carotid endarterectomy, carotid stenting, cerebrovascular disease, ischemic stroke
F Aziz. Rethinking The Six Weeks Waiting Approach To Carotid Intervention After Ischemic Stroke. The Internet Journal of Surgery. 2006 Volume 11 Number 1.
Atherosclerotic disease of extracranial carotid arteries is responsible for approximately 20% to 30% of strokes in North America each year. Currently, there are two treatment modalities for treatment of symptomatic carotid artery disease: Carotid endarterectomy (CEA) and Carotid artery stenting (CAS). Timing of carotid intervention after acute stroke is controversial. This text is meant to review literature on this controversial issue. Initially it was thought that any carotid intervention should not be done within six weeks after the onset of acute stroke, however newer data shows the risk of postoperative intracranial hemorrhage depends on the type of initial neurological defect, vascular territory of the stroke, infarct size, degree of midline shift on CT and the level of consciousness. We conclude that in appropriately selected patients, carotid intervention should be done as soon as possible after acute stroke.
Atherosclerotic disease of extracranial carotid arteries is responsible for approximately 20% to 30% of strokes in North America each year. Currently, there are two treatment modalities for treatment of symptomatic carotid artery disease: Carotid endarterectomy (CEA) and Carotid artery stenting (CAS). Timing of carotid intervention after acute stroke is controversial. We will review literature on both of these treatment modalities and timing of treatment after acute stroke. The first successful CEA was performed by DeBakey in 1953. Currently, approximately 200.000 carotid endarterectomies are done in the US per year. CAS was first performed in 1994. Both single-center reports1 and worldwide surveys2 of CAS have demonstrated results approaching those of endarterectomy, typically in high-risk patients with significant comorbidities excluded from previous surgical trials3.
After carotid intervention has restored a normal carotid bifurcation lumen and normal blood flow, hyperperfusion will occur in the ipsilateral hemisphere until resistance vessels regain their ability to constrict and autoregulation is reestablished4. Post operative ipsilateral hyperperfusion can last as long as 11 days after endarterecomy. Because of the poor results of CEA in 1960, and reports of deaths from post operative intracranial hemorrhage5, there has been a fear that early CEA after stroke might convert a non hemorrhagic stroke into a hemorrhagic stroke or increase the size of infarcted area. So an arbitrary time period of six weeks after stroke was chosen to be the optimal time for surgery, although there has been no scientific evidence to prove this myth.
Retrospectively, patients who developed postoperative intracranial hemorrhage had several features in common. They had high-grade carotid stenosis, and hypoperfusion based on physiologic measurements. Postoperatively, they had ipsilateral increased cerebral flow7.
Incidence of post operative intracerbral hemorrhage ranges from 0.3% to 1.2%8. The risk factors include postoperative hypertension, history of previous cerebral infarction and postoperative anticoagulation9.
Literature Against Early CEA After Stroke
The first study which reported cerebral hemorrhage after CEA was a retrospective study of 900 patients who underwent CEA. Six patients had post operative cerebral hemorrhage, five out of these six had surgery between 2 and hours after angiography. All had this complication at 3 to 6 days after surgery. All vessels were patent postoperatively. The study concluded that the patients with recent cerebral infarction should wait for at least 1-2 weeks before they can safely undergo CEA.5
Literature In Favor Of Early CEA After Stroke
Litrature Agianst Early Carotid Artery Stenting
CAS is a newer modality as compared to CEA. There has been one retrospective study, including 39 patients who had CAS after a mean time of 55 +/- 34 hours. Degree of carotid artery stenosis was 86 +/- 11%. In 37 procedures, complete recanalization was achieved, and in 2 procedures the residual stenosis was mild. Minor disabling stroke was reported in 2 patients and death subsequent to intracranial hemorrhage in 1 patient. The study concluded that CAS is safe after acute ischemic stroke if infarction volume is small and neurological deficit is mild23.
Literature In Favor Of Carotid Artery Stenting
Trials Comparing CEA & CAS
As discussed above, the recent literature supports the role of carotid intervention in the early phase after an acute stroke. Given that currently we have both CEA and CAS available as intervention in acute stroke, the question remains as to what is the best option after early stroke. CEA has been in practice for over 50 years now, and CAS is a relatively newer technique. Level I evidence supports CEA as the standard treatment of severe asymptomatic and symptomatic carotid stenosis.
The CAVATAS Trial28 (Endovascular versus surgical treatment in patients with carotid stenosis in the Carotid And Vertebral Artery Transluminal Angioplasty Study) was a randomized prospective trial which showed that rates of major outcome events within 30 days of first treatment did not differ significantly between endovascular treatment and surgery (6.4% vs 5.9%). The median delay from randomization to treatment was 20 days in patients assigned to endovascular treatment and 27 days (14-41) in patients allocated to the surgical group. However, the time period between the diagnosis and the treatment was not mentioned.
CA-RESS84 (Carotid Artery Revascularization using Endarterecomy or Stenting Systems) is a multicenter prospective nonrandomized trial, which showed no significant differences in combined death/stroke rates at 30 days (3.6% CEA vs. 2.1% CAS) or at 1 year (13.6% CEA vs. 10% CAS). However the time period between the onset of stroke and the treatment was not mentioned.
Currently, SAPPHIRE trial (Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy) showed results that only 5.8% of the stent patients had strokes compared to 7.7% of those who had surgery. The risk of myocardial infarction was 2.5% in the stent patients versus 8.1% of those who had surgery. The mortality rate was 7% for the stent patients at one year compared to 12.9% for the surgery patients.
Patients with a stroke who are candidates for carotid intervention represent a heterogenous group, and the risk of postoperative intracranial hemorrhage depends on the type of initial neurological defect, vascular territory of the stroke, infarct size, degree of midline shift on CT and the level of consciousness24.
Level of consciousness in stroke patients may be an independent predictor of the risk of hemorrhagic transfusion. Mortality is twice as great in patients with a depressed level of consciousness who had an operation within 13 days compared with those who underwent surgery after an interval of 2 weeks. 11
Patients with a stable, acute stroke (neurological deficit lasting >24 hours), a normal CT scan, and a normal level of consciousness can probably undergo CEA shortly after the diagnosis is made and evaluation is complete. In this instance, the risk of stroke would seem to approximate that of patients who have suffered a TIA 26
Patients with a low density on CT without significant shift, a stable neurological deficit, and a normal level of consciousness have been reported to safely undergo early surgery with low risk27
Based on the data presented above, we conclude that every patient with acute stroke should be individulized on the basis of age, CT scan findings (absence or presence of midline shift, focal hypodensity), history of prior CEA or CAS. An expert opinion should be formed with the contribution from neurologist, vascular surgeon and interventional radiologist. High risk patients should be treated with urgent CAS after the correction of the coagulation cascade. Low risk patients should undergo carotid endarterctomy as soon as possible, because the patency rates after CEA are better than those of CAS.
Faisal Aziz, M.D. Department of Surgery New York Medical College Munger Pavilion, Suite 211 Valhalla, NY 10595 Tel. (914) 594-3241 Fax. (914) 594-4359 E-mail: firstname.lastname@example.org