Improved cerebral perfusion and metabolism after stenting for basilar artery stenosis: technical case report

Hemodynamic changes following wingspan stent placement--a quantitative magnetic resonance angiography study

BACKGROUND

Quantitative magnetic resonance angiography (QMRA) is a noninvasive imaging modality that provides anatomic and physiologic measurements of arteries. We used QMRA to assess hemodynamic changes following Wingspan stent placement for intracranial stenosis.

METHODS

We reviewed patients treated with Wingspan stents for intracranial stenosis who had baseline and follow-up QMRA data. We compared volumetric flow rates (VFRs) (mL/minute) pre- and poststenting using paired t-tests. P<.05 was considered significant.

RESULTS

Among 9 patients (mean age 65.8 years, mean 71% degree of stenosis), lesions were located in the supraclinoid internal carotid arteries in 3, middle cerebral arteries in 3, and intracranial vertebrobasilar arteries in 3. VFR and degree of stenosis were moderately correlated (r=-.670, P=.002). The mean VFR in the stenotic artery increased from 81.2 mL/minute to 133.3 mL/minute (P=.020) or by 64.2% after stenting. Total cerebral blood flow, flow in nonstented vessels, and collateral flow in circle of Willis vessels did not significantly change.

CONCLUSION

We found that QMRA is a promising noninvasive method for the measurement of cerebral hemodynamics following intracranial Wingspan stent placement. Larger prospective studies are needed to confirm our findings.

Treatment and Short-Term Follow-up of Symptomatic Atherosclerotic Intracranial Artery Stenosis by Stent-Assisted Angioplasty

SUMMARY

Atherosclerotic intracranial artery stenosis can cause hypoperfusion of brain tissues and embolus formation, causing stroke. Conservative medical treatment seemed to have little effect on the natural history and prevent the stroke attack caused by artery stenosis. The purpose of stent-assisted angioplasty is to reconstruct the damaged vessels: the indications, feasibility, effectiveness, complications and follow-up for this new treatment method are discussed. A series of 32 cases with symptomatic intracranial artery stenosis were accepted from 1998 to 2002. The mean age was 42 yrs (31 ~ 76 yr), male/female ratio=23/9. All patients were refractory to optimal medical therapy. Lesions included 12 middle cerebral arteries (37.5%), six basilar arteries (18.75%), three distal ICAs (9.38%) and 12 intracranial Vas (37.5%). All patients were treated by methods of transluminal stent-assisted angioplasty under general anesthesia. Patients were premedicated with Aspirin (300mg/per day) and Ticlopidine (250mg/per day), this was continued for six weeks after the procedure. Medical history, anamnesis, and treatment protocol were reviewed and evaluated retrospectively, shortterm follow-up (2mths ~ 1 yr) was also obtained. Primary clinical presentations were TIAs (21/32, 65.63%), minor stroke ( 8/32, 25%) and severe stroke (3/32, 9.38%). 31 cases (96.86%) were successfully implanted with coronary stents within the stenosed vessels; technical success rate was 96.86%. Instant angiographic results showed the stenosed extent had decreased from 72.36% +/- 5.69 to 10.16% +/- 6.94. One vessel ruptured during the procedure, the patient recovered after surgical repair of the ruptured vessel. Clinical follow-up demonstrated symptoms resolved in most patients (30/32, 93.75%) within the follow- up period, two cases with MCA stenosis had TIAs within two months after the procedure. 12 cases accepted angiographic follow-up.Velocities of stented vessels of five cases (5/21, 23.81%) increased compared to instant results, suggesting restenosis, three of them were confirmed by angiography which included two cases with MCA stenosis (figure 3) and one with distal VA, one of the five cases had recurred TIAs. With the newer generation of coronary stent, this technique seemed safe, feasible and effective to prevent stroke attack, but the indication is very important for the technical success. Restenosis remains a common problem as with coronary stenting. Long-term follow-up will be needed.

Elective stenting for symptomatic middle cerebral artery stenosis presenting as transient ischaemic deficits or stroke attacks: short term arteriographical and clinical outcome

BACKGROUND

Although stent assisted angioplasty is an effective treatment for coronary and peripheral arterial disease, its efficacy in intracranial arteriosclerotic disease has not been verified.

OBJECTIVES

To assess the radiographic and clinical outcome of stent assisted angioplasty for symptomatic middle cerebral artery (MCA) stenosis.

METHODS

We attempted stent assisted angioplasty in 14 patients with symptomatic high grade stenosis (>60%) on the proximal portion of the MCA, who had experienced either recurrent transient ischaemic attacks (TIAs) resistant to medical therapy or one or more stroke attacks. Patient records were analysed for angiographic characteristics, degree of stenosis, pre-procedural regimen of anti-platelet and/or anti-coagulation agents, use of devices, procedure related complications, pre-operative and post-operative single photon emission computed tomography (SPECT) findings, and clinical and radiographic outcomes.

RESULTS

Stent assisted angioplasty was successfully performed in 8 of 14 patients without any serious complications and unsuccessful in 2 of 14 patients due to the tortuous curve of the internal carotid artery siphon. Four patients had complications. Two patients had an arterial rupture; one patient was rescued by an additional stent and balloon tamponade, the other patient died. Complications in the other two patients included thrombotic occlusion and distal thrombosis. Residual stenosis was less than 50% in diameter in all the patients. All eight patients who underwent follow up cerebral angiography had no restenosis. Follow up SPECT showed improved perfusion in the affected MCA territory in all the tested patients with TIA and in one of three stroke patients. Using the modified Rankin Scale at follow up, four of five TIA patients and five of six stroke patients were assessed as functionally improved or having a stable clinical status.

CONCLUSION

Although the re-stenosis rate in stent assisted angioplasty seems to be better than in primary balloon angioplasty as reported previously, the complication rate is still high. Elective stenting is an alternative therapeutic method for the prevention of secondary ischaemic stroke in stroke patients with MCA stenosis, and seems to be a potentially effective but also hazardous therapeutic technique in patients with recurrent TIAs. This study indicates the need for randomised control trial data of this intervention. Additionally, long term follow up data and additional clinical experience are required to assess the durability of this procedure.