Coronary Artery anomalies and surgical aspects

1. CONGENITAL CORONARY
ANOMALIES
Akshay Deshmukh
DNB Trainee in CTVS, NICS

2. • Congenital Coronary Anomalies are seen in 1 to 5% of population.
• 20% of these have the potential to cause coronary ischemia and its
sequalae.
• Any congenital abnormalities in the coronary system can have major
deleterious effects on heart function.
• It is also possible that even subtle variation in the patterning of
coronary vessels has significant but uncharacterized effects on
myocardial structure and function.

3. • Let us define normal features of coronary anatomy to differentiate
from anomalies.

4. Development of the Coronary
System

5. • The mammalian heart is one of the most vascularized organs of the
body.
• Still, not a single cell that makes up the coronary system of the heart
arises from the heart. All the cells that make up the coronary system
come from outside the heart, are brought to the heart and
differentiate into blood vessels only when they are in the heart.
• And all of this happens without ever tapping into the blood that
courses through the heart lumen.

6. Not Everybody Has a Coronary System!
• It should be noted that not all organisms with heart have coronary systems. Some
of the species get blood supply to their heart directly from the circulating luminal
blood in the heart.
• Among the vertebrates, mammals, reptiles and avians have coronary system,
complete with arterial output and venous return. What these species have in
common is that they depend on pulmonic respiration and lack cutaneous
respiration. The hearts of these organisms have complete anatomical and / or
physiological separation of oxygenated and deoxygenated blood.
• So in these species, getting fresh oxygenated blood to the right side of the
myocardium from the circulating luminal blood is not an option. Also these
species have developed very thick walled ventricles.
• Thus an alternative method of delivery – The Coronary System was necessary.

7. Structure of the Coronary Vascular System
• The blood supply to the heart of higher vertebrates actually originates
outside the heart from the ascending aorta.
• These arteries travel well-defined routes along the surface of the heart in
the epicardium and give rise to branches that penetrate the substance of
the myocardium.
• Small muscular arteries are found throughout the myocardium that further
branch into an extensive capillary bed that embraces nearly all of the
cardiac myocytes. The venous return to the coronary sinus courses over the
surface of the heart with accompanying arteries.
• Although the major arteries and veins travel together over the surface of
the heart, the origin of the coronary arteries and termination of the
coronary sinus are different & Epicardial lymphatics do not appear to travel
with arteries and veins.

8. Circle and Loop Model
• Major epicardial arteries
traverse the AV groove and
interventricular groove to form a
circle and loop model.
• They give branches which
descend down from this circle.
• Till this branching stage, some
amount of consistency is seen in
the anatomy.

9. • These epicardial branches then give small penetrating intramural
arteries. This branching system is highly variable except for 2
important things,
1. There is a fairly consistent spacing between these penetrating
muscular arteries.
2. The branching of these arteries leaves no myocytes untouched.
• This variation in the origin, number, and patterning of the coronary
system is far greater than variation seen in valves, myocardium,
and/or great vessels.

10. Origin of cells that make the Coronaries
• Coronaries develop from mesenchymal cells coming from epicardium
which comes from ‘Septum Transversum’. Lets see how.
• The tubular heart is formed as an endothelial tube within a muscular tube.
Both these layers come from lateral plate mesoderm. (and the only cell
types in heart that come from lateral plate mesoderm)
• Till 24th day of development, heart has only endothelium and myocardium
and lacks epicardium.
• Epicardium arises from an epithelium associated with ‘Septum
Transversum’ which also gives origin to the pleura, parietal pericardium,
diaphragm and peritoneum. This epithelium is named as PEO –
Proepicardial Organ.
• PEO balloons out from the septum transversum and approaches the
surface of the heart towards sinoatrial pole.

11. • Epicardial migration (aka ‘The First Directed Migration’) proceeds over the
atria first and somewhat later over the ventricles. The advancing
epithelium (continuous simple squamous) spreads out over the heart,
eventually covering the entire myocardium and pericardial cavity.
• Failure of this First Directed Migration due to disruption of cellular
adhesion system results in embryonic death suggesting critical function of
epicardium in cardiac development.
• During the next stage of development, some cells lose contact with the
epicardial epithelium. These cells become freely migratory mesenchyme
and move into the subepicardial connective tissue space (EMT – epithelia
to mesenchymal transition).
• EMT is dependent on a Friend Of GATA 2 (FOG-2) regulated signalling
pathway from myocardium (FOG-2 is specific to myocardium).
• In FOG-2 null embryos, pericardium is present but no mesenchym is
generated and thus no coronaries are formed. These embryos die with
multiple cardiac anomalies.

12. • The spreading epicardium fills up the space in the AV groove and has
abundant mesenchymal cells.
• In this region, some of the mesenchymal cells coalesce to form
channels within the connective tissue space and become the
endothelium of the coronary vessels. Other mesenchymal cells take
up positions adjacent to this endothelium and differentiate into
arterial smooth muscle. (So, the first coronary vessel is formed in the
AV groove).
• These channels then fuse to form blood vessels. Note that there is no
blood flow and hence no blood pressure at this time in the
coronaries.
• So it is interesting that the initial size of the proximal and distal
coronary arteries is set in the absence of blood flow. (Mechanisms
governing this are still unknown).

13. • Then there is ‘The Second Directed
Migration’ of the EMT cells into the
developing myocardium. These
cells traverse the entire thickness
of the myocardium till they reach
the endothelium of the heart. (But
they don’t penetrate the
endothelium. If they do – Coronary
cameral fistula).
• Subsequently they transform into
vascular endothelium and vascular
smooth mucles cells to form plexi.
• These plexi are then remodeled
into definitive arteries, capillaries
and veins. (Dysregulation of this
remodeling can result into
Coronary AV fistula)

14. • The proximal end of the coronary arteries actually grows into the
aorta, penetrating the tunica media and finally the intima. Final
connection to the aorta involves local apoptotic events that
eventually lead to the melding of coronary endothelia with that of the
aorta. (Failure of this apoptotic event results into congenital coronary
osteal atresia.)
• Considering the very complex nature of this developmental system,
errors are bound to happen.
• Errors of misconnection – (these are always radial and not
longitudinal i.e. malpositioned coronary vessels are not observed up
the ascending aorta, but they are observed at the correct level and
are radially misplaced on the aorta or pulmonary artery.)
1. ALCAPA
2. Anomalous Connection of MCA to Aorta
3. Anomalous Coronary Artery Course between Aorta and PA

15. To summarize this complex part, just understand that,
1. Coronaries originate from epicardium.
2. Coronaries don’t shoot out from aorta as aortic branches but are
developed on and in the myocardium to be fused with the aorta
later.
3. Circuitry of the coronary vascular system is well established and
even completed before the system ‘taps into’ the systemic
circulation.

16. Classification of Coronary Artery Anomalies
• But the surgically important
ones are,
1) Coronary Aretriovenous Fistula
2) ALCAPA
3) Anomalous Connection of a
Main Coronary Artery to Aorta
4) Congenital Ostial Atresia of the
Left Main Coronary Artery

17. Coronary Aretriovenous Fistula

18. • Direct communication between a coronary artery and the lumen
of any one of the four cardiac chambers, the coronary sinus or
its tributary veins, or the superior vena cava, pulmonary artery,
or pulmonary veins close to the heart.
• First described by Krause in 1865.
• First reported in literature by Trevor in 1912
• First repair using CPB was by Swan and colleagues in 1959.

19. Morphology
• RCA 50 to 55%
• LCA 35%
• Both 5%
• Almost invariably part of a normally distributed coronary artery with a normal
branching pattern. Rarely, the involved artery is anomalous.
• The fistula occurs either in the main vessel that continues beyond the fistula (a
side-to-side pattern) or at the termination of the main vessel itself, or at a branch
(an end artery).
• Proximal to the fistula, the artery is always dilated, elongated and may be
serpiginous and/or aneurysmal, and these changes are roughly proportional to
the size of shunt.
• Giant aneurysms are seen exclusively with RCA entering RV or LV.
• Beyond fistula, if the artery continues, it has a very very small calibre.

20. • More than 90% of fistulae open into right heart chambers or their
connecting vessels producing L-R shunts. These have rapid systolic and
diastolic runoffs. Of these,
o40% to RV
o25% to RA
o15 – 20% to PA
o7% to CS
o1% to SVC
• About 8% of fistulae drain into left heart chambers or their tributaries,
usually the left atrium, less often the left ventricle (about 3%), and rarely
the proximal pulmonary veins.
• Left heart fistulae are not, of course, AV fistulae but arterioarterial and
therefore do not produce a left-to-right shunt.
• Shunt occurs only during diastole when they enter the left ventricle,
because fistulae usually close off during systole, and also because there is
no pressure gradient.

21. • The fistulous opening when single, is about 2 to 5mm, and usually has
fibrous margin. Most fistulae to the LV are single.
• Occasionally there may be several openings (16%) or a localized
angiomatous network of vessels (10%).
• The cardiac chambers associated with the fistula show dilatation
except LV.
• Fistulous connection to CS causes its aneurysm and it’s the only site
reported of having aneurysmal rupture in case of a coronary fistula.
• Fistulous opening is a site of turbulence and 5% cases present with
infective endocarditis.
• Coincidental congenital (ASD, VSD) and acquired (valvular, coronary)
lesions are seen with 25 to 30% cases.

22. Clinical Features
• Most are asymptomatic and present either because of a continuous
murmur, or mild cardiomegaly and plethora on chest radiograph or
because of coronary angiography done for other reasons.
• Dyspnea and Fatigue (from L-R shunt)
• Angina (7%) and MI (3%) – more common in older patients.
• Heart Failure (12 to 15%)
o Associated with large shunts in pediatric patients
o In older patients it is due to long standing shunt.
o More common in CS connection
• AF – seen in fistulous connection with RA
• Chills and fever – in IE

23. Diagnosis
• Examination
 Continuous murmur (except in LV connection)
Systolic thrill
Wide pulse pressure
• ECG – normal, may show signs of chamber overload.
• CXR – mild cardiomegaly with plethora or can be normal
• 2D ECHO & Doppler – shows enlarged coronary and dilated chambers.
• Cardiac Catheterisation – Gold Standard.

25. Natural History
• Small fistulae remain small, moderate ones slowly increase in size.
• Spontaneous closure is very rare.
• Large fistulae cause early symptoms and early heart failure (but rarely
before 20 years of age)
• Heart Failure is most common in 5th and 6th decade.
• 5% develop IE
• Aneurysm formation is seen in 9% of paediatric and 14 to 29% of
adult population.

26. Technique of Operation
• Standard median sternotomy with preparation made for use of CPB.
CPB is indicated when
1. Artery is dilated and tortuous
2. Inaccessible site off pump e.g. AV groove
3. Fistula is in course of artery rather than at termination, so as to
avoid ligation of the distal coronary.
4. Aneurysm requiring excision
• Fistula location to be marked with a stitch before going on CPB
(standard bicaval and aortic cannulation with left side vent in LA)
• Cardioplegia given while clamping the fistula site with a finger.

27. 1. RA, LA, PA – open the chamber and close the fistula from within
with over and over suture with pledgeted mattress suture.
2. Ventricle or Large fistula and artery continuing beyond the fistula-
open the coronary artery and close the fistula with a running
suture, f/b closure of the arteriotomy with 6-0 or 7-0 prolene. If
closing from within the chamber, fistula can be identified using
cardioplegia (useful in trabeculated part).
3. Aneurysm – To be excised always. If very large, unroofing to be
done with ligation of coronary proximal and distal to the sac f/b
CABG.
4. CABG – When there is no other option but to ligate the feeding
coronary (provided the artery distal to fistula is adequate sized).

28. • Post op mortality in absence of giant aneurysm and need for CABG is
almost zero. (4% in case of the later).
• No recurrent fistulae, no symptom recurrence and no late mortality is
observed.
• Even if asymptomatic, i/v/o the probability that at least some of the
fistulae will increase in size and therefore eventually produce
symptoms and heart failure, the tendency for development of IE, the
low probability of spontaneous closure, and the safety and efficacy of
operation, it is recommended that diagnosis of a coronary AV fistula
is an indication for operation unless the shunt is small (Qp/Qs < 1.3).

29. Anomalous Connection of Left
Coronary Artery to Pulmonary Artery
(ALCAPA)

30. • The whole of the LMCA or only the LAD or LCX branch connects
anomalously to the proximal MPA or very rarely to the proximal right
PA.
• Branching pattern of the anomalously connecting left coronary artery
remains normal. The RCA arises normally from the aorta and has a
normal branching pattern.
• Collaterals from RCA feed the left coronary artery, in which flow is
reversed, so that the left coronary artery drains into the PA.

31. • 1886 – Brooks described the condition and explained the pathophysiology (retrograde
flow theory) for the first time.
• 1933 – Bland, White and Garland described the syndrome a/w the anomaly.
• 1953 – Mustard used turned down left Common Carotid Artery for anastomosing on left
coronary
• 1957 – Apley used left Subclavian in the same manner.
• 1959 – Sabiston & collegues performed first surgical correction and verified the
retrograde flow theory of Brooks.
• 1966 – Cooley used RSVG from aorta to LAD and tied the proximal end of the anomalous
connection near PA.
• 1972 – Tingelstad performed first translocation procedure (but it was for anomalous
connection of RCA)
• 1974 – Neches did similar procedure for anomalous connection of LMCA. Also suggested
interposition of left Subclavian free graft to increase the length if inadequate.
• 1979 – First Tunnel Operation
Using Pericardium by Hamilton
Using PA wall by Takeuchi
• Initially all these procedures carried very high postop mortality (as high as 75%) but it
came down drastically with advent of temporary ventricular assistance in the 90s.

32. Morphology
• The anomalous LMCA connects most often to the sinus of Valsalva
immediately above the left or posterior cusp of the pulmonary trunk and
rarely from that above the right cusp.
• Collateral communications between right and left coronary arteries are
always present.
• LV is always hypertrophied and greatly dilated, with dilatation often
involving primarily the LV apex. Diffuse LV fibrosis is virtually always
present with or without evidence of recent and old anterolateral MI.
• Fibrosis is most marked in the subendocardial layer. Focal calcification may
be present in fibrotic areas. Secondary subendocardial fibroelastosis of
variable degree is usually present.
• Chronic ischemic process causes devitalization of myocardium at cellular
and biochemical level (Hibernating Myocardium).

33. • Mitral Valve Regurgitation may be seen resulting from any of the
following-
o extensive fibrosis and calcification of papillary muscles
o endocardial fibroelastosis involving mitral apparatus
o abnormally placed papillary muscle
o LV dilatation resulting in annular dilatation

34. Clinical Features and Diagnosis
• Symptoms appear usually after 2 months when postnatal high PAP regresses
allowing runoff into PA through the anomalous connection and hence coronary
steal.
• Infants present with poor feeding, poor weight gain
• Angina in infants presenting as – feeding interruption with breathlessness,
sweating, baby drawing up knees and arching the back with cry and/or scream.
• Cases with anomalous connection of only LAD or only LCX present during
adulthood.
• Adults present with similar c/o dyspnoea, angina and sometimes palpitations.
• Examination-
o non specific systolic murmur or more specific diastolic murmur of MR
o Precordial lift
o crepitations throughout the lung fields
o hepatomegaly

35. • ECG – ischemic changes in lateral leads with signs of old ALWMI (Q
waves)
• CXR – Cardiomegaly, interstitial pulmonary oedema
• Cardiac Enzymes - elevated
• ECHO and Doppler – low LVEF (<20%), large RCA, anomalous LMCA
connection to PA showing retrograde flow.
• Cardiac Cath – gold standard, shows single RCA with opacification of
pulmonary trunk due to retrograde flow.

38. Natural History
• 65% die during first year of life (but rarely before 2 months)
• If death does not occur during the first year, the hazard lessens
considerably and the chronic phase of natural history is reached. Survival
to this stage may be related to presence of rich inter arterial collaterals.
• Survival beyond the first year may also be related to marked right
dominance, with RCA supplying not only the diaphragmatic portion of the
LV but also much of the septum and lateral wall.
• Still these patients continue to be at risk of death from chronic heart failure
secondary to ischemic LV cardiomyopathy.
• After 4th decade, sudden cardiac death as seen with IHD is more than due
to chronic heart failure.

39. Indications for surgery and choice of
operation
• Diagnosis is an indication for urgent surgery at any age regardless of the
clinical status.
• Creating a two-artery coronary system is indicated in all situations
including critically ill infants. (Preferably at a higher centre with availability
of ventricular assist device)
Procedure of choice is Translocation
If not possible then,
Takeuchi Procedure is the second choice in children
LIMA to LAD is the second choice in adults.
• MV repair or replacement in adults if needed (in younger patients only if
very severe MR)

40. Two Artery Coronary System
• Anomalous coronary connection
is corrected so that both RCA
and LMCA are connected to
aorta with separate openings.
• Both arteries carry blood supply
independently.
Single Artery Coronary System
• Anomalous coronary connection
is tied off from PA so that only
RCA is connected to aorta and
through collaterals its supplies
left coronary system.
• Tying off of LMCA from PA
prevents retrograde runoff and
hence coronary steal.

41. Technique of Operation
• After sternotomy, the pericardium is opened without touching the heart, because
even the slightest trauma can induce ventricular fibrillation.
• Preferably, arterial cannulation of both the aorta and PA is used with a bifurcated
system to maximize myocardial perfusion with single venous cannulation.
• Snuggers are placed around the left and right pulmonary arteries and are
tightened as CPB is initiated to prevent perfusion steal into the pulmonary bed
from the pulmonary trunk arterial cannula. A left-sided vent is placed in the RSPV.
• Cardioplegia is delivered simultaneously into the aortic root and pulmonary trunk
using a bifurcated cardioplegia delivery system. If delivering cardioplegia only into
the aortic root, we have to occlude the branch PAs.
• Myocardial protection during aortic clamping is particularly important for two
reasons: 1) the existing compromised state of the myocardium 2) potential for
inadequate delivery of cardioplegia to LV because of the anomalous coronary
system.
• When the opening of the anomalously connecting LMCA is posterior or right-
sided, the coronary artery translocation technique is used while if it is on the left-
sided aspect of the pulmonary trunk, the tunnel operation should be considered.

42. 1) LMCA Translocation
• A sizable button of pulmonary
artery wall around the coronary
ostium is excised.
• The left coronary artery is carefully
mobilized for a short distance.
• The button around the coronary
ostium is anastomosed to the aorta
with 7-0 monofilament absorbable
sutures.
• Pulmonary trunk is reconstructed
by end-to-end anastomosis, and
the coronary artery explant site is
patched with pericardium or PTFE.

44. Translocation Surgery Video

45. 2) Tunnel Operation (Takeuchi Repair)
• A hole (4-5mm) is made in aortic wall at a point at which the left wall of the aorta
is in contact with the right side of the pulmonary trunk.
• Directly opposite to this a similar hole is made on the left side of the pulmonary
trunk.
• These openings are sewn together with continuous 7-0 polypropylene to create
an aortopulmonary window.
• Using a flap of anterior pulmonary trunk wall hinged on the right, the anterior
wall of the tunnel is created, completing the tunnel directing blood from the
aortopulmonary window across the back of the pulmonary trunk to the
anomalously connecting left coronary artery.
• Defect in the anterior wall of the pulmonary trunk is reconstructed with a patch
of pericardium or PTFE.
• If RVOT narrowing happens due to the tunnel, then it is augmented with TAP
using pericardium.

47. Modified Takeuchi
• Here, tunnel is created using a PTFE patch or pericardial patch instead
of using a flap from pulmonary trunk wall.

48. Modified Takeuchi Repair Video

49. 3) Subclavian to Left Coronary Anastomosis
• Indicated when the anomalous coronary
ostium within the pulmonary trunk is
remote from adjacent aorta, making
direct coronary translocation impossible
and Takeuchi repair difficult.
• Aortic clamping and cardioplegia isn’t
needed.
• The left subclavian artery is dissected as
far distally as possible and then ligated
and divided.
• Coronary is mobilized on a generous
button of pulmonary sinus tissue.
• End to end anastomosis is done using 7-0
monofilament absorbable suture.

50. 4) Yacoub’s Technique of Autologous Flap

51. 5) Ligation of Left Coronary Artery
• In the current era, this procedure may be applicable as an interim
measure to stabilize critically ill patients before more formal
revascularization.
• Carried out in the simplest manner through a limited left
anterolateral fourth ICS thoracotomy.
• Anomalous connection is ligated close to the pulmonary trunk wall
with a single transfixing suture or metal clips.

52. • These patients have poor LV prior to the surgery so coming off needs
lot of patience and GTN along with LA pressure monitoring.
• Low cardiac output can be anticipated during the first few
postoperative days and might require temporary left ventricular
assistance.
• Two coronary artery systems survive better as compared to Coronary
Ligation Method.
• Early post op mortality is nearly 14%, most of the deaths occur from
acute cardiac failure.
• Significant MR is associated with early mortality.
• Long term survival is excellent after any of the described procedure.
• Antiplatelet therapy is required post operatively.
• Functional status remains good postop (NYHA I & II)

53. Anomalous Connection of a
Main Coronary Artery to Aorta

54. 1) Either the left main coronary artery connects to the aorta in a site other
than the left coronary sinus or sinotubular junction
2) Or the right coronary artery connects to a site other than the right
coronary sinus or sinotubular junction.
• Have interatrial (between aorta and PA) course or uncommonly
retroaortic/prepulmonic or trans-septal course.
• Commonly has intramural course within the aortic wall
• Occasionally has osteal stenosis
• Rarely the anomalous artery does not arise from the opposite coronary
sinus, but rather from the posterior (noncoronary) sinus.
• It was first described in 1974 by Cheitlin
• Anomalous connection of RCA is more common than LMCA.

55. Clinical Features and Diagnosis
• True prevalence is unknown
• 99% are asymptomatic
• Symptomatic patients present in 2nd or 3rd decade with angina or syncope
or sudden cardiac arrest.
• ECHO is used to define the ostial position and interarterial course of the
vessel and can reveal whether there are one or two ostia and whether
there is an intramural course. But ECHO has limitations if the two ostia are
closely placed.
• MRA, CT and Angiography can be used for determining morphology
further. CT has limitation in younger patients due to faster heart rate.
• Most clinical events, including sudden death, occur in the second and third
decades of life, and more commonly in males

58. Indications & Technique of Operation
• Ischemia, whether reversible or not, is an indication for operation.
• Syncopal event, angina, or an episode of sudden death with
resuscitation is an indication for operation.
• Presence of the anomalous connection without ischemia, symptoms,
or concerning morphologic characteristics is probably not an
indication for operation in the first decade of life.
• The goal of surgery is to eliminate the risk of the interarterial
component of the vessel.

59. Morphology based surgical management protocol

60. Unroofing

61. Lateral Translocation of Pulmonary Trunk

62. Anterior Pulmonary Artery Translocation

63. Congenital Ostial Atresia of the
Left Main Coronary Artery

64. • Very rare, with fewer than 50 reported cases in the literature.
• In this coronary anomaly, there is no LMCA ostium; rather, the
correctly positioned LAD and circumflex coronary arteries have a blind
ending and they receive blood flow retrogradely through the RCA via
at least one collateral vessel.
• Usually occurs in the absence of other structural heart disease.
• The main pathophysiology from congenital left main ostial atresia is
inadequate collateral vessel flow from the RCA causing myocardial
ischemia and has a high potential for sudden cardiac death.

65. Clinical Features and Diagnosis
• Age at presentation is variable.
• Despite age at presentation, almost every patient reported in the
literature was symptomatic at diagnosis.
• Infants generally present with heart failure symptoms, including
feeding difficulty, failure to thrive (D/D includes ALCAPA and
Cardiomyopathy)
• Older patients may be diagnosed after experiencing syncope,
dyspnea, angina, and ventricular tachyarrhythmias.
• For any age, sudden death may be the first presentation.

66. • CXR – in infants may show signs of heart failure (pulmonary
congestion), adults usually have normal cxr findings.
• ECG – may be normal or may show ischemic changes in lateral leads,
signs of old ALWMI.
• ECHO & Doppler – Dilated LV with low EF and MR (D/D ALCAPA),
doppler shows retrograde floe from right coronary system to left.
• Cardiac Catheterisation – Gold Standard, direction of flow from the
RCA to the left coronary system and whether the PA is filled
retrogradly should be identified.

67. Technique of Operation
• Goal is to create Two Coronary Artery System.
• An incision is made vertically in the aorta to the desired location of
the ostium and then extended down towards LMCA. The incision
should end prior to the LAD and circumflex coronary artery
bifurcation. PA to be transected if required for adequate exposure.
• An atretic membrane, if present, should be removed.
• An autologous pericardial patch is then used to reconstruct the LMCA
ostium.
• Alternatively, Saphenous vein or a PTFE patch can be used.
• In elderly patients with associated atherosclerotic coronary disease, a
straightforward CABG is done. CABG is avoided in younger patients as
graft patency is limited with any conduit.

69. Thank You!
Reference
Kirklin
Sabiston
Development of Coronary System – Reese, Mikawa, Bader AHA 2002
Coronary Anomalies – Paolo Angelini AHA 2007
Coronary Anomalies – Hauser HEART 2005
MMCTS – YouTube
Dr Prashant Shah - YouTube