Natural history of dolichoectatic vertebrobasilar aneurysms: a multinational study
Authors: Rezai Jahromi Behnam , Dashti Reza , Ota Nakao , Dabbagh Ohadi Mohammad Amin , Srinivasan Visish , Fiorella David , Kaukovalta Hanna , Laakso Aki , Schwartz Christoph , Kivisaari Riku , Zamotin Vladimir , Lindgren Antti , Koivisto Timo , Silva João M. , Rustemi Oriela , Kelahaara Milla , Jahromi Babak S. , Killer-Oberpfalzer Monika , Potts Matthew B. , Noda Kusumo , Hecker Constantin , Griessenauer Christoph J. , Numminen Jussi , Göhre Felix , Andrade-Barazante Hugo , Hijazy Ferzat , Wessels Lars , Kalani M. Yashar S. , Vajkoczy Peter , Spetzler Robert F. , Jääskeläinen Juha E. , Kawashima Akitsugu , Winkler Ethan , Tähtinen Olli , Latini Roberto , Meessen Jennifer , Tanikawa Rokuya , Lawton Michael T. , Niemelä Mika 
Published: December 2024

OBJECTIVE
Dolichoectatic vertebrobasilar aneurysms (DVBAs) are expansions of arterial tissue leading to aneurysmal formations without an obvious neck. Their natural history is poorly understood; usually patients are admitted with thromboembolic complications and/or neurological symptoms from the mass effect. There have not been international collective data, and correct timing for highly risky treatments has been under discussion. The goal of this study was to define the natural history of DVBA by long-term follow-up in an international population of patients with DVBA.

METHODS
The authors collected data in 382 patients with DVBAs from 11 centers in Europe, the US, and Japan. The patients were followed until new ischemic or hemorrhagic stroke, symptomatic compression of the brainstem or cranial nerves, decline in modified Rankin Scale score, or death. Treatment excluded patients from further analysis. Demographic and radiological characteristics of patients were collected and a new classification was created based on the radiological characteristics of the DVBA. In total 223 patients were treated conservatively in the first phase of treatment. The data required for natural history calculations were available for 221 patients, with a cumulative follow-up of 622.3 patient-years. Kaplan-Meier and Cox regression analyses were used to assess risk factors with an influence on patient outcomes.

RESULTS
In total, 21.5% of patients were admitted due to the mass effect, and there were 67 (30%) patient deaths during follow-up, 45 (20.2%) of which were related to aneurysms. The annual mortality and morbidity were 10.8% and 1.6%, respectively. Most of the patients with DVBAs were male, although sex did not affect prognosis when compared to the radiological characteristics of the lesion. The natural history of DVBAs was also impacted by a new classification, in which an age 50 years and older predicted mortality. Furthermore, a DVBA’s maximum diameter was directly proportional to adverse events.

CONCLUSIONS
This study verifies the malignancy of DVBAs and encourages invasive treatment in the early phase of disease progression based on radiological characteristics and patient age when a treatment option is considered suitable. This also stresses the need for continued investigations to develop new therapeutics with acceptable safety profiles.