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Long-term evaluation of EC-IC bypass patency
U Schick1, M Zimmermann, D Stolke
1Department of Neurological Surgery, University Hospital GHS Essen, Federal Republic of Germany.
Insights
Extracranial-intracranial (EC-IC) bypass surgery offers limited long-term stroke prevention benefits. While some patients show improvement, bypass graft patency declines over time, suggesting limited utility.
Area of Science:
- Neurosurgery
- Vascular Surgery
- Neurology
Background:
- Extracranial-intracranial (EC-IC) bypass surgery was re-evaluated for specific stroke prevention cases.
- Previous studies, like the EC-IC Bypass Study Group in 1985, showed no clear surgical benefit.
- Recurrent focal cerebral ischemia with impaired hemodynamics prompted re-evaluation of surgical revascularization.
Purpose of the Study:
- To examine the long-term benefits and patency rates of EC-IC bypass surgery.
- To assess the efficacy of bypass surgery in patients with recurrent ischemic events due to carotid artery occlusion.
Main Methods:
- Retrospective study of 47 patients undergoing EC-IC bypass after 1985.
- Follow-up averaged 5.6 years, assessing neurological status, TCD, angiography, CT, and SPECT.
- Analysis included patency rates of vein grafts and STA-MCA procedures.
Main Results:
- Neurological improvement seen in 23% of patients; early surgery yielded better results.
- 22% experienced worsening with further ischemic events.
- Vein graft patency was 50%, STA-MCA procedure patency was 91%; graft occlusion occurred over time.
Conclusions:
- EC-IC bypass provides limited long-term benefit for stroke prevention.
- Bypass graft function deteriorates, suggesting primary benefit within the first year post-ischemia.
- Indications may include patients with maximal medical therapy failure, progressive ischemia, and hemodynamic compromise.
Abstract:
The EC-IC Bypass Study Group could not detect any benefit from surgery compared to medical management in the prevention of stroke in 1985 [15]. During the past years surgical revascularization was re-evaluated and considered as an appropriate treatment for a small subgroup of patients with recurrent focal cerebral ischaemia and impaired haemodynamics. This retrospective study examines the long-term benefit and patency rate of bypass. We present a follow-up of 5.6 years of 47 patients, all of whom underwent bypass surgery after 1985. Forty patients suffered recurring transient ischaemic attacks due to uni- or bilateral internal carotid artery occlusion. Examination included neurologic status, TCD with CO2 or Diamox challenge, angiography, CT and SPECT scans. Neurological improvement was seen in 23% of patients with better results after early surgery, a worsening in 22% suffering further ischaemic events on a postoperative average of 2.8 years. Patency rate for vein graft material was 50%, for the STA-MCA procedure 91%. Occlusion of the vein graft occurred on an average after 1.4 years, other anastomosis after 2.7 years. We conclude that only few patients derived long-term benefit from EC-IC bypasses. Functioning of the bypass worsens over time, suggesting a role for surgery predominantly in the first year of ischaemic events due to insufficient collateral supply. Actual indications for bypass surgery may be patients with failure of maximal medical therapy and progressive ischaemia and haemodynamic compromise.