Commentary: Multiple small branch retinal arteriolar occlusions following coil embolization of internal carotid artery aneurysm.

Sir,

I have gone through the article titled “Multiple small branch retinal arteriolar occlusions following coil embolization of internal carotid artery aneurysm.”[1]

The detachable coil system, now is a well-established innovative technology for the management of both the ruptured and unruptured cerebral aneurysm.[2] This is because the coil can be repositioned repeatedly until it is appropriately placed within the aneurysm sac. However, once the coil is detached the operator can no longer control it.

Hence, the two coil technique can be used as a technical variation of multiple microcatheter technique for non-assisted coiling of small aneurysm.[2] This will ensure that the coil will not detach till the end of the procedure. Although, thromboembolic complications are described in clinical reports of retinal infarcts following coil embolization, they are rare.[2] This may be due to subtle platelets or due to fibrin emboli.

The procedure may be accomplished with stent-assisted coiling that predominantly utilizes Cerecyte coils. The procedure might include heparinization, which would need Plavex to be administered 7 days before the surgery and post-operative too.

It may be a polyvinyl alcohol (PVA) embolism causing occlusion as some particles may be present in the catheter even after flushing with saline.[3] Commonly found in arteriosclerotic subjects, it may not be possible to completely remove all the particles from the microcatheter.

Post-operative embolism can be prevented by:

Microcatheter used for injecting emboli may be removed and a new microcatheter should be used to perform post-embolization arteriographic study[4]

Contrast dye should be injected through large guiding catheter instead of microcatheter. This will avoid manipulation which will in turn prevent any injury[5]

Blood clots can form inside the guiding catheter, on the coils or in the parent vessels. This can be avoided by giving anti-platelet medicines

Aneurysm rupture may be avoided by guidewire on coil.

It can be concluded that mean rate of embolization per carotid artery stenting (CAS) procedure has been reported as 74 particles per stenotic lesion. This causes retinal damage. This is because an increased quantity of embolus that is flushed to inter-cranial vessels in CAS. Hence the correlation between retinal artery embolism and inter-cranial vascular embolism should be monitored with regards to monitoring of patients following CAS.

Ophthalmic evaluation is important following CAS due to possibility of embolism retinal artery. Patient should be advised of the risk of permanent visual morbidity and require very close periodic monitoring of visual status in terms of visual acuity, pupillary reaction, fundus examination, visual fields, and angiography if required to diagnose the ailment with in time. It is better to prevent thromboembolic complications by proper hematological investigations and pre-operative evaluation, for event-free surgery. Post-operative vigilance is also important to take care.