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Page 2 of 8 Machiraju. Vessel Plus 2019;3:25 I http://dx.doi.org/10.20517/25741209.2019.08

remains as one of the major healthcare entities that drains Billions of dollars and the treatment at best
is only a temporizing situation without a permanent cure for the disease entity. The patient’s genetic
background, dietary habits, stress, lack of exercise, diabetes, smoking, other socioeconomic conditions
and many more factors contribute towards varying outcomes. As physicians became comfortable with the
existing methods of treatments, newer drugs and surgical techniques, percutaneous catheters and varying
stents came into the field that have provided the impetus for physicians to constantly learn while providing
care. This has resulted in improvements on one side and ongoing sporadic catastrophic events on the other
[1,2]
side . This paper will outline the changes that have occurred over the years on the overall treatment of
the disease.

EVOLUTION OF THERAPEUTIC OPTIONS
It was believed that the occlusion of coronary arteries led to myocardial ischemia or infarction from the
[3]
pathological specimens. But it was not until Sones and Shirely performed several hundred coronary
cine angiograms and showed the lesions in the coronary artery branches and their anatomical variations,
surgeons could not plan a method of treatment to tackle the occlusions. Several advances occurred
simultaneously that incorporated cardiopulmonary bypass routinely into cardiac surgery and surgeons
gained experience to tackle peripheral vascular disease as well. Development of microvascular instruments,
fine suture materials, wearing surgical loupes and a head light for better visualization have helped to improve
technical proficiency for coronary artery bypass surgery (CABG). Improvements in myocardial protection
starting from intermittent aortic cross clamping and a fibrillating heart to a completely quiescent heart
with antegrade and retrograde blood cardioplegia gave an enormous leap forward for CABG surgery.

Saphenous vein was the preferred conduit until late 1970s in CABG surgery. At that time, it was shown
to have a better patency when used to bypass left (Lt) anterior descending (LAD) artery, though there
are graft failures to the other branches of coronary arteries. LAD being the most important blood vessel,
was bypassed with the best quality of the available vein. The graft being straight and short, carried high
blood flow into the large myocardial segment. These factors contributed to the high patency rate. A vein
which lies normally in a low-pressure vascular system, once subjected to arterial pressure and blood flow,
showed evidence of complete endothelial cell damage of the intima and subsequent development of rapid
atherosclerosis. Though use of Lt internal thoracic artery (LITA/LIMA) in CABG was performed much
[4]
earlier by Kolesov, universal acceptance by surgeons did not happen until Floyd Loop’s landmark article
about the long-term benefits of arterial graft to LAD using LITA. Subsequently as more and more data
became available about vein graft atherosclerosis, surgeons have slowly adopted the use of more arterial
grafts using right internal thoracic, radial (RA) and gastro epiploic arteries.

COMPLETE SURGICAL MYOCARDIAL REVASCULARIZATION
Before percutaneous coronary intervention (PCI) became a generally acceptable procedure to treat
coronary artery stenosis, surgical revascularization with bypass grafts had been the standard of care to
treat patients with significant CAD. During the peak of surgical myocardial revascularization in late 80s,
CABG was only performed in large Medical centers in the hands of highly trained surgeons who were
able to tackle even small blood vessels the size of 1 mm. Anatomically right (Rt.) Coronary artery has a rt.
ventricular branch, posterior descending (PDA) and posterolateral (PLB). Lt coronary artery has LAD, 1 or
2 diagonal branches and main circumflex (CX) branch giving several marginal branches on the posterior
wall of the Lt. ventricle. Between the LAD and CX a large ramus branch can come on to the lateral wall.
Every suitable vessel with 70% or above stenosis was bypassed. Surgeons were able to perform 3 to 6
bypasses on an average and even the number increased to 7 or 8 depending on the coronary anatomy
and diffuse nature of the disease. Complete surgical revascularization is accomplished when all the
stenotic blood vessels are bypassed. While this is considered as an anatomical classification, a functional