Long-term outcome of endovascular stenting for symptomatic basilar artery stenosis

Although different types of coronary stents and balloon angioplasty with a nominal pressure of 8 to 14 atm were used in this case series, there was no correlation between types of balloon or stents and periprocedural complications. Fifteen patients received IV heparin for 24 hrs followed by combination therapy with clopidogrel and aspirin. Three patients were placed on oral anticoagulants for 6 months and long-term clopidogrel therapy. Lesions were crossed using 0.014-in microwire instead of 0.035-in microwire as Zaidat noted. We appreciate the identification of this error in our article.

Presenting TIAs, individual patient medications, length-of-stay and neurointensive care management after the procedures were not found to be associated with long-term outcome and therefore not detailed in our article. Our figure was used to show the feasibility of stenting for different types of stenotic lesions. The left anterior inferior cerebellar artery (AICA) in case B was visible distal to the vertebrobasilar junction in the post-stenting image.

Zaidat et al might have misidentified the loop between basilar artery and left AICA in the pre-stenting image as AICA. The loop was actually part of the left posterior inferior cerebellar artery. Consistent with other report, [2] our study also demonstrated that symptomatic occlusion of pontine perforating arteries were very uncommon. During follow-up, five patients reported transient symptoms, including dizziness (2), sensation of head congestion (1), neck pain (1) and hand incoordination (1).

It is well known that patients often experience non-specific symptoms after endovascular procedures that are not TIAs. We identified no basilar artery stenting failure in our study, confirming other series reporting more than 95% success rate of stenting for basilar artery stenosis and other intracranial atherosclerotic lesions. [2-4]

Despite the limitations in retrospective study, our data showed that with a mean 26.7 ± 12.1-month follow-up, 83.3% of patients had an excellent long-term outcome without vascular death. Therefore, endovascular stenting for symptomatic basilar artery stenosis appeared to be safe and effective in reducing stroke risk and death, and should be further evaluated by randomized clinical trial.

References

1. Yu W, Smith WS, Singh V, et al. Long-term outcome of endovascular stenting for symptomatic basilar artery stenosis. Neurology 2005;64:1055-1057.

2. Gomez CR, Misra VK, Liu MW, et al. Elective stenting of symptomatic basilar artery stenosis. Stroke 2000;31:95-99.

3. SSYLVIA Study Investigators. Stenting of Symptomatic Atherosclerotic Lesions in the Vertebral or Intracranial Arteries (SSYLVIA): study results. Stroke 2004;35:1388-92.

4. Jiang WJ, Wang YJ, Du B, et al. Stenting of symptomatic M1 stenosis of middle cerebral artery: An initial experience of 40 patients. Stroke 2004;35:1375-80.

The method section inaccurately described the type of wire used to cross the lesion. It is unlikely that high-grade stenosis would be crossed using 0.035-in wire instead of the standard 0.014-in microwire. The balloon types that are used for pre-dilatation and the specific coronary stent types are known to affect procedural outcome but were not mentioned. Under, over, or nominal inflation of the stent-mounted balloon were not described. It is unclear how long heparin was administered or the combination of clopidogrel and aspirin following the procedure.

Prior to stenting, there was no description of the presenting TIAs. Two patients were not treated with any type of medical therapy but there are no details about the type of antiplatelet treatment in the others. After the procedure, there is no mention of in-hospital length-of-stay after the procedures or worsening of pre-existing deficits and TIAs. Some patients may require neurocritical care for several days with blood pressure and fluid augmentation to maintain adequate cerebral perfusion.

In the legends of the selected images, there was no mention of jailing perforating arteries; including loss of the left anterior inferior cerebellar artery in case B. In the long-term outcome, five cases with "dizzy spells" were not counted as possible vertigo or TIAs.

In the Discussion section, the authors conclude that the BA stenting appeared to be safe and effective. This study has many limitations to validate this conclusion. The cases where BA stenting failed are not mentioned which makes it difficult to interpret the success of current techniques.

We agree with the authors that further trials are needed to better evaluate this controversial subject. However, prior to further studies (involving the BA in particular), newer stents and delivery systems designed for intracranial arteries are needed. This is vital to avoid future setbacks in neurointerventional procedures. Given the current available data and techniques, BA stenting may be reserved for those patients with high-grade symptomatic stenosis who did not respond to combined aspirin and clopidogrel therapy.

References

1. Yu W, Smith WS, Singh V, et al. Long-term outcome of endovascular stenting for symptomatic basilar artery stenosis. Neurology 2005;64:1055-1057.