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Page 2 of 9 Abdelhaliem et al. Vessel Plus 2020;4:31 I http://dx.doi.org/10.20517/2574-1209.2020.13

Pulsatile forms of tinnitus are the rarer manifestation of this condition, where the ringing symptoms
[3]
experienced are associated with the vascular system . Carotid stenosis is generally accepted as the most
[3]
common cause of arterial pulsatile tinnitus .
In current vascular surgery practice, tinnitus is very much correlated with the presence of distorted
extracranial or intracranial blood vessels or to the presence of intracranial hypertension. Therefore,
precluding an abnormally functioning auditory system. The heartbeat synchronous tinnitus is as we
know a predominantly vascular pathology in origin and by in large can be diagnosed by different forms
of angiography, including classical intravenous or intra-arterial angiography, computed tomography
angiography, or more commonly magnetic resonance angiography.

Pulsatile tinnitus is typically subdivided into arterial heartbeat synchronous or venous “hum-like”
[4]
pulsatile tinnitus . It has been referred to as objective tinnitus. These perceived pulsations are most likely
transmitted through the cerebrospinal fluid to the cochlea; a mechanism similar to what has been proposed
[5,6]
as an explanation for bone conduction .

Carotid artery atherosclerotic disease has been widely linked to tinnitus; however, reports emerging on
stenotic subclavian, external carotid artery and reversal of blood flow in an aberrant occipital artery have
[7-9]
also been implicated in the causality of pulsatile tinnitus . The impact of flow disturbances in the carotid
arteries on the inner ear has not yet been investigated thoroughly, and reports are very much limited by
single-centre biased reporting. Direct meaning from such experiences has not been sufficient to bridge
the gap in evidence in the literature. As the population is ageing, the standard techniques of audiology
and oto-neurological testing is also a challenge to conduct in elderly populations, particularly in those
with dementia. This coupled with a general absence of public awareness has not led to the introduction of
generalised therapeutic interventions. These factors are likely to exacerbate the current health economic
turmoil associated with the clinical care of this condition due to the surge of referrals to oto-neurological
clinics and vascular surgery practices.

From a vascular surgery perspective and standpoint, carotid artery stenosis as a pre-existing cause
for pulsatile tinnitus can be corrected with dilation and stenting or carotid endarterectomy [10,11] . Such
intervention is believed to abolish the turbulent flow and ameliorate the clinical presentation allowing
for a reasonable patient-related quality of life. However, it is currently unclear what clinical practice to
implement due to the lack of clear evidence of best practice published in the literature. For example,
ipsilateral carotid endarterectomy has been shown to effectively reduce if not eliminate pulsatile tinnitus
[12]
in greater than 90% of patients with demonstrated intracranial carotid artery stenosis . However, it is
imperative to draw a meaningful conclusion from reported experiences and to be able to draw indications
on when endarterectomy is to be favoured over the rather quantified approach of stenting. The location of
the lesion is no longer sufficient to deduce the best applicable practice and more up to date guidelines are
required for treating this disease.

This wide evidence-based literature review aims to describe the current understanding of the natural
history and pathology of this condition in respect to carotid artery disease, as well as to compare the
current therapeutic, clinical and surgical interventions utilised to allow clinicians and patients to make
a well-informed decision in regard to their management plan. We also aim to outline the gap in existing
evidence pertaining to this entity and to reflect on potentially different focuses for furthering evidence-
based practice in this field.

IS THERE A PHANTOM PERCEPTION BETWEEN CAROTID ARTERY DISEASE AND TINNITUS?
Carotid artery stenosis may be asymptomatic or have subtle neurological presentation albeit of motor
or sensory origin. Therefore, identifying a clinically significant carotid artery stenosis can be difficult to