Sandra Ferns, on behalf of the LOTUS study group

1. De novo aneurysm formation and growth of untreated aneurysms 5-year MRA follow-up in a large cohort of patients with coiled aneurysms Sandra Ferns, on behalf of the LOTUS study group Depts of Neurosurgery and Radiology, AMC Amsterdam Depts of Neurology and Radiology, UMC Utrecht Dept of Radiology, St. Elisabeth Ziekenhuis, Tilburg Dept of Neurosurgery, Slotervaart Ziekenhuis Amsterdam Depts of Neurosurgery and Radiology, Leiden UMC Depts of Neurosurgery and Radiology, VUMC Amsterdam Depts of Neurology and Radiology, Maastricht UMC All in the Netherlands

2. Contents • Introduction • LOTUS study design • LOTUS study results • Case • Conclusion

3. Background • Multiple intracranial aneurysms –40%1 • De novo formation and rate of growth unclear2 • Growth ↑ rupture risk1,3 Purpose: To determine 5-year incidence de novo aneurysm formation and growth of untreated aneurysms 1; Wiebers DO et al Lancet 2003, 2; Koffijberg H et al J Neurosurg 2008, 3; Juvela S et al J Neurosurg 2000

4. Methods LOTUS STUDY • multicenter prospective >5yrs follow-up study of patients with adequately coiled aneurysms • 7 participating Dutch centers with MEC approval

5. Methods PATIENTS • Inclusion criteria: • age 18-70 • coiling >4.5 years ago • GOS 4-5 • adequate occlusion after 6 months • no contra-indications for MRA at 3 Tesla Selection of patients with fixed follow-up duration of 5 ± 0.5 years

6. Methods IMAGING • 3 Tesla MRI, Philips Medical Systems • T2 weighted images • MOTSA 3D TOF • Standard MIP and VR 3D reconstructions EVALUATION • 2 observers • Additional aneurysms: compared with initial angiography • Unchanged • Grown • De novo • Not comparable

7. Methods ANALYSES • Proportion de novo aneurysm formation and growth • Patient- and aneurysm characteristics • Patients with versus without additional aneurysms • Patients with versus without growth of additional aneurysms

8. Results • 276 patients follow-up 5 ± 0.5 years; 1332 patient years • 50/ 276 (18%) had 75 additional aneurysms • ♀ RR 2.03, 95%CI 1.03-3.98

9. Results 13% 58 / 63 known; 92%, 95% CI 85- 99% 2 / 276 patients: 0.7%, 95% CI: 0.2- 2.6% 5 / 63 known; 8%, 95% CI 1- 15% Age, gender, aneurysm size no predictor growth

10. Results: 2 de novo 5-year cumulative incidence 0.75% (95% CI 0.2- 2.7%) ♀, 56 jr →3 mm MCA ♂, 66 jr →3 mm Basilar tip Both left untreated

11. Results: 5 grown • 5 aneurysms in 4 patients ♀, 49 jr → ICA 3 → 6 mm ♂, 45 jr → pericall a 2 → 3 mm ♂, 66 jr → pcoma 2 → 3 mm ♀, 53 jr → PICA 2 → 3 mm → Bastip 4 → 6 mm COILED COILED

12. CASE Grown additional aneurysm

13. 49 year-old woman, 5 additional aneurysms Grown left carotid tip aneurysm 3x3  4x6 mm (pcoma aneurysm 2x1 mm conform)

14. Results: Clinical implications • 2 grown and 2 incomparable aneurysms treated in 3 patients (1.1%, 95% CI: 0.4- 3.1%) • 8 patients extra imaging follow-up (2.9%, 95% CI: 0.9- 4.9%)

15. Conclusions • Follow-up MRA 5 years after coiling has a low yield for detection of clinically relevant additional aneurysms 5-year incidence de novo formation: 0.7% (2/276) 5-year incidence treatment of additional: 1.1% (3/276)

16. AMC S.P. Ferns, PhD student C.B.L.M. Majoie, radiologist (Principle investigator) R. van den Berg, radiologist M.E.S. Sprengers, radiologist J.C. van Rijn, radiologist J.J. Schneiders, PhD student P.M. Bossuyt, clinical epidemiologist W.P. Vandertop, neurosurgeon B.A. Coert, neurosurgeon St. Elizabeth Ziekenhuis Tilburg W.J.J. van Rooij, radiologist M. Sluzewski, radiologist Slotervaart Ziekenhuis B.J.C.M. Hummelink, neurosurgeon LOTUS study group • UMCU • G.J.E. Rinkel, neurologist • B.K. Velthuis, radiologist • G.A.P. de Kort, radiologist • J.D. Schaafsma, neurologist resident • VUMC • F. Barkhof, radiologist • J.C.J. Bot, radiologist • LUMC • P.A. Brouwer, radiologist • M.A. van Walderveen, radiologist • MUMC • W.H. van Zwam, radiologist • R. van Oostenbrugge, neurologist