### Description

The SYNTAX score has a number of components that reflect the complexity of coronary artery disease. The basic score involves the location of the lesion in a coronary artery and the extent of involvement.

Patient selection: coronary artery disease, before and after coronary artery bypass grafts (CABG)

Steps:

(1) Determine whether the left or right coronary artery is dominant.

(2) Identify the location of the lesion in a coronary artery segment.

(3) Determine the degree of stenosis for the lesion.

(3a) A lesion less than 50% is not considered significant and so is weighted x0.

(3b) A lesion with 50 to 99% occlusion is weighted x2.

(3c) A lesion with 100% (complete) occlusion is weighted x5

points for the lesion =

= (points for segment read from table) * (weighting factor)

Right Coronary Artery Dominance

Segment

Name

Points

1

RCA proximal

1

2

RCA mid

1

3

RCA distal

1

4

Posterior Descending

1

16

Posterolateral branch from RCA

0.5

16a

Posterolateral branch from RCA

0.5

16b

Posterolateral branch from RCA

0.5

16c

Posterolateral branch from RCA

0.5

5

Left main

5

6

3.5

7

2.5

8

1

9

First diagonal

1

9a

First diagonal

1

10

Second diagonal

0.5

10a

Second diagonal

0.5

11

Proximal circumflex

1.5

12

Intermediate or anterolateral

1

12a

Obtuse marginal

1

12b

Obtuse marginal

1

13

Distal circumflex

0.5

14

Left posterolateral

0.5

14a

Left posterolateral

0.5

14b

Left posterolateral

0.5

15

Posterior descending

n.a.

Left Coronary Artery Dominance

Segment

Name

Points

1

RCA proximal

0

2

RCA mid

0

3

RCA distal

0

4

Posterior Descending

n.a

16

Posterolateral branch from RCA

n.a

16a

Posterolateral branch from RCA

n.a

16b

Posterolateral branch from RCA

n.a

16c

Posterolateral branch from RCA

n.a

5

Left main

6

6

3.5

7

2.5

8

1

9

First diagonal

1

9a

First diagonal

1

10

Second diagonal

0.5

10a

Second diagonal

0.5

11

Proximal circumflex

2.5

12

Intermediate or anterolateral

1

12a

Obtuse marginal

1

12b

Obtuse marginal

1

13

Distal circumflex

1.5

14

Left posterolateral

1

14a

Left posterolateral

1

14b

Left posterolateral

1

15

Posterior descending

1.