How Many Arterial Grafts is Enough?

Bruce Lytle MD

Baylor Plano Heart Hospital

100

90

80

70

100

90

80

70

100

90

80

70

ITA vs SVG 10-Year Survival by Extent of Disease

2 4 6 8 10 2 4 6 8 10 2 4 6 8 10

Pe

rce

nt

93.4

P=0.05

79.5

90.0

82.6

71.0

P=0.0001 P=0.0001

ITA N=332Vein N=440

ITA N=714Vein N=1,063

ITA N=1,249Vein N=2,116

88.0

One-Vessel(LAD) Two-Vessel(LAD) Three-VesselLoop. et al: NEJM 314:1-6. 1986

Patency of ITA and SVG to the LAD at One-Year Intervals

100

90

80

70

60

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Per

cen

t P

aten

t

Catheterization Intervals (Years)

168 48 57 5141 27

238 8

76 26044

302 431 93

62

69 82

73

47

20

13

34

5363

96

Internal Thoracic Artery N=855 GraftsSaphenous Vein N=1445 Grafts

Loop, et al; NEJM 314:1-6, 1986

44

Are Two ITA Grafts Better Than One?

100

80

60

40

20

0

Survival

Reoperation

(1786)

(2969)

(2889)

(1763)

BITA n=1989SITA n=4147

P<0.001

Su

rviv

al %

Reo

peratio

n (%

) / year)

5

4

3

2

1

0

328

453

401

302

0 2 4 6 8 10 12

Years After CABG

Survival and Reoperation 1 vs 2 ITA Grafts

Matched Survival

BITA

SITA

20

40

60

80

100

0 6 12 18

%

Years

What is the Magnitude of the Benefit ?

And How Many Patients Benefit?

Survival Difference

8070

6050

4030

AGE0

5

10

1520

YEARS

d_surviv

-10

-5

0

5

10

15

The Incremental Benefit of the LITA-LAD vs SVG is, for most patients, greater than that for BITA vs LITA-LAD

Skeletonize the ITAs

ITA Preparation Pedicled

Cohen et al: JTCS 1999

ITA Preparation Skeletonized

Cohen et al: JTCS 1999

Sequential ITA Grafts Add Substantial Complexity

The more ITA grafts have been done the less benefit

further ITA grafts add

Radial Artery vs Saphenous Vein (RAPS)

Functional Graft Occlusions

Radial 12%

SVG 19.7%

Complete Graft Occlusion

Radial 8.9%

SVG 18.6%

510 Patients – 9 Canadian Center269 Late Angiography (7.7 years)

P = 0.03

P = 0.002

Deb et al JACC: 2012

Probability of Graft Patency100

80

60

40

20

00 3 6 9 12 15

LITA

RITA

SVG

RA

Number of years following surgery

Pro

bab

ility

of

gra

ft p

aten

cy (

%)

LITA graft n=2443RITA graft n=991Radial graft n=1108SVG graft n=3238

Tatoulis et al. 2011

For All Arterial Grafts Patency is Related to

Coronary Stenosis

Risk Factors ITA Occlusion

Factor P

Lesser Proximal Stenosis <.0001

Time after CABG

Non-LAD <.0001

LAD .5

Right ITA <.0001

Smoking <.0001

Female Gender .0003

Later Date of Surgery.01

Graft Patency vs Coronary Stenosis

100

80

60

40

20

0

%

<60

Tatoulis et al (2004)

>60

LITA<60 >60

RITA<60 >60

RA

P<0.01 P<0.001 P<0.01

The Most Common Cause of a Failed Arterial Graft is

Competitive Flow

But the decrement in patency is not large

Failed bypass grafts do not appear to compromise

survival

How Many Arterial Grafts?

• LITA-LAD for Everyone• A second ITA graft to the second most

important stenotic vessel further improves outcomes

• Radial artery grafts increase operative complexity little

• Complex ITA grafting, RGEA grafting are not generic operations

• Do an operation that will work on that day

100

80

60

40

20

00 5 10 15 20 25

%

Years

LITA - LADSurvival & Revascularization

CompleteIncomplete (n = 791)

97%91%

81%

69%

93%

82%

68%

52%