The Vascular Society and Royal College of Physicians assessed NHS carotid endarterectomies performed from October 2009 to September 2010.
Compared with previous years' audits, they found some evidence of improved performance against national standards.
In addition, information collection rates rose - 79 per cent of possible data was collected as part of the latest audit. However, some hospitals failed to provide any data and the audit found significant regional variations in care.
Only 40 per cent of patients received surgery within NICE's two-week time limit from symptom onset and just 2 per cent received surgery within the 24-hour target.
Consultant vascular surgeon Mr David Mitchell, who led the audit, said: 'Despite the good work by many clinicians, this study shows that we have a long way to go if we are to meet current NICE guidance of getting 100 per cent of patients who need surgery into the operating theatre within 14 days of symptoms.'
He added: 'Fast referral to TIA clinics where staff can identify those at high risk of stroke, begin treatment and rapidly refer to the nearest vascular surgery unit for surgery, is absolutely vital in preventing needless strokes and deaths.'