Download Take home message

Take home message
• Indications of CABG
• Commonly use grafts
Arrhythmia surgery
What is atrial fibrillation (AF)?
• The presence of irregular, fibrillatory waves that vary in size,
shape and timing on ECG, with no associated effective atrial
contraction and is usually associated with an irregular
ventricular response.
• Leads to:
• acute and sometimes life threatening decompensation of
otherwise compensated cardiac disease;
• stasis of blood in the atria, which promote clot formation and
the occurrence of thromboemboli;
• symptoms of palpatation.
Mechanism of AF:
1. Rapid firing focus usually located near the pulmonary veins;
2. Micro-reentrant circuits that propagate within the atrial tissue.
Treatment Options ?
• 1. Antiarrhythmic Drug Therapy
• 2. DC Cardioversion
• 3. Ablation of the atrioventricular node and implantation of a
pacemaker
• 4. Catheter based focal ablation
• 5. The Maze Procedure
• No procedure apart from the Maze procedure has ever been able to
alleviate the 3 physiologic consequences of AF:
a. Tachycardia - maintian sinus rhythm
b. Hemodynamic compromise – maintain atrial transport function
c. Stroke - prevention of thromboembolism
MAZE procedure
• It is the “cut and sew” operation introduced by Cox and colleagues in
1987.
• With the use of carefully placed incisions, a narrow & tortuous path
of atrial tissue is created that direct the sinus-node impulse across
the septum to the atrioventricular node.
• The incisions are strategically placed so that no area is wide enough
to sustain a re-entry circuit and thus no atrial fibrillation can occur.
• In addition, the atrial appendages are excised and the pulmonary
veins are isolated.
• It permits the depolarization & activation of all the atrial tissues, and
thus maintains its transport function.
Energy sources
• Radiofrequency
– Irrigated
– Non-irrigated
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Cryothermal
Microwave
Ultrasound
Laser
Transmural lesion
Lesions created in Modified Maze III procedure over LA
Patient selection
• Carried out in all patients who have documented AF & are going to
have open heart surgery
• Conversion to SR in ~ 70-80% in 6 months postop
• Success depends on:
– Age
– Atrial size
– Duration of AF
• Risks include: longer operative time, damage to coronary system,
injury to esophagus, pulmonary vein stenosis, complete heart block
with permanent pacemaker insertion (5%), failure of treatment.
Take home message
• Mechanism of AF
• Rationale of MAZE procedure
• Potential risks
Aortic surgery
• Aortic dissection
• Aortic aneurysm
• Combination of both
Indications for operation:
1. Acute type A aortic dissection
(medical emergency)
2. Aortic dissection with
complications:
-symptomatic,
-rapid expansion,
-leakage,
-thromboembolic event,
-uncontrolled hypertension,
-dissecting aneurysm size >
5.5cm at ascending aorta or
size > 6.5cm at descending
aorta.
Widened mediastinum: noted in 50% of patients with aortic dissection.
Actual value of CXR for specific diagnosis of aortic pathology is
limited.
CXR may be helpful (1) to rule out important life-threatening
pathology: like pneumothorax, hemothorax, perforated GI ulcer…….
(2) to have initial assessment & for clinical comparison
Type A aortic dissection repair by interposition graft:
High risk operation, mortality rate ~ 7-15%
Complications includes: bleeding, stroke, acute renal failure,
mediastinitis, pulmonary failure, thromboembolic event……
Even in successful repair, patients still require life-long follow-up for
hypertensive control, residual aorta monitoring with imaging……
Ascending aorta
Recommendations for surgery:
Descending aorta
Normal individual
>5.5cm ascending aorta aneurysm
>6.5cm descending aorta aneurysm
Marfan /Bicuspid aortic valve/ Familial
thoracic aortic disease……
Lower threshold for surgery
Elefteriades JA, et al. Ann Thorac Surg 2002;74(5):S1877-S1880
8.2cm
8.7cm
Take home message
• Indications of surgery in aortic dissection &
aneurysm
Heart transplantation
REGISTRY DATABASE:
Number of Transplants Reported
ORGAN
Transplants Reported
from 7/1/2007 through
6/30/2008
Total Transplants
Reported through
6/30/2008
3,208
84,740
60
3,466
2,560
29,732
Heart
Heart-Lung
Lung
ISHLT
2009
INDICATIONS of heart transplant
• End stage heart failure (HF) not amenable to optimal
medical & surgical therapy
• NYHA class III-IV
• VO2max= Peak O2 consumption <15ml/kg/min
• Estimated 1 year survival <50%
Medical tx of HF
Surgical tx of HF
Biventricular pacing
High risk revascularization
AICD
Mitral valve repair
LV restoration therapy
Ventricular assisted device
DIAGNOSIS IN ADULT HEART TRANSPLANTS
ISHLT
2009
Assessment of Recipient
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•
•
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•
•
CARDIAC
ECHOcardiogram
ECG, 12 lead
Holter
VO2max
Coronary angiogram
Viability study
Right heart catheterization + Pulmonary vascular
resistance (PVR)
Myocardial biopsy
Current Recipient Status Criteria of the United Network for Organ
Sharing (UNOS)
Status IA
A. Patients who require mechanical circulatory assistance with one or more of the following
devices:
1.Total artificial heart
2.Left and/or right ventricular assist device implanted for 30 days or less
3.Intra-aortic balloon pump
4.Extracorporeal membrane oxygenator (ECMO)
B.Mechanical circulatory support for more than 30 days with significant device-related
complications
C.Mechanical ventilation
D.Continuous infusion of high-dose inotrope(s) in addition to continuous hemodynamic
monitoring of left ventricular filling pressures
E.Life expectancy without transplant less than 7 days
Status IB
A.A patient who has at least one of the following devices or therapies in place:
1.Left and/or right ventricular assist device implanted for more than 30 days
2.Continuous infusion of intravenous inotropes
Status II
All other waiting patients who do not meet status Ia or Ib criteria
Matching: SIZE
• Donor size is matched to recipient size on height basis
• Discrepancy greater than 20% is considered significant
• To have larger donors for recipients whose preoperative
pulmonary hemodynamics suggestive of pulmonary
hypertension
Matching: ABO COMPATIBILITY
• As in the cases of blood transfusion
• There are cases of hyperacute rejection occurred when
transplantation performed across incompatible ABO
blood group
• Lead to build up of blood group O recipient
Surgeon’s role
Organ preservation, explantation
& implantation
Use of cardioplegic solution &
hypothermia
• A single flush of cardioplegic or preservative solution
• Static hypothermic storage at 4 to 10°C
Ischemic time
• Current benchmark for acceptable ischemic time is
240mins
• Longer ischemic time may not result in perioperative
mortality but reflect in prolonged postoperative inotrope
dependence & prolonged ICU stay.
Implantation surgery
2. Bi-atrial technique
1. Bi-caval technique
Preserves normal atrial morphology
Synchronous atrial contractility
Preserves SA, AV node function
Preserves TV competence
Donor heart