Cardiac Surgery

Annotations:

• AKA coronary angiography

1. Indications

   Annotations:

   • - assessment of extent of CAD - assessment to inform management plan - do they need angioplasty or CABG surgery. - can also assess ventricular function and valvular function.
2. Procedure

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   • Catheter is inserted into femoral artery under local anaesthetic. Catheter is passed into the coronary arteries via the aorta. Dye is injected to assess for narrowing of CA's (angiogram)

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• Percutaneous - through the skin Transluminal - down the lumen of the blood vessel Balloon angioplasty +/-  Balloon in the coronary artery

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• CPB replaces your heart and lungs during surgery. Blood drawn off via a cannula from the RA to a membrane oxygenator (adds O2 and removes CO2) Blood is retrned to the body via anohter cannula into the ascending aorta. Heat exchanger allows body cooling/rewarming Once CPB is established lung ventilation is discontinued, systemic cooling begins and the aorta is cross clamped.

1. Problems

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   • - Whole body inflammatory response (SIRS) - ARDS -RBC damage (anaemia) - Coagulopathies - Emboli - Haemorrhage - Renal failure - Peri-operative MI or CVA - arrhythmias

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• Stops the heart activity and allows surgery on a motionless heart.  Cold crystalloid cardioplegia is the most common. However it can cause phrenic nerve damage.

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• Coronary artery bypass graft surgery. Sternotomy cutting through the aponeurosis of pec major. With a sternotomy - bony union takes up to 12 weeks. No heavy liting is allowed. Wound complications are more common in - obese, diabetics and elderly.

1. Procedure

   Annotations:

   • Occluded or marrowed sections of the coronary arteries are bypassed. Graft a blood vessel between the ascending aorta and a point on the coronary artery distal to the obstruction. Surgery takes about 4-6 hrs
2. Grafts
   1. Saphenous vein

      Annotations:

      • The saphenous vein is turned inside out. It must be free from varicose veins and DVT. May cause LL oedema post-surgery.
   2. Internal mamillary artery

      Annotations:

      • Grafts are not always long/wide enough Requires entry into the pleural space Greater impairment of lung function post op
   3. Radial artery

      Annotations:

      • Assess the patient with allens test Use non-dominant arm. Can spasm as it has thciker tunica media than other grafts.

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• Beating heart surgery Octopus device is used. Theatre is kept warm to avoid heat loss. HR and contractility is reduce with beta blockers and calcium antagonists. Avoids problems associated with CPB and cross clamping of the aorta.

1. Pros

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   • Fewer inotropes Fewer dysrhythmias (AF) Less need for pacing Cheaper Ideal for risky patients
2. Contrandications

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   • Cardiomegaly Small of diffusely disease vessels Severe left ventricle dysfunction

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• Minimally invasive direct coronary artery surgery. - beating heart surgery - small incision - only -2 arteries can be bypassed - technically difficult

1. Regurgitation

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   • Blood flows back through a leaky valve. This leads to progressive volume overload and heart failure.
2. Stenosis

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   • - narrowing - congenital - scarring - calcification

1. Mechanical valve replacement

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   • - noisy - greater durability - need lifelong coagulation
2. Tissue valves

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   • Xenografts - animal tissue Homografts - from humans - No anticoagulation required - Risk of deterioration is higher.

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• Intra aortic balloon pump. Balloon is inserted into the descending aorta. It is connected to and operated by an external device.

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• Pump to bypass the failing ventricle/s. LVAD cannulas placed in either in left atrium or ventricle and blood returned into pulmonary artery. Reduced workload of the heart aids recovery of tissue compromised by ischaemia.

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• Vasodilator Decreases pulmonary artery pressure (decreasing afterload) Improves oxygenation

1. Aims

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   • Improve efficiency of ventilation Improve exercise tolerance Aid sputum clearance Reduce breathlessness Reduce post-op pain Maintain mobility of upper body Education
2. Pre-op

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   • Only for patients at risk - pre-existing resp diseases - poor mobility e.g amputees or severe arthritis - anxiety - neurological conditiond - learning difficulties
3. post-op

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   • Day 1 If extubated....SIT OUT OF BED! (avoid pushing through arms) Supported cough MOS if possible (plus TEEs) For Day 2...same as above but...MOBILISE Day 3 and onwards:  Progress mobility to stairs. Give postural advice Check shoulder ROM - bilateral UL exercises Advice regarding exercise progression and sternotomy Discharge day 4-6. 6 weeks post-op - cardiac rehab