Key Message:
Absent left circumflex coronary (LCX) artery though rare and benign
should be considered in patients with chest pain and differentiated from
atherosclerotic coronary artery disease for better management &
prognosis.
Case Summary:
An 80 year old female with hypertension presented in ER with history of
chest pain on exertion, giddiness and palpitation. On examination her
pulse was 62 beats per minute, Respiratory rate 20 breaths per minute,
blood pressure was 110/70 mm of Hg & oxygen saturation of 97 %.
Cardiovascular examination and initial electrocardiogram showed no
abnormalities or ischemic changes. Routine blood work, cardiac enzymes
and chest X-ray were within normal limits. Echocardiogram showed mitral
and tricuspid regurgitation with left ventricle ejection fraction of
55%. Stress (treadmill) test was not done in this patient.
Computed tomography coronary angiography (CTCA) showed absent LCX in
atrioventricular groove with right coronary dominance and prominent RCA
(right coronary artery) extending beyond right ventricular margin. No
ectopic origin of LCX was identified. Normal origin of LCA (left
coronary artery) was noted giving off prominent LAD (left anterior
descending) artery and its first diagonal branches. The LCX territory
was supplied by branches of PDA (posterior descending artery) & PLV
(posterior left ventricular) and terminal branches of LAD. Total Calcium
score was 0.4.
The patient was kept under observation for 24 hrs and discharged the
following day under medical management and advised regular follow-ups.
Congenital absence of LCX artery is a rare coronary artery anomaly with
a reported incidence between 0.003 % and 0.067%[1]. Usually it’s benign and asymptomatic and
discovered incidentally. It has been reported that congenital absence of
the LCX might be associated with systolic click syndrome and could
present with chest pain, episodic rapid heartbeats, and syncope[2] which was observed in our patient. CTCA is
currently the choice modality for detection of this anomaly over
catheter angiography as it is less invasive and also helps in better
delineating the course of the vessel in relation to cardiac chambers[3].
While the absence of LCX has yet to be significantly associated with any
major cardiac event, identification of this anomaly is crucial when
performing cardiac interventions because such patients are at increased
risk of being misdiagnosed during cardiac catheterization procedures,
also they require extra care while performing cardiac bypass procedures
to avoid accidental ligation or transection of anomalous vessels and to
ensure that the grafts are placed properly to restore perfusion to
ischemic myocardium [4,5].