Surgery for Acquired Heart Disease

1
Surgery for Acquired Heart Disease

• Michael S. Firstenberg, M.D.
• Assistant Professor of Surgery
• Division of Cardiothoracic Surgery
• The Ohio State University Medical Center

2
Cardiac Surgery the bad

• Medical School
• 5 years General Surgery
• 2 years clinical/basic science research
• 2 years CT Fellowship
• 1 year advanced Fellowship
• Job opportunities
• Stress/Work hours

3
Cardiac Surgery the good

• You operate on the heart
• Huge impact on patients lives!
• Potential to fix the sickest patients in the
  hospital.
• Technically and intellectually challanging.
• Worse ways to make a living

4
Introduction

• Cardiopulmonary Bypass
• Coronary Artery Disease
• Valvular Heart Disease
• Transplant
• Mechanical Assist Devices

5
The Father of Bypass
6
CPB Basic Principles

• Full anticoagulation
• Heparin
• Venous drainage
• Right atrium
• SVC/IVC
• Oxygenator
• Pump
• Arterial Inflow
• Aorta
• Femoral artery
• Axillary artery

7
CPB Cardiac Arrest

• Cardiopledgia
• K (hyperkalemic arrest)
• Energy substrates
• Free radical scavangers
• Antegrade aortic root
• Retrograde coronary sinus
• Deep Hypothermic Circulatory Arrest

8
CPB Myocardial Oxygen DemandUnloading the heart

• Allen BS, Rosenkranz ER, Buckberg GD, et al
  Studies of controlled reperfusion after ischemia,
  VII high oxygen requirements of dyskinetic
  cardiac muscle. J Thorac Cardiovasc Surg 1986
  92543.)

9
CPB Myocardial Oxygen ConsumptionInfluence of
temperature
10
CPB Factor Activation
Bleeding Coagulopathy Factor activation
doesnt help that we have to heparinize!
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CPB Inflammatory Activation
Ischemia/Reperfusion
Reactive Oxygen Species
12
CPB - Pros and Cons

• Rest myocardium
• Operate on still heart
• Bloodless field
• Allows opening of chambers
• Keeps patient stable

• Hemolysis
• Consumption
• platelets
• clotting factors
• Cytokine activation
• Embolism

13
nevertheless a cornerstone
14
Coronary Artery Disease
15
Anatomy Right Coronary Artery

• RCA
• anterior on aorta
• R A-V groove
• nodal arteries
• acute marginal
• postero lateral
• posterior descending

16
Anatomy Left Anterior Descending

• LAD
• branch of Left main
• septal
• diagonal
• apex

17
Anatomy Left Circumflex Artery

• Left A-V groove
• obtuse marginals
• posterior descending
• postero lateral

18
CAD What is it?
19
CAD Why is it a problem?
20
Canadian Cardiovascular SocietyAngina
Classification
21
CAD Goals of Therapy

• IMPROVE BLOOD FLOW
• Relief of symptoms
• Prevention of complications
• Mortality
• MI
• CHF
• Arrhythmias
• Prolong quality and quality of life

22
CAD Outcomes / Prognosis
23
Coronary Artery Disease - Treatment

• Medical
• Beta blockers, ASA, Nitrates
• Risk factor modification
• Smoking, Lipid control, diet, activity
• Interventional
• PTCA
• Stents
• Surgery
• CABG Coronary Artery Bypass Grafting
• TMR Transmyocardial Revasc.
• Transplant

24
AHA/ACC Guidelines for CABGAsymptomatic/mild/sta
ble Angina    

• Asymptomatic/mild Angina
• Class I        
• left main stenosis        
• left main equivalent (proximal LAD and proximal
  circumflex)        
• triple-vessel disease    
• Class IIa        
• proximal LAD stenosis and one or two vessel
  disease    
• Class IIb        
• one or two vessel disease not involving proximal
  LAD
• Stable angina
• Class I        
• left main stenosis        
• left main equivalent (proximal LAD and proximal
  circumflex)        
• triple vessel disease        
• two vessel disease with proximal LAD stenosis and
  EF lt50 or demonstrable ischemia        
• one or two vessel disease without proximal LAD
  stenosis but with a large territory at risk and
  high risk criteria on noninvasive testing        
• disabling angina refractory to medical
  therapy    
• Class IIa        

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AHA/ACC Guidelines for CABGUnstable Angina /
Acute MI    

• Unstable Angina
• Class I
• proximal LAD stenosis with one vessel
  disease       
• one or two vessel disease without proximal LAD
  stenosis, but with a moderate territory at risk
  and demonstrable ischemia        
• ongoing ischemia despite medical therapy    
• Class IIa        
• proximal LAD stenosis and one or two vessel
  disease    
• Class IIb        
• one or two vessel disease not involving the LAD
• ST segment elevation (Q-wave) MI    
• Class I  None    
• Class IIa Ongoing ischemia despite medical
  therapy    
• Class IIb        
• progressive heart failure with remote territory
  at risk        
• primary reperfusion within 612 hours

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Timing of CABG post MIVery limited role in acute
MI
27
CAD PTCA vs Medicine

• Hazard ratios for PTCA versus medicine.

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CAD PTCA vs CABG
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CAD CABG vs Medical Therapy

• Hazard (mortality) ratios for CABG surgery versus
  medicine

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CAD Survival Advantage

• Extension of survival in months for various
  subgroups of patients with chronic stable angina
  treated by surgery as compared with those treated
  by medicine in seven prospective, randomized,
  controlled trials.

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CAD Treatment Moving Target

• Safer surgery
• Myocardial protection
• Anesthesia
• Better peri-operative care
• Better medications
• Statins
• Beta-blockers

• Sicker patients
• Higher expectations
• Lifestyle modification

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Surgery CABG

• CPB arrested heart
• Off-pump (20)
• Conduits
• IMA (L/R)
• Aorto-Coronary
• Vein (Saphenous)
• Radial Artery
• Other / Exotic
• NOT
• Prostetic
• Non-autologous

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CABG On Pump

• Benefits
• Comfortable for the surgeon
• Bloodless field
• Motionless field
• Myocardial protection
• Exposure to all vessels for total
  revascularization
• Risks
• Aortic cannulation
• Cerebral Emboli
• Dissection
• Negative effects of cardiopulmonary bypass

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CABG Off Pump

• OPCAB
• Beating heart
• No CPB
• Lower heparin
• Lower risk
• Technically difficult
• ?outcome?

35
CABG Durability Conduit Patency
100
405
175
1389
343
167
1054
291
338
222
402
456
415
1967 1989 (even better with modern meds!)
4780
1756
5796
Percent Patent
1366
80
1535
1589
1553
1345
1183
N 5657 N24145
ITA SVG
1029
738
1475
60
1 2 3 4 5 6 7 8 9 10 11 12
Years
36
CAD CASS Registry Survival
100 80 60 40 20 0
Surgical
37

Medical
27
0
5
10
15
Caracciolo, E., et Al., Circulation 1995 91
2325-2334.
Years
37
CABG Survival Extent of Disease
100
80
60
Survival ()
40
SVD / IMA Patients
DVD / IMA Patients
TVD / IMA Patients
20
0
2
4
6
8
20
0
10
12
14
16
18
2
4
6
8
20
0
10
12
14
16
18
Years
38
CAD Treatment

• What about people who you cant do a CABG on?
• Previous CABG
• Growing number of redo-CABGs
• Poor targets
• No conduit
• Too sick

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Transmyocardial Laser Revascularization

• Create Reptilian Circulation
• Patients deemed non revascularizable
• Documented ischemia
• Carbon dioxide / Holmium YAG laser
• 30-40 holes drilled
• Thoracotomy

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Transmyocardial Laser Revascularization

• Outcomes
• improved angina
• increased exercise tolerance
• increased quality of life scores
• decreased medical regimen
• higher rate of survival free of cardiac events

NEJM vol. Sept 1999 34114
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Valve Disease

• Tricuspid
• Pulmonic
• Mitral
• Aortic

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Valve Surgery Repair vs Replacement
No Coumadin Less durability Re-operations
Coumadin More durability Bleeding Embolic
complications
Patient factors and preference the most important
considerations
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Tissue Valves
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Mechanical Valves
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Aortic Valve Disease
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Anatomy Aortic Valve

• The noncoronary leaflet straddles the central
  fibrous body overlying the anterior leaflet of
  the mitral valve.
• The conduction tissue traverses the membranous
  septum between the right coronary and noncoronary
  leaflets.

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Aortic Valve Pathology

• Stenosis
• bileaflet
• calcifications
• Insufficiency
• annulus
• leaflet prolapse
• Both

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Aortic Stenosis Calcification
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Aortic Stenosis The Problem
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AVR Grading Aortic Stenosis

• Mild aortic stenosis area gt1.5 cm2
• Moderate aortic stenosis area 1 to 1.5 cm2
• Severe aortic stenosis area lt1.0 cm2

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Aortic Stenosis Disease Progression
not to mention the effects of CAD
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Aortic Regurgitation

• Improper or inadequate coaptation of the valve
  leaflets during diastole.
• Allows previously ejected blood to flow
  retrograde into the left ventricle.
• Effective stroke volume is reduced.
• Unlike aortic stenosis, both volume and pressure
  overload of the left ventricular chamber occurs.
• Volume overload secondary to regurgitant flow
• Pressure overload is due to the increased wall
  stress
• Law of Laplace.
• Acute overload leads to immediate decompensation
  and signs of left-sided failure as left
  ventricular end-diastolic volume is exceeded.
• Chronic volume/pressure overload allows for
  compensatory changes in left ventricular volume,
  leading to eccentric hypertrophy of the chamber.

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AVR Surgery
54
AVR Cribier Edwards Perc. ValveThe Future?
55
AVR Tissue Valve Durability
Current Thoughts Young Patients Mechanical
Valves Pregnancy Risk of re-op Lifestyle Middl
e Age Mechanical Risk of re-op Patient
preference Elderly Tissue valves Risk of
coumadin Influence of other comorbidities
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AVR Long Term Survival
57
AVR Low EF Survival
58
Mitral Valve Disease
59
Mitral Valve Anatomy
60
Mitral Valve Anatomy
61
Mitral Valve Anatomy
62
Mitral Stenosis

• Generally the result of rheumatic heart disease.
• Very rare in the U.S. (and modern countries)
• Nonrheumatic causes
• Severe mitral annular and/or leaflet
  calcification
• Congenital mitral valve deformities
• Malignant carcinoid syndrome
• Neoplasm
• Left atrial thrombus
• Endocarditic vegetations
• A definite history of rheumatic fever can be
  obtained in only about 50 to 60 of patients
  women are affected more often than men by a 21
  to 31 ratio. Nearly always acquired before age
  20, rheumatic valvular disease becomes clinically
  evident one to three decades later.

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Mitral Regurgitation EtiologyMuch larger problem
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Etiology Mitral Regurgitation Carpentier's
functional classification

• Type I Leaflet motion is normal.
• Type II Due to leaflet prolapse or excessive
  motion.
• Type III (restricted leaflet motion) is
  subdivided into restriction during diastole ("a")
  or systole ("b"). Type IIIb is typically seen in
  patients with ischemic MR.

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Functional Mitral Regurgitation
Normal
CHF
Bolling Sem. Thor. Card. Surg. 2002
66
Mitral Regurgitation Grading
67
Mitral Valve Surgery Indications

• Complications
• Left atrial enlargement
• Pulmonary Hypertension
• Atrial fib.
• LV Dysfxn
• Symptoms
• Endocarditis

68
Mitral Repair Annuloplasty

• Reduce annular dilatation
• Reduce volume overload
• Reduce ventricular stress response
• Reverse remodeling

69
Mitral Repair Leaflet Resection
70
Mitral Valve Replacement
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Outcomes Degenerative Mitral DiseaseMitral
Valve Repair
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Outcome Repair vs Replacement
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MR Why Fix?

• Survival after diagnosis according to degree of
  mitral regurgitation as graded by effective
  regurgitant orifice (ERO) being 20 mm2 or higher,
  or less than 20 mm2. From Grigioni F,
  Enriquez-Sarano M, Zehr KJ, et al Ischemic
  mitral regurgitation long term outcome and
  prognostic implications with quantitative Doppler
  assessment. Circulation 2001 1031759.)

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Survival After MVR
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Survival Repair is Better!
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Mitral Repair Sounds Great

• But
• 60 of Functional MR never gets addressed
• gt50 of all valve surgery is replacement most
  are mechanical
• Why?
• Technically difficult
• Surgeon preference/bias
• Outcomes
• ?Not sure

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When Fixing the Heart Doesnt Work

• REPLACE IT
• Transplant
• Mechanical Support

78
Norman Shumway
79
Cardiac Transplantation

• gt 5,000 patients listed for cardiac
  transplantation in the U.S.
• 20-30 per year die waiting
• lt 2500 cardiac transplants performed per year in
  the U.S.
• unchanged since 1989 despite more marginal donors
  utilized

ISHLT database
80
Cardiac Transplantation
ISHLT
2004
J Heart Lung Transplant 2004 23 796-803
81
Long-Term Functional Status
82
Transplant Underlying Diagnosis

• CAD 45
• Dilated CM 45
• Valvular 4
• Congenital 2
• Retransplant 2
• Misc. 2

83
Transplant UNOS Status

• Status 1A
• Mecahnical support for acute decompensation and
  includes
• VAD (R/H)
• TAH
• IABP
• ECMO
• Complications on mechanical support
• Intubated
• Infusion of high-dose IV inotrope
• Survival lt 7 days
• Status 1B
• VAD (R/L)
• Cont. infusions of IV inotropes

• Status 2
• All other actively listed patients
• Status 7
• Patients is temporarily removed from active
  waiting list

84
Transplant Donor selection

• Age lt55    
• Absence of the following        
• Prolonged cardiac arrest        
• Prolonged severe hypotension        
• Preexisting cardiac disease              
• Severe chest trauma with evidence of cardiac
  injury        
• Septicemia       
• Extracerebral malignancy        
• Positive serologies for HIV, hepatitis B, or
  hepatitis C        
• Hemodynamic stability without high-dose inotropic
  support (lt20 µg/kg/min dopamine)
• Cardiac donor evaluation    
• Past medical history and physical examination
• Electrocardiogram    
• Chest roentgenogram    
• Arterial blood gases    
• Laboratory tests (ABO, HIV, HBV, HCV)    
• Cardiology consultation (echocardiogram cath)

85
Transplant Donor cardiectomy.
86
Transplantation Implant
87
Transplant Rejection A Worse Disease?
Symptoms Asymptomatic Unexplained
arrhythmias Congestive Heart Failure Cardiogenic
shock vs Infection/Sepsis About 30 have some
rejection in the first 6 months
88
Transplant Survival
89
Mechanical Assist Device
90
The Last Hope Mechanical Support

• Bridge to myocardial recovery
• Short term
• Long term
• ?recovery / healing
• Bridge to transplantation
• Save the sickest patients
• Make a bad candidate into a good one
• ? making the problem worse
• Destination therapy
• non-transplant candidates
• ? chronic rejection in transplanted patients
• ? change age limitation for transplant listing
• ? can it be better than transplantation

91
Selection criteria for VAD

• Accepted as candidate for cardiac transplantation
  (relative)
• Absence of coagulopathy or gastrointestinal
  hemorrhage
• Heart failure (CI lt1.8 L/min/m2, left atrial
  pressure gt25 mmHg, systolic blood pressure lt90
  mmHg), despite        
• Corrected metabolism (temperature, acid-base,
  electrolytes)        
• Adequate preload, appropriate afterload
  reduction        
• Maximal inotropic support        
• Intra-aortic balloon pump assistance
• Reality what kind of mood we are in on any
  given day.

92
Types of Mechanical Support

• Short term support
• Pulsatile
• Continuous flow
• Bridge to transplant
• Pulsatile
• Continuous flow

93
Left Ventricular Assist Device

• Inflow from the LV apex
• Outflow into the ascending aorta
• Percutaneous driveline attached to power source
  and controller

94
Abiomed BVS 5000(i)

• Easy implant/explant
• Versatile
• univentricular
• biventriccular
• Good patient support
• Paracorporeal
• Difficult to mobilize patient
• Aggressive anticoagulation

95
Long Term LVAD Thoratec

• Easy implant/explant
• Versatile
• univentricular
• biventricular
• Good patient support
• Paracorporeal
• Complex initial setup
• Able to mobilize patient
• Anticoagulation

96
Total Artificial Heart AbioCor

• First Human implant July 2, 2001