Posted in Anatomy of heart, tagged coronary anatomy, dual rca, dual right coronary artery, right coronary artery, right main left main on August 16, 2016| Leave a Comment »
RCA is known for unusual variants.Here is a right main trunk which divides into two major branches, both taking a surprisingly similar course.Shall we refer it to as Dual RCA or is it an early RV branch ? But how can both run posterior and parallel ?
PS: His LAD and LCX were normal.
Posted in Uncategorized, tagged coronary angiogram, medical management of cad, misuse of coronary angiogram, RCA, right coronary artery on November 3, 2011| 2 Comments »
This is an RCA of a patient who had chronic stable angina , class 2 with moderate anti anginal medication.
What shall we do ?
The correct response would be 5
Without knowing the status LAD and LCX . . . RCA should not be touched . Further, the concept of tackling the coronary artery by itself is fundamentally wrong ! We are supposed to tackle patient’s symptom , reduce future risk of events and not merely their coronary artey !
His LAD and LCX was near normal. In the weekly cath meet PCI to mid RCA covering the critical segment was strongly debated but lost a close race .
The final decision was to allow the patient to continue intensified medical management (Statin 80mg /Metoprolol 100mg ) . He is comfortable with that .
Medical management in a tight single vessel disease can never be digested by any Interventional cardiologist whatever may be the guidelines !
Final message
Do not decide PCI on the basis of how ugly a coronary artery looks , rather spend some time on true symptomatology , optimise baseline therapy and re assess risk profile
One learned dictum is , do not meddle a RCA , however severe the lesion may be if LAD and LCX are fine.*
*This rule is not applicable in ACS
Posted in Cardiology - Clinical, cardiology -ECG, Cardiology -Interventional -PCI, cardiology -Therapeutics, Cardiology -unresolved questions, cardiology- coronary care, cardiology-Anatomy, Cardiology-Arrhythmias, tagged acc aha, acs, acute coronary syndrome, cardiogenic shock, co dominat coronary circulation, coronary artery, domianant lcx, dominat rca, failed thrmbolysis, inferior stemi, inferior vs anterior mi, infero lateral mi, infero posterior mi, infero posterior stemi, left anterior descending, left circumflex artery, nstemi, primary pci, right coronary artery, rv infarction, rv mi, stemi on July 17, 2009| 7 Comments »
Myocardial infarction (STEMI) occurs in two distinct arterial territories .The anterior LAD circulation and postero- inferior RCA/LCX circulation.The incidence is equally shared.
There has been some learned and unlearned perceptions about Inferior MI.
Inferior MI is less dangerous than anterior MI. True or false ?
Answer: Essentially true in most situations.
Reasons.
Inferior wall of the heart (strictly speaking there is no walls for heart , only surfaces , which blends with adjacent areas) inferior wall is formed by diaphragmatic surface and posterior surface.Inferior MI can occur by either RCA or LCX obstruction.The outcome of inferior MI is determined by mainly by the extent of LV myocardial damage it inflicts.To quantitate this we need to know , how much of LV is supplied by RCA , or LCX or combination of both ? This depend on the coronary dominance .It is estimated , the bulk of the LV is supplied ( up to 75% ) by LCA. This becomes further high in left dominant circulations . In fact , it is believed LV can never get involved in non dominant RCA occlusions. This has brought in a new terminology called “Small inferior MI”.Inferior STEMI due to PDA occlusion or in a co -dominant circulation is not yet studied
Apart from the above anatomical considerations the following clinical observations have been made regarding inferior MI.
When can Inferior MI be dangerous ?
Anatomical factors
Inspite of the above factors inferior MI can not be taken lightly . Especially when it extend into posterior, lateral , (Rarely anterior) segments.
While posterior extension is often tolerated , lateral extension is very poorly tolerated .This is probably explained as the extension involves the vital free wall of LV and the laplace forces could precipitate LVF. Free wall rupture is also common in this situation.
Posterior extension , predominantly involves the surface of RV which is less important hemodynamically. Of course incidence of MR due to it’s effect on posterior mitral leaflet can be trouble some.
High risk clinical catagories.
Out of hospital STEMI are at equal risk irrespective of the territories involved .This is because, primary VF does not differentiate , whether ischemia comes from RCA or LAD .
How different is the clinical outcome of infero-posterior MI with reference to the site of coronary arterial obstruction ?
The sequence of outcome From best to worse : Non dominant RCA* → Dominant RCA but distal to RV branch → LCX dominant with large OMs
* It is believed an acute proximal obstruction of a non dominant RCA may not be mechanically significant, but can be electrically significant as it retains the risk of primary VF and SA nodal ischemia. The ECG changes can be very minimal or some times simple bradycardia is the only clue. One should be able to recognise this entity (Non dominant RCA STEMI) as the outcome is excellent and these patients would never require procedure like primary PCI
** A inferior MI due to a dominant LCX and a large OMs have comparable outcome as that of extensive anterior MI. The ECG will reveal ST elevation in both inferior and lateral leads.
***In patients with prior CAD and collateral dependent multivessel disease the inferior anterior sub classification does not make much sense as entire coronary circulation can be mutually interdependent.
Final message
Inferior STEMI generally lacks the vigor to cause extensive damage to myocardium in most situations .Further they respond better to treatment. Risk stratification of STEMI based on the location of MI has not been popular among mainstream cardiologists. This issue needs some introspection as the costly and complex treatment modalities like primary PCI is unwarranted in most of the low risk inferior MIs.
Related posts in my blog:
1.Why thrombolysis is more effective in RCA?
Posted in cardiology -ECG, Cardiology -Interventional -PCI, Cardiology -unresolved questions, Cardiology-Coronary artery disese, Infrequently asked questions in cardiology (iFAQs), tagged 64 slice ct scan, atrioventricular groove, bifurcation, coronary angiogram, coronary artery, interventricular groove, left amin, left anterior descending, ramus intermedius, right coronary artery, trifurcation lesion on December 16, 2008| 16 Comments »
Coronary arterial circulation is the life line for the human heart and it’s survival.Typically it is supplied by two coronary arteries, left and right coronary artery.Both, together carry about 250ml of blood every minute.( Approxinately equal to a cup of coke ! ).These coronary arteries generally divide in a predetermined fashion , and have multiple branches . It is a mystery , what decides this branching pattern
Is it like a our palmar crease ? or the cerebral gyri ?
However , it does follow a certain rule, one major coronary artery will follow the four important grooves of heart. In the left side , left main coronary artery (LM) originates in the left coronary sinus (Size varying between 1mm -20mm) and usually bifurcates into LAD and LCX. The left anterior descending artery (LAD) runs in anterior interventricular groove while , the right atrio ventriculo groove carries the right coronary artery(RCA) .Left circumflex artery (LCX) traverses the left atrio ventricular groove.The most inconstant branch is the posterior descending artery (PDA) which runs in the posterior interventricular groove.PDA can arise from either RCA, LCX or both or even from LAD.
The major branches of LAD are called diagonal and septal while the branches of LCX are called obtuse marginal(OM).There can be two to three diagonal and OMs.
The left main coronary artery instead of bifurcating into two , it trifurcates into three vessels.(LAD, LCX, Ramus)
The real incidence could vary betweenn (10% to 30%) depending upon the series.
It generally goes in the angle between the LAD and the LCX.It may either behave like a large OM or a diagonal branch.It supplies the lateral free wall of the LV many times.The peculiarity of this vessel is it does not run in a anatomical groove .It simply slides over the free surface of LV.Rarely, a very abnormal course of ramus, criss cross the aorta and pulmonary artery .
We don’t know yet. But it is very likely since it is an early branch from left main, it might have a predilection for atherosclerosis as like LAD or LCX ostium.In fact now we recognise more of trifurcation lesions involving three branches of left main .
What would be the ECG finding if a large ramus is the culpirit vessel during STEMI ?
This scenario could be rare.
ACS in ramus could present as ST elevation in 1/Avl /V5,V6
But it is realised , whenever the ECG changes are not fitting with typical ASMI or a lateral MI one should suspect a ramus lesion
What is the significance of ramus for an interventional cardiologist ?
PCI in ramus is a rare opportunity for a cardiologist .The issue here is, if ramus is involved adjacent LAD and LCX is also likely to be involved .So it would logically be a multivessel , complex angioplasty.Isolated ramus lesion could be tackled easily.Another issue here could be ,since this vessel is not within any anatomical groove stent deployment would have a poor support and prone for mobilisation and migration .
Dr.S.Venkatesan MD 