Incidence of Spontaneous Obliteration in Untreated Brain Arteriovenous Malformations

Abstract

BACKGROUND Spontaneous obliteration (SpO) of untreated arteriovenous malformations (AVMs) is rare with fewer than 100 cases reported. The incidence and predisposing factors of SpO remain unclear, impeding our understanding of lesion progression in untreated patients. OBJECTIVE To determine the incidence rate and predisposing factors of SpO in a North American cohort. METHODS AVMs were retrospectively evaluated at our institution for over 25 yr. Untreated AVMs were divided into 2 groups: SpO-AVMs and non-SpO-AVMs. All statistical results were based on univariate analyses. Incidence was generated from counts of SpO over the untreated interval in patient years from birth until obliteration, treatment, or last follow-up. RESULTS One hundred fifty-four patients had untreated AVMs; SpO was observed in 4. Average ages were 49.0 ± 23.6 and 48.7 ± 20.4 yr in the SpO-AVM and non-SpO-AVM group, respectively (P = .98). Average AVM sizes were 2.0 ± 1.8 cm (SpO-AVMs) and 3.7 ± 2.6 cm (non-SpO-AVMs, P = .25). All SpO-AVMs and 40 (27.0%) non-SpO-AVMs had a ruptured presentation (P = .006). A single draining vein was observed in all SpO-AVMs and 39 (32.8%) non-SpO-AVMs (P = .01). Deep venous drainage was not observed in any SpO-AVMs, but in 81 (57.9%) non-SpO-AVMs (P = .04). Mean follow-up time was 37.0 ± 42.6 and 75.6 ± 161.7 mo in SpO-AVM and non-SpO-AVMs patients, respectively. Of the 2 SpO-AVM patients with postobliteration follow-up, 1 experienced recanalization. From a 672-patient cohort, the incidence of SpO over 28 961 patient years was 0.014%. CONCLUSION SpO-AVMs have an annual incidence rate of approximately 0.014% and tend to present with rupture, a single draining vein, and superficial venous drainage. Expectation of SpO for untreated AVMs is not justified, and patients should anticipate life-long hemorrhagic risk for untreated AVMs.

Spontaneous obliteration of brain arteriovenous malformations: illustrative cases

“…The incidence of death or sustained disability, reported in the first 4 years of conservative management of unruptured AVMs in the Scottish Intracranial Vascular Malformation Study (SIVMS), was 9 per 100 patient-years. 16 Compared with the spontaneous obliteration rate of 1.4% quoted by Liew et al, 8 death or severe disability was more than 600 times more likely to occur during the first 4 years of conservative management than spontaneous obliteration. 8 Similarly, SpOAVM was 242 times less likely to occur than death or symptomatic stroke, an outcome that was observed after 3.39 per 100 patient-years in the medical arm of the A Randomized trial of Unruptured Brain Arteriovenous malformation (ARUBA) trial.…”

“…A recent institutional study reported an incidence of 0.014 per 100 patient-years. 8 Compression of the nidus by a hematoma and thrombosis of a prominent draining vein have been described as two suggested mechanisms. 5 , 8 , 9 …”

“… 8 Compression of the nidus by a hematoma and thrombosis of a prominent draining vein have been described as two suggested mechanisms. 5 , 8 , 9 …”

“…A recent institutional study reported an incidence of 0.014 per 100 patient-years. 8 Compression of the nidus by a hematoma and thrombosis of a prominent draining vein have been described as two suggested mechanisms. 5,8,9 The management goals of AVM focus on preventing primary hemorrhage and the subsequent sequelae of disabling stroke or death.…”

Stereotactic Radiosurgery With vs. Without Prior Embolization for Brain Arteriovenous Malformations: A Propensity Score Matching Analysis

“…Several previous studies indicated lower obliteration rates for unruptured bAVMs compared with ruptured AVMs after SRS ( 28 , 29 ). The investigators postulated a possible synergism between radiation and hemorrhage for AVM obliteration via mechanisms of endothelial damage, myofibroblast proliferation, and progressive endoluminal occlusion and thrombosis ( 30 , 31 ). Nevertheless, previous studies did not explore the obliteration rate of the SRS strategy and Em+SRS strategy in the ruptured and unruptured subgroups.…”