Keywords
aortic coarctation - cognitive impairment - Montreal cognitive assessment
Introduction
Coarctation of the aorta, the sixth most common form of congenital heart defect, rarely
presents in the adult population. Pathologically, it is a narrowing in the lumen of
the aorta secondary to medial wall thickening and aortic wall tissue infolding.[1] When presenting in adulthood, the most common symptoms are hypertension and fatigue.
Failure to intervene may lead to congestive heart failure, aortic dissection or rupture,
and endocarditis or intracranial bleeding.[1]
[2] We report an interesting case where the diagnosis and treatment of coarctation of
the aorta in an adult led to objective and subjective improvement in her cognitive
function.
Case Presentation
A 64-year-old female with history of hypertension, depression, and fatigue presented
with balance impairment and swishing in her ears. She was known to have baseline cognitive
impairment confirmed by the Montreal Cognitive Assessment (MoCA) score of 19 determined
by her primary care provider.
Due to concern for vertebral artery disease, she underwent an extracranial cerebrovascular
duplex investigation, which demonstrated bilateral vertebral artery stenosis of 50
to 90%. This prompted further evaluation with computed tomography angiogram that demonstrated
severe narrowing of the proximal descending thoracic aorta, immediately distal to
the origin of the left subclavian artery ([Fig. 1]). An aortogram and selective left subclavian artery angiogram was obtained for further
evaluation and noted no significant stenosis of the vertebral arteries but a very
high-grade stenosis of the aorta just distal to the subclavian artery consistent with
coarctation of the aorta. On further questioning, the patient revealed she had reproducible
leg pain caused by exercise and alleviated by rest consistent with claudication.
Fig. 1 Computed tomography angiography notable for aortic coarctation with narrowing of
aortic lumen distal to origin of left subclavian artery. White arrow pointing at site
of coarctation. BA, brachiocephalic artery; LCCA, left common carotid artery; LSA,
left subclavian artery.
A left axillary bifemoral bypass using 8-mm ringed polytetrafluoroethylene was performed.
At the 2-week follow-up appointment, she stated that she was able to walk without
leg pain, her balance issues had resolved, and the “swishing” in her ears had improved.
Her primary care provider readministered the MoCA screen and the patient scored a
26, within normal range. Subjectively her energy, sleep, and memory had all improved.
Objectively, her hypertension improved, and she required only one of her three antihypertensive
medications postoperatively.
Discussion
Aortic coarctation presenting in adults is rare and can be difficult to diagnose due
to the nonspecific symptoms.[1]
[2]
[3] These symptoms are secondary to the juxtaductal aortic narrowing resulting in increased
left ventricular afterload and hypertension proximal to the obstruction with decreased
flow distal to the obstruction.[1] Dyspnea, fatigue, headache, and hypertension are the most common presenting signs
reported in the literature.[1]
[2]
[3] Physical examination findings consisting of decreased or absence femoral pulses
can aid in the diagnosis.
To our knowledge, this is the first case of coarctation of the aorta demonstrated
to show an objective improvement in cognitive function following surgical treatment.
The patient's MoCA score improved from a level of moderate cognitive impairment to
within the normal range 14 weeks after her operation.
Our first hypothesis is that her low MoCA score was secondary to chronic fatigue.
A meta-analysis by Cockshell and Mathias[4] lends some credence to this theory, as they noted objective cognitive deficits in
patients with chronic fatigue syndrome in the domains of attention, memory, and reaction
time. In our patient, the cognitive deficits seen may be due to the physiology of
the coarctation syndrome rather than the symptom of fatigue.
A second hypothesis is that the patient's chronic hypertension (requiring three antihypertensive
medications) resulted in an alteration of cerebral microcirculation. It is known that
hypertension has detrimental effects on cognition and that malignant hypertension
impacts cerebrovascular autoregulation.[5] The alteration in cerebral microcirculation can lead to regional cerebral perfusion
deficits causing a suppression of brain activity and cognitive dysfunction.[6] Her cognitive improvement could therefore be secondary to improvement in cerebral
microcirculation from decreased episodes of hypertension and reduced afterload from
her left axillary artery to bifemoral arteries bypass.
A third hypothesis is that coarctation of the aorta leads to altered cerebral blood
flow possibly impairing cognition. A study performed by Wong et al[7] utilized transcranial Doppler to assess patients with coarctation of the aorta and
demonstrated increased intracranial vessel stiffness, impaired vasoreactivity to carbon
dioxide, widened pulse pressure, and a trend toward impaired vasodilator response
to visual stimuli. These alterations in cerebral blood flow may cause impaired endothelial
function resulting in a reduced increase in perfusion during neuronal activation which
could contribute to poor cognitive performance.[7]
There are multiple described surgical approaches to coarctation, including open resection
and interposition graft, stenting, or extra-anatomic bypass. During our angiogram,
we were unable to traverse a wire across the coarctation prohibiting placement of
stent. Due to the requirement of a thoracotomy for interposition graft placement,
the patient elected to undergo a left axillary artery to bifemoral arteries bypass,
despite the lower rates of patency. Her graft has remained patent with most recent
follow-up after 3 years.
Coarctation of the aorta is a challenging diagnosis to make in adults without a high
index of suspicion or imaging demonstrating this pathology. We have identified cognitive
impairment as an additional symptom of coarctation of the aorta that can be used to
help identify this rare but serious condition. However, we are reporting a single
case with only one set of pre- and postprocedure cognitive assessments, and the conclusions
must be guarded.
