Coronary artery by pass graft surgery has become the most common cardiac surgery done world over ever since it was first introduced by Favalaro in 1969.The common indications are, triple vessel disease and left main disease in any of the following situationsE.
Elective CABG(Non emergent)
1.Chronic stable angina
Either emergent or elective
1.Unstable angina
Emergency CABG*
1.Acute myocardial infarction.-Cardiogenic shock
2.Failed thrombolysis
3.Failed primary PCI
4.Complications during routine PCI(Cath lab crashes ! etc)
5.As an associate procedure after a mechanical complication during MI (Septal rupture, Acute MR etc)
*In emergency situations even a single vessel disease would require a CABG
Hybrid CABG
Combining CABG and PCI in the same patient is followed in very few centres .(Example LAD graft and RCA angioplasty)This is done in patients who have co morbid conditions who can not tolerate prolonged surgical times.Further there can be situations one lesion is very ideal for PCI while for other grafting is the only solution.
Controversial CABG
1.CABG as a primary revascularisation in STEMI*
(Rarely done now , almost obsolete , primary PCI has almost replaced it . . . but it is still useful if performed within 6 hours of MI )
2.Incidentally detected CAD* following routine coronary angiogram.
( *CABG for incidentally detected asymptomatic CAD is increasing in many parts of world )
Inappropriate CABG
If it’s triple vessel disese it must be CABG -CASS study (1980s)
Coronary artery surgery study (CASS) still has considerable influence among the cardiology community in the decision making process for CABG , even though it is many decades old .There has been a phenomenal development in both medical as well as interventional techniques since CASS . (Thrombolysis, Statins, ACEI, PCI DES to name a few) .
When CASS study was done many decades ago,it was believed triple vessel disese constitute a homogeneous population and carry the same clinical significance . For example a 90% proximal LAD , 50% RCA and 50% OM technically qualify for a CABG and unfortunately , some of them are subjected to it even in 2008 ! Now we clearly know, it is not the number of diseased vessels that is important, but it’s location, severity , LV function, presence or absence of diabetes . Finally , the presence of revascularisation eligible myocardium must be documented in all post MI patients . (Technically referred to viable & ischemic myocardium ).
Currently , with the PCI & medical management has grown so much, CABG should be reserved only for, critical triple vessel disese , with at least one proximally located lesion (Mostly LAD or Left main ), especially in diabetic individuals.
Dr.S.Venkatesan MD 