Balloon-assisted microcatheter navigation for AVM embolization: technical note

Embolization of Ruptured Infratentorial Pial AVM in Pregnancy

A primigravida 22-year-old woman, at a gestation of 23 weeks, experienced bleeding from a pial arteriovenous malformation (AVM) located in the right cerebellum. After interdisciplinary consensus and with the informed consent of the patient and her family, AVM embolization was performed. Complete occlusion of the AVM was achieved by embolization with PHIL (precipitating hydrophobic injectable liquid). The calculated dose in the uterus was less than 1 µSv, which represents a negligible risk of harmful effects on the fetus. She delivered a baby at 37 weeks of gestation by cesarean section without complications. No congenital disorders were diagnosed by standard screening methods until the age of the newborn was two years. The angiography protocol must be optimized to minimize the radiation dose. Adequate shielding protection of the uterus is important. Premature termination of pregnancy is not necessary. Multidisciplinary care of neurologists, neurosurgeons, interventional radiologists, anesthesiologists, neonatologists, and obstetricians is necessary.

Balloon-Assistance for the Transcirculation Access of a Remodeling Balloon for Coiling of Wide-Necked Aneurysms: Report of Two Cases

Balloons are valuable tools in the armamentarium of a neurointerventionist. In this report, we describe 2 cases in which a balloon aided in the navigation of a second remodeling balloon through difficult vascular anatomy. The first case was a patient with a ruptured proximal posterior inferior cerebellar artery aneurysm and the second case was a patient with a ruptured anterior communicating artery aneurysm. In both cases, the coiling microcatheter and the remodeling balloon catheters were advanced through different vessels. The remodeling balloon reached the target location using a transcirculation approach, and the navigation of the remodeling balloon was aided by utilizing a second balloon. Challenging vascular anatomy is often encountered when performing neuroendovascular procedures. The strategy of using balloon assistance for the transcirculation access of a remodeling balloon can be used successfully in difficult situations to manage complex aneurysms.

S-shaped distal access catheter supported microcatheter navigation into the lenticulostriate artery feeders of brain arteriovenous malformations

BACKGROUND

Although the embolization of lenticulostriate artery feeders is often warranted in the treatment of brain arteriovenous malformations, it is technically challenging due to steep and repeated angulations. Here, we describe our novel technique of navigating a flow-guided microcatheter into lenticulostriate artery feeders using the strong support provided by an S-shaped distal access catheter.

METHODS

We reviewed our retrospective cohort of brain arteriovenous malformations, in which lenticulostriate artery feeders were attempted to embolize.

RESULT

During the study period, endovascular embolization was performed in 25 arteriovenous malformations cases. Of these, eight lenticulostriate artery feeders were present in six cases (24%). In two cases, lenticulostriate artery feeder catheterization was avoided from the beginning due to the small diameters of the feeders. After all, microcatheter navigation for lenticulostriate artery feeders were attempted in four cases with six lenticulostriate artery feeders. In all the six feeders, the S-shaped distal access catheter was successful in supporting the microcatheter to advance distally to the lenticulostriate artery feeders, even if other approaches were unsuccessful. Of the six catheterized lenticulostriate artery feeders, four were embolized. Symptomatic infarction in the lenticulostriate artery territory and mild vasospasm occurred in two cases each, but they did not result in permanent neurological deficits.

CONCLUSION

Although some potential complications need to be considered, the S-shaped distal access catheter technique appears to be an effective alternative approach to gaining access to difficult feeders of arteriovenous malformations.

Safety and Efficacy of Transvenous Embolization of Ruptured Brain Arteriovenous Malformations as a Last Resort: A Prospective Single-Arm Study

BACKGROUND AND PURPOSE

The efficacy and safety of transvenous embolization for brain arteriovenous malformations remains unclear, given the very limited number of cases reported. This prospective study was performed to assess this technique in ruptured AVMs.

MATERIALS AND METHODS

Twenty-one consecutive patients with ruptured brain AVMs who underwent transvenous embolization were prospectively followed between November 2016 and November 2018. The Spetzler-Martin grade was I in 3 AVMs (14.3%), II in four (19.0%), III in eleven (52.4%), and IV in three (14.3%). The complete AVM occlusion rate was calculated from 6-month follow-up DSA images. Occurrence of hemorrhage and infarction after embolization was evaluated using CT and MR imaging within 1 month after the operation. The mRS was used to assess the functional outcomes.

RESULTS

Complete AVM nidus obliteration was shown in 16 (84%) of 19 patients with technically feasible AVMs immediately after embolization. One (5%) patient with a small residual nidus after treatment showed complete obliteration at 13-month follow-up. There were 5 hemorrhages and 1 infarction; 4 patients' symptoms improved gradually. The percentage of cases with mRS ≤ 2 rose from 57.1% (12/21) before embolization to 66.7% (14/21) at 1-month follow-up. Both the morbidity and mortality rates were 4.8% (1/21).

CONCLUSIONS

Transvenous embolization can be performed only in highly selected hemorrhagic brain AVMs with high complete obliteration rates, improved functional outcomes, and acceptable morbidity and mortality rates, but it should not be considered as a first-line treatment.

Transvenous embolization of arteriovenous malformations

Embolization of arteriovenous malformations is characteristically used as part of a multimodal treatment approach, pre-operatively to facilitate microsurgical resection or as a preradiosurgical adjunct. The concept of AVM cure via embolization alone has gained popularity in recent years. Embolization of AVMs has been most commonly performed transarterially, with the transvenous route traditionally eschewed given concern over precipitating premature venous occlusion and consequent hemorrhage. However, the transvenous approach in treating AVMs offers several distinct advantages compared to the transarterial route and can be used in instances when the latter is not feasible, with several series having proven its efficacy and safety. Conceptually, AVM embolization performed via the transvenous route achieves complete obliteration by directly and facilely targeting the nidus. Nidal embolisate penetration is facilitated by control of arterial inflow via systemic or local hypotension. Innovation in endovascular strategies has led to significantly improved obliteration rates. The experience with transvenous AVM embolization is reviewed and discussed.

Extending the indications for transvenous approach embolization for superficial brain arteriovenous malformations

INTRODUCTION

Transarterial embolization is the standard endovascular treatment strategy for intracranial arteriovenous malformations (AVMs). The transvenous approach has been indicated for the embolization of deep AVMs meeting a set of strict eligibility criteria. The present study aims to assess the safety and efficacy of the transvenous approach for superficial AVMs.

METHODS

A retrospective series of 12 patients presenting with cortical AVMs were treated by endovascular embolization using a transvenous approach with a curative intent.

RESULTS

Nine patients (75%) had ruptured AVMs at admission. The mean nidus size was 1.9 cm, six patients (50%) had a nidus in eloquent areas and the median Spetzler-Martin grade was 2. The rate of immediate angiographic occlusion of the AVMs was 91.6% (11/12). One patient in whom immediate angiographic occlusion was not achieved showed spontaneous occlusion at the 6-month follow-up. No procedural or clinical complications were observed. The mean and median modified Rankin scale (mRS) scores at discharge were 1.7 and 2 (range 0-3, SD=0.96), and the mean and median mRS scores at 6 months were 1.6 and 2 (0-3, 1.16). Nine patients (75%) were independent (mRS ≤2) at discharge and 11 patients (91.6%) were independent (mRS ≤2) at the 6-month follow-up.

CONCLUSIONS

The curative transvenous embolization of superficial intracranial AVMs is feasible and appears safe and effective when strict anatomical selection is respected. This technique extends the current indications for transvenous embolization of intracranial AVMs and may improve cure rates while reducing embolization-related complications.