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Embryology:
-myocardial cells initially get nourshment fr blood direction via trabeculations at endocardial surface
-The trabecs dvp--> sinusoids, thus stuff can diffuse
-Proepicardial protrusion of primordial liver cells--> proepicardium & epicardial cells--> migrate over heart surface & the epi cells invade to --> subepicardial matrix to --> coronary vasculature plexus. They then do epithelial mesenchymal transformation. Capillaries then get associated w these cells to --> mature cells. Small vssls on the heart surface fuse and grow inward to penetrate the Ao (not coronary buds fr ao sinuses growing out to fuse w cor arteries...
Anatomy:
-L Main CA
--> Circumflex Branch- goes post'ly in AV groove
--> L Ant Desc Branch
-LCA supplies only free wall of LV (unless LCA dominant)
-R Coronary Artery
-->Small Conal branch
-then goes post'ly along AV groove (opposite direction as LCA)
-Septum gets Q fr perforating branches fr the ant and post desc CA's
-69% people the RCA is dominant- gives rise to post desc CA, which then goes to apex to supply posterior ventric septum, inf wall of LV, and AV nd.
-11% people- LCA dominant, so --> post desc CA
-20-57% pts w bicsupid Ao vlv or AS have LV dominant systems and short L main CA
-20% people- codominance
-There are collaterals between CA branches, and can get bigger if there's a P gradient bn branches
-Cardiac Veins
-Arise fr prox part of L sinus horn & the common cardinal veing
-Great cardinal vn starts @apex & runs up the ant IV groove, then entrs CS, just below L lower pulm vn
-Coronary Sinus runs around L edge of heart in post AV groove, and enters RA near AV nd
-Middle Vein runs up the post AV groove to enter CS
-Posterior Ventric vn drains the free wall of LV, into CS
-Small Cardiac vein runs w RCA in R post part of AV groove, and drains into CS or into RA
-Small veins draining RV free wall enter into CS or into RA
ANOMALIES OF CORONARY ARTERIES IN THE ABSENCE OF STRUCTURAL HEART DISEASE
Normal Variations:
-Usually, RCA & LCA come from the middle of the Ao sinuses, but may come from STJ or aobve
-Ostium position doesn't affect Q
-Ostia can be round, oval, elliptical
-Usally perpendicular to Ao wall
-Conus branch of RCA commonly has separate origin
-1% of ppl have separate origin of the LAD & L Circumflex, esp w bicuspid Ao vlv
-no clinical signif to above xx
Abnormal Origin of the RCA or LCA from Inappropriate Sinus
Anomalous Origin of LCA Branches from Right Sinus of Valsalva
-L CMX from R main CA
-#1 anomaly (1/3 of all CA anomalies)
-L CMX passes behind Ao to get to where it normally supplies.
-Usually no xx fr it, but could be compressed if both mitral &Ao prosthetic fixation rings placed
-Also, increased risk of atheromas
-L Main CA from Right Sinus of Valsalva
-less common, more xx
-4 Possible Paths:
-Post to Ao
-Ant to RVOT
-Within ventric septum beneath the RV infundibulum (#1 way)
-B/n Ao & RVOT
-This version is assoc w sudden death/premie MI/ischemia, usually just post exercise.
-Some of these pts had syncope/CP w exercise
-Most had slitlike ostium of LMCA, w an intramural course within Ao root for ~1.5cm
-LAD from R Sinus of Valsalva
-Rare unless CHD: TOF common
-LAD passess ant to RVOT or thru IVS, but rarely bn Ao and RVOT
-If +atheroma at ostium of common art trunk, then most of heart will get ischemic, so it would be ~ to LMCA stenosis.
Anomalous Origin of RCA Branches from the Left Sinus of Valsalva
-R Main CA from L sinus of Valsalva is common (30% of CA anomalies), esp Aisain/Hispanic
-RCA runs bn Ao and RVOT to get to R side of the AV groove, then Nl path.
-Newer reports that it is not benign, and related to ischemia/infarct/sudden death, w an angulated artery and slitlike ostium.
Single Coronary Artery
Single CA fr Ao, then branches.
-+/- Atretic cord connecting part of the artery to a sinus of valsalva without any ostium.
-40% of these are assoc w other cardiac xx- TGA, TOF, Truncus, Cor-Cameral fistulas, bicuspid Ao vlv
-Can be fr R or L.
-Very variable path, eg. can follow its normal path, adn then cont to other side of heart, or some branches can pass bn the GA's.
-If fr R side, then RCA can follow Nl RCA path and then continue as an L CMX CA, which then --> LAD
-Or, after RCA arises it can --> branch to L heart that goes post to Ao and then gives L CMX and LAD
-Or, a separate branch can go ant to RV infundibulum to --> LAD before continuing on as circumflex...
-Most are ASx unless there's an atheroma, though some have had early death
-Variants w a major branch passes bn Ao & RV infundibulum that are greatest risk for sudden death, though other types can --> ischemia.
LCA or RCA Arising from Posterior Sinus of Valsalva
-rare, not associated with early/sudden death
Mechanism of Death (in above anomalies):
-myocardial ischemia, but ? mech
-LV myocardium has much demand w exercise
-Ao root distends w exercise in systole--> compress/stretch an artery that runs in its wall
-likely have ischemia--> VF
Sx/Si:
-Most don't cause ischemia, espec if the branch doesnt go bn Ao and RV infundibulum.
-Even if bn AO/RVOT, they don't always--> sudden/early death, but can--> Sx- syncope, prolonged CP before a fatal event... Usually during or just after strenuous exercise
Dx:
-If any syncope/sev CP w/ or p exercise--> investigate well
-Usually negative exam
-Check resting ECG for LVH/RVH, prior infarct, arrhythmia
-Echo- check coronary origin/path, intracardiac xx, HCM
-ensure CA don't pass bn GA's (highest risk of death)
-TEE, MRI, CT if needed to check anatomy
-Stress test- useful, but can miss patients who then get sudden death
ALCAPA: Anomalous Left Coronary Artery from the Pulmonary Artery
-usually fr L post facing sinus
-No xx as fetus, bc pressures ans SaO2 are ~same in Ao/PA, thus no stim to --> collaterals
-As PA SaO2 drops postnatally and PA P drops to < systemic
--> myocardial vessels dilate to reduce R and increase Q, but it quickly is unable to compensate, --> ischemia starts.
-Initially only ischemic w exertion (crying/feeding)
-Infarct at Ant-Lat LV free wall ==> decr LV Fx--> CHF, worsened by MR bc of dilated MV ring/infarct and dysfx'l AL papillary
-Collaterals bn Nl R and abNl LCA get bigger, and then RCA gets bigger bc of the incr Q
-BUT, the Q in these collats ends up going to the (low pressure) PA instead of the LCA (hi R)
-15% of pts have collaterals that can support them thru adulthood
Path:
-usually isolated; assoc w PDA, VSD, TOF, CoAo
-if +phtn p big VSD, pt might adequately perfuse myocardium (bc PA P ~Ao P...)
-closing the VSD may decr PA P--> xx!!
-RCA dilation, large collaterals, LCA seen entering MPA, usually at L pulm sinus
-Big heart in infants, dilated/hypertroph LV & LA, w AL paps atrophied/scarred and short cords, endocardial fibroelastosis
-Often thinned walls at AL LV and apex bc of infarctions, +/- mural thrombi
-In adults there is usually thin LV wall (like a vein!), but less large as infant, and no endocard fibro
Sx/Si:
-Some have paroxysms of difficulty/distress w feeds in first few months of life, +/-ALTE
-Many present w CHF Sx, some w Sx as infant that then improve/resolve
-Older kids may be ASx, or have DOE, syncope, angina pectoris w effort
-Sudden death p exertion is common
-MI/CHF rare in adults
-PE- +/-CHF Sx; +big heart, +/-RV enlarge w loud P2 if LV failure --> phtn
-soft/absent S1 if MR or soft continuous murmur at lUSB bc of anomalous coronary Q to PA (~to a small PDA sound)
ECG:
-Ant-Lat infarct at presentation usually - c/s ALCAPA strongly if:
-AbNl Q waves at I, aVL, V4-6
-AbNl R waves or Rwave progression in L precordials
Imaging:
-CXR- CM, big LA, pulm edema (like most CM's)
-Nuclear myocardial perfusion imaging- highly Sx--> reduced uptake at ant-lat ischemic area, but not Sp, seen w other CM
-Echo- see LCA to PA attachment, w color flow check to see where Q goes...; esp c/s ALCAPA if big RCA
-CT- quick, see anatomy well
-Cath/Angio- less needed now...; ....
NHx:
-87% present as infants
-65-85% of these pts die by 1yo fr CHF (usually p 2mo)
-Few get better on own; others never get Sx- ? bc they have much collateral Q or restrictive opening bn the LCA and PA (so Q fr collats goes into coronaries & not PA's)
-even these ppl are at incr risk for sudden death, esp p exercise
Tx:
-Older kids benefit from surgical ligation of LCA origin fr PA to prevent steal, espec if good collats, though still get late sudden death in some
-Ligate origin of LCA and use a subclavian artery or saphenous venous graft has worked, but xx = thrombi/stenosis, w late obliterative changes in saphenous vein grafts, and can --> xx bc over teh next ~3 yrs postop the collaterals fr RCA regress
-Grafts w Internal Mammary ARtery do better, are good for older kids
-Direct reimplantation of LCA origin to Ao (w button of PA...) works and is the standard Tx in many places
-Takeuchi procedure = Ao-Pulm window made and then a tunnel fashioned to direct Q fr Qo to L coronary ostium (!)
-In past, they delayed surgery to 18-24mo old bc mortality was ? higher in sickest infants, but now w more experience we have much improved outcomes w early surgery.
-Signif pre-op MR bc of pap muscle xx is a risk factor for both mortality and late mitral valve surgery
-Some report even a 2 vessel repair is do-able even in sick pts, if you use an LVAD postop
RARE CORONARY ANOMALIES
-Coronary Atresia
- no extramural coronary arteries - rare, seen w P Atresia and Ao Atresia. Both --> pressure in small, hypertrophied RV/LV =/above Ao P, and enlarged sinusoids --> Q fr ventricle to the distal coronary arterial branches (!)
-Stenosis/Atresia of a Coronary Ostium
-at first few mm of the LCA - very very rare; pt gets collats fr RCA
--> sudden death, angina, MI, CHF
-All Coronaries from PA
-Both RCA and LCA or single CA are fr the PA
-Won't survive infancy w/o correction unless there's pulm htn
-LAD from PA
-Most presented later in life (20-60yr), w angina, MI, MR...
-L Circ CA from PA/branches
-all dx as kids...
-RCA fr PA
-rare, ischemia, syncope, CM, sudden death
Dx:
-continuous murmur at LSB
-ECG & CXR Nl
-Echo/Doppler/Angio --> RCA fr PA w retrograde Q fr RCA to PA
Tx:
-Most ASx; surgical correction often rec'd bc risk of sudden death --> reimplant RCA to AO
MISC ANOMALIES:
Myocardial Bridges
-Nly, the coronaries are epicardial- on surface, w only the terminal branches penetrating
-Commonly, epicardial art can dip beneath epicardium for a few mm, so there's a muscle bridge over it
-Ischemia/Infarct have been assoc w these, w improved ischemia p myotomy
-Angio: local narrowing w systole, patent w diastole
-Very common, w few pts w sx, so only Tx if angina on ECG/stress test
-Can be problematic in kids w HCM - assoc w CP, DOE, VT/VF, arrest in some studies
CORONARY ARTERY PATTERNS WITH CHD
COMPLETE TGA
-Terminology controversial bc everything's moved around
-Facing Sinuses = the 2 sinuses adjacent to the PA
-If the GA's are side by side, then they are Ant & Post Facing Sinuses
-If the GA's are oblique, then they are L Ant or R Post
-If the GA's are ant-post, then they are R or L
-Incr risk of cor anomalies if +VSD or +side by side GA's
-W Ant-Post GA's, usually Nl CA's: CA's usually take shortest course to reach their distribution, so w Ao ant, PA post, the LCA and circ pass ant to RVOT
-W Side-Side GA's, often see L circ from RCA, and goes post to PA
-May have inverted CA's- RCA fr L ant sinus and LCA fr R post sinus
-Sometimes, they may be intramural, or w branches passing bn GA's
TOF
-40% TOF have extra long, large conus artery, supplying the mass of the myocardium
-5% LAD fr RCA and passes across RVOT
-Sometimes, a single CA fr either sinus (L or R) w a branch crossing heart across RVOT or behind Ao
-If a major artery crosses RVOT, it makes transannular incision harder bc u don't want to cut it, so must cut parallel to artery, just above/below it, and tunnel under it, or bypass it w a conduit
Corrected TGA (L-TGA)
-Ao is ant & left of PA, and the 2 CA's come fr the facing sinuses, like w d-TGA
-The ant sinus is usually the noncoronary sinus
-Nomenclature confusion
-Some: R and L sided vessel, based on sinus origin
-Some: Describe arteries by the territory of supply (used by M/A)
-LCA supplies LV but arises fr R facing sinus, passes in front of PA and divides into LAD and circ, then passess in front of RAA in the AV groove
-RCA supplies RV but arises fr L facing sinus and runs in AV groove, in front of the LAA to end as teh post descending artery
-Might just have a single CA from the R facing sinus
DILV
-No true IVS and no typical IV groove
-Arterial branches running along the border of teh rudimentary outlet chamber = Delimiting artersies, instead of ant desc arteries
-When the outlet chamber is ant & right, the Ao and PA are related like D-TGA
-RCA arises fr R facing Ao sinus, and runs along R AV sulcus
-LCA arises fr L facing sinus, and continues around the L AV groove as circumflex
-When the outlet chamber is ant & left, the Ao and PA are related like L-TGA
-R and L main CA come fr R and L cor sinuses, and the ant desc CA might come fr either or theri might be 2 delimiting arteries bordering the rudimentary outlet chamber
DORV
-Usually Nl, except that Ao sinus is rotated clockwise, so the RCA arises ant and the LCA arises post
-If Ao is ant & right, then CA's are like D-TGA, w RCA fr R facing sinus
-15% single CA fr ant or post
Truncus Arteriosus
-RCA and LCA usually Nl origin
-If >3 cusps, then can't use regular descriptions. The LMCA arises fr post sinus usually
CONGENITAL ANOMALIES OF THE AORTIC ROOT
Aortic-LV Defect (Tunnel)
-Rare, = connection bn Ao and LV
-Described as above RCA os, w a ridge beneath it, and passes behind RV infundib, thru the ant upper part of the IVS to enter LV just below the R and L Ao Cusps
-CHF as infant, w Sx of AI - wide PP, low DBP, hyperactive dilated LV and big LA, loud to and fro murmur at base.
-ECG- LVH, LAE
-CXR- CM, +/-CHF signs; all pts w dilated Ao, bulge of enlarged R Ao sinus
-Echo- Doppler can DDx this fr AI, and fr a cor-LV fistula
-Tx = surgery, but big xx of AI postop
Aneurysms of Sinus of Valsalva
-Rare
-DDx fr diffuse dilation of Marfans, this is local dilation
-Usually congenital, but also p infective endocarditis (but also can --> IE)
Path:
-R Ao sinus most affected, then noncoronary sinus
-1/3-1/2 assoc w VSD at outlet septum
-Often Ao cusp prolapse and progressive AI fr fibrous changes to the vlv
-also assoc w CoAo, ASD, TOF, PDA
-The aneurysm can rupture into any cardiac chamber, and can have fistulas...
-Some can --> RVOT obstruction, distort AO vlv to --> AI, compress LCA--> ischemia, --> conduction xx, and complete HB.
Sx:
-ASx till they rupture--> tearing chest/upper abd pain, and if huge shunt dvp quickly--> CHF Sx quickly, but takes more time if only dvp small fistulas
-Small Fistula--> continuous murmur like a DA but loudest at 3-4th IS
-Large Fistula--> wide PP, collapsing pulse, LVH
-RVH if fistula enters R heart
-If fistula to LV, can --> to and fro murmur like PDA
-If +VSD, get a confusing combined murmur
-ECG: hypertrophy if chronic, ischemia/conduction xx if compression of CA/conduction system
-CXR: big heart, CHF.
-Echo- check color..., TEE may give better info
-Cath- CT/MRI replaces it to get hemodynamics/amt of Q shunted...
Mgt:
-Tx the CHF w AL reduction
-Needs surgical correction
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