Left main coronary artery atresia is a rare
condition with unclear etiology. In LMCAA, the left
coronary system receives blood only from collateral
arteries from the RCA. Thus, the heart may eventually
be unable to cope with collateral circulations and
develop myocardial ischemia. Patients mostly present
with nonspecific symptoms depending on their age
group and the formation of collateral vessels from the
RCA to the LCA. Adult patients usually present with
angina pectoris at an advanced age when collateral
flow cannot keep pace with myocardial demands.
Children and adolescents often present with chest
pain, dyspnea, syncope, tachyarrhythmia, and sudden
cardiac death.[
2,
3] Infants mostly present with growth
retardation and myocardial infarction.[
2] Catastrophic
situations like sudden cardiac arrest, low cardiac
output, and cardiomyopathy, as seen in our case, can
also be the first symptoms of infants with LMCAA.[
5,
6]
Since these symptoms are not specific to LMCAA,
the clinical diagnosis might be neglected. Thus, other
coronary anomalies should be excluded to reach a
correct diagnosis. As stated in a retrospective study by
Yildiz et al.,[
1] LMCA was the most common anomalous
vessel. Separate origins of LAD and circumflex artery
from the left coronary sinus of Valsalva were the most
common anomaly and should be excluded in patients
presenting with symptoms of myocardial infarction.
An ALCAPA is one situation that LMCAA can be
confused with and should be differentiated from.[
2,
7]
Although congenital atresia of the LMCA usually
occurs as an isolated cardiac lesion, concomitant
anomalies including bicuspid aorta, supravalvular aortic
stenosis, right coronary ostial stenosis, pulmonary
stenosis, ventricular septal defect, and mitral valve
prolapsus secondary to myocardial ischemia can be
encountered.[4,8,9]
The diagnosis of LMCAA can be done by coronary
angiographic findings, which usually show no left
coronary ostium and LCA filled in a retrograde manner
via the RCA instead of antegrade blood flow. In recent
years, MDCT has also played an essential role in
diagnosing LMCAA in older children and adults
and can be used in patients suspected of congenital
coronary artery abnormalities.[3,10] According to some
researchers, MDCT provides more precise details in
a less invasive way than coronary angiography and is
thus recommended to evaluate congenital coronary
abnormalities.[11] Multidetector computed tomography
not only defines the anatomic course and the ostium
shape but also has no complications as coronary spasm
than conventional coronary angiography. However,
there is no reliable research reporting the use of
MDCT in infants with coronary anomalies.[9] The
physician may merge findings that are revealed by
transthoracic echocardiography examination and
MDCT or cardiac catheterization. The absence of
retrograde filling from LAD to the pulmonary artery
may support the possible diagnosis of LMCAA.
The prognosis of LMCAA is poor.[2] Due to
the symptomatic nature of LMCAA and the risk
of sudden cardiac death, patients in the pediatric
population with LMCAA should undergo surgical
intervention to restore the antegrade flow to the left
coronary system. Various surgical interventions have
been described, and coronary artery bypass grafting
using the internal mammary artery or the saphenous
vein has been identified as the treatment of choice,
regardless of the caliber of left-sided vessels.[4,8,12] A
LIMA graft for LMCAA appears to be a reasonable
early interventional approach with successful results
one year postoperatively. Nevertheless, due to the
rarity of this disease, long-term postoperative
outcomes have not been reported.[2,4,5,8,9,11] Alternative
to bypass grafting, direct surgical reimplantation or
reconstruction of the LMCA using the azygos vein
has been described to provide the shortest and most
efficient way for blood to the myocardium.[6,12,13]
The advantages of direct surgical reimplantation
relative to bypass grafting is to provide antegrade flow without a bypass material. However, direct
surgical reimplantation could not be performed in
small infants with LMCAA. The long-term results
of bypass grafting in pediatric patients are reasonable
and good results have been reported before.[12,14]
In conclusion, LMCAA is an extremely rare
congenital coronary anomaly in which the left coronary
ostium and the left main trunk in the LCA system are
absent. Considering the severe symptoms, such as
myocardial infarction or sudden cardiac death, surgical
revascularization should most likely be the treatment
choice.
Patient Consent for Publication: A written informed
consent was obtained from the parent of the patient.
Data Sharing Statement: The data that support the
findings of this study are available from the corresponding
author upon reasonable request.
Author Contributions: Idea/concept, writing the article:
S.B., B.K., E.E.; Design, data collection and/or processing,
analysis and/or interpretation, literature review, references
and fundings; materials: S.B., B.K.; Control/supervision,
critical review: E.E.
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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