Size Matters! Stent-Length Is Associated With Thrombembolic Complications After Carotid Artery Stenting
To the Editor:
We examined the article by Schillinger et al,1 in which the authors describe the results of a multicenter registry investigating the potential effect of open- versus closed-cell design stents on periprocedural complications after carotid artery stenting (CAS). In contrast to a previously published study,2 they found no association between stent design and the 30-day combined rate of transient ischemic attack, stroke and death.
Aside from the stent design (ie, open-cell versus closed-cell) the length of the stent might be an additional factor associated with outcome after CAS. While the length of a stenosis has already been identified as a major risk factor for thromboembolic complications after CAS,3–5 the choice of an adequately sized stent will not only depend on the length of the stenosis, but also on other variables including the tortuosity of the target vessel or the distance of the stenosis from the carotid bifurcation. The stent length could therefore become a useful overall risk marker for CAS, reflecting the length of the lesion, as well as the technical complexity of the procedure. To address this issue, we retrospectively analyzed our updated prospectively evaluated single-center experience of CAS6 and primarily focused on the impact of stent length (20, 30 and 40 mm) on the combined 30 day minor-, major-stroke and death-rate. In addition, if complete data were available, we used the appearance of new diffusion-weighted imaging (DWI) lesions in patients who received pre- and postinterventional DWI7 as a second outcome parameter. The study population comprised 276 patients (male: 74.6%; mean age: 69.1±9.0 years; symptomatic stenosis: 56.5%) with completed clinical follow-up. Of those, 170 patients (male: 77.6%; mean age: 69.5±9.0 years; symptomatic stenosis: 56.5%) also completed pre- and postprocedural DWI. In all patients only 2 different types of open-cell designed stents were used (Precise and Smart-Stents, Fa. Cordis). Patients who received a stent of 20 mm (n=60), 30 mm (n=121) or 40 mm (n=95) length had a clinical periprocedural stroke and death-rate of 3.3%, 5.0% and 8.4%, respectively (P for linear trend=0.17). Postprocedural new DWI lesions (20 mm: n=35; 30 mm: n=74; 40 mm: n=61) occurred significantly more often with the increase of stent-length (45.7%, 67.6% and 78.7%; P for linear trend <0.01; see the Figure). The type of the open-cell–designed stents had no influence on the clinical or imaging outcome parameters.
The length of the stent used for CAS shows a clear association with the appearance of new postprocedural DWI lesions. However, within our analysis, clinical outcome parameters were not significantly associated with stent-length, which is likely related to the relatively small number of patients and clinical outcome events.
Maybe, Schillinger et al could use their large database to address this important issue.
Schillinger M, Gschwendtner M, Reimers B, Trenkler J, Stockx L, Mair J, Macdonald S, Karnel F, Huber K, Minar E. Does carotid stent cell design matter? Stroke. 2008; 39: 905–909.
Mathur A, Roubin GS, Iyer SS, Piamsonboon C, Liu MW, Gomez CR, Yadav JS, Chastain HD, Fox LM, Dean LS, Vitek JJ. Predictors of stroke complicating carotid artery stenting. Circulation. 1998; 97: 1239–1245.
Kastrup A, Gröschel K, Schulz JB, Nägele T, Ernemann U. Clinical predictors of transient ischemic attack, stroke, or death within 30 days of carotid angioplasty and stenting. Stroke. 2005; 36: 787–791.
Kastrup A, Nägele T, Gröschel K, Schmidt F, Vogler E, Schulz J, Ernemann. Incidence of new brain lesions after carotid stenting with and without cerebral protection. Stroke. 2006; 37: 2312–2316.