The Source for Neurovascular News and Education

May 28, 2024


Key Points:

  • Meta-analysis compares deconstructive, reconstructive endovascular treatment of ruptured blisterlike aneurysms
  • Deconstructive techniques yield more early occlusion but higher stroke risk


Endovascular treatment of ruptured blisterlike aneurysms achieves high rates of occlusion and good long-term neurological outcomes, according to results from a meta-analysis presented on July 30, 2015, at the Society of NeuroInterventional Surgery meeting in San Francisco, CA. Deconstructive vs reconstructive techniques have higher initial occlusion rates but also elevated perioperative stroke risks. 

Most of the procedures (90.6%) were reconstructive techniques—including coiling, stent-assisted coiling, stenting, flow diversion, Onyx liquid embolic agent (Covidien) and stenting, or a combination—and the rest were deconstructive.Aymeric Rouchaud, MD, and colleagues from the Mayo Clinic (Rochester, MN) looked at data from 31 studies published between 1980 and 2014 that included 265 procedures performed in 258 patients (mean age 47.6 years; 73% women) for ruptured blisterlike aneurysms. The mean dome size was 2.4 mm and 19.3% of patients had a mean Hunt and Hess grade of 4/5. The mean length of follow-up was 14.8 months. 

 The Next Step

“With the advent of coated devices, I expect flow diverters to have even more impact on the treatment of blisterlike aneurysms,” Dr. Ricardo Hanel says. 

Overall, endovascular treatment resulted in initial occlusion in 40.6% of patients and mid- to long-term occlusion in 72.8%. The retreatment rate through follow-up was 19.3%, and about three-quarters of patients (76.2%) had a good long-term neurological outcome, defined as a modified Rankin Scale score ≤ 2.

Deconstructive and reconstructive approaches yielded similar rates of procedural complications, overall perioperative morbidity, mortality, and intracranial hemorrhage, early rebleeding, retreatment, and mid- to long-term occlusion. Deconstructive techniques provided a greater likelihood of initial occlusion (77.3% vs 33.0%; P = .0003), although that came at the cost of a higher rate of perioperative stroke (29.1% vs 5.0%; P = .04).

Through follow-up, there was no difference in the percentage of patients who had a good neurological outcome between the reconstructive and deconstructive groups (76.2% vs 79.9%; P = .30).

About a quarter (25.8%) of the reconstructive procedures involved flow-diverter stents, and results, including good neurological outcome, were largely similar regardless of whether such devices were used. Flow diversion was associated, however, with a higher rate of mid- to long-term occlusion (90.8% vs 69.7%; P = .005) and a lower rate of retreatment (6.6% vs 27.1%; P = .0002).

Ruptured Blisterlike Aneurysms Dangerous, Challenging         


Blisterlike aneurysms, which are attributed to subadventitial dissection resulting in a focal wall defect, account for only a small fraction of intracranial aneurysms—0.3% to 1.0% overall and 0.9% to 5.6% of ruptured aneurysms. They are associated with high rates of spontaneous or treatment-induced rebleeding and death, particularly after rupture. 

Treating blister-like aneurysms is a challenge because they do not have a defined neck and the aneurysm sac has a very thin wall, according to Dr. Rouchaud. One option, surgery consisting of wrapping or trapping with bypass, is accompanied by high perioperative mortality and morbidity rates.

Evidence on the safety and efficacy of endovascular techniques is limited to small retrospective cases series, but this meta-analysis suggests both deconstructive and reconstructive approaches are effective. Furthermore, because of similar outcomes when compared with other types of reconstructive procedures, flow diversion is a reasonable choice, despite the need for antiplatelet therapy, Dr. Rouchaud said.

He told WLNCMD in a telephone interview that there will likely be increasing use of flow diverters moving forward.

In an email with WLNCMD, Ricardo A. Hanel, MD, PhD, of Baptist Health System (Jacksonville, FL), agreed, saying, “[The meta-analysis] does demonstrate that use of flow-diverter [stents], Pipeline [Covidien] specifically, seems to be a good option for this special type of challenging ruptured brain aneurysm. 

Although the meta-analysis included a small number of procedures and cannot provide definitive proof of efficacy, it does support greater use of flow diversion, he said.

“Deconstructing techniques have significant morbidity, especially in ruptured aneurysms,” Dr. Hanel said. “With the advent of coated devices, I expect flow diverters to have even more impact on the treatment of blisterlike aneurysms.”

Dr. Rouchaud pointed out that the best way to determine whether flow diverters are superior to other options is through an RCT but said that such a study probably will not be possible because there are so few cases. 

He also acknowledged that the meta-analysis was limited by the inclusion of retrospective, noncomparative studies; the lack of homogeneity across studies; the small size of some treatment groups; the lack of standardization in outcomes reporting; and the fact that the types of endovascular approaches used changed over time. 


Rouchaud A, Brinjikji W, Cloft H, Kallmes D. Endovascular treatment of ruptured blisterlike aneurysms: a systematic review and meta-analysis with focus on deconstructive versus reconstructive and flow diverter treatments. Presented at: Society of NeuroInterventional Surgery Annual Meeting; July 30, 2015; San Francisco, CA.




  • Dr. Rouchaud reports no relevant conflicts of interest.
  • Dr. Hanel reports consulting for Codman, Covidien, Medina Medical, MicroVention, and Stryker, and holding stock in Blockade and Medina Medical.