Practical issues arising from hyper-acute carotid interventions

In Leicester, UK, rapid-access surgery for symptomatic carotid stenosis has been offered since October 2008. Ross Naylor reviews the practical lessons that have been learned with the experience. He discussed this topic at CX35 on Tuesday.

By Ross Naylor

 

When the trials randomised “recently symptomatic” patients to carotid endarterectomy or medical therapy, symptoms had to have occurred

Consequently, there has been a move towards performing surgery as soon as possible after the index event (ie treating transient ischaemic attack on a par with unstable angina). NICE advise that patients should undergo surgery

Some surgical/interventional colleagues have not actively embraced the move towards expedited intervention. For them, patients benefit from a period of stabilisation and assessment (in order to reduce procedural risk), while others believe that intervening early is associated with an unacceptably high procedural risk that may negate any benefit conferred through early intervention. The reality is, however, that the surgeon who operates within two weeks with a 10% procedural risk is still likely to prevent more strokes (in the long term) than the surgeon who defers surgery for four weeks and then operates with a 0% risk!

The Leicester Unit has offered a rapid-access surgery service since October 2008. All patients are seen in a 24/7 cerebrovascular clinic and those with 50–99% stenoses are transferred to the Vascular Unit for expedited surgery. 400+ symptomatic patients have now been treated (12%

First; it is not unusual (in the hyper-acute setting) for the duplex operator to comment that there is a critical stenosis that does not appear to open out into a normal calibre vessel. In the past (when patients were randomised some time after the index event), this might have been diagnosed as “near occlusion” (little benefit from surgery), but this is not the case in the hyper-acute setting. The diagnostic “give-away” is that high velocities are maintained across the stenosis (even if the distal lumen cannot be visualised) and CT angiography almost always shows a reconstructable vessel. In “near occlusion”, there are very low systolic velicities and little or no diastolic flow. Accordingly, corroborative imaging is mandatory (in the hyper-acute period) before recommending against urgent carotid surgery.

Second; anyone setting up this kind of service better get used to seeing recurrent events in up to 15% of patients between admission and surgery (despite being on antiplatelet and statin therapy). Up to 40% of patients referred acutely will have spontaneous embolisation on transcranial Doppler. Recurrent events (prior to surgery) were rarely encountered in the past, largely because patients were not referred so quickly.

Third; patients undergoing surgery (using general anaesthetic) with a pre-existing neurological deficit will almost always suffer a transient worsening of their deficit postoperatively. In the past, this was an indication for re-exploration. The “key” to management is how quickly the patient recovers from anaesthesia. If it is relatively quick, they will return to their pre-operative neurological status within an hour or so. Accordingly, it is important to warn recovery staff who may otherwise be alarmed at the apparent neurological deterioration.

Fourth; be prepared to adopt even more obsessive attention to surgical technique. We have found that careless skin preparation can trigger embolisation and transcranial Doppler is invaluable in warning of the embolising (unstable) patient during carotid mobilisation.

Fifth; be prepared to encounter a higher prevalence of post-endarterectomy hypertension (25% in theatre recovery, 25% back on the ward). This is usually seen in patients with poorly controlled blood pressure pre-operatively and it is essential that medical/nursing staff have guidelines for managing this condition. If you are going to treat patients in the hyper-acute period, you cannot adopt an ad hoc approach to blood pressure management, as patients will be subject to a greater risk of hyperperfusion stroke or intracranial haemorrhage.

Finally; (and contrary to what has previously been expected), our experience of operating in the hyperacute period has not been associated with a significant increase in procedural risk.

However; if you still harbour doubts about the benefit of intervening in the hyperacute period, ask yourself how you would want to be treated should you suffer a transient ischaemic attack and have a significant carotid stenosis?

Thought so! Don’t your patients deserve the same?

2015-07-11T02:23:23+00:00