Safety and cost of stent-assisted coiling of unruptured intracranial aneurysms compared to coiling or clipping

Jennifer A Frontera

By Jennifer A Frontera

Stent-assisted coiling has evolved as an aneurysm treatment option for patients with large, side-wall or wide-neck aneurysms. Although stent-assisted coiling has been associated with lower angiographic recurrence rates than coiling alone for anatomically challenging aneurysms, high complications rates have been published. One study reported permanent neurological complications in 7.4% and procedure related mortality in 4.6% of patients, which was significantly higher than for those treated with coiling alone.(1) An editorial following this study commented on an “alarmingly high serious complication rate of stent-assisted coiling” in this cohort of largely unruptured aneurysms with a benign natural history.(2)

Recently, we explored the safety and cost of stent-assisted coiling vs. coiling or clipping of unruptured aneurysms.(3) We reviewed 116 patients who underwent stent-assisted coiling, coiling or clipping from 2003 to 2010, and compared the complications, length of stay, discharge disposition, cost, and rates of residual aneurysm, recanalisation and retreatment at six to 12 months. Stent-assisted coiling was performed in 47 (41%) patients, coiling in 36 (31%) and clipping in 33 (28%). Groups were well matched for age, gender, and aneurysm location, but aneurysm size and neck size were significantly larger in stent-assisted coiling patients. Periprocedure aneurysm rupture occurred in one clipped patient (3%) and one stent-assisted coiling patient (2%), (p=0.816).  Asymptomatic angiographic complications occurred in two stent-assisted coiling patients (4%) including carotid dissection related to deployment of a stent and thrombus formation on a coil mass.

Symptomatic complications occurred in two (6%) clipped patients (peri-procedure aneurysm rupture and procedure related stroke) and one (2%) stent-assisted coiling patient (periprocedure rupture). Overall, complication rates did not vary between groups (p=0.387 for any complication across all three groups).  Length of stay and good discharge disposition (discharged home, home with a health aid or to acute rehabilitation) were significantly better in stent-assisted coiling and coiled patients, compared to clipped patients. Based on these data, stent-assisted coiling appeared to be safe in this cohort compared to coiling or clipping.

However, stent-assisted coiling comes at a cost. We examined hospitalisation costs, which typically comprise over 85% of costs related to aneurysm repair and 12-month follow-up, according to some studies.(4, 5) After adjustment for inflation, overall direct cost (a sum of hospital costs related to patient care) and overhead (a sum of costs related to the overall operation of the hospital, not directly related to patient care) were significantly higher in the stent-assisted coiling group compared to the coiled or clipped groups. Median direct cost for stent-assisted coiling was US$22,544 vs. US$12,933 for coiling and US$14,656 for clipping, (p=0.001). The largest component contributing to higher overall direct cost was angiographic cost. Patients who underwent stent-assisted coiling had larger aneurysms and therefore significantly more coils (median 7 vs. 4.5 in the coiling group) and significantly more expense for these coils (US$7983), compared to the coiling alone group (US$5,385). The cost of the stent itself ranged from approximately US$5,200 (Enterprise stent, Codman) to US$5,315 (Neuroform stent, Stryker). Stent-assisted coiling patients also required more staged treatments than coiled or clipped patients. Though there was no statistically significant difference, the total direct cost for two-stage treatment was US$34,262 compared to US$18,462 for single stage treatment (p=0.160). Similarly, treatment of larger aneurysms (>10mm) incurred higher overall direct costs than repair of aneurysms ≤10mm, (p=0.241).  Nonetheless, even after adjusting for aneurysm and neck size and retreatment, stent-assisted coiling was still significantly more expensive than clipping or coiling.

Overhead was also higher for stent-assisted coiling patients, which may reflect longer procedure time, longer anaesthesia time, higher staffing needs and higher facilities costs. The location where procedures are performed (ie. operating room vs. angiography suite) may also contribute to differences in overhead. The costs of performing an endovascular procedure in a bi-plane operating room vs. angiography suite may vary from institution to institution based on the types of staff that are required for each location (ie. scrub nurses, nurse anaesthetists, anaesthesiologists), the time required to perform a procedure in each location, and unmeasured costs or savings, such as the impact on the volume of other non-vascular procedures that may be performed if the operating room or radiology suite was not being occupied for an aneurysm repair procedure. Additionally, centres that routinely perform combined surgery and angiography procedures (ie. aneurysm clipping followed immediately by post clipping angiography) may see particular cost savings for a bi-plane operating room.

Despite the increased expense, stent-assisted coiling is a reasonable and safe therapeutic option. Indeed, for certain aneurysm locations and morphologies, and in high surgical risk patients, it may be the only reasonable option. Lower coil and stent costs over time may allow stent-assisted coiling to become a more affordable treatment strategy.

Jennifer A Frontera is an associate professor of Neurosurgery and Neurology at The Cleveland Clinic, Cleveland, USA


1. Piotin M, Blanc R, Spelle L, Mounayer C, Piantino R, Schmidt PJ, et al. Stent-assisted coiling of intracranial aneurysms: clinical and angiographic results in 216 consecutive aneurysms. Stroke; 2010 Jan;41(1):110-5. PubMed PMID: 19959540.

2. van Rooij WJ, Sluzewski M, Peluso JP. Alarmingly high serious complication rate of stent-assisted coiling in unruptured intracranial aneurysms: the need for reflection and reconsideration. Stroke. 2010 Apr;41(4):e191; author reply e2. PubMed PMID: 20167906. Epub 2010/02/20. eng.

3. Frontera JA, Moatti J, de Los Reyes KM, McCullough S, Moyle H, Bederson JB, et al. Safety and cost of stent-assisted coiling of unruptured intracranial aneurysms compared with coiling or clipping. Journal of Neurointerventional Surgery. 2012 Dec 7. PubMed PMID: 23223396.

4. Roos YB, Dijkgraaf MG, Albrecht KW, Beenen LF, Groen RJ, de Haan RJ, et al. Direct costs of modern treatment of aneurysmal subarachnoid hemorrhage in the first year after diagnosis. Stroke; 2002 Jun;33(6):1595-9. PubMed PMID: 12052997.

5. Wolstenholme J, Rivero-Arias O, Gray A, Molyneux AJ, Kerr RS, Yarnold JA, et al. Treatment pathways, resource use, and costs of endovascular coiling versus surgical clipping after aSAH. Stroke; 2008 Jan;39(1):111-9. PubMed PMID: 18048858.