Extracranial to intracranial bypass for intracranial atherosclerosis

In a randomised controlled trial (RCT; n=1,377) comparing 663 patients who had extracranial to intracranial (EC‑IC) bypass with 714 patients who had medical treatment only, the rate of cerebral and retinal ischaemic events was higher in the EC‑IC-bypass group (12% [81/663]) than in the medical group (3% [24/714]) within 30 days of surgery (or 39 days of randomisation for the medical group), no p value reported. The same RCT reported a higher rate of major stroke, defined as an 'inability to function without assistance', in the group who had EC‑IC bypass (3% [20/663]) compared with the medical-treatment-only group (1% [9/714]), within 30 days of surgery or 39 days of randomisation, p value not reported. A case series of 876 patients with occlusive cerebrovascular disease reported no statistically significant difference in the rate of post-procedure stroke in asymptomatic patients who had EC‑IC bypass (2% [2/123]) when compared with asymptomatic patients who had intracranial stenting (4% [10/243], p=0.341). The same case series reported a statistically significantly higher rate of post-procedure stroke in symptomatic patients who had EC-IC bypass (25% [32/126]) than in symptomatic patients who had intracranial stenting (10% [40/384], p<0.001).

In the case series of 876 patients with occlusive cerebrovascular disease, asymptomatic patients were no more likely to be transferred to another care facility, rather than home, if they had EC‑IC bypass (16% [19/121]) when compared with patients who had intracranial stenting (9% [21/237], p=0.08). Symptomatic patients were statistically significantly more likely to be transferred to another care facility, rather than home, if they had EC‑IC bypass (66% [80/121]) when compared with patients who had intracranial stenting (53% [180/338], p=0.08). In a case series of 415 patients who had EC‑IC bypass, destination at discharge for patients with post-procedure stroke was home (59% [41/69]), short-term facility (25% [17/69]) and long-term facility (9% [6/69]).

The following adverse events were reported in the RCT of 195 patients who had EC‑IC bypass: epidural or subdural haematoma (2% [2/97]), seizures (2% [2/97]), respiratory disorder (1% [1/97]), hypotension (1% [1/97]), and wound infection (1% [1/97]). The following adverse events happened to the same patient (1% [1/97]): deep vein thrombosis, atrial flutter, cardiac tamponade and pulmonary embolus. Haemorrhage, haematoma complicating the procedure, hydrocephalus, ventriculostomy, mechanical ventilation, deep vein thrombosis, pulmonary embolism and placement of an inferior vena cava filter were reported in the case series of 415 patients who had EC‑IC bypass (no frequencies were reported).

Reperfusion injury with cerebral oedema was reported in 1 patient in a case series of 85 patients who had EC‑IC bypass.

Temporary dysesthesia on the graft harvest site (1/13) and haematoma at the graft harvest site (1/13) was reported in a case series of 13 patients who had EC‑IC bypass.

As well as safety outcomes reported in the literature, specialist advisers are asked about anecdotal adverse events (events which they have heard about) and about theoretical adverse events (events which they think might possibly happen, even if they have never done so). For this procedure, specialist advisers listed no anecdotal adverse events. They did not identify any theoretical adverse events that had not previously been reported.