Previous studies have provided limited data
supporting the association between retinal
microvasculature changes and CAD. In one such study,
Tabatabaee et al.[
3] demonstrated a strong correlation
between retinal arterial atherosclerosis and the extent
and severity of CAD using fundus photography. In
addition, Wong et al.[
11] confirmed the link between
retinal arteriolar narrowing and the development
of CAD by measuring the diameters of individual
arterioles and venules on retinal photographs.
Arnould et al.[10] carried out a study where
they compared the superficial retinal layer (SRL)
vascular length (VL) of 44 healthy individuals to
that of 237 patients who had been hospitalized
for acute coronary syndrome. They found that
in the parafoveal zone (excluding the central
fovea), there was a significant decrease in SRL VL after matching 44 healthy individuals with
44 hospitalized patients.[10,12] The study established
a connection between the retinal microvascular
features and the cardiovascular risk profile of
hospitalized patients. Patients with a lower VL were
generally older and had a higher incidence of high
blood pressure and diabetes mellitus. They also had
a lower left ventricular ejection fraction and worse
biological parameters, such as higher blood glucose,
glycated hemoglobin A1c (HbA1c), creatinine, and
N-terminal probrain natriuretic peptide. The study
also identified two independent parameters, namely
left ventricular ejection fraction and the burden of
cardiovascular risk factors assessed by the American
Heart Association risk score, which were negatively
associated with the VL. Additionally, Arnould et
al.[10] found moderate correlations between VL and
two risk scores: Global Registry of Acute Coronary
Events and the Reduction of Atherothrombosis
for Continued Health. They also investigated the
relationship between OCTA measured VL and
hemodynamic variables in patients with myocardial
infarction both during the acute phase and three
months after cardiac rehabilitation.[13,14]
The study did not reveal any notable distinctions
between the two time points or the OCTA parameters
and cardiac hemodynamic variables, whether they
were acute or chronic, such as left ventricular ejection
fraction, aortic blood flow, systolic blood pressure,
diastolic blood pressure, and cardiac output. This
implies that the regulation of retinal microvasculature
is not influenced by that of systemic circulation,
indicating that it is self-regulated. However, it is
important to note that the study did not assess the VL
in the deep retinal layer (DRL), and the number of
participants in the study was limited.[13]
Wang et al.[15] conducted a study that used OCTA
to examine the relationship between vessel density,
blood flow in the retina and choroid, and CAD.
Their findings indicated a significant reduction in
vessel density and flow area in most zones, except for
SRL and DRL in the fovea in CAD patients. The
researchers further analyzed the correlation between
the changes in fundus microvasculature and the
Gensini score, which reflects the severity of stenosis,
in each coronary artery branch. They discovered
that the degree of stenosis in the left main coronary
artery, proximal left circumflex artery, and right
coronary artery had a significant negative association
with VD changes in the SRL and DRL. Proximal
stenosis of the left anterior descending artery had a
negative relationship with VD in the DRL. In terms
of choroidal flow changes, negative correlations were
found between this parameter and the severity of
stenosis in the left main coronary artery, proximal left
circumflex artery, and right coronary artery.[15]
In summary, the research outcomes indicate
that OCTA has the potential to offer valuable
insights into microvascular alterations linked to
cardiovascular diseases and the capability to identify
diminished ocular perfusion among patients with
CAD. According to this investigation, there was a
significant decline in the SCP and DCP vessel density
metrics in CAD patients compared to their healthy
counterparts. These findings indicate that patients
with CAD experience a reduction in ocular perfusion,
which may be associated with systemic vascular
dysfunction.[10] Additionally, several investigations
have highlighted the correlation between OCTA
parameters and the severity or progression of CAD,
suggesting that OCTA could serve as a noninvasive
biomarker with clinical utility for predicting the risk
of cardiovascular disease.[14]
The use of OCTA as a means of monitoring
ocular perfusion and identifying vascular irregularities
in patients with CAD could be a viable option.
Nevertheless, additional investigations are required
to validate these results and explore the possible
contributions of OCTA in managing CAD patients.
The conclusions of our research indicate that OCTA
could be employed as a screening method for the
prompt detection of CAD in populations with a high
risk of the condition.
Furthermore, we found that OCTA is a reliable
and noninvasive method for detecting early-stage CAD in high-risk patients showing reduced retinal
vessel density, choroidal vessel density, and flow area.
Therefore, early interventions such as percutaneous
coronary intervention should be actively pursued
to prevent myocardial infarction in such patients.
Regular ophthalmic follow-up for high-risk patients
may also effectively reduce the morbidity of ocular
complications.
Previous studies have assessed the relationship
between retinal vascular changes and CAD. For
instance, a study including 109 CAD patients
demonstrated a strong correlation between the
degree of retinal arterial atherosclerosis and the
severity and extent of CAD.[16] Some studies have
also suggested that the diameter of retinal vessels,
particularly arterioles, may predict the risk of CAD
and stroke-related deaths in middle-aged individuals,
which suggests that microvascular changes may
contribute to the development of CAD.[15,17]
Our study revealed a decrease in both the
SCP and DCP among patients with CAD. These
results indicate that minor modifications in retinal
vascularization could potentially function as early
warning signals of cardiovascular disease, allowing
cardiologists to intervene promptly. As a result,
implementing this approach may prove successful
in minimizing the frequency of myocardial
infarctions.
Several theories have been suggested to account
for these findings. Atherosclerotic alterations in the
fundus vessels have been linked to thickening of
the microvascular wall, lipid buildup, fibrosis, and
calcification of larger arteries. Consequently, retinal
arteriolar narrowing triggers premature microvascular
injury. Individuals with CAD exhibit similar
pathological characteristics in their coronary arteries as
those found in the fundus vessels. As a result, changes
in retinal or choroidal microvasculature may mirror
systemic macrovascular modifications, particularly in
instances of coronary artery stenosis.[15,16]
Although coronary angiography is the
recognized benchmark for diagnosing
cardiovascular diseases, it has some disadvantages,
including adverse reactions and injuries caused
by the contrast agent. Consequently, in some
cases, there is a preference for less invasive
techniques. One such approach is coronary
computed tomography angiography, which offers
several benefits over traditional angiography. Nevertheless, it is unsuitable for some vulnerable
patients. In these instances, OCTA provides
a novel, noninvasive, drug-free diagnostic
alternative.[15,18,19]
Several limitations were present in our study,
including a homogeneous population, a relatively
limited sample size, and a lack of long-term follow-up.
Additionally, our study exhibited low statistical power
due to its relatively limited sample size.
In conclusion, this study revealed a reduction
in vessel density across various retinal layers in
CAD patients, despite the absence of any observable
clinical symptoms. These outcomes imply that CAD
individuals may experience retinal vascular harm at an
early stage. Optical coherence tomography angiography
proves to be an effective and precise diagnostic
method for detecting early-stage retina and choroid
damage in CAD patients. Further comprehensive and
longitudinal investigations are essential to substantiate
these findings.
Data Sharing Statement: The data that support the
findings of this study are available from the corresponding
author upon reasonable request.
Author Contributions: Conception and design of the
research, acquisition of data, analysis and interpretation of the
data, Statistical analysis and Obtaining financing, writing of
the manuscript: C.T., S.G., T.O., O.U.F.; Critical revision of
the manuscript for content: C.T., T.O., O.U.F.
Conflict of Interest: The authors declared no conflicts
of interest with respect to the authorship and/or publication
of this article.
Funding: The authors received no financial support for
the research and/or authorship of this article.
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