3. DEFINITION
A coronary artery bypass grafting (CABG) is a surgical
procedure widely used to treat coronary heart disease. It
diverts blood around narrowed or clogged parts of the major
arteries (blood vessels), to improve blood flow and oxygen
supply to the heart.
4. OBJECTIVES
Control of ischemic symptoms
Prevention of myocardial infarction
Prolongation of life
5. INDICATIONS
Those with siginificant >75% left main coronary artery stenosis
Those with triple vessel disease with left ventricular dysfunction or
complex lesions not well suited to balloon dilatation
Demonstrated reversible ventricular dysfunction and clinical
evidence of congestive heart failure
Unstable angina
Evolving MI
6. CONT…
Exercise induced hypotension or ventricular arrhythmias secondary
to myocardial ischemia
Stable angina refractory to adequate medical therapy and interfering
with the patients ability to function at an acceptable level
7. TARGET VESSELS
Degree of narrowing of the arterial lumen
Size of the artery distal to the stenosis
Viability of muscle supplied by the artery
Presence of diffuse disease in the distal portion of the artery
13. GUIDELINES FOR SELECTING GRAFT
• The internal mammary artery should be used to bypass the LAD
when bypass of the LAD is indicated.
• As an adjunct to the left internal mammary artery, a second
arterial graft (the right internal mammary artery or radial artery)
should be considered in appropriate patients.
• Use of bilateral internal mammary arteries should be considered
in patients who are not at high risk for sternal complications.
(Cleveland clinic journal of medicine)
14. INTERNAL MAMMARY ARTERY
The LIMA( Left internal mammary artery) is the vessel of first
choice.
IMA Usually are patent for many years postoperatively (10-year
patency >90%) because of the fact that <4% of IMAs develop
atherosclerosis, and only 1% have atherosclerotic stenoses of
hemodynamic significance
15. Cont…
It is preferred to saphenous vein because of its long term patency
rates
Factors thought to contribute to superior long term patency are
1.)The ITA’S smaller size more closely approximates coronary
artery diameter
2.)Flow may be less turbulent because of similarities in ITA and
coronary artery geometer
3.)ITA grafts have no valves or varicosities
4.)The ITA retains the biologic processes of an intact arterial vessel
16. Cont…
An ITA can be used either as a pedicle or free graft
In pedicle graft : origin is left intact and distal is anastomosed with
target coronary artery
If used as a free graft: it is excised at its proximal and distal ends
and anastomosed proximally to the aorta and distally to the target
coronary artery
Bilateral ITA is generally reserved for very young patients with
accelerated atherosclerosis, absence of venous conduits
17. Cont…
Bilateral grafting indications are
a.)lower extremities amputation
b.)previous saphenous vein ligation
c.)severe varicose veins
A higher incidence of respiratory insufficiency is reported may be
due to phrenic nerve dysfunction
However it is almost transient and rarely interferes with
postoperative recovery
19. Saphenous vein
Saphenous vein grafts is common in patients older than 75 yrs of
age
Their disadvantage is a declining patency with time
10% to as many as 25% of them occlude within 1 year of CABG
additional 1% to 2% occlude each year during the 1 to 5 years after
surgery; and 4% to 5% occlude each year between 6 and 10 years
postoperatively.Therefore,10 years after CABG 50% to 60% of
SVGs are patent, only half of which have no angiographic evidence
of atherosclerosis
20. Cont…
Preoperative assessment of arterial blood flow to the lower
extremities is important, if peripheral arterial occlusive disease is
present, wound healing may be compromised
Vein is harvested with the least degree of arterial disease
Since lymphatic drainage from the vein is interrupted patients
develop edema
Patients who are immobilised for a long time deep vein thrombosis
may increase
21. Alternative conduits
Other arterial conduits ,such as the radial, gastroepiploic, and inferior epigastric
arteries, have been used in CABG.
Radial artery graft patency is best when used to graft a left-sided coronary artery
with high grade stenosis and worst when utilized on the lower pressure right
heart.
The gastro epiploic artery is most often used to bypass the right coronaryartery or
its branches,but it is prone to spasm. The 1-, 5-, and 10-year patency rates of the
gastro epiploic artery are reportedly 91%, 80%, and 62%, respectively
Due to its length,the inferior epigastric artery is usually used as a “Y” or “T”
graft or may be used as free graft. It is also prone to spasm .Its reported1-year
patency is about 90%
24. CONT,..
It is a sterile, non‐pyrogenic solution for cardiac perfusion in a
Viaflex bag.
And is used to induce cardiac stasis and to protect the myocardium
during open‐heart surgery.
It is used in combination with ischaemia and hypothermia to induce
cardiac arrest during open heart surgery and to preserve the
myocardium during asystole
25. CARDIOPULMONARY BYPASS
Cardiopulmonary bypass (CPB) describes a system used to
temporarily perform the functions of heart and lungs during
operative procedures on the heart or great vessels
26.
27. Cont..
CPB is called extracorporeal circulation
Venous cannulae are used to drain blood from the right side of the
heart into CPB circuit
As blood is pumped through the circuit it is oxygenated, filtered,
cooled or warmed and returned by means of arterial cannula to the
systemic circulation
CPB may be either total( all venous blood is diverted into the
extracorporeal circuit) or partial( some venous blood returns to the
heart and is ejected into aorta
28. Cont..
Any cardiac operations that involves use of CPB is termed as open
heart surgery whether a cardiac chamber is opened or not
30. VENOUS AND ARTERIAL CANNULA
Venous blood is diverted into the CPB circuit using one or two
large bore cannulae
A single cannula is inserted through a small incision in the
anterolateral aspect of the right atrium
Oxygenated blood is returned to the systemic circulation by means
of cannula inserted in the ascending aorta
31. oxygenator
Device that oxygenates blood and facilitates co2 exchange
Two types
a) Bubble oxygenator
b) Membrane oxygenator
32. RESERVOIR
CPB reservoir 500 to 3000 ml of blood
Purpose is to reserve a volume of blood in the extra corporeal
circuit to allow escape of air from the blood to allow the rate of
blood return
33. ARTERIAL PUMP
Primary component of CPB System
Propels oxygenated blood into the patients arterial circulation
34. LEFT VENTRICULAR VENT
Placement of vent in the left ventricle
To prevent distension of left ventricle when it is not ejecting
Aorta Is cross clamped
35. CARDIOTOMY SUCTION
Specially designed catheter to aspirate blood
The catheter is placed in the mediastinum
Aspirated blood is directed towards extracorporeal circuit
38. ON PUMP CABG
In on-pump CABG the heart is stopped with the body’s blood
supply being maintained by the cardiopulmonary bypass (CPB)
machine.
While the heart is stopped the surgeon performs the graft procedure
With the grafting complete, the body is removed from the
cardiopulmonary bypass machine and the heart is restarted
( Global journal of health sciences)
39. ADVANTAGES
On pump Coronary artery bypass (ONCAB) is the more traditional
method of performing bypass surgery.
However its resultant inflammatory effects cause renal dysfunction,
gastrointestinal distress and cardiac abnormalities which forced the
surgeons to look for alternatives to the procedure
(Global journal of health science)
40.
41.
42. OFF PUMP CABG
Off-pump CABG, the area around the blocked coronary artery is
stabilized while the surgeon grafts the blood vessel on the pumping
heart.
Newer procedure to On-pump CABG
Doesn’t require the use of the cardiopulmonary bypass machine
( Global journal of health sciences)
43. ADVANTAGES
Off pump coronary artery bypass (OFCAB) gained popularity, as a
variant of on-pump coronary artery bypass, due to its recently
discovered effects
Less inflammation,
Less morbidity
More cost effective
(Global journal of health sciences)
45. Cont..
5.Chest X ray
6. ECG
7. ECHO
8. Angio in selected cases
9.USG – Abdomen in selected cases
46. 3. Preparations
Whole body shaving from neck to toe
Savlon/ ethanol/ Dettol- antiseptic soap -3 baths
Chlorhexidine mouth wash
Betadine scrub clean of surgical area
Washed clean clothes after shaving and washed clean dress on day
of surgery . Foot cover after bath
47. Cont….
4. Incentive spirometry
5. Recording vitals – TPRBP
6. Daily weight recording for all cardiac cases( if weight above
3kgs to inform surgeons)
48. CONT..
6. Drugs:
Inj.TT ½ cc for all adult
Beta blockers- CONTINUE
Diuretics- STOP
7. Consent
8.NPO
50. CONT,..
If ITA is used it is first immobilised before cannulation for CPB
Left ITA is harvested( great care is taken it is a reactive conduit and
is vulnerable to spasm)
Saphenous vein is harvested simultaneously
52. Cont..
After it is accomplished rt atrium and aorta are cannulated and CPB
is initiated
Body temperature is maintained at 28c
Cardioplegic solution is administered to produce cardiac arrest
Epicardium overlying the CA is incised and anterior wall of the
artery is opened
A probe is passed into the artery to measure its size and then
anastomosis is done
53. Cont…
After grafting is completed a flow probe is used to measure blood
flow
If flow is > 100ml/min vasodilated
Myocardium is warmed sufficiently to resume electrical rhythm
Weaned from CPB
Cannulae are removed . Hemostasis achieved
Sternum is fastened with heavy suture material
Skin incision is closed
55. Cont,..
Investigations as per protocol
Weight recording
Salt & water restrictions(adult- salt 3g/ day, water 1.5 L /day)
Anti coagulation counselling
Dressings
Peripheral line – remove after 24 hrs after shifting to ward if no IV
needs and patient stable
