Introduction Incidentally found small aneurysms with relatively low risk of rupture are often observed with periodic imaging studies. The importance of follow-up is emphasized since more studies show that the risk of rupture can significantly increase if an aneurysm shows growth over time. Meanwhile, little is known about the follow-up compliance of these relatively low-risk aneurysm patients after the initial diagnosis of the aneurysm. The patients are often diagnosed by non-specialists and sent to tertiary care, including Neurosurgery, Neurology, or Neuro IR service. The amount of patients who follow the recommendation and see tertiary care consultations is also unknown. Therefore, we performed a retrospective compliance analysis of the patients diagnosed with unruptured intracranial aneurysms. We also analyzed the factors associated with non-compliance using multivariate analysis.

Materials and Methods Utilizing the Cohort Discovery Tool (CDT) software, i2b2, we identified patients diagnosed with unruptured aneurysms in our institution’s data warehouse in the past 10 years and conducted medical chart reviews of each patient. The follow-up imaging of CT or MR Angiogram was scheduled at 3 months, 6 months, 1 year, and 2 years since the initial diagnosis followed by an annual or biannual imaging. For those who were non-compliant, we performed individual telephone interviews to analyze the reasoning for their non-compliance. The patients were divided into two groups of compliant vs. non-compliant patients based on the first 2 year compliance. The demographic factors, intervention type, age, gender, ethnicity, with or without primary care physician, insurance type, and specialty type at the initial encounter, were analyzed and the factors associated with non-compliance were evaluated using multivariate logistical regression analysis.

Results CDT screening data showed that 777 patients were diagnosed with at least one unruptured aneurysm by various services such as emergency medicine, internal medicine, diagnostic radiology, neurosurgery and neurology. Of these, 362 patients who underwent retrospective analysis of the medical chart review and telephone interview, were included in the study. The mean and median follow-up period was 1.5 years and 2 months, respectively. One hundred seventy-one patients (47%) showed 2-year compliance, and 191 patients (53%) were non-compliant. Five patients (1.4%) had a rupture of the aneurysm during the follow-up and three patients (0.8%) died. Telephone interviews conducted for those 113 non-compliant patients showed that the cause of poor compliance was related to 1) unawareness of the importance of a follow-up visit (36%), 2) unable to attend due to other reasonings (11%), and 3) properly followed elsewhere (2%). Eighty four (49%) compliant and 64 (37%) non-compliant patients received tertiary care consultation. The only factor associated with non-compliance was whether the patient received a tertiary care consultation after the diagnosis (<0.001).

Conclusion Many unruptured aneurysm patients with relatively low risk of rupture were lost in follow-up before being referred to the tertiary care consultation. The major reason for non-compliance was a lack of patient education by the tertiary care specialists after the initial diagnosis. Improved clinical approaches may be required to educate patients and ensure a proper understanding of follow-up care.

Disclosures H. Kaur: None. I. Yuki: 4; C; Stockholder of start-up company, AquaTex medical.. T. Shimizu: None. J. Xu: None. K. Golshani: None. F. Hsu: 4; C; Stockholder of start-up company, AquaTeX medical. S. Suzuki: 2; C; Medtronic Consultant.. 4; C; Stockholder of start-up company, AquaTeX medical.