CARDIOVASCULAR JOURNAL OF AFRICA • Vol 21, No 4, July/August 2010
AFRICA
223
A coronary artery anomaly: type IV dual left anterior
descending artery
M CELIK, A IYISOY, T CELIK
Summary
Coronary artery anomalies are seen in about 1.3% of
patients undergoing coronary angiography. However, the
dual type of left anterior descending (LAD) artery is a rare
form of coronary artery anomaly. There are four types of
dual LAD; type IV describes the anomaly of a rudimentary
LAD artery terminating in the mid-portion of the anterior
interventricular sulcus, and the presence of another LAD
originating from the right coronary artery and continuing to
the anterior interventricular sulcus.
Keywords:
coronary artery anomaly, type IV dual left anterior
descending artery
Submitted 12/1/10, accepted 10/3/10
Cardiovasc J Afr
2010;
21
: 223–224
DOI: CVJ-21.014
Congenital anomalies such as origin, course and distribution of
coronary arteries occur in 0.64 to 1.3% of patients undergoing
coronary angiography. Although 80% of these coronary anoma-
lies are benign, 20% may cause symptoms.
1
The left anterior descending (LAD) artery courses along
the anterior interventricular sulcus (AIVS) towards the cardiac
apex, and anomalies of this coronary artery are extremely rare.
The presence of a short and long LAD in the AIVS is described
as a dual LAD. The short LAD travels and terminates in the
AIVS and does not reach the cardiac apex, whereas the long
LAD, which originates either from the left main coronary artery
(LMCA) or the right coronary artery (RCA), enters the distal
part of the AIVS and reaches the cardiac apex.
2
There are four
types of dual LAD. Type IV dual LAD differs from the first three
types in the origination of the long LAD from the RCA. In this
report, we present a case of type IV dual LAD.
Case report
A 56-year-old woman with a two-year history of hyperlipidaemia
was admitted to our hospital because of chest pain, especially
during exercise. The physical examination and resting electrocar-
diogram (ECG) were normal and transthoracic echocardiography
showed no wall-motion abnormality. Also, there was no abnor-
mality in the standard biochemical tests. Her treadmill exercise
test showed 1 to 2 mm down-sloping ST-segment depression in
leads V4 to V6. Subsequently, the patient underwent coronary
angiography for the evaluation of coronary artery disease.
Coronary angiography revealed a coronary artery anomaly of
type IV dual LAD with a short LAD, which originated from the
LMCA and terminated in the mid-portion of the AIVS. The long
LAD originated from the RCA, entered into the distal part of the
AIVS and travelled towards the apex of the heart. There was no
haemodynamically severe stenosis in her coronary arteries and a
decision was made to treat medically. The patient was discharged
in good condition without any complications.
Discussion
Coronary artery anomalies have become more relevant since the
widespread application of coronary angiography. Interventional
cardiologist should therefore be more familiar with these anoma-
lies in order to make a more accurate diagnosis. Dual LAD is one
of these coronary artery anomalies.
The presence of two coronary arteries in theAIVS is described
as dual LAD. Spindola-Franco and colleagues
3
reported that the
incidence of dual LAD was about 1% in normal hearts and most
of the patients were asymptomatic. Nevertheless, this anomaly
can be found relatively often in patients with congenital heart
disease such as tetralogy of Fallot and complete transposition of
the great arteries.
4
The anomalous origin of the left circumflex
artery from the right coronary artery, associated with type IV
dual LAD has also been reported.
5
Spindola-Franco and co-workers
3
reported an angiographic
description of dual LAD and classified it into four subtypes
according to the origin and course of the long LAD. Type I: the
long LAD courses in the AIVS, descends on the left ventricular
side of the short LAD, and then re-enters at the distal part of the
AIVS. Type II: the long LAD courses in the AIVS, descends on
the right ventricular side of the short LAD, and then re-enters at
the distal part of the AIVS. Type III: the long LAD courses intra-
myocardially proximally in the ventricular septum, and appears
on the epicardial surface in the distal part of the AIVS. Type IV:
the long LAD unusually originates from the right coronary artery
and then enters the AIVS.
In our patient, the long LAD originated from the RCA and
entered the distal part of the AIVS. Therefore the diagnosis of
type IV dual LAD, according to the classification of Spindola-
Franco and colleagues,
3
was made.
Type IV dual LAD is a rare congenital anomaly of the coro-
nary arteries and it may cause misdiagnosis, and mistreatment
when diagnosed. When a short or a hypoplastic LAD is present
in the proximal part of the AIVS, type IV dual LAD should be
kept in mind. The exact description of coronary artery anatomy
is essential in patients undergoing percutaneous coronary inter-
vention or coronary artery bypass graft (CABG) operations.
6
The short LAD can be misdiagnosed as a total occlusion of
the LAD; however, the diagnosis of dual LAD (type IV) can be
Department of Cardiology, Gulhane Military Medical
Academy, School of Medicine, Ankara, Turkey
MURAT CELIK, MD
ATILA IYISOY, MD
TURGAY CELIK, MD,
