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OFF-PUMP CORONARY ARTERY BYPASS SURGERY
VERSUS ON-PUMP CORONARY ARTERY BYPASS
SURGERY
Thesis
Submitted in for full Fulfillment of
The Doctorate Degree (M.D) in Cardiothoracic Surgery
By
ABDELHAMID FATHI ALI
(M.B.; B.Ch., M.Sc., Banha University)
Under supervision of
PROF. DR. MOHAMED KHAIRY ELSHAFEY
Professor of Cardiothoracic Surgery,
Faculty of Medicine, Banha University
PROF. DR.
PROF. DR.
HANY ABDELMOTELEB
ELRAKHAWY
Assistant Professor of Cardiothoracic
MOHAMED MOHAMED
SAFFAN
Assistant Professor of Cardiothoracic
Surgery,
Surgery,
Faculty of Medicine, Banha University
Faculty of Medicine, Banha University
Faculty of Medicine,
Banha University
2016
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INTRODUCTION
In a retrospective study comparing patients with multivessel disease
operated on on-pump and off-pump, no difference in morbidity and
mortality, was found, however, there was a lower necessity of blood
transfusion in patients operated on off-pump . (Kshettry V et al., 2000)
In a prospective not randomized, study no difference between the two
groups in the incidence of either postoperative morbidity or in the use of
blood was found . Standing out is that all patients were multivessel in both
groups, and the number of the grafts in the patients operated on off-pump
was significantly lower. (Bull D et al., 2001).
On the other hand, in a prospective and randomized study excluding
patients with lesion in the distal portion of the circumflex artery, show the
number of grafts per patient was similar. No difference in hospital mortality
was found, but in the off-pump group there was
lower pulmonary
infections, necessity of vasoactive drugs, bleeding, blood transfusion, minor
intubation time, in-stay ICU, and lesser cost . (Ascione R et al., 1999).
Off-pump myocardial revascularization is considered a new alternative
to perform coronary artery with minimal damage.
Several studies have been done to identify clinical differences between
off-pump versus on-pump myocardial revascularization . (Gerola L et al.,
2004).
Significant difference was found in in-hospital morbidity in the off-pump
group, with less of blood products and inotropic drugs, minor incidence of
atrial fibrillation, chest infection, time to extubation, and less, intensive care
unit and hospital stay. In fact, this study in randomized studies was one of
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the few studies that found a significant difference in low risk-patients
regarding main hospital morbidities, and not only a difference in the use of
blood products and hospital stay. (Angelini G et al., 2002)
Several times the off-pump approach was performed in patients with
lesion in one or two vessel disease, whereas cardiopulmonary bypass was
used in patients with multivessel disease. In addition, in some prospective
studies in patients with multivessel disease, the group operated on off-pump
received a significantly lower number of grafts when compared with patients
operated on-pump . (van Dijk D et al., 2001)
Heterogenous results in the literature were presented. In some reports is
shown superiority in the off-pump procedure over conventional surgery, in
others there is no shown difference between the methods . (Gerola L et al.,
2004)
In fact, the advantage of using off-pump myocardial revascularization is
being documented in high risk subgroups . (Yokoyama T et al., 2000)
Specific analysis performed in chronic pulmonary patients (Guller M et
al., 2001), elderly (Bull D et al., 2001), and severe left ventricular
dysfunction (Arom K et al., 2000), have demonstrated the advantage of
using off-pump over on-pump myocardial revascularization . (Gerola L et
al., 2004)
Several comparative studies, including multivessel diseases, have
described a number of grafts per patients significantly lower in patients
operated on off-pump . (kshettry V et al., 2000) (Bull D et al., 2001).
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This represents a bias of selection in retrospective analysis . (Gerola
Let al., 2004)
In light of these facts, our study is to compare on-pump versus offpump myocardial revascularization regarding their indications , candidate
patients , recent techniques , difficulties , results and complications .
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PATIENTS AND METHODS
This work included eighty patients who underwent isolated first time
coronary artery bypass grafting, 40 patients who were done by on-pump
CABG all in Banha University Hospital (Group A) and the other 40 patients
by off-pump technique who were done in National Heart institute except 2
patients who were done in Banha University Hospital (Group B) between
August 2013 and July 2015.
Statistical Analysis :
Results were expressed as mean standered deviations (SD) or number
(%). Comparison between the two groups was performed using the unpaired
student t test. While comparison between preoperative and postoperative
data within the same group was performed using paired student t test.
Categorical data were compared using Chi square test. Statistical
significance was defined as a probability value equal to or less than 0.05. All
analyses were performed with statistical package of MINITAB, release 12.1
for WINDOWS.
Study design:
The study is a prospective observational
non-randomized patient
study which included 80 patients .
They were divided into two groups I
and II, each group of 40
patients:
 Group I : underwent CABG by on-pump technique.
 Group II : underwent CABG by off-pump technique.
Inclusion criteria:
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1 - Ischemic heart disese with indications for coronary artery bypass
surgery for revascularization according to the guidelines for myocardial
revascularization in patients with CAD not more than 3 vessels.
2- Lt main disease .
3- Good Left ventricular function (EF > 40 %) .
4 - Elective CABG .
5 - Patients with normal renal and hepatic function (Creatinine less than
2mg/dl, total Bilirubin less than 2.5mg/dl, and AST, ALT less than 100
u/ml).
6 - Both sexes are involved .
7 -Age between 30-70 years old .
Exclusion criteria:
1- Patients having more than three vessel lesions . ( as it is difficult to
perform complete myocardial revascularization with > 3 vessel
lesions with off-pump technique ) .
2- Recent myocardial infarction (within1month).
3- EF less or equal than 40 %.
4- Patients who have combined cardiac surgery, e.g. Valve surgery or
aorta surgery with CABG.
5- Urgent CABG or redo myocardial revascularization.
6- Patients in cardiogenic shock .
7- Patients with radiological investigation showing severely calcified
aorta .
8- Patients with chronic renal failure (Creatinine >2 mg / dl).
9- Patients with hepatic insufficiency (total Bilirubin more than
2.5mg/dl, AST, and ALT more than 100 u/ml).
Patients with history of cerebrovascular strokes or carotid artery disease .
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10- Patients with chronic obstructive pulmonary disease.
11- Patients > 70 years old.
Methods :
Both groups assessed according to the following preoperative,
intraoperative, and postoperative protocol:
Preoperative Assessment :
1. History taking :
- A detailed proper history taking including: patient age, sex, IHD risk
factors.
- Functional classification according to Canadian Cardiovascular
Society Classification of angina.
2. Preoperative risk factors for coronary atherosclerosis:
Hypertension (HTN) , insulin dependant diabetes mellitus (IDDM) ,
peripheral vascular disease and family history of ischemic heart
disease.
3. - Complaint:
Chest pain according to Canadian classification :
-0 Asymptomatic.
-1 Anginal pain on strenuous exercise.
-2 Anginal pain on moderate exercise.
-3 Anginal pain on mild exertion.
-4 Anginal pain at any level of physical exertion.
4. Clinical examination:
a. General examination: To detect signs of heart failure
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and examine lower limbs for varicose veins and signs
of arterial ischemia.
b. Cardiac examination: To detect any murmur and additional heart
sounds.
5. Routine preoperative laboratory investigations:
- Liver and kidney function tests.
- Complete blood count (CBC).
- Fasting and 2hr post prandial blood sugar.
- Coagulation profile.
- Serum electrolytes.
- Lipid profile
6. Routine preoperative radiological investigations:
Plain chest x-ray both postero-anterior and lateral views.
7. Electrocardiogram( ECG):
12 lead ECG to evaluate preoperative ischemic changes , previous
myocardial infarction and cardiac arrhythmias.
8. Echocardiographic assessment including:
Due to its accuracy, non-invasiveness, accessibility and simplicity,
echocardiography was used as our tool to evaluate left ventricular functions.
The following data were collected:
a. Left ventricular end-diastolic dimension (LVEDD).
b. Left ventricular ejection fraction.
c. Regional wall motion abnormalities, using regional wall motion score
index (WMSI): In WMSI heart is divided into 16 segments of
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myocardial wall, each segment takes a score from one to four as
follows:
1. Normal kinesis.
2. Hypokinesis
3. Akinesis
4. Dyskinesis.
9. Coronary angiography:
Was our only routine imaging modality to evaluate the number and
severity of stenotic lesions in the different coronary arteries. This should be
within last 6-month provided no ischemic events had happened during this
period.
10. Peripheral arterial duplex of carotid arteries : only for patients > 60
years old .
11. Radio-isotopic scanning: Thallium viability study to assess feasibility
of surgery based on the presence of significant amount of reversible
ischemia only in patients who had MI > 1 month ago or old MI .
Intraoperative Data :
- Utmost care was given to all patients during induction of anaesthesia
by experienced anesthesia team due to their high risk.
- Anaesthesia was induced using propofol 1.2 mg/Kg, pancuronium 0.1
mg/Kg and fentanyl 8-15 μg/Kg and was maintained by air/oxygen
and propofol 2-3 mg/Kg per hour .
Group (B) off-pump group: Standard midline sternotomy incision was
used to expose the heart, left internal mammary artery and great saphenous
vein were harvested, anticoagulation was achieved using 150 units/Kg of
heparin, the activated clotting time was maintained above 250 seconds, deep
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pericardial retraction sutures are placed, the heart was stabilized using
stabilizer ( octopus ). LIMA was anastomosed to LAD at first then obtuse
marginal branches, diagonals and finally the RCA territory. Before opening
the target vessel silastic stitches were used proximal to the anastomosis,
intracoronary shunts were not routinely used. This was followed by proximal
anastomoses which were performed with systemic blood pressure not
exceeding 90 mm Hg.
Conversion from off-pump group to on-pump group was planned if
persistent ventricular arrhythmias with electrocardiographic changes usually
associated with hemodynamic compromise and heart distention. Once
conversion is indicated the earlier the better to avoid myocardial insult and
improve outcome.
Group (A) on-pump group: Standard midline sternotomy incision was
used to expose the heart, left internal mammary artery and great saphenous
vein harvested. Ascending aorta is palpated to detect any calcification.
Anticoagulation was achieved using 250 units/Kg of heparin, the activated
clotting time was maintained above 480 seconds. CPB was instituted with a
single right atrial cannula and ascending aorta perfusion cannula, standard
bypass management included membrane oxygenators, non-pulsatile flow of
2.4 L/min per m2 and a mean arterial blood pressure greater than 50 mm Hg.
Myocardial protection was achieved in patients in on pump CABG group
using either antegrade intermittent warm blood cardioplegia for induction of
normothermic hyperkalaemic arrest and myocardial protection or retrograde
cold cardioplegia or antegrade cold intermittent cardioplegia.
The following operative data were collected in all patients:
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1. Aortic cross clamp time (in group I): This is the ischemic time
recorded from applying the aortic clamp until removal of the clamp.
2. Total bypass time (in group I): This is the time from initiating the
cardiopulmonary bypass until weaning from the cardiopulmonary
bypass.
3. Total operation time: This is the time calculated from the beginning of
the skin incision to the end of skin closure.
4. Number of grafts: The number of grafts done in each group.
5. Types of used conduits.
6. Index of completeness of revascularization . ( N. of grafts done / N. of
grafts planned )
7. Number of cases which was necessary to convert from off-pump to
on-pump CABG.
8. Use of inotropic support .
9. Use of intra-aortic balloon if indicated .
I- Intensive Care Unit Evaluation:
1. Hemodynamics:
Blood pressure , heart rate , urine output .
2. Electrocardiogram:
ECG was routinely done, immediately upon arrival of the patient to the
ICU and immediately repeated whenever indicated to detect new ECG
changes in the form of ischemia, infarction and arrhythmias.
3. Post-operative ventilation :
The time from arrival to the ICU until weaning from mechanical
ventilation was calculated in both groups.
4. Post-operative blood loss and blood transfusion .
5. The use of inotropic drugs or intra-aortic balloon.
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6. Total intensive care unit stay.
7. The level of creatine kinase (CK) and its isoenzyme CK-MB:
8. Labs:
(CBC, liver and kidney functions and coagulation profile).
9. Clinical assessment for early post operative morbidity:
e.g. stroke .
II- One Week Evaluation:
Patients will be evaluated one week after surgery by the following:
1. 12 leads ECG .
2. Echocardiography:
For assesment of ejection fraction .
3. Post operative complications:
As embolic, cerebrovascular, renal, and hepatic complications.
4. Total hospital stay.
III- Three and Six Months Evaluation:
Patients will be evaluated 3 and 6 months after surgery by the following:
l. 12 leads ECG.
2. Echocardiography.
3. Follow up of complications
SURGICAL STRATEGIES FOR ON-PUMP CABG
Intravenous access was established through two large-bore peripheral
venous lines and central venous access is via an internal jugular approach
prior to the induction of general anesthesia. Monitoring lines typically
include one or more arterial lines, including a femoral arterial line in patients
for whom one anticipates that a perioperative intra-aortic balloon pump
(IABP) may be required.
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The patient was positioned in the decubitus supine position with arms
tucked at the side. The operative field is prepped to include the lower neck,
the chest, and abdomen between the anterior axillary lines and the lower
extremities circumferentially .
Incisions :
Midline sternotomy incision was performed, with the skin incision
extending from a point midway between the angle of Louis and the sternal
notch, to just below the tip of the xiphoid process. Either the scalpel or
electrocautery used to extend the incision through the subcutaneous tissues
down to the sternum. Special attention was given to identify the middle of
the sternum. The middle of the sternal periosteum was marked with the
electrocautery. Attention was then turned to the sternal notch where the
interclavicular ligament was divided, allowing palpation of the posterior
aspect of the sternal manubrium. The xiphoid process was identified and
divided in the midline with heavy scissors or electrocautery. The sternum
was divided in the midline either from the top down or bottom up depending
on the surgeon’s preference. Bleeding points in the sternal periosteum were
cauterized with care not to strip all of the periosteum away from the edges .
Once the sternum has been divided, the ITA was harvested . Harvest of the
saphenous vein or sometimes the RA was initiated simultaneous with the
sternotomy.
Cannulation and Establishment of Cardiopulmonary Bypass :
The pericardium was divided vertically down to the diaphragm and the
inferior attachment of the pericardium to the diaphragm was divided
transversely. The remnant of thymic tissue and pericardial fat was divided in
the midline until the inferior aspect of the left innominate vein identified.
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Placement of pericardial retraction sutures to create a pericardial cradle
improves exposure of the ascending aorta and right atrium. The distal
ascending aorta inspected and manually palpated for soft nonatherosclerotic
areas suitable for cannulation and cross-clamping . Systemic anticoagulation
achieved prior to arterial cannulation with intravenous administration of 300
to 400 U/kg of unfractionated heparin. Prior to aortic cannulation the
systolic blood pressure was reduced below100 mm Hg to minimize the risk
of aortic dissection. Two partial-thickness concentric diamond-shaped pursestring sutures using 3-0 Tevdek or polypropylene suture were placed in the
distal ascending aorta just proximal and to the left of the innominate artery
origin; the size of the purse strings was one-third greater than the aortic
cannula tip. The ends of the sutures were passed through rubber tourniquets
that will be used for tightening the purse strings. The aortic adventitia within
the purse strings was divided in preparation for aortotomy. The adventitia
just superior to the planned aortotomy was grasped with a forceps and an
aortotomy equal in size to the cannula tip created with a no. 11 blade.
Bleeding was controlled with slight inferior traction of the forceps on the
adventitia. The aortic cannula was inserted and properly positioned, and the
purse strings tightened. The rubber tourniquet was secured to the aortic
cannula with a heavy silk tie and then the cannula secured to the skin. The
aortic cannula was then de-aired and connected to the arterial end of the
pump tubing. Intraluminal positioning of the cannula was confirmed by
watching for the cannula to fill with arterial blood and by confirming a
pulsatile waveform with the perfusionist .
Venous cannulation was accomplished with a two-stage venous cannula
inserted in the right atrial appendage. Polypropylene purse-string suture
placed around the tip of the right atrial appendage. The purse string was
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wide enough for easy access of the selected venous cannula. An atriotomy
was made with scissors at the tip of the appendage, both edges of the atrial
appendage are grasped with forceps, and the incision was extended
superiorly and inferiorly to a size appropriate for the venous cannula. Small
bridging fibers of muscle were divided with scissors to permit easy entry of
the cannula and the venous cannula was inserted. Sometimes , a partial
occlusion clamp was placed on the right atrial appendage at the level of the
purse-string suture to simplify preparation of the cannulation site, and once
this was accomplished , the clamp was removed and the cannula inserted.
The purse-string suture was tightened and the rubber tourniquet secured to
the venous cannula with a heavy silk tie. The tip of the venous cannula was
in the inferior vena cava. The venous line then connected to the pump
tubing. After ensuring that the appropriate activated clotting time target has
been reached, cardiopulmonary bypass was initiated. An aortic root cannula
for administration of cardioplegia and venting was placed in the ascending
aorta. Also , it was sometimes placed at the site of a planned proximal
anastomosis. Retrograde cardioplegia was sometimes also used if there was
left main disease, severe proximal multivessel disease, or poor left
ventricular function (LVF).
Target vessels was easier to identify before cardioplegic arrest while they
are fully distended in their native state. Target locations are usually
confirmed by visual inspection and epicardial examination with the location
of planned distal anastomoses marked with a scalpel. Systemic cooling to
between 28 and 34°C was preferred . Cardioplegia was administered either
warm, tepid (25°C), or cold via antegrade or retrograde routes. Sometimes
cardioplegia was even administered simultaneously both antegrade and
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retrograde. Adequacy of myocardial protection was assessed with intraoperative monitoring of myocardial temperature or pH .
Distal Anastomoses :
-Arteriotomy :
Grafting the most ischemic area first will permit early antegrade delivery
of cardioplegia through the graft. We performed the left internal thoracic
artery-to-LAD artery anastomosis last to avoid tension and potential
disruption of the anastomosis . Opening into a plaque may force
endarterectomy, while injury to the posterior wall with the knife transforms
a straightforward anastomosis into a complex repair. The arteriotomy was
performed with a no. 11 blade and extended with fine Pott’s scissors
proximally and distally. The arteriotomy matched the conduit diameter, and
was at least 1.5 times the diameter of the distal coronary. Distal anastomoses
were typically constructed with 7-0 polypropylene suture. Sutures spaced to
prevent leaks at the conclusion of the anastomosis. To increase anastomotic
area bevelling the conduits at approximately 30° and notch them at the heel
was done.
-Anastomotic Technique :
In all patients of group (A) , anastomoses were performed with continuous
running suture technique which was initiated at the lateral midpoint for
virtually all anastomoses . The conduit
brought onto the field with a
mosquito clamp on the adventitia at the toe of the conduit. An end-to-side
anastomosis was accomplished with approximately 12 sutures. Starting at 3
o’clock on the right side of the vessel, the suture was passed outside-in on
the conduit and then inside-out at the corresponding location of the target
coronary vessel. Two more stitches were taken before the heel, one directly
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in the heel, and then two more on the left side of the anastomosis before
parachuting the conduit down to the target vessel. The anastomosis was then
completed by placing another six stitches evenly spaced in the same manner
around the toe until the other thread is encountered. Care was taken to
prevent suturing the back wall of the coronary, and the proper amount of
tension on the follow-through was provided to avoid both leakage and a
purse-string effect. Pedicled conduits were suture-fixated to the adjacent
epicardium. The LITA was used for multiple sequential anastomoses to the
circumflex territory with grafting of the RITA to the LAD artery.
Fig. (9) Distal anastomosis suturing for RCA in on-pump CABG
Coronary Endarterectomy :
The need for endarterectomy arouse intraoperatively when no soft site
was identified for arteriotomy or when the vessel has was inadvertently
opened in an extensively diseased area not amenable to grafting.
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The technique of endarterectomy required that the central core was
extracted adequately in order to relieve obstruction of the branch vessels.
Patency of the graft to the endarterectomized vessel depended upon the
adequacy of run-off, therefore the distal endpoints of the endarterectomy
core were smoothly tapered.
Open
extended
technique
was
preferred
when
the
LAD
is
endarterectomized .The vessel was opened as far proximal as possible . The
segment was reconstructed with a long hood of the conduit of choice or a
vein patch into which the ITA was anastomosed. The circumflex artery was
the most infrequently endarterectomized vessel in our patients of group (A) .
Proximal Anastomoses :
Proximal anastomoses of saphenous vein or RA to the aorta were
performed on partial occlusion clamp after all distal anastomoses.
Anastomotic Technique :
Once an appropriate site for aortotomy was identified, the fatty tissue
overlying the aorta is removed. An arteriotomy was created with a no. 11
blade, and a 4 to 5 mm punch was used to create a circular aortotomy. The
size of the punch will vary depending on the size of the conduit graft. The
proximal aspect of the conduit was beveled and then notched at the heel. A
running 5-0 polypropylene suture was used for a venous graft and a 6-0
polypropylene suture for an arterial conduit. The long axis of the graft was
aligned at an appropriate angle to the ascending aorta. The anastomosis was
completed with eight stitches in most cases; symmetry in the spacing of
sutures was present to obtain a hemostatic anastomosis.
Weaning from Cardiopulmonary Bypass :
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Upon completion of all anastomoses, the patient was prepared for
transition from supported circulation to native circulation. Prior to separation
from cardiopulmonary bypass, hemostasis of all possible surgical sites and
appropriate de-airing was confirmed. The patient
rewarmed to
normothermia if cooled and the acid-base status and electrolyte
abnormalities corrected. Weaning from bypass was otherwise the same as
for other cardiac surgical cases. Issues particular to CABG included
attention to avoid overdistention of the heart, which may place grafts on
tension and disrupt anastomoses. Deairing as usual was very important as if
air has entered the heart, bubbles may pass into the aorta and down the
bypass grafts. This may cause arrhythmias and regional wall motion
abnormalities in the distributions supplied by the grafts .
SURGICAL STRATEGIES FOR OFF-PUMP CABG
-LAD and Diagonals approach :
At 1st approaching the left anterior descending artery (LAD) and diagonal
artery. The LAD artery was the easiest target to reach. Being located on the
anterior surface of the heart, minimal surgical mobilization was required.
The free edge of the left side of pericardium is held and lifted up by the
assistant as the operator anchors a single stitch just above the phrenic nerve
where the apex of heart normally bulges in the pericardium. This brings the
apex of myocardium straight on the mid-line and has the advantage of being
stable through out the suturing period. Classically, sponges behind the heart
have the disadvantage of gradually getting wet, then losing volume and
necessitating repositioning by surgeon. The diagonal artery was generally
approached in a similar fashion. A second stitch close to the left inferior
pulmonary vein (LIPV) was needed to create more myocardial rotation and
19
facilitate lateral access. The table is generally rotated 20 degrees towards the
surgeon with slight Trendelenburg position .Special care should be taken
with positioning of stabilizer for diagonal artery its type was ( Octopus
stabilizer ) . The diagonal artery crosses the path of left ventricular out flow
tract. Any significant deformation of the funnel shape of the left ventricular
out flow tract will create obstruction and build up left ventricular after load.
The LAD artery running on top of the septum and has a less compromising
effect during stabilization. The PDA was approached in alike manner. The
apex brought on the mid-line, as described with the LAD artery, the table
was set in a 30-degree "head down" position with a 30-degree telt towards
the right sited operator. The closest to the base of the heart the target vessel
was the easier. The coronary stabilization was difficult when the mid PDA
was targeted for anatomical reasons, oscillation of the apex frequently
impedes satisfactory stabilization. Apical suction in these circumstances
enhanced the stabilization.
Fig. (10) Distal anastomosis for LAD using cardiac stabilizer
-RCA approach :
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As with LAD artery, the RCA is one of the target vessels that require the
least surgical manipulations. To bring the RCA in the middle of the surgical
field, 2 pericardial stitches were anchored, one just above the inferior vena
cava and the other in the same plane just above left atrium, table is rotated
20 degrees opposite to the operator with 20-30 degree head down tilt
position. This brought mid-RCA straight on the midline and really easied
positioning of the stabilizer . 4 deep pericardial stitches ranging between the
left superior pulmonary vein (LSPV) and the IVC. The lungs deflated first.
Then, the assistant had to pull the free edge of the pericardium while his
right hand, holding the wall suction, retracts the pericardium. This generally
enhanced the vision field of the operator obviously, care was taken not to
anchore these stitches too deeply, especially toward the pleural space. The 4
stitches were superficial and located close to the base of the heart about 1-2
cm away from pericardial attachment to the heart.
-Anastomotic Technique :
The suturing technique was similar to what was familiar with in on-pump
surgery. This generally consisted of parachuting 3 or 4 suspended stitches
before completing the running suture. Polypropylene 7-0 or 8-0 sutures were
deployed for internal thoracic artery grafting (sequential and distal)
according to size of distal vessel a blood less field is obtained by gently
snaring the target coronary artery with silicone vessel loops proximally, the
loops are crossed over, whereas distally, a single loop is used to avoid
damaging the distal bed. Intracoronary shunts were used in 15 patients .
Surgical strategies were performed including
that the most stenotic
vessels were always revascularized first .Second, when a saphenous vein or
radial artery conduit was used, the proximal anastomosis was completed
once the distal anastomosis completed, before the next distal anatomosis.
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Antegrade flow provided needed supportive blood flow through the
collaterals during next coronary cross-clamping. Normally LAD artery or
RCA are revascularized first. Third, generally a pre-ischemic test of 2
minutes before grafting the LAD artery especially when the stenosis is not
critical .
- Approaching the obtuse marginal artery:
4 deep pericardial stitches ranging between the left superior pulmonary
vein (LSPV) and the IVC were done . Then the needle passed of the
pericardial suture away from the heart and not towards it to avoid
myocardial injury. The first suture is anchored just above the LSPV. The
second below the LIPV. The third was located between the LIPV and IVC.
The fourth one is very dose to the IVC once completed, this generally
provides a complete verticalization of the heart. Then, the stabilizer was
applied with minimal myocardial contact, minimizing further hemodynamic
disturbances, because all the coronary arteries converge towards the apex, by
controlling the apex, an access to all of them was available .
Intracoronary shunts were employed only when ischemia was suspected.
Fourth, the ascending aorta was side-clamped only once during the
procedure to minimize aortic trauma and all the proximal anastomoses were
completed during the same period. Fifth, systemic pressure was always
reduced around 90-100 mm Hg before and during the entire side-clamping
of the ascending aorta. Sixth, the anterior and inferior territories were always
revascularized before the circumflex artery.
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