with a minimum length of 300 cm. All coils, intrasaccular devices, and stents tested were compatible with the system and could be advanced or retracted safely and placed accurately. All 6 clinical procedures were technically successful, with all intracranial steps being performed robotically with no conversions to manual intervention or failures of the robotic system. There were no procedure-related complications or adverse clinical outcomes.

CONCLUSIONS

This study demonstrates the feasibility of robot-assisted neurointerventional procedures. The authors’ results represent an important step toward enabling remote neuroendovascular care and geographic equalization of advanced endovascular treatments through so-called telestroke intervention.

Free access

Improving long-term outcomes in pediatric torcular dural sinus malformations with embolization and anticoagulation: a retrospective review of The Hospital for Sick Children experience

Jerry C. Ku, Brian Hanak, Prakash Muthusami, Karl Narvacan, Hidy Girgis, Karel terBrugge, Timo Krings, James T. Rutka, and Peter Dirks

OBJECTIVE

Torcular dural sinus malformations (tDSMs) are rare pediatric cerebrovascular malformations characterized by giant venous lakes localized to the midline confluence of sinuses. Historical clinical outcomes of patients with these lesions were poor, though better prognoses have been reported in the more recent literature. Long-term outcomes in children with tDSMs are uncertain and require further characterization. The goal of this study was to review a cohort of tDSM patients with an emphasis on long-term outcomes and to describe the treatment strategy.

METHODS

This study is a single-center retrospective review of a prospectively maintained data bank including patients referred to and cared for at The Hospital for Sick Children for tDSM from January 1996 to March 2019. Each patient’s clinical, radiological, and demographic information, as well as their mother’s demographic information, was collected for review.

RESULTS

Ten patients with tDSM, with a mean follow-up of 58 months, were included in the study. Diagnoses were made antenatally in 8 patients, and among those cases, 4 families opted for either elective termination (n = 1) or no further care following delivery (n = 3). Of the 6 patients treated, 5 had a favorable long-term neurological outcome, and follow-up imaging demonstrated a decrease or stability in the size of the tDSM over time. Staged embolization was performed in 3 patients, and anticoagulation was utilized in 5 treated patients.

CONCLUSIONS

The authors add to a growing body of literature indicating that clinical outcomes in tDSM may not be as poor as initially perceived. Greater awareness of the lesion’s natural history and pathophysiology, advancing endovascular techniques, and individualized anticoagulation regimens may lead to continued improvement in outcomes.

Free access

The safety profile and angioarchitectural changes after acute targeted embolization of ruptured arteriovenous malformations

Ann Mansur, Alex Kostynskyy, Timo Krings, Ronit Agid, Ivan Radovanovic, and Vitor Mendes Pereira

OBJECTIVE

The aim of this study was to 1) compare the safety and efficacy of acute targeted embolization of angiographic weak points in ruptured brain arteriovenous malformations (bAVMs) versus delayed treatment, and 2) explore the angioarchitectural changes that follow this intervention.

METHODS

The authors conducted a retrospective analysis of a prospectively acquired database of ruptured bAVMs. Three hundred sixteen patients with ruptured bAVMs who presented to the hospital within 48 hours of ictus were included in the analysis. The first analysis compared clinical and functional outcomes of acutely embolized patients to those with delayed management paradigms. The second analysis compared these outcomes of patients with acute embolization to those with angiographic targets who did not undergo acute embolization. Finally, a subset of 20 patients with immediate postembolization angiograms and follow-up angiograms within 6 weeks of treatment were studied to determine the angioarchitectural changes after acute targeted embolization. Kaplan-Meier curves for survival between the groups were devised. Multivariate logistical regression analysis was conducted.

RESULTS

There were three deaths (0.9%) and an overall rerupture rate of 4.8% per year. There was no statistical difference in demographic variables, mortality, and rerupture rate between patients with acute embolization and those with delayed management. Patients with acute embolization were more likely to present functionally worse (46.9% vs 69.8%, modified Rankin Scale score 0–2, p = 0.018) and to require an adjuvant therapy (71.9% vs 26.4%, p < 0.001). When comparing acutely embolized patients to those nonacutely embolized angiographic targets, there was a significant protective effect of acute targeted therapy on rerupture rate (annual risk 1.2% vs 4.3%, p = 0.025) and no difference in treatment complications. Differences in the survival curves for rerupture were statistically significant. Multivariate analyses significantly predicted lower rerupture in acute targeted treatment and higher rerupture in those with associated aneurysms, deep venous anatomy, and higher Spetzler-Martin grade. All patients with acute embolization experienced complete obliteration of the angiographic weak point with various degrees of resolution of the nidus; however, some had spontaneous recurrence of their bAVM, while others had spontaneous resolution over time. No patients developed new angiographic weak points.

CONCLUSIONS

This study demonstrates that acute targeted embolization of angiographic weak points, particularly aneurysms, is technically safe and protective in the early phase of recovery from ruptured bAVMs. Serial follow-up imaging is necessary to monitor the evolution of the nidus after targeted and definitive treatments. Larger prospective studies are needed to validate these findings.

Free access

Vertebral artery aneurysms and the risk of cord infarction following spinal artery coverage during flow diversion

Adam A. Dmytriw, Anish Kapadia, Alejandro Enriquez-Marulanda, Carmen Parra-Fariñas, Anna Luisa Kühn, Patrick J. Nicholson, Muhammad Waqas, Leonardo Renieri, Caterina Michelozzi, Paul M. Foreman, Kevin Phan, I-Hsiao Yang, Vincent M. Tutino, Christopher S. Ogilvy, Ivan Radovanovic, Mark R. Harrigan, Adnan H. Siddiqui, Elad I. Levy, Nicola Limbucci, Christophe Cognard, Timo Krings, Vitor Mendes Pereira, Ajith J. Thomas, Thomas R. Marotta, and Christoph J. Griessenauer

OBJECTIVE

Coverage of the anterior spinal artery (ASA) ostia is a source of considerable consternation regarding flow diversion (FD) in vertebral artery (VA) aneurysms due to cord supply. The authors sought to assess the association between coverage of the ASA, posterior spinal artery (PSA), or lateral spinal artery (LSA) ostia when placing flow diverters in distal VAs and clinical outcomes, with emphasis on cord infarction.

METHODS

A multicenter retrospective study of 7 institutions in which VA aneurysms were treated with FD between 2011 and 2019 was performed. The authors evaluated the risk of ASA and PSA/LSA occlusion, associated thromboembolic complication, complications overall, aneurysm occlusion status, and functional outcome.

RESULTS

Sixty patients with 63 VA and posterior inferior cerebellar artery aneurysms treated with FD were identified. The median aneurysm diameter was 7 mm and fusiform type was the commonest morphology (42.9%). During a procedure, 1 (61.7%) or 2 (33.3%) flow diverters were placed. Complete occlusion was achieved in 71.9%. Symptomatic thromboembolic complications occurred in 7.4% of cases and intracranial hemorrhage in 10.0% of cases. The ASA and PSA/LSA were identified in 51 (80.9%) and 35 (55.6%) complications and covered by the flow diverter in 29 (56.9%) and 13 (37.1%) of the procedures, respectively. Patency after flow diverter coverage on last follow-up was 89.2% for ASA and 100% for PSA/LSA, not significantly different between covered and noncovered groups (p = 0.5 and p > 0.99, respectively). No complications arose from coverage.

CONCLUSIONS

FD aneurysm treatment in the posterior circulation with coverage of ASA or PSA/LSA was not associated with higher rates of occlusion of these branches or any instances of cord infarction.

Full access

Mechanical thrombectomy in pediatric stroke: systematic review, individual patient data meta-analysis, and case series

Kartik Bhatia, Hans Kortman, Christopher Blair, Geoffrey Parker, David Brunacci, Timothy Ang, John Worthington, Prakash Muthusami, Hazem Shoirah, J Mocco, and Timo Krings

OBJECTIVE

The role of mechanical thrombectomy in pediatric acute ischemic stroke is uncertain, despite extensive evidence of benefit in adults. The existing literature consists of several recent small single-arm cohort studies, as well as multiple prior small case series and case reports. Published reports of pediatric cases have increased markedly since 2015, after the publication of the positive trials in adults. The recent AHA/ASA Scientific Statement on this issue was informed predominantly by pre-2015 case reports and identified several knowledge gaps, including how young a child may undergo thrombectomy. A repeat systematic review and meta-analysis is warranted to help guide therapeutic decisions and address gaps in knowledge.

METHODS

Using PRISMA-IPD guidelines, the authors performed a systematic review of the literature from 1999 to April 2019 and individual patient data meta-analysis, with 2 independent reviewers. An additional series of 3 cases in adolescent males from one of the authors’ centers was also included. The primary outcomes were the rate of good long-term (mRS score 0–2 at final follow-up) and short-term (reduction in NIHSS score by ≥ 8 points or NIHSS score 0–1 at up to 24 hours post-thrombectomy) neurological outcomes following mechanical thrombectomy for acute ischemic stroke in patients < 18 years of age. The secondary outcome was the rate of successful angiographic recanalization (mTICI score 2b/3).

RESULTS

The authors’ review yielded 113 cases of mechanical thrombectomy in 110 pediatric patients. Although complete follow-up data are not available for all patients, 87 of 96 (90.6%) had good long-term neurological outcomes (mRS score 0–2), 55 of 79 (69.6%) had good short-term neurological outcomes, and 86 of 98 (87.8%) had successful angiographic recanalization (mTICI score 2b/3). Death occurred in 2 patients and symptomatic intracranial hemorrhage in 1 patient. Sixteen published thrombectomy cases were identified in children < 5 years of age.

CONCLUSIONS

Mechanical thrombectomy may be considered for acute ischemic stroke due to large vessel occlusion (ICA terminus, M1, basilar artery) in patients aged 1–18 years (Level C evidence; Class IIb recommendation). The existing evidence base is likely affected by selection and publication bias. A prospective multinational registry is recommended as the next investigative step.

Full access

Unruptured intracranial aneurysms in children: 18 years’ experience in a tertiary care pediatric institution

Daniel-Alexandre Bisson, Peter Dirks, Afsaneh Amirabadi, Manohar M. Shroff, Timo Krings, Vitor Mendes Pereira, and Prakash Muthusami

OBJECTIVE

There are little data in the literature on the characteristics and natural history of unruptured intracranial aneurysms in children. The authors analyzed their experience with unruptured intracranial aneurysms in the pediatric population at their tertiary care pediatric institution over the last 18 years. The first objective was to assess the imaging characteristics and natural history of these aneurysms in order to help guide management strategies in the future. A second objective was to evaluate the frequency of an underlying condition when an incidental intracranial aneurysm was detected in a child.

METHODS

The authors conducted a Research Ethics Board–approved retrospective review of incidental intracranial aneurysms in patients younger than 18 years of age who had been treated at their institution in the period from 1998 to 2016. Clinical (age, sex, syndrome) and radiological (aneurysm location, type, size, thrombus, mass effect) data were recorded. Follow-up imaging was assessed for temporal changes.

RESULTS

Sixty intracranial aneurysms occurred in 51 patients (36 males, 15 females) with a mean age of 10.5 ± 0.5 years (range 9 months–17 years). Forty-five patients (88.2%) had a single aneurysm, while 2 and 3 aneurysms were found in 3 patients each (5.8%). Syndromic association was found in 22 patients (43.1%), most frequently sickle cell disease (10/22 [45.5%]). Aneurysms were saccular in 43 cases (71.7%; mean size 5.0 ± 5.7 mm) and fusiform in the remaining 17 (28.3%; mean size 6.5 ± 2.7 mm). Thirty-one aneurysms (51.7%) arose from the internal carotid artery (right/left 1.4), most commonly in the cavernous segment (10/31 [32.3%]). Mean size change over the entire follow-up of 109 patient-years was a decrease of 0.6 ± 4.2 mm (range −30.0 to +4.0 mm, rate −0.12 ± 9.9 mm/yr). Interval growth (2.0 ± 1.0 mm) was seen in 8 aneurysms (13.3%; 4 saccular, 4 fusiform). An interval decrease in size (8.3 ± 10.7 mm) was seen in 6 aneurysms (10%). There was an inverse relationship between aneurysm size and growth rate (r = −0.82, p < 0.00001). One aneurysm was treated endovascularly with internal carotid artery sacrifice.

CONCLUSIONS

Unruptured pediatric intracranial aneurysms are most frequently single but can occur in multiples in a syndromic setting. None of the cases from the study period showed clinical or imaging signs of rupture. Growth over time, although unusual and slow, can occur in a proportion of these patients, who should be identified for short-term imaging surveillance.

Full access

Interval angioarchitectural evolution of brain arteriovenous malformations following rupture

Hengwei Jin, Stephanie Lenck, Timo Krings, Ronit Agid, Yibin Fang, Youxiang Li, Alex Kostynskyy, Michael Tymianski, Vitor Mendes Pereira, and Ivan Radovanovic

OBJECTIVE

The goal of this study was to describe changes in the angioarchitecture of brain arteriovenous malformations (bAVMs) between acute and delayed cerebral digital subtraction angiography (DSA) obtained after hemorrhage, and to examine bAVM characteristics predicting change.

METHODS

This is a retrospective study of a prospective institutional bAVM database. The authors included all patients with ruptured bAVMs who had DSA in both acute and delayed phases, with no interval treatment of their bAVM, between January 2000 and April 2017. The authors evaluated the existence or absence of angioarchitectural changes. Demographic data, radiological characteristics of hemorrhages, and angioarchitectural features of the bAVMs of the two patients’ groups were analyzed. Univariate and multivariate logistic analyses were performed to identify predictors of angioarchitectural change.

RESULTS

A total of 42 patients were included in the series. Seventeen (40.5%) patients had angioarchitectural changes including bAVM only visible on the delayed DSA study (n = 8), spontaneous thrombosis of the AVM (n = 3), or alteration of the size or the opacification of the nidus (n = 6). The factors associated with angioarchitectural changes were a small nidus (3.8 ± 7.9 ml vs 6.1 ± 9.5 ml, p = 0.046), a superficial location (94.1% vs 5.9%, p = 0.016), and a single superficial draining vein (58.8% vs 24.0%, p = 0.029).

CONCLUSIONS

Angioarchitectural changes can be seen in 40% of ruptured bAVMs between the acute- and delayed-phase DSA. A small nidus, a superficial location, and a single superficial draining vein were statistically associated with the occurrence of angioarchitectural changes. These changes included either enlargement or spontaneous occlusion of the bAVM, as well as subsequent diagnosis of a bAVM following an initial negative DSA study.

Full access

Pipeline embolization of posterior circulation aneurysms: a multicenter study of 131 aneurysms

Christoph J. Griessenauer, Christopher S. Ogilvy, Nimer Adeeb, Adam A. Dmytriw, Paul M. Foreman, Hussain Shallwani, Nicola Limbucci, Salvatore Mangiafico, Ashish Kumar, Caterina Michelozzi, Timo Krings, Vitor Mendes Pereira, Charles C. Matouk, Mark R. Harrigan, Hakeem J. Shakir, Adnan H. Siddiqui, Elad I. Levy, Leonardo Renieri, Thomas R. Marotta, Christophe Cognard, and Ajith J. Thomas

OBJECTIVE

Flow diversion for posterior circulation aneurysms performed using the Pipeline embolization device (PED) constitutes an increasingly common off-label use for otherwise untreatable aneurysms. The safety and efficacy of this treatment modality has not been assessed in a multicenter study.

METHODS

A retrospective review of prospectively maintained databases at 8 academic institutions was performed for the years 2009 to 2016 to identify patients with posterior circulation aneurysms treated with PED placement.

RESULTS

A total of 129 consecutive patients underwent 129 procedures to treat 131 aneurysms; 29 dissecting, 53 fusiform, and 49 saccular lesions were included. At a median follow-up of 11 months, complete and near-complete occlusion was recorded in 78.1%. Dissecting aneurysms had the highest occlusion rate and fusiform the lowest. Major complications were most frequent in fusiform aneurysms, whereas minor complications occurred most commonly in saccular aneurysms. In patients with saccular aneurysms, clopidogrel responders had a lower complication rate than did clopidogrel nonresponders. The majority of dissecting aneurysms were treated in the immediate or acute phase following subarachnoid hemorrhage, a circumstance that contributed to the highest mortality rate in those aneurysms.

CONCLUSIONS

In the largest series to date, fusiform aneurysms were found to have the lowest occlusion rate and the highest frequency of major complications. Dissecting aneurysms, frequently treated in the setting of subarachnoid hemorrhage, occluded most often and had a low complication rate. Saccular aneurysms were associated with predominantly minor complications, particularly in clopidogrel nonresponders.