Surgical Myocardial Revascularization Everything Old is New Again Matt Maxwell MD, FACS Director, Cardiovascular Surgery International Heart Institute of Montana
Surgical Myocardial Revascularization
Everything Old is New Again
Matt Maxwell MD, FACSDirector, Cardiovascular Surgery
International Heart Institute of Montana
In the beginning, God created the Heavens and the Earth and populated
the Earth with broccoli, cauliflower and spinach, green and yellow and
red vegetables of all kinds, so Man and Woman would live long and healthy
lives.
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.
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.
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.
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 and
chicken-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."
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.
Then God brought forth the potato, naturally low in fat and brimming
with nutrition. And Satan peeled off the healthful skin and sliced the
starchy center into chips and deep-fried them. And Man gained pounds.
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.
God sighed and created quadruple bypass surgery.
Then Satan created Stents
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
Revascularization
• Coronary Artery Bypass Grafting– 1963 Garrett and
DeBakey SV to RCA
• Coronary Angioplasty– 1975 conceptualized
Dotter– 1976 performed by
Gruenzig
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
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
Myocardial Hypoperfusion
Myocardial Hypoperfusion
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?
When to Revascularize (2)
• Medical Imperatives– Large territory asymptomatic ischemia– ? Diabetes– Ischemic Mitral Regurgitation– Ischemia induced malignant arrythmias
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
Percutaneous Revascularization
• Transcatheter approach to coronary artery
• Angioplasty• Angioplasty/Stent• Direct Stent
Surgical Revascularization
• Coronary Artery Bypass Grafting– CABG
• Arterial Conduits– Internal Mammary– Radial– Gastroepiploic– Bovine?
• Venous Conduits
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
Surgical Revascularization
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
Surgical Revascularization
• Beating Heart (Off Pump) versus Arrested Heart (with cardiopulmonary bypass)
– No consistently significant clinical differences in approaches
Surgical RevascularizationOften as adjunct to other procedures
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
Bypass Conduit Choice
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.
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
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
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
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
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
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
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.
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; 44:2149-56
• Topol EJ: Aspirin with bypass surgery - from taboo to new standard of care. N Engl J Med 2002;
17:1359-60
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
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
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
Controversies
• Medical Management vs Revascularization– Stable angina patients are safely treated with
selective revascularization
– Multi-vessel disease with normal LVEF
– Diabetics? (Less controversial)
Drug Eluting Stents versus Coronary Artery Bypass Grafting in Patients with Diabetes Mellitus
Ann Thoracic Surgery 2006;82:1692-97 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
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
Recurrent Symptoms Following Surgical Revascularization
• Early Graft Loss• Technical• Intimal hyperplasia• Hypercoaguable states
• Incomplete revascularization – Missed or inadequate target – Progressive disease
Revascularization as Primary Therapy for Myocardial Infarction
• Improves Outcomes vs Medical Therapy
Adjunctive Transmyocardial Laser Revascularization
• Holmium:YAG 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
Outpatient CAB
• Subramanian Lenox Hill NY• Jan-July 2003
– 30 patients- OPCAB, robot assisted ITA harvest, robotic stabilization and positioning2.6 grafts per patient2 re-op bleeding1 sternotomy for grafting15 discharged <24 hrs post op
Horizons
• Gene Therapy• Stem Cell Therapy• Vascular endothelial growth stimulation• Endoscopic revascularization
• Effective and Pervasive Prevention Strategy
Thank You
• Questions?