Extracranial–intracranial bypass in atherosclerotic cerebrovascular disease: report of a single centre experience

Abstract

Despite the failure of the international extracranial–intracranial (EC–IC) bypass study in showing the benefit of bypass procedure for prevention of stroke recurrence, it has been regarded to be beneficial in a subgroup of well-selected patients with haemodynamic impairment. This report includes the EC–IC bypass experience of a single centre over a period of 14 years. All consecutive 72 patients with atherosclerotic occlusive cerebrovascular lesions associated with haemodynamic compromise treated by EC–IC bypass surgery were retrospectively reviewed. Pre-operatively, 61% of patients presented with minor stroke and the remaining 39% with recurrent transient ischemic attacks (TIAs) despite maximal medical therapy. Angiography revealed a unilateral internal carotid artery (ICA) stenosis/occlusion in 79%, bilateral ICA stenosis/occlusion in 15%, MCA stenosis/occlusion in 3% and other multiple vessel stenosis/occlusion in 3% of the cases. H₂¹⁵O positron emission tomography (PET) or 99mTc-HMPAO SPECT with acetazolamide challenge was performed for haemodynamic evaluation of the cerebral blood flow (CBF). All the patients had impaired haemodynamics pre-operatively in terms of reduced regional cerebrovascular reserve capacity and rCBF. Standard STA-MCA bypass procedure was performed in all patients. A total of 68 patients with 82 bypasses were reviewed with a mean follow-up period of 34 months. Stroke recurrence took place in 10 patients (15%) resulting in an annual stroke risk of 5%. Improved cerebral haemodynamics was documented in 81% of revascularised hemispheres. Patients with unchanged or worse haemodynamic parameters had significantly more post-operative TIAs or strokes when compared to those with improved perfusion reserves (30% vs.5% of patients, p < 0.05). In conclusion, EC–IC bypass procedure in selected patients with occlusive cerebrovascular lesions associated with haemodynamic impairment has revealed to be effective for prevention of further cerebral ischemia, when compared with a stroke risk rate of 15% reported to date in patients only under antiplatelet agents or anticoagulant therapy.

Key words:

• EC–IC bypass
• carotid occlusion
• haemodynamic compromise
• H₂¹⁵O PET
• stroke prevention

Acknowledgements

Authors thank Professor H.-G. Imhof, professor emeritus University of Zurich, for the collaborative contribution.

Declaration of interest:

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.