Op cab

OP CAB :- Techniques and outcome

-DR MANOJ P NAIR Lead Consultant(Cardio Thoracic Surgery)

Aster Medcity,Cochin,South India.

• 1951 Vineburg implanted the internal mammary

artery into the myocardium

• First successful OPCAB was performed in 1961

and Kolesov in 1964 performed the first

successful anastomosis of left internal

mammary

• Outshone by the development of CPB

• Resurgence of technique in 1980s in isolated

centers especially with limited resources

• On pump CABG Vs OPCAB- controversial &

focus of discussion in the field of cardiac

surgery .

• OP CAB is essentially coronary artery bypass

grafting without the help of cardio pulmonary

bypass

Placement of graft to more than one of the three

major coronary arteries is safely possible with

stabilization devices which keep the operating

area of the heart still

Stabilizers…

ON PUMP OFF PUMP

Evolved methodology Evolving methodology

Conduct of operation and preoperative selection “ well defined “

Still incompletely defined and still evolving

Anaesthetic Management

“Close communication between surgeon

and Anaesthesiologist”

Surgeon to Anaesthesiologist

• Positioning of heart

• Displacement of Heart

• Shunt placement

• Coronary artery occlusion

Anesthesiologist to Surgeon

• Ischemic changes in ECG

• ECG amplitude may be severely decreased

• ST segment changes may be underestimated

• TEE to determine RWMA and right and left

ventricular volumes

Surgical steps

• Median sternotomy

• Conduits harvested:saphaneous vein, internal thoracic

artery, radial artery..

• Heparinization done after the completion of mammary

artery dissection

• Pericardium opened,stay sutures placed

• In older patients epicardial ultrasound of Ascending aorta

Heparin

• Protocol varies from institution to institution

• Minimum of 5000 U to full heparinization (3mg/kg)

Heparin Reversal

With protamine

• No administration

• Partial

• Full dose

Temperature management

• Hypothermia should be avoided

• Normothermia with warm IV fluids

and irrigation fluids

• Warming blanket or mattress

• Humidification of airway

• Warm temperature in operating room

Surgical Technique

To maintain hemodynamic stability

• Positioning-Trendelenburg position – Increasing

preload

• Rotation of Operating table

• Opening of Right pleura

Surgical technique continued..

• Opening right pericardium vertically

• Minimize the manipulation of heart

• Optimal exposure of lateral wall of heart

• Ventricular pacing to prevent bradycardia while RCA

grafting

Pre op insertion of IABP

• Increase the tolerance of manipulation of heart

in high risk patients

Exposure of LV surfaces

• Apex of heart towards ceiling

• Lateral displacement

• Apex to right or left

Use of stay sutures• Stay sutures are placed in the posterior

pericardium opposite the oblique sinus(most

dependent part of the pericardial cavity)

Continued….

• Should avoid injury to aorta and esophagus

• Adjust orientation of the snares

• Circumferential pressure on the heart should be

avoided

Myocardial protection in OP CAB

• Brief coronary occlusion to visualize vessels-

Regional- Global dysfunction

• Olden days-Intermittent pharmacologic arrest

+profound bradycardia

• Ischemic preconditioning

Myocardial protection..

• Fluids and vasopressors

• good exposure of target vessels

• Selection of order of anastomosis

• Intracoronary shunts

• PADCAB

Exposure of RCA or PDA

• Marked elevation of apex of the heart with minimal

lateral displacement

• Using Octopus and or starfish

PDA position

Exposure of distal RCA

• Leftward traction

• Table left and Trendelenburg position

Exposure of LAD

Left and upward towards the head

Exposure of OM

• Elevation of the apex and lateral displacement

to the right

• Pericardial and right pleural openings

• Table rightward and Trendelenburg position

Sequence of grafting

• LIMA to LAD

• Vein/radial to the OM

• Proximal anastomosis

• Vein/radial to PDA or RCA

• Proximal anastomosis

General guideline

• Graft the artery that has the evidence of

collateral blood supply to the distal arterial bed

• Vessels without demonstrable collateral blood

supply are grafted last

OP CAB Vs ON PUMP

• Numerous studies and few conclusions

• Meta analysis

• Large retrospective studies

• Randomized trials

Evolving trends

• Less blood loss and transfusion requirements

• Less myocardial enzyme release in 24 hours

• Less early Neurocognitive disorders.

• Same length of hospital stay,mortality rate

• Same long term neurological function

• Cardiac outcome

• Quality of life

• In severely calcified Aorta where clamping can

cause direct neurological complications

• Large scale prospective studies are needed

• Still “evolving”

Findings favoring OP CAB

• Probably less bleeding

• Probably less renal dysfunction

• Probably less short term NCD,especially if aorta

is calcified

• Possibly shorter overall length of hospital stay

Findings favoring On Pump CABG

• Less technically demanding

• Shorter “learning curve”

• Possibly better long term graft patency

• Easier to graft posterior (Cx) Bypass targets

• Probably more bypass grafts constructed

ref: Circulation 2005

Current indications for OP CAB

• Age 70 years

• Low ejection fraction

• Reoperative surgery

• Patients with significant comorbidities

• Cerebral vascular disease

• Peripheral vascular disease

Current indications..

• Hepatic disease

• Bleeding disorders

• COPD

• Renal dysfunction

• Atheromatous or calcified aorta

• Patients who refuse blood products

• Duration – 10 years

• Total No – 2098

• Standard CABG - 1617

• OP CAB – 481

• Mortality in standard CABG - 6.8

• Mortality in OP CAB - 1.7

Selection of patients in OP biased

SINGLE SURGEON EXPERIENCE

Conclusion :

• Both OP CAB and standard CABG give excellent

results

• Neither should be judged,inferior to the other

Thank You