Treatment/Prognosis Flashcards
What are the 3 Tx options for AVMs?
Sg, radiosurgery, and endovascular embolization
When is Tx indicated?
An Hx of previous rupture is the most important consideration; other factors include pts with an estimated elevated risk of future hemorrhage d/t younger age, AVM location, size, or other vascular features.
What is a simple way to approximate the risk of recurrence?
Lifetime risk of hemorrhage = 105 – pt age in yrs.
What is the goal of Tx with AVMs? Why?
Complete obliteration is the goal, there is no benefit or decreased risk of bleed if the obliteration is partial.
Is Tx of unruptured AVMs beneficial?
Possibly. The ARUBA trial is the only RCT to address this issue and compared medical management alone to medical management +interventional therapy (neurosurgery, SRS, or embolization). It was stopped early when the risk of death or stroke was found to be significantly lower in the medical management group (HR 0.27; 95% CI 0.14–0.54). (Mohr JP et al., Lancet 2014) However, in those pts who had imaging evidence of obliteration, an 85% risk reduction of stroke was noted (HR 0.15; CI 0.02–0.53; p = 0.002). (Hanakita S et al., Stroke 2016)
Which lesions are most amenable to Sg?
Those with low (I–III) Spetzler–Martin scores are most amenable to Sg.
What is frequently done for grade III lesions before Sg?
Embolization can be performed for grade III lesions before Sg.
What is the main advantage of Sg?
Immediate cure and reduction in the risk of hemorrhage
For what AVM lesions is SRS preferred?
Radiosurgery is preferred for lesions <3 cm that are located in deep or eloquent regions of the brain.
What is the main disadvantage of SRS for AVMs?
The main disadvantage of SRS is the lag time of 1–3 yrs to complete obliteration (i.e., continued bleeding risk).
How does RT lead to AVM obliteration?
Vascular wall thickening (fibrointimal hyperplasia) and luminal thrombosis from RT effect result in obliteration of the AVM.
Is the bleeding risk completely eliminated after SRS?
No. It is reduced by ∼54% during latency period and 88% after obliteration but not eliminated. (Maruyama K et al., NEJM 2005; Yen CP et al., Stroke 2011)
On what do SRS cure rates for AVMs primarily depend?
Size of AVM: 81%–91% if <3 cm, lower if >3 cm (Maruyama K et al., NEJM 2005)
What can be done for high-grade AVMs (IV–V) not amenable for Sg?
Staged SRS (different components targeted at separate sessions) (Sirin S et al., Neurosurg 2006)
For which AVMs can embolization be curative?
AVMs <1 cm that are fed by a single artery can be cured by embolization alone.
