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PHASES Aneurysm Rupture Risk

PHASES (Greving 2014)

Estimates the absolute 5-year rupture risk of an incidental intracranial saccular aneurysm from six factors — Population, Hypertension, Age, Size, Earlier SAH and Site — and maps the 0–22 point total to the published risk lookup.

Also searched as: unruptured

Population
Arterial hypertension

History of or treated hypertension (1 point).

Patient age

≥ 70 years adds 1 point.

years
Maximum aneurysm diameter

<7 mm: 0; 7.0–9.9: 3; 10.0–19.9: 6; ≥20 mm: 10 points.

mm
Earlier SAH from a different aneurysm

Prior subarachnoid hemorrhage from another lesion (1 point).

Aneurysm site

ACA includes anterior communicating and pericallosal arteries; posterior circulation includes vertebral, basilar, cerebellar and posterior cerebral arteries.

Information
Incomplete input
  • Please provide: population, maximum aneurysm diameter (mm), patient age (years), aneurysm site, hypertension status, history of SAH from another aneurysm.

How this tool works

PHASES was derived from a pooled analysis of six prospective cohort studies of unruptured intracranial aneurysms (Greving 2014). Points are assigned for population (Japanese 3, Finnish 5), hypertension (1), age ≥ 70 years (1), maximum diameter (7.0–9.9 mm: 3; 10.0–19.9 mm: 6; ≥ 20 mm: 10), earlier subarachnoid hemorrhage from another aneurysm (1) and site (MCA 2; ACA, posterior communicating or posterior circulation 4). The total (0–22) corresponds to a published 5-year absolute rupture risk from 0.4% (≤ 2 points) to 17.8% (≥ 12 points). The score informs, but does not decide, the balance between preventive treatment and imaging surveillance.

References

Implemented from the cited published sources. Educational use only; confirm against current guidelines before clinical use.

Clinical questions that use this

Vetting guides that reach for this tool.