Unruptured intracranial aneurysm follow-up and treatment after morphological change is safe: observational study and systematic review.
BACKGROUND
The management of small unruptured incidentally discovered intracranial aneurysms (SUIAs) is still controversial. The aim of this study is to assess the safety of a management protocol of SUIAs, where selected cases with SUIAs are observed and secured only if signs of instability (growth) are documented.


METHODS
A prospective consecutive cohort of 292 patients (2006-2014) and 368 SUIAs (anterior circulation aneurysms (ACs) smaller than 7 mm and posterior circulation aneurysms smaller than 4 mm without previous subarachnoid haemorrhage) was observed (mean follow-up time of 3.2 years and 1177.6 aneurysm years). Factors associated with aneurysm growth were systematically reviewed from the literature.


RESULTS
The aneurysm growth probability was 2.6±0.1% per year. The rate of unexpected aneurysm rupture before treatment was 0.24% per year (95% CI 0.17% to 2.40%). The calculated rate of aneurysm rupture after growth was 6.3% per aneurysm-year (95% CI 1% to 22%). Aneurysms located in the posterior circulation and aneurysms with lobulation were more likely to grow. Females or patients suffering hypertension were more likely to have an aneurysm growing. The probability of aneurysms growth increased with the size of the dome and was proportional to the number of aneurysms diagnosed in a patient.


CONCLUSIONS
It is safe to observe patients diagnosed with SUIAs using periodic imaging. Intervention to secure the aneurysm should be performed after growth is observed.
Neurosurgery Division, Department of Clinical Neurosciences, Faculty of Medicine, Geneva University Medical Center, Geneva, Switzerland.
Renato
R
Gondar
Neurosurgery Division, Department of Clinical Neurosciences, Faculty of Medicine, Geneva University Medical Center, Geneva, Switzerland.
Oliver Pascal
OP
Gautschi
Neurosurgery Division, Department of Clinical Neurosciences, Faculty of Medicine, Geneva University Medical Center, Geneva, Switzerland.
Johanna
J
Cuony
Neurology Division, Department of Clinical Neurosciences, Faculty of Medicine, Geneva University Medical Center, Geneva, Switzerland.
Fabienne
F
Perren
Neurosurgery Division, Department of Clinical Neurosciences, Faculty of Medicine, Geneva University Medical Center, Geneva, Switzerland.
Max
M
Jägersberg
Neurosurgery Division, Department of Clinical Neurosciences, Faculty of Medicine, Geneva University Medical Center, Geneva, Switzerland.
Marco-Vincenzo
MV
Corniola
Department of Neurosurgery, University Medicine Göttingen, Georg August University Göttingen, Göttingen, Germany.
Bawarjan
B
Schatlo
Neurosurgery Division, Department of Clinical Neurosciences, Faculty of Medicine, Geneva University Medical Center, Geneva, Switzerland.
Granit
G
Molliqaj
Neurosurgery Division, Department of Clinical Neurosciences, Faculty of Medicine, Geneva University Medical Center, Geneva, Switzerland.
Sandrine
S
Morel
Interventional Neuroradiology Division, Department of Radiology and Medical Informatics, Faculty of Medicine, Geneva University Medical Center, Geneva, Switzerland.
Zsolt
Z
Kulcsár
Neuroimaging Division, Department of Medical Imaging, Toronto Western Hospital, Toronto, Ontario, Canada.
Vitor
V
Mendes Pereira
Neuroradiology Division, Hirslanden Clinic, Zürich, Switzerland.
Daniel
D
Rüfenacht
Neurosurgery Division, Department of Clinical Neurosciences, Faculty of Medicine, Geneva University Medical Center, Geneva, Switzerland.
Karl
K
Schaller
Neurosurgery Division, Department of Clinical Neurosciences, Faculty of Medicine, Geneva University Medical Center, Geneva, Switzerland.
Philippe
P
Bijlenga
D000328:Adult; D000368:Aged; D017542:Aneurysm, Ruptured / Q000000981:diagnostic imaging / Q000628:therapy; D015331:Cohort Studies; D005260:Female; D006801:Humans; D033162:Incidental Findings; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000628:therapy*; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D061214:Patient Safety; D018579:Patient Selection; D018570:Risk Assessment; D057832:Watchful Waiting