Training, competency, and credentialing standards for diagnostic cervicocerebral angiography, carotid stenting, and cerebrovascular intervention: a joint statement from the American Academy of Neurology, the American Association of Neurological Surgeons, the American Society of Interventional and Therapeutic Neuroradiology, the American Society of Neuroradiology, the Congress of Neurological Surgeons, the AANS/CNS Cerebrovascular Section, and the Society of Interventional Radiology

Deep learning based detection of intracranial aneurysms on digital subtraction angiography: A feasibility study

BACKGROUND

Digital subtraction angiography is the gold standard for detecting and characterising aneurysms. Here, we assess the feasibility of commercial-grade deep learning software for the detection of intracranial aneurysms on whole-brain anteroposterior and lateral 2D digital subtraction angiography images.

MATERIAL AND METHODS

Seven hundred and six digital subtraction angiography images were included from a cohort of 240 patients (157 female, mean age 59 years, range 20-92; 83 male, mean age 55 years, range 19-83). Three hundred and thirty-five (47%) single frame anteroposterior and lateral images of a digital subtraction angiography series of 187 aneurysms (41 ruptured, 146 unruptured; average size 7±5.3 mm, range 1-5 mm; total 372 depicted aneurysms) and 371 (53%) aneurysm-negative study images were retrospectively analysed regarding the presence of intracranial aneurysms. The 2D data was split into testing and training sets in a ratio of 4:1 with 3D rotational digital subtraction angiography as gold standard. Supervised deep learning was performed using commercial-grade machine learning software (Cognex, ViDi Suite 2.0). Monte Carlo cross validation was performed.

RESULTS

Intracranial aneurysms were detected with a sensitivity of 79%, a specificity of 79%, a precision of 0.75, a F1 score of 0.77, and a mean area-under-the-curve of 0.76 (range 0.68-0.86) after Monte Carlo cross-validation, run 45 times.

CONCLUSION

The commercial-grade deep learning software allows for detection of intracranial aneurysms on whole-brain, 2D anteroposterior and lateral digital subtraction angiography images, with results being comparable to more specifically engineered deep learning techniques.

Treatment of Intracranial Aneurysms: Clipping Versus Coiling

Intracranial aneurysms (IAs) have an estimated incidence of up to 10 % and can lead to serious morbidity and mortality. Because of this, the natural history of IAs has been studied extensively, with rupture rates ranging from 0.5 to 7 %, depending on aneurysm characteristics. The spectrum of presentation of IAs ranges from incidental detection to devastating subarachnoid hemorrhage. Although the gold standard imaging technique is intra-arterial digital subtraction angiography, other modalities such as computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are being increasingly used for screening and treatment planning. Management of these patients depends upon a number of factors including aneurysmal, patient, institutional, and operator factors. The ultimate goal of treating patients with IAs is complete and permanent occlusion of the aneurysm sac in order to eliminate future hemorrhagic risk, while preserving or restoring the patient's neurological function. The most common treatment approaches include microsurgical clipping and endovascular coiling, and multiple studies have compared these two techniques. To date, three large prospective, randomized studies have been done: a study from Finland, International Subarachnoid Aneurysm Trial (ISAT), and the Barrow Ruptured Aneurysm Trial (BRAT). Despite differences in methodology, the results were similar: in patients undergoing coiling, although rates of rebleeding and retreatment are higher, the overall rate of poor outcomes at 12 months was significantly lower. As minimally invasive procedures and devices continue to be refined, endovascular strategies are likely to increase in popularity. However, as long-term outcome studies become available, it is increasingly apparent that they are complementary treatment strategies, with patient selection of critical importance.

Complication rates and center enrollment volume in the carotid revascularization endarterectomy versus stenting trial

BACKGROUND AND PURPOSE

Evidence indicates that center volume of cases affects outcomes for both carotid endarterectomy and stenting. We evaluated the effect of enrollment volume by site on complication rates in the Carotid Revascularization Endarterectomy Versus Stenting Trial (CREST).

METHODS

The primary composite end point was any stroke, myocardial infarction, or death within 30 days or ipsilateral stroke in follow-up. The 477 approved surgeons performed >12 procedures per year with complication rates <3% for asymptomatic patients and <5% for symptomatic patients; 224 interventionists were certified after a rigorous 2 step credentialing process. CREST centers were divided into tertiles based on the number of patients enrolled into the study, with Group 1 sites enrolling <25 patients, Group 2 sites enrolling 25 to 51 patients, and Group 3 sites enrolling >51 patients. Differences in periprocedural event rates for the primary composite end point and its components were compared using logistic regression adjusting for age, sex, and symptomatic status within site-volume level.

RESULTS

The safety of carotid angioplasty and stenting and carotid endarterectomy did not vary by site-volume during the periprocedural period as indicated by occurrence of the primary end point (P=0.54) or by stroke and death (P=0.87). A trend toward an inverse relationship between center enrollment volume and complications was mitigated by adjustment for known risk factors.

CONCLUSIONS

Complication rates were low in CREST and were not associated with center enrollment volume. The data are consistent with the value of rigorous training and credentialing in trials evaluating endovascular devices and surgical procedures.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00004732.

Cerebrovascular neurosurgery in evolution: the endovascular paradigm

Endovascular technique represents an important, minimally invasive approach to treating cerebrovascular disease. In this article, we discuss the origins of endovascular neurosurgery as a discipline in the context of important technical milestones, evidence-based medicine, and future cerebrovascular neurosurgical training. Cerebrovascular neurosurgery has seen a steady, convergent evolution toward the surgeon capable of seamless incorporation of open and endovascular approaches to any complex vascular disease affecting the central nervous system. Neurosurgery must assume the leadership role in the multidisciplinary neurovascular team.

Safety of carotid stenting (CAS) is based on institutional training more than individual experience in large-volume centres

BACKGROUND

Operator training is a key factor for the safety of carotid stenting (CAS). Whether institutional practice is associated with improved individual operator outcomes is debated.

OBJECTIVE

To evaluate the effect of the institutional experience on outcomes of new trainees with CAS, a retrospective analysis of a prospectively held database was performed.

METHODS

The overall study period, 2004-2012, was divided into two sequential time frames: 2004-April 2006 (leaders-team phase) and May 2006-2012 (expanded team phase). In the first frame, a single leader-operators team that first approached CAS and passed the original institutional learning curve, performed all the procedures; in the following expanded-team phase, five new trainees joined. Institutional CAS training for new trainees was based on a team-working approach including selection of patients, devices and techniques and collegial meetings with critical review and discussion of all procedural steps and imaging.

RESULTS

A total of 431 CAS procedures were performed in the leaders-team phase and 1026 in the sequential expanded-team phase. Periprocedural complication rates in the two time frames were similar: stroke/death (3.0% vs. 2.1%; P = 0.35), stroke (2.8% vs. 2.1%; P = 0.45) major stroke (0.9% vs. 0.6%, P = 0.49), death (0.2% vs. 0%; P = 0.29) during the leaders-team and expanded-team phase, respectively. However, rates of CAS failure requiring surgical conversions (3.7% vs. 0.8%; P < 0.0001) and mean contrast use (91.6 vs. 71.1 ml; P = 0.0001) decreased in the expanded phase. In the expanded-team frame (May 2006-2012), there was no mortality, and stroke rates were comparable between the leader and new operator teams: 2.6% vs. 1.2%; P = 0.17.

CONCLUSIONS

Institutional experience, including instruction on selection of patients and materials best suited for the procedure, is a primary factor driving outcomes of CAS. An effective team-working approach can reliably improve the training of new trainees preserving CAS safety and efficacy.

Carotid Artery Stenting - Strategies to Improve Procedural Performance and Reduce the Learning Curve

Carotid artery stenting (CAS) remains an appealing intervention to reduce the stroke risk because of its minimal invasive nature. Nevertheless, landmark randomised controlled trials have not been able to resolve the controversies surrounding this complex procedure as the peri-operative stroke risk in a non-selected patient population still seems to be higher after CAS in comparison to carotid endarterectomy. What is more, these trials have highlighted that patient outcome after CAS is influenced by patient- and operator-dependant factors. The CAS procedure exhibits a definitive learning curve resulting in higher complication rates if the procedure is performed by inexperienced interventionists or in low-volume centres. This article will outline strategies to improve the performance of physicians carrying out the CAS procedure by means of proficiency-based training, credentialing, virtual reality rehearsal and optimal patient selection.

[Intracerebral aneurysm--treatment options, informed consent, and legal aspects]

All medical subspecialties and, in particular, high-tech field neurosurgery are subject to continuous change in therapeutic concepts due to novel treatment options emerging through research and evolution in the field. Hence, the question arises if the patient's informed consent needs to be adjusted in the face of multiple therapeutic options with different configurations of risk/benefit relationships. In this paper we discuss different therapeutic scenarios with regard to ruptured intracerebral aneurysms (RIA) and unruptured intracerebral aneurysms (UIA), and we advise the medical doctor involved in the process. Indeed, experienced neurosurgeons and endovascular interventionalists are very familiar with the management of these scenarios; likewise, interns, residents, and otherwise affiliated physicians may be faced with these situations. In general, asymptomatic and mentally capacitated patients as well as legal guardians of minor patients and of mentally incapacitated patients with incidental aneurysms and more than one therapeutic option need to be accurately informed about the advantages and disadvantages of the treatment options available to them. In case of emergency or when treating a mentally disabled patient who is incapable of making a sound judgment and has no legal guardian, the attending doctor will have to choose the best possible treatment option.

Vascular imaging in stroke: comparative analysis

Advances in stroke treatment have mirrored advances in vascular imaging. Understanding and advances in reperfusion therapies were made possible by improvements in computed tomographic angiography, magnetic resonance angiography, neurovascular ultrasound, and renewed interest in catheter angiography. As technology allows better noninvasive vascular diagnosis, digital subtraction angiography (the remaining gold standard for vascular imaging) is increasingly used for rescue procedures and elective interventions. This review will examine specific advantages and disadvantages of different vascular imaging modalities as related to stroke diagnosis.

Successful interdisciplinary management of the misdeployment of two self-expanding stents into the internal carotid artery: a case report

Introduction

With the widespread use of carotid artery stenting, previously unknown technical mistakes of this treatment modality are now being encountered. There are multiple strategies for the treatment of in-stent restenosis. With regard to surgical management, endarterectomy and patch plasty are favored. To the best of our knowledge, this report is the first description of a complete stent removal by the eversion technique.

Case presentation

We report the case of a 63-year-old Caucasian man with misdeployment of two stents into his stenotic proximal internal carotid artery, resulting in a high-grade mechanical obstruction of the internal carotid artery lumen. With the contralateral internal carotid artery already occluded and associated stenoses of both proximal and distal vertebral arteries, an interdisciplinary therapeutic concept was applied. Bilateral balloon angioplasty and stenting of the proximal and distal stenotic vertebral arteries were carried out to provide sufficient posterior collateral blood flow, followed by successful surgical stentectomy and carotid endarterectomy using the eversion technique. Duplex scanning and neurological assessments were normal over a 12-month follow-up period.

Conclusions

Interdisciplinary treatment is a recommended option to protect patients from further impairment. Further evaluation in larger studies is highly recommended.

Interventional neurology: a reborn subspecialty

Neurologists have a long history of involvement in cerebral angiography; however, the roots of neurologist involvement in therapeutic endovascular procedures have not been previously documented. As outlined in this article, it has taken the efforts of several early pioneers to lay the ground work for interventional neurology, a specialty that has become one of the fastest growing neurological subspecialties. The ground work, along with a great clinical need, has allowed the modern interventional neurologist to tackle some of the most intractable diseases, especially those affecting the cerebral vasculature. The institutionalization of interventional neurology as a subspecialty was first advocated in 1995 in an article entitled, "Interventional Neurology, a subspecialty whose time has come." The institutions created in the wake of this article have provided the framework that has allowed interventional neurology to transition from "a subspecialty whose time has come" to a subspecialty that is here to stay and thrive.

Transradial carotid stenting in a patient with bovine arch anatomy

Carotid stenting in difficult arch anatomy can be safely done by transradial route depending upon operator's experience. Left carotid artery stenosis with bovine arch anatomy can be approached by right arm approach (radial/brachial) easily. In cases with bovine arch anatomy, left arm approach by modified looping technique is still possible. We report a case of carotid stenting in a patient with bovine arch anatomy using percusurge anchoring technique through left radial approach.