High Rate of Serious Complications with Stent-Assisted Coiling in Unruptured Intracranial Aneurysms: Lessons to Learn

This post was written by Dr. Willem Jan van Rooij.

Re: Piotin M, Blanc R, Spelle L, Mounayer C, Piantino R, Schmidt PJ, Moret J. Stent-Assisted Coiling of Intracranial Aneurysms. Clinical and Angiographic Results in 216 Consecutive Aneurysms. Stroke 2010;41:110-15; published online before print December 3 2009, doi:10.1161/STROKEAHA.109.558114

However, some of us propagate a more liberal use of intracranial stents because the stent should attribute to a more durable aneurysm occlusion on the long-term by diverting the flow and by creating a mesh at the level of the neck to be colonized and covered by endothelial cells. In view of these perceived advantages, some even place a stent after successful aneurysm occlusion by simple coiling. The key question in this issue is: Does the potential better long-term result with use of stents negate the higher expected rate of complications?

One answer to this question is provided by the recently published study by Piotin. Clinical and imaging results of 216 patients with aneurysms (181unruptured and 35 ruptured) that were treated with stent assistance were compared to results of 1109 aneurysms (549 ruptured and 560 unruptured) that were treated without stent. Permanent neurological procedure-related complications occurred in 7.4% (16 of 216) of the procedures with stents versus 3.8% (42 of 1109) in the procedures without stents. Procedure-induced mortality occurred in 4.6% (10 of 216) of the procedures with stents versus 1.2% (13 of 1109) in the procedures without stents. In other words, with stent assisted treatment, 12% of patients either died or had permanent neurological deficit as a direct consequence of the treatment. How about the angiographic results, are these better with stent than without stent? Aneurysms treated with a stent had a higher rate of initial incomplete occlusion (35% versus 18%). Only about half of the stented aneurysms had angiographic follow-up and there were less recurrences 15% (17 of 114) versus 34% (259 of 774).

Unfortunately, the authors did not further analyse the high rate of complications with stent assisted coiling (vessel perforations, aneurysm perforations, thrombo-embolic complications). They also did not provide a definition of a recurrence and more important, the rate of retreatment in both groups was not reported. Although there were fewer recurrences after stenting, the recurrence rate of 15% with stent assistance is within the normal range of 10-20% reported for coiling in general.

The results of the study by Piotin give a clear answer to our previous question: the complication rate of stent assisted coiling is alarmingly high in a population harboring mostly unruptured aneurysms located on sites that are easily accessible for surgery while the follow-up results are comparable to results of coiling in general.

In my opinion, the use of this dangerous stent-assisted coiling should be discouraged and restricted to those cases where a stent is absolutely necessary and no alternative treatment is available. For sure, placement of a stent after successful coiling should be deterred since by placing the stent the procedure is converted from low-risk to high-risk.

Finally, we should not blame the bad handling of the device for the increased complication rate; it is always the operator who decides what materials to use. The introduction of newer stents with safer handling is not an excuse for denying disappointing results.

High Rate of Serious Complications with Stent-Assisted Coiling in Unruptured Intracranial Aneurysms: Lessons to Learn
Mauricio Castillo • Univ of North Carolina

I am Division Chief of Neuroradiology at the University of North Carolina in Chapel Hill. In addition, I am a Professor of Radiology and the current Editor-in-Chief of the American Journal of Neuroradiology. I trained in Diagnostic Radiology at the University of Miami and was a Neuroradiology fellow at Emory University.