coronary circulation and anomalies dr ravi ghatnatti Ipgmer, kolkata

Left Main or left coronary artery (LCA) Left anterior descending

(LAD) diagonal branches (D1,

D2) septal branches

Circumflex (Cx) Marginal branches

(M1,M2) Right coronary artery

Acute marginal branch (AM) AV node branch Posterior descending artery

(PDA)

The LCA divides almost immediately into the circumflex artery (Cx) and left anterior descending artery (LAD).On the left an axial CT-image. The LCA travels between the right ventricle outflow tract anteriorly and the left atrium posteriorly and divides into LAD and Cx.

Left main artery dividing into Cx with obtuse marginal branch (OM) AND LAD with diagonal branches (DB)

In 15% of cases a third branch arises in between the LAD and the Cx, known as the ramus intermedius or intermediate branch. This intermediate branche behaves as a diagonal branch of the Cx.

The LAD travels in the anterior interventricular groove and continues up to the apex of the heart.The LAD supplies the anterior part of the septum with septal branches and the anterior wall of the left ventricle with diagonal branches.The LAD supplies most of the left ventricle and also the AV-bundle.

The diagonal branches come off the LAD and run laterally to supply the antero-lateral wall of the left ventricle.The first diagonal branch serves as the boundary between the proximal and mid portion of the LAD (2).There can be one or more diagonal branches: D1, D2 , etc.

 

The Cx lies in the left AV groove supplies the vessels of the lateral wall of the left ventricle.Obtuse marginals (M1, M2).10% of patients have a left dominant circulation in which the Cx also supplies the posterior descending artery (PDA).

In 50-60% the first branch of the RCA -Rt conus branch.

In 36%- Directly from aorta

Also known as – ARTERIA CONI ARTERIOSI, THIRD CORONARY.

Anastomoses with a similar left coronary branch around pulmonary trunk – ANNULUS OF VIEUSSENS

In 60% a sinus node artery arises as second branch of the RCA.The RCA continues in the AV groove posteriorly and gives off a branch to the AV node.In 65% of cases -right dominant circulation. The PDA supplies the inferior wall of the left ventricle and inferior part of the septum.

The large acute marginal branch (AM) supplies the lateral wall of the right ventricle.

American Heart Association classification of coronary artery segmental anatomy.Coronary artery segments are numbered 1

through 15.

Dewey M et al. Ann Intern Med 2006;145:407-415

©2006 by American College of Physicians

Figure on a circumferential polar plot, of the 17myocardial segments and the recommended nomenclature fortomographic imaging of the heart

Assignment of the 17 myocardial segments to the territoriesof the left anterior descending (LAD), right coronaryartery (RCA), and the left circumflex coronary artery (LCX).

collaterals

Kugel's artery “ARTERIA ANASTOMOTICA

AURICULARIS MAGNA” This artery passes from either the

proximal right or left coronary artery down along the anterior margin of the atrial septum to anastomose with the A-V node branch of the distal RC artery

Arterial calibre

Both main stems and larger branches : 1.5-5.5mm

Diametre increases up to 30th yr

Effect of Coronary Artery Diameter in Patients Undergoing Coronary Bypass Surgery

Small mid-LAD diameter is associated with substantially increased risk of in-hospital mortality with CABG………….support the hypothesis that smaller coronary arteries explain higher perioperative mortality with CABG in women and smaller people.

Nancy J. O'Connor, MS; Jeremy R. Morton, MD; John D. Birkmeyer, MD; Elaine M. Olmstead, BA; Gerald T. O'Connor, PhD, DSC; for the Northern New England Cardiovascular Disease Study Group

SPECIAL FEATURE

Subintimal fibro-muscular-elastic thickening, already developing during the first months of life.

The coronary arteries represent the enlarged vasavasorum of larger vessels in the heart.

The definition of a coronary artery should be made without taking into account of its origin and proximal course but focusing on its intermediate and distal segments and/or its dependent micro vascular bed

CORONARY ARTERY MINIMALLY REQUIRED FEATURESLeft anterior descending (LAD) Location: the anterior interventricular

sulcusSubepicardial position (but not infrequently intramyocardial)Provides septal branches and follows the direction of the septum.Accompanied by a conspicuous venous branch (greater cardiac vein)

Circumflex (Cx) Location: the left side of the coronary sulcusSubepicardial positionProvides at least one marginal branch

Right coronary artery (RCA) Location: the right side of the coronary sulcusSubepicardial positionProvides at least the right ("acute") marginal branch

Angelini P – Coronary arteryanomalies – current clinical issues.Definition, classifications, incidence,clinical relevance and treatment guidelines. Tex Heart Inst J 2002;29:271-278

The variable features of the coronary arteries

LEVEL VARIABLES

1.Ostium Number of ostiaLocationSizeAngle of originationShape (e.g. slit-like; membrane)

2. Size Small sizePresence of a diaphragm

3. Proximal course Especially intramural tractConsider angle of origin

4. Mid-course Intraseptal tract or looping

5. Intramyocardial ramifications Regional distribution

6. Termination Regional distribution

Coronary anomalies of clinical and surgical relevance

anomalous pulmonary origins of the coronaries(APOC);

anomalous aortic origins of the coronaries (AAOC);

congenital atresia of the left main (CALM)

coronary aterio-venous fistulas (CAVF);

coronary bridging (myocardial bridging);

coronary aneurysms (CAn);

coronary stenosis

ANOMALOUS PULMONARY ORIGIN OF THE CORONARY ARTERIES

APOC "Major anomalies"

ALCAPA severe Origin formPulmonary sinus: 1, 2 or NF

ARCAPA severe, rare -do-

ACxPA Severe, rare -do

ARCLCPA Severe, rare -do-

ANOMALOUS AORTIC ORIGIN OF THE CORONARIES

AAOC "Minor anomalies"

LMCA from sinus1 RCA from sinus 2 LAD from sinus 1LAD from RCACx from sinus 1Cx from RCASingle coronary arteryInverted coronary arteriesOther

1/3 of all coronary anomalies

CORONARY ARTERIO-VENOUS FISTULAS

CAVF "Major anomalies"

RCA to RVLAD to RARCA, LAD to LVCx to PADiag to CSOM to SVCSingle coronary to LA

congenital / acquiredsingle / multipleassociated with: TOF ASD, VSD, PDAPulm. atresia + intact septum

Angiographic classification:Type A = proximal(proximal dilated, distal normal)Type B = distal(entire length dilated)

INTRAMYOCARDIAL COURSE (MYOCARDIAL BRIDGING)

Bridging

CxLADRCAMultipleOther atypical / rare

Symptomatic or asymptomaticInnocuous or may require surgery

Stenosis at stress test:Group I <50%Group II 50-75%Group III > 75%

CORONARY ANEURYSMS (CAn)CAnØ > 1.5 xdiameterof adjacentnormalcoronaryarteryRCA

Cx and LADCx and RCALAD and RCACx, LAD and RCACx and LADCx and RCALAD and RCACx, LAD and RCA

CxLADRCACxLAD

Type I(diffuse, 2-3 vessels)Type II(diffuse in 1 vessel +Localized in other) Type III(diffuse in 1 vessel) Type IV(localized in 1 vessel)

88% in malesCongenital (types I-IV)Acquired:-atherosclerotic;- Kawasaki, Marfan, Ehlers-Danlos, Takayasu- other systemic diseases, polyarteritis, scleroderma- infectious (incl. syphilis)- traumaticAneurysm +/- stenosis

ALCAPA •

ALCAPA results in the left ventricular myocardium being perfused by relatively desaturated blood under low pressure, leading to myocardial ischemia

• L-R SHUNT

INCIDENCE-1in 30,000 to 1 in 300000

The infantile type• Few or no collaterals myocardial ischemia ensues

• Poor feeding

Adult type Accounts for 10-15% Large collaterals Fatigue,

Dyspnea, Palpitations and effort angina

Mitral regurgitation

ECG Myocardial enzymes X-ray aortic root angiography MRA,CTA

SURGERY INFANTS-EMERGERY ADULTS-ELECTIVE PROCEDURES: MODIFIED TAKEUCHI OPERATION DIRECT REIMPLANTATION CORONAR ARTERY BYPASS

GRAFTING

ANAMALOUS CORONARY ARTERY COURCE BETWEEN AORTA AND PULMONAR ARTERY LCA arising from rt

sinus of Valsalva The LCA courses

between the aorta and pulmonary artery.

This interarterial course can lead to compression of the LCA resulting in myocardial ischemia.

0.1 to 0.3% No physical finding Innocent murmur in children Sudden death Genetic link

ECG Echocardiography Angiography CTA, MRA Intravascular USG Myocardial perfusion scan

SURGERY MUST for asymptomatic anamalous

left coronary artery Procedures: Unroofing procedure Creation of a neo-ostium Translocation with reimplantation CABG in adults

The single coronary artery

Type I: “true single coronary”: one artery supplies the entire heart ;

" Type II: single artery divides in RCA and LCA (actually 2 coronaries with common aortic origin);

" Type III: other atypical patterns

Lesions or disease processes affecting its proximal course that might induce dramatic events

Single/complex malformations of the heart (tetralogyof Fallot, DORV, persistent truncus arteriosus,pulmonary atresia with intact septum, TGA, etc.)

Congenital atresia of the left maincoronary artery (CALM)

flow in the LAD and Cx is not centrifugal but centripetal (i.e. retrograde).

No ostium of the left main coronary artery and the proximal LMCA ends blindly

An association was found with supravalvular aortic stenosis especially in William’s syndrome

Fistula

A large LAD giving rise to a large septal branch that terminates in the right ventricle (blue arrow).

Left-to-right shunt, left-to-left shunt Distal coronary circulation steal Diagnosed during murmur evaluation Angina uncommon CCF, atrial fibrillation Spontaneous rupture, endocarditis

Qp/Qs is seldom larger than 1.8A special distinction pulmonary atresia with intact

ventricular septum –”right ventricular-dependent circulation”

a proximal coronary artery with severe luminal stenosis / occlusion

obliteration the RV cavity leads to ischemia

Echocardiography Angiography MRA

SURGERY Ligation if distally placed, without CPB Ligated with multiple pledgeted

sutures Over sewing of the origin of fistula Direct closure from chambers with

pericardial patch CABG if distal perfusion affected

Myocardial bridging Incidence at

catheterization is 0.5-16%

The depth of the vessel under the myocardium is more important that the lenght of the myocardial bridging.

Doubtful hemodynamic significance

Complete transposition of the greatarteries (TGA)

The “normal” coronary disposition in TGA is: 1LCx 2R

Two anomalies are associated with intramural course : LAD and Cx (1LCx 2R) or of the RCA and LAD (1RL 2Cx)

The origin and course of the sinus nodeartery is important in view of the atrial

switchoperations (Mustard or Senning).

Congenitally corrected transposition ofthe great arteries (CC-TGA) The morphology of the coronary arteries

“follows” that of the ventricles, beyond their origin and proximal course

The atrioventricular and ventriculoarterialdiscordance render the coronary

disposition“anomalous” Single coronary artery arising fromthe aortic sinus 1

Tetralogy of Fallot (TOF) Incidence 2-9% Anamalies of particular importance

are:1.Vessel crossing the RVOT: conspicuous conal branch, origin of the LAD from the RCA or

from the aortic sinus 1,

origin of the LMCA from sinus 1, origin of the Cx from the RCA or

aorticsinus 1, Origin of the RCA from sinus 2 origin of the LAD from the NF sinus

of the pulmonary trunk;

2. Coronary artery contributes- to pulmonary blood flow (TOF with

pulmonary atresia). the coronary artery may be connected

to the pulmonary system being the major or sole source of pulmonary flow

To conclude

Coronary anomalies represent a goodexample of the dilemma between “doing

toomuch” and “doing too little”.

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