J Cardiol 2007 Sep; 50（3）: 199– 203

Single Left Coronary Artery With
Microfistula Communicating With
the Left Ventricle : A Case Report
YoichiUECHI, MD

Koichi

HIGA, MD

Abstract ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
A 79-year-old man with lung cancer undergoing chemotherapy and radiation complained of chest pain.
Coronary angiography revealed that the right coronary artery arose from the distal branch of the left circumflex artery. In addition, a left coronary artery-to-left ventricular microfistula was recognized coincidentally. Multidetector row computed tomography revealed no other cardiac anomalies besides the single left
coronary artery. No evidence of ischemia was noted during exercise stress myocardial scintigraphy. No
vasospasm provocation study was performed, as it was considered to be potentially life-threatening for apatient with the single coronary system. In general, single coronary artery may occasionally represent a
potentially fatal condition, so careful attention must be paid to its anatomical features.
────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────J Cardiol 2007 Sep; 50（3）:199 −203

Key Words■ Congenital heart disease■ Coronary vessels

INTRODUCTION
Single coronary artery, arising from the aortic
trunk from a single coronary ostium and supplying
the entire heart, is a rare congenital anomaly of thecoronary circulation. 1−5）Coronary artery-to-leftventricular microfistula is also an uncommon
form6−8）of the various types of congenital coronary
arterial fistulas reported.3−5）Single coronary arteryis occasionally associated with other congenital
cardiac malformations.1,2,9）Here we report a veryrare case of single coronary artery coexisting withleft coronary artery-to-left ventricular microfistula.
CASE REPORT
A 79-year-old man was referred to our hospitalfor the evaluation of chest pain. He was undergoing
chemotherapy and radiation under a diagnosis ofsquamous cell carcinoma of the left lung. He complained of shortness of breath on exertion and had
an approximately 2 months history of sufferingfrom recurrent episodes of rest angina at night,
which was sometimes relieved by sublingual nitro-■ Angiography

glycerin. He had no coronary risk factors other thansmoking habit.
Electrocardiography revealed supraventriculartachycardia or ventricular premature contractions,which were exacerbated by exertion. However, nosignificant ischemic changes could be documented
at the time of chest pain. Physical examination
revealed no abnormal heart murmurs. Chest radiography revealed the lung tumor in the left upper lungfield, but no evidence of cardiac enlargement.
Electrocardiography at rest showed biphasic orinverted T waves in leads Ⅱ, Ⅲ, aⅤF, and Ⅴ3−Ⅴ6,
with frequent premature supraventricular contractions. Transthoracic two-dimensional echocardiography showed no regional wall motion abnormality
or left ventricular hypertrophy. No significant
valvular abnormalities were recognized.
Diagnostic coronary angiography was performed
4 days after admission. The left coronary artery was
engaged and its ostium was located at its normal
position in the left sinus of Valsalva. The origin anddistribution of the main trunks on the left side,
namely, the left anterior descending artery and the──────────────────────────────────────────────
牧港中央病院 内科 : 〒 901−2131 沖縄県浦添市牧港 1199 番地
Department of Internal Medicine, Makiminato Chuou Hospital, Okinawa
Address for correspondence : UECHI Y, MD, Department of Internal Medicine, Makiminato Chuou Hospital, Makiminato 1199,
Urasoe, Okinawa 901−2131 ; E-mail : uechiy@r9.dion.ne.jp
Manuscript received March 26, 2007 ; revised May 14, 2007 ; accepted May 17, 2007

199

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Uechi, Higa

Fig. 1 Coronary angiogram in the anteroposterior projection with 30 degree caudal angulation
The right coronary artery arises from the distal branchof the left circumflex artery and continues retrogradely
along the normal right coronary artery distribution（arrowheads）.
LAD ＝ left anterior descending artery ; LCX ＝ left circumflex artery.

left circumflex artery were normal, but the rightcoronary artery arose from the distal left circumflex
artery, following the normal course of the rightcoronary artery distribution retrogradely. The distal
portion was tapered, and terminated near the rightsinus of Valsalva（Fig. 1）. There was no evidenceof stenotic lesions of the coronary arteries.
Aortography confirmed the absence of the rightcoronary artery ostium（Fig. 2）. Left ventriculography showed a normal-sized ventricle with an ejection fraction of 72%. Our routine catheterization
study usually includes the acetylcholine provocation test to rule out vasospastic angina, but we
decided against proceeding with this test because of
the risk of life-threatening multi-vessel spasm inthe patient with a single coronary system.
During the review of the angiograms, we noticed
that after the injection of the contrast medium into
the left coronary artery, the margin of the left ventricle also filled faintly at the end of diastole withthe contrast medium arising diffusely from the left
coronary artery, mainly the mid and distal portionsof the left anterior descending artery（Fig. 3）. We
finally made a diagnosis of microfistula arisingfrom the left coronary artery and draining into theFig. 2 Aortogram in the left anterior oblique view
Absence of the ostium of the right coronary artery isclearly confirmed.
LMT ＝ left main coronary trunk ; LCC ＝ left coronary
cusp ; RCC ＝ right coronary cusp.

Fig. 3 Coronary angiogram in the right anterior
oblique view
A small microfistula between the left anterior descending artery and the left ventricular cavity（arrowheads）isobserved.
Abbreviation as in Fig. 1.

J Cardiol 2007 Sep; 50（3）: 199– 203

Single Left Coronary Artery

201

Fig. 4 Multidetector row computed tomography scanusing maximum intensity projection
A single left coronary artery is visualized and the rightcoronary ostium is not visible（arrowheads）. Calcified
atherosclerotic lesions are also noted.
Abbreviations as in Figs. 1, 2.

left ventricular cavity.
Multidetector row computed tomography was
performed to ascertain the diagnosis of the single
coronary artery, which confirmed the presence ofthe single coronary artery（ Fig. 4）and also theabsence of any constriction of the coronary arteries
by the great vessels（ Fig. 5）. However, themicrofistula could not be visualized by this modality. Exercise stress myocardial scintigraphy using
thallium-201 was performed to detect any evidenceof myocardial ischemia. No symptomatic or significant electrocardiographic evidence of ischemia wasnoted during this test, and myocardial perfusion
was not significantly impaired（Fig. 6）.
The patient suffered no anginal attacks during
the course of his stay at our hospital, and was discharged after a week of hospitalization with nitroglycerin medication, because vasospastic angina
could not be ruled out at this time.
DISCUSSION
The incidence of single coronary artery withanomalous origin of the right coronary artery fromthe left circumflex artery is 0.02% to 0.04% in
patients undergoing coronary angiography.1−4）In
our case, the right coronary artery originated fromJ Cardiol 2007 Sep; 50（3）: 199– 203

Fig. 5 Multidetector row computed tomography scanusing volume rendering
The coronary arteries are not compressed between theaorta and the pulmonary trunk.
Ao ＝ aorta ; PT ＝ pulmonary trunk. Other abbreviations as in Figs. 1, 2.

the distal left circumflex artery and crossed the crux
to continue toward the right sinus of Valsalva.
Several cases of this type of single coronary arteryhave been reported previously.1−4,9）Single coronary artery is occasionally associatedwith other congenital cardiac anomalies, such as
coronary arteriovenous fistula.1,2,9）In our case, asmall coronary artery-to-left ventricular microfistula was accidentally identified coexisting with thesingle coronary artery. Coronary artery-to-left ventricular multiple microfistulas are defined as multiple microcommunications between one or morecoronary arteries and the cavity of the left
ventricle.8）Acquired coronary arterial fistula is rare
but occurs after external thoracic trauma or as aconsequence of surgery or myocardial biopsy.10）
The present patient had no such past history, but therelationship between the coronary artery-to-leftventricular fistula and the lung cancer after radiotherapy was unclear.
Microfistulas between one or more coronary
arteries and the left ventricular cavity have an incidence of 0.06%.8）Previously, a case of single right202

Uechi, Higa

StressDelay

Short axis

StressDelay

StressHorizontal long axis

Delay

Vertical long axis

Fig. 6 Cardiac radionuclide single photon emission computed tomography scan using thallium-201
There is no significant exercise-induced impairment of myocardial perfusion.
S ＝ septal ; A ＝ anterior ; L ＝ lateral ; I ＝ inferior ; AP ＝ apical.

coronary artery with left circumflex artery-to-leftventricular fistula was reported,11）but the present
case of single left coronary artery with left coronary artery-to-left ventricular microfistula isunique. The coronary artery-to-left ventricular
microfistula is usually small, in contrast to the morecommonly encountered congenital fistulas between
the coronary arteries and right heart structures（ right atrium, right ventricle or pulmonary
artery）.10）The small size of this type of coronary
fistula is attributed to the similar diastolic pressuresin the coronary capillary bed and the left ventricular cavity.12）Although the pathophysiologic originof fistulas draining into the left ventricle is obscure,morphological studies suggest that interferencewith developmental changes might produce anabnormally prominent thebesian system with themorphological appearance of a coronary microfistula.13）
Patients with single coronary artery are sometimes symptomatic, and some of these anomalies
are associated with ischemic events and sudden
death.1,3,14,15）Several mechanisms of myocardialischemia are possible in cases of single coronary
artery, such as entrapment of an anatomicallyectopic artery between the aorta and the pulmonary
trunk, coronary vasospasm, and atheroscleroticchanges in the coronary artery.1,3,14,15）In our case,coronary angiography showed no significant organic stenoses and multidetector row computed tomography revealed no evidence of compression of thecoronary artery between the great vessels. Although
we could not definitely exclude coronary spasm,
our case appeared to be the benign type of single
coronary artery.
The acetylcholine or ergonovine test is usuallyneeded to evaluate coronary spasm. A patient withsingle coronary artery suffered vasospasm of theaberrant coronary artery induced by ergonovine.14）
At the time of the catheterization study, we decided
against the test to provoke coronary arterial spasm
because vasospasm of the single coronary system
might result in the same situation of a life-threatening multi-vessel spasm. Therefore, we could not
rule out vasospasm, but a plausible reason for thesymptoms in our case was chronic insufficient
blood flow from the abnormally distributed atherosclerotic vessels and resultant ischemic myocardium, exacerbated by the underlying coronary steal
phenomenon caused by the microfistula.
While we could not find any evidence of myocardial ischemia, we considered that the symptoms in
our patient could be of cardiac origin, and that thepatient should remain under careful observation
because of the risk of future ischemic events withthe progression of coronary atherosclerosis or spontaneous vasospasm in his single coronary system.
From the clinical point of view, awareness ofsuch anomalous origins of the coronary arteries isimportant to establish the precise diagnosis andmake appropriate therapeutic decisions based oncoronary angiography.

J Cardiol 2007 Sep; 50（3）: 199– 203

Single Left Coronary Artery

要

203

約

左冠動脈左室瘻を合併した左単冠動脈の 1 例
上地

洋一

比嘉

耕一

右冠動脈が左回旋枝から起始している左単冠動脈に，左冠動脈左室瘻を合併したまれな症例を経験したので報告する．症例は 79 歳の男性で，肺癌に対し化学療法と放射線療法を受けていた．胸痛の訴えがあったため，冠動脈疾患の精査を目的に心臓カテーテル検査を行った．冠動脈造影検査の結果，左冠動脈の起始部およびその分枝は解剖学的に正常であったが，右冠動脈が左回旋枝の遠位部より起始していることが明らかとなった．さらに，左冠動脈左室瘻の合併も認められた．マルチスライスコンピューター断層撮影上，左単冠動脈以外の心奇形は認められなかった．運動負荷心筋シンチグラフィーにおいて，心筋虚血は認められなかった．冠動脈の攣縮誘発試験は，単冠動脈の患者に対しては致命的な不整脈を惹起する危険性が高いと思われ行わなかった．一般的に，単冠動脈の中には致命的な症例もあることから，その解剖学的な特徴には注意を払うべきである．

J Cardiol 2007 Sep; 50（3）: 199 −203

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