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?