Surgical Myocardial Revascularization

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Surgical Myocardial Revascularization

• Everything Old is New Again
• Matt Maxwell MD, FACS
• Director, Cardiovascular Surgery
• International Heart Institute of Montana

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In the beginning, God created the Heavens and the
Earth and populated the Earth with broccoli,
cauliflower and spinach, green and yellow andred
vegetables of all kinds, so Man and Woman would
live long and healthy lives.
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Then using God's great gifts, Satan created Ben
and Jerry's Ice Cream and Krispy Creme Donuts.
And Satan said, "You want chocolate with that?"
And Man said, "Yes!" and Woman said, "and as long
as you're at it, add some sprinkles." And they
gained 10 pounds. And Satan smiled.
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And God created the healthful yogurt that Woman
might keep the figure that Man found so fair. And
Satan brought forth white flour from thewheat,
and sugar from the cane and combined them. And
Woman went from size 6 to size 14.
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So God said, "Try my fresh green salad." And
Satan presented Thousand-Island Dressing, buttery
croutons and garlic toast on the side.And Man
and Woman unfastened their belts following the
repast.
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God then said, "I have sent you heart healthy
vegetables and olive oil in which to cook them."
And Satan brought forth deep fried fish
andchicken-fried steak so big it needed its own
platter. And Man gained more weight and his
cholesterol went through the roof. God then
created a light, fluffy white cake, named it
"Angel Food Cake," and said, "It is good." Satan
then created chocolate cake and named it "Devil's
Food."
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God then brought forth running shoes so that His
children might lose those extra pounds. And Satan
gave cable TV with a remote control so Man would
not have to toil changing the channels. And Man
and Woman laughed and cried before the flickering
blue light and gained pounds.
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Then God brought forth the potato, naturally low
in fat and brimming with nutrition. And Satan
peeled off the healthful skin and sliced
thestarchy center into chips and deep-fried
them. And Man gained pounds.
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God then gave lean beef so that Man might consume
fewer calories and still satisfy his appetite.
And Satan created McDonald's and its99-cent
double cheeseburger. Then said, "You want fries
with that?" And Man replied, "Yes! And super size
them!" And Satan said, "It is good." And Man went
into cardiac arrest.
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God sighed and created quadruple bypass surgery.
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Then Satan created Stents
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Revascularization

• Restores unobstructed coronary arterial Inflow
• Proximal one half of coronary arterial tree
• Does not affect microcirculation
• Can be accomplished surgically or percutaneously
• Directed at hypoperfusion syndromes

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Revascularization

• Coronary Artery Bypass Grafting
• 1963 Garrett and DeBakey SV to RCA
• Coronary Angioplasty
• 1975 conceptualized Dotter
• 1976 performed by Gruenzig

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Myocardial Hypoperfusion Spectrum

• Angina/Recurrent Angina
• Acute Myocardial Infarction
• 20 Mortality
• 25 2 year Mortality
• Ischemic Cardiomyopathy
• Hibernating Myocardium
• Congestive Heart Failure
• Ischemic Mitral Regurgitation

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Myocardial Hypoperfusion

• O2 supply/demand mismatch
• Myocardial Hypertrophy with endocardial
  hypoperfusion (Aortic Stenosis)
• Coronary Spasm
• Cardiac Muscle bridge with occlusion
• Embolic coronary occlusion
• Athrosclerotic plaque

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Myocardial Hypoperfusion
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Myocardial Hypoperfusion
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When to Revascularize?

• Unacceptable Lifestyle limiting sx
• Severe angina or equivalent that interferes with
  ones usual activities despite optimal medical
  management
• Anatomic Imperatives
• Left main coronary stenosis
• 3 Vessel coronary obstruction
• Proximal Left Ant. Descending lesion?

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When to Revascularize (2)

• Medical Imperatives
• Large territory asymptomatic ischemia
• ? Diabetes
• Ischemic Mitral Regurgitation
• Ischemia induced malignant arrythmias

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Myocardial RevascularizationApproaches

• Percutaneous
• PTCA
• Athrectomy
• Brachy Therapy
• PTCA (Courage)
• Stent
• Drug Eluting Stent

• Medical Therapy
• (Rare regression of Plaque)
• Beta blocker
• Antiplatelet agents
• Statins
• Omega 3 Fish Oil

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Percutaneous Revascularization

• Transcatheter approach to coronary artery
• Angioplasty
• Angioplasty/Stent
• Direct Stent

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Surgical Revascularization

• Coronary Artery Bypass Grafting
• CABG
• Arterial Conduits
• Internal Mammary
• Radial
• Gastroepiploic
• Bovine?
• Venous Conduits

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Surgical Revascularization

• Advantages
• Complete Revasc
• Durability
• LIMA/LAD 90 20 yr patency
• Radial Artery, SV
• Life expectancy
• 3V impaired LVEF
• Left Main stenosis
• Diabetics with 3V CAD

• Disadvantages
• Procedural Risks
• Death, stroke, bleeding, transfusion, infection,
  renal failure, transient pulmonary dysfunction
• Recovery Time (6wk)
• Cognitive Dysfunction?
• Resource Intense

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Surgical Revascularization
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Resource Requirements

• Procedural cost for angioplasty
• 20K
• 20K (.25) (reintervention rate in first 5 years)
• 2000 (cost of plavix)
• 27,000
• Procedural cost for coronary bypass
• 40K
• 40K(.1)
• 44,000

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Surgical Revascularization

• Beating Heart (Off Pump) versus Arrested Heart
  (with cardiopulmonary bypass)
• No consistently significant clinical differences
  in approaches

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Surgical RevascularizationOften as adjunct to
other procedures
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Bypass Conduit Choice

• Critical differences in outcomes are apparent
  when one considers choice of conduit for bypass
• Survival
• Event free survival
• Time to recurrent symptoms

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Bypass Conduit Choice
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Arterial Grafting Imperatives

• Left Internal Mammary Artery to Left Anterior
  Descending artery (LIMA to LAD)
• Imparts the single biggest benefit to recipient
• Pedicle graft is superior to free graft
• LIMA to LAD patency is as high as 90 at 20 years
  follow-up
• Provided survival benefit from any observation
  point, at any age, either gender.

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Mammary Artery Grafting

• Non LAD targets benefit from arterial grafts
• Durability better than saphenous veins
• Flow reserve (of arterial graft) is superior
• Pedicle grafts superior to free grafts
• RIMA to LAD has similar results to LIMA
• Bilateral Mammary superior to single mammary
• Mammary resistant to athrosclerosis

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Radial Artery Grafting

• Radial Artery is a reactive muscular artery
• Less susceptible to athrosclerosis (though not
  privileged)
• Superior durability when compared to vein grafts
  when several provisos are met
• Competitive flow restriction
• ? RCA target
• Vasodilator for early accommodation

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Radial Artery Grafting

• Competitive flow versus minimal luminal diameter
  proximally
• Adequate run-off
• Complete palmar arch
• May be less reliable in diabetics
• Requires two months of relaxation
• Poor choice when vasoconstrictors needed

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Saphenous vein Grafting

• Plentiful and predictable conduit
• Less competitive flow issues
• Superior early flow characteristics
• Susceptible to athrosclerosis (50 ten year
  patency)
• May not be appropriate for recipient vessels less
  than 1.5 millimeters

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Multiple Arterial Grafting Superior to Single
Arterial Grafting

• Cleveland Clinic data over twenty years
• LIMA to LAD provides single biggest benefit
• Increasing number of arterial grafts (when
  compared to similar number of vein grafts)
  reduces MACE and late mortality (12 years)
• Radial Artery Grafts are not reliable absent
  proximal 80 stenosis and good runoff

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Bilateral Internal Thoracic Artery Grafting

• Cleveland Clinic 2004
• 8123 SITA and 2001 BITA
• Propensity matched pairs
• Survival BITA 89 81 67 50
• SITA 87 78 58 37
• Post op years 7 10 15 20

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Internal Thoracic Artery Graft Patency

• Competitive flow and patency
• Cleveland Clinic (2003) 50,278 patients underwent
  CAB with ITA (72-99)
• 2,999 angiograms of 2,121 ITA grafts
• Unadjusted ITA patency was 93, 89, 90 and 92
  at 1,5,10 and 15 years post op.

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Maintenance of Graft Patency With Secondary
Prevention Strategies

• Greater use of indicated secondary preventive
  therapies after coronary bypass is associated
  with a lower two year death or infarction rate
  (HR 1.7)
• Graft patency is improved with ASA, Statins
• Goldman S, Zadina K, Mortiz T, et al Long-term
  patency of saphenous vein and left internal
  mammary artery grafts after coronary artery
  bypass surgery. J Am Coll Cardiol 2004
  442149-56
• Topol EJ Aspirin with bypass surgery - from
  taboo to new standard of care. N Engl J Med 2002
  171359-60

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Cholesterol and Recurrent Events (CARE) 1996

• Documented AMI
• Normal Cholesterol
• Pravastatin for a mean of 5 years
• 24 reduction in composite endpoint
• Fatal or new MI, need for coronary
  revascularization or CVA

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Statins in Coronary Artery Bypass Surgery

• Reduction in plasma LDL
• Aid mobilization of marrow derived endothelial
  progenitor cells and accelerate
  re-endothelialization of coronary vessels and
  grafts
• Reduce post operative IL-6
• Improve early vein graft patency and reduce early
  lesions

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Statins in CARE

• Prior CABG patients
• Reduction in composite endpoints of death, MI, or
  CAD death
• Subgroup analysis but statins play a role in
  post CABG patients

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Controversies

• Medical Management vs Revascularization
• Stable angina patients are safely treated with
  selective revascularization
• Multi-vessel disease with normal LVEF
• Diabetics? (Less controversial)

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Drug Eluting Stents versus Coronary Artery Bypass
Grafting in Patients with Diabetes Mellitus Ann
Thoracic Surgery 2006821692-97 Hebrew
University Hospital

• Jan 2002 - Jan2005 518 Consecutive Diabetics
  underwent revascularization
• 176 PCI with cypher stents
• 342 treated surgically (LIMA and BIMA favored)
• Angina recurred 39 Cy 15 sg
• Reinterventions 25 5
• Death- no different
• Mean Follow-up 18 months

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Preoperative Asymptomatic Ischemia

• Up to 20 of patients have asymptomatic or highly
  atypical or unreliable anginal symptoms
• Provocative testing in the early postoperative
  period is indicated to insure adequate
  revascularization
• Diabetes, Renal Failure

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Recurrent Symptoms Following Surgical
Revascularization

• Early Graft Loss
• Technical
• Intimal hyperplasia
• Hypercoaguable states
• Incomplete revascularization
• Missed or inadequate target
• Progressive disease

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Revascularization as Primary Therapy for
Myocardial Infarction

• Improves Outcomes vs Medical Therapy

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Adjunctive Transmyocardial Laser
Revascularization

• HolmiumYAG Laser as adjunct
• CAB alone vs. CAB/ TMR
• 220 total patients randomized in multicenter
  trial
• Mean follow-up 5 yrs
• Both groups has significant improvement in angina
  scores vs. pro-op
• No change in survival
• Significant reduction in angina withTMR

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Outpatient CAB

• Subramanian Lenox Hill NY
• Jan-July 2003
• 30 patients- OPCAB, robot assisted ITA harvest,
  robotic stabilization and positioning
• 2.6 grafts per patient
• 2 re-op bleeding
• 1 sternotomy for grafting
• 15 discharged lt24 hrs post op

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Horizons

• Gene Therapy
• Stem Cell Therapy
• Vascular endothelial growth stimulation
• Endoscopic revascularization
• Effective and Pervasive Prevention Strategy

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Thank You

• Questions?