***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: One completed randomised trial was found. In one subgroup of this trial, 16 patients with symptomatic severe vertebral artery stenosis were randomised to endovascular treatment (eight patients) or medical treatment alone (eight patients). There were no strokes in any arterial territory or deaths from any cause in either group within 30 days of treatment (endovascular group) or 30 days of randomisation (medical group). In the endovascular group, two patients had a posterior circulation transient ischaemic attack at the time of the procedure. In the endovascular group, the mean vessel stenosis at follow up was 47% (range 0% to 80%). Patients were followed up for a mean of 4.5 years in the endovascular group and 4.9 years in the medical group. There were no further vertebrobasilar territory strokes in either group for the duration of follow up. Morbidity and mortality was related to carotid and coronary artery disease in this study. There is currently insufficient evidence to assess the effects of percutaneous transluminal angioplasty with or without stenting or primary stenting for vertebral artery stenosis.
Output:

This review found results from one arm of a trial only involving a very small number of patients. The results suggest that endovascular treatment can be carried out with a high degree of technical success at the time of treatment but there is insufficient evidence to determine whether the risk benefit ratio favours endovascular intervention over conservative management. Randomised trials need to be designed to determine whether the endovascular treatment is more successful than conservative treatment at reducing the long term risk of stroke or death.