HEART SURGERY
Open heart surgery is most commonly performed for CAD, valvu-
lar dysfunction, and congenital heart defects. The procedure
requires temporary cardiopulmonary bypass (blood is diverted
from the heart and the lungs and mechanically oxygenated and
circulated) to provide a dry, bloodless field during the operation.
Newer and less invasive procedures include minimally invasive
direct coronary artery bypass (MIDCAB) and port access proce-
dures. Heart transplant will not be discussed. For information on
percutaneous ventricular assist devices, see Box 12-2.
Types of Procedures
Coronary Artery Bypass Graft
1. Traditional CABG surgery involves anastomosis of a
bypass conduit or a graft (leg and arm veins) anastomosed
to the aorta, with the other end of the graft secured to a
distal portion of a coronary vessel. The graft “bypasses”
the obstructive lesion in the vessel, and adequate blood
flow is restored to the heart muscle supplied by the artery.
(The vessel of choice is usually an internal mammary
artery because it remains unobstructed for longer than
saphenous vein grafts.)
a. Multiple grafts can be placed to bypass lesions.
b. Traditional procedure is done through sternotomy.
c. The heart is stopped, and the cardiopulmonary bypass
machine is used.
2. Primarily done to alleviate anginal symptoms and
improve survival and quality of life.
3. Indications for CABG include:
a. Left main coronary artery stenosis of 70% or greater.
b. Proximal vessel disease greater than 50% to 70%
stenosis of three main coronary arteries.
c. Multivessel disease and decreased left ventricular
function.
d. UA.
e. Chronic stable angina that is lifestyle-limiting and unre-
sponsive to medical therapies or PTCA and stenting.
4. Relative contraindications for CABG include:
a. Small coronary arteries distal to the stenosis.
b. Severe aortic stenosis.
c. Severe left ventricular failure with coexisting pul-
monary, renal, carotid, and peripheral vascular disease.
Valvular Surgery
1. Prosthetic or biologic valves are placed in the heart as
definitive therapy for incompetent heart valves. Mechan-
ical valves are of man-made material and require a life-
time of therapy with anticoagulation medications.
2. Valve repair or replacement can be done in conjunction
with CABG surgery.