Bleeding risk from aneurysm high in hemorrhagic AVM radiosurgery

By Liam Davenport, medwireNews Reporter

In patients undergoing stereotactic radiosurgery (SRS) for hemorrhagic arteriovenous malformations (AVMs), endovascular or surgical strategies that reduce bleeding risk should be used if an aneurysm is found, advise US researchers.

The team, led by L Dade Lunsford, from the University of Pittsburgh in Pennsylvania, says: "The presence of a patent aneurysm was significantly associated with an increased rehemorrhage risk... We found that patients with hemorrhagic AVM with treated aneurysms were significantly less likely to rehemorrhage after SRS."

They add: "This result indicates that aneurysm management reduces combined bleeding risks during the latency interval after SRS."

The team identified 407 patients who underwent SRS for hemorrhagic AVM between 1987 and 2006, of whom 45 (11%) had an associated aneurysm that was most commonly located on the circle of Willis.

After a median follow up of 66 months, AVMs were assessed by magnetic resonance imaging in 255 patients and by angiography in 188. The total obliteration rate after SRS on either measure was 56%, 77%, 80%, and 82% at 3, 4, 5, and 10 years, respectively.

The annual hemorrhage rate decreased from 3.4% before SRS to 1.3% afterwards. The cumulative rate of AVM rehemorrhage after SRS was 3.2%, 4.3%, 5.5%, 6.6%, and 9.7% at 1, 2, 3, 5, and 10 years, respectively, the team reports in Stroke.

In a case-matched comparison, the annual rate of AVM rehemorrhage was 1.0% in patients without aneurysms versus 6.4% in those with patent aneurysms and 0.8% in those with a clipped or embolized aneurysm.

The cumulative rate of rehemorrhage was 2.8%, 4.4%, and 5.2% at 1, 3, and 5 years, respectively, in patients without aneurysms, while the respective rates in patients with aneurysms were 12.2%, 21.5%, and 26.7% and the rates in those with clipped or embolized aneurysms were 0%, 6.2%, and 6.2%.

Analysis confirmed that the presence of a patent aneurysm in patients with hemorrhagic AVM was significantly associated with an increased risk for rehemorrhage, at a hazard ratio of 4.9.

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