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Machiraju. Vessel Plus 2019;3:25 I http://dx.doi.org/10.20517/2574-1209.2019.008 Page 3 of 8

classification is used when the blood vessels in the ischemic zones of the myocardium are only bypassed
ignoring the areas that already had myocardial infarction and myocardial scarring. Number of distal
anastomosis are counted and matched to the number of stenosis in the blood vessels that are technically by
passable todetermine whether a CR or incomplete myocardial revascularization (IR) is performed.

In anatomical classification, a completely occluded blood vessel proximally is bypassed as long as it is open
distally and is suitable for bypass. It is considered that next to the scar tissue there is a zone of ischemic
myocardium that can get benefit from blood flow through the bypass graft. It can also provide retrograde
collateral flow to the other connecting vessels. The typical example is bypassing an open distal Rt.
Coronary artery after it’s complete proximal occlusion. Most of the patients had at-least one arterial graft
to LAD and the remaining grafts were performed with saphenous vein. LAD revascularization is the key
part of CR when-ever there is evidence of 70% or more stenosis.

LAD atherosclerosis presents in different forms: (1) Proximal severe stenosis with excellent distal vessel
and a bypass graft can be sutured anywhere distal to the stenosis; (2) Proximal stenosis followed by an
open LAD along with diffuse atherosclerosis in the middle and the distal LAD is open at the apex of the
Lt ventricle requiring bypass to both proximal and distal segments to protect the entire septum as well the
anterior and apical segments of the myocardium; and (3) completely occluded LAD with atherosclerotic
process and will need extensive endarterectomy to revascularize the vessel. Such large endarterectomy not
only removes the atherosclerotic plaque from the LAD but also removes the plaque from the opening of
the septal branches and can improve the blood flow to the interventricular septum. By-passes requiring to
diagonal, ramus and marginal branches on the Lt side will add up to 7 or 8 distal anastomosis very easily.
Apart from LAD, bypassing another major vessel in the Lt coronary system has also increased the survival
benefit.

Use of all arterial grafts to the Lt coronary system was popularized by creating a LIMA+RIMA as a “T”
graft and performing multiple sequential grafts to the marginal branches with free RIMA graft and LIMA
being anastomosed to the LAD as an in situ graft. Prior to “T” grafting became popular, my preferred
operation was an in situ RIMA graft across the midline to LAD and LIMA graft to an OM branch
whenever applicable. In aortic arch disease there is higher chance of Lt subclavian artery to get occluded
than innominate artery. The next arterial graft that got popularized is the RA graft taken from the
[5-7]
nondominant hand. This is also used as a free graft from the aorta or as “T” graft from the LIMA graft .
The patients that were discharged from the hospital with-out any perioperative morbidity had performed
well, free of anginal symptoms and without repeat hospital readmissions for myocardial infarction or heart
[8]
failure. Zimarino et al. reviewed 28 studies that included 8,3695 patients that were treated with surgery as
well as PCI. Patients who had CR with multi vessel coronary artery disease (MVCAD), at 4.5 years follow up
showed less mortality and less repeat further interventions. CR performed as an elective surgical procedure
[9]
has better outcomes over medical therapy or PCI in diabetic patients with MVCAD. Takagi et al. did
metanalysis of patients from fourteen studies and compared 3,0389 patients and found that patients who
had complete surgical revascularization did have 37% less mortality when followed over a period of time
compared to similar group of patients that had IR.

REASONS FOR SHIFT OF PARADIGM
Changes in the trends of bypass grafting using multiple arterial grafts, introduction of “off-pump” CABG
and operating on several coronary artery branches with multiple stents and advances in PCI procedures,
complicated the CABG. Emergency surgical revascularization on patients who are loaded with antiplatelet
agents also precluded prolonged surgical procedures for fear of perioperative bleeding complications.
Collaborative effort between cardiologists and cardiac surgeons to address CAD, led to hybrid procedures