TIMI score

TIMI (Thrombolysis In Myocardial Infarction) score is used in patients with NSTEMI (Non ST-segment elevation myocardial infarction), STEMI (ST-segment elevation myocardial infarction) and unstable angina to define risk. TIMI Study Group established this risk score. TIMI Study Group is an Academic Research Organization affiliated with Harvard Medical School, and Brigham and Women’s Hospital in Boston. This score was derived from patients enlisted to randomized controlled trials of low molecular weight heparins. The main advantages of TIMI score are its simplicity and ease of use.

TIMI risk score for patients with NSTEMI or unstable angina:

Seven variables are used to assess risk in NSTEMI or unstable angina including age of patient, risk factors for coronary artery disease, prior coronary artery stenosis, ST-segment deviation on ECG, prior aspirin intake, severe anginal chest pain within 24 hours and elevated cardiac markers. It is done immediately after an attack.

1. Age of patient:

Age of patient Score
Less than 65 years 0
65 years or more 1

 

2. Risk factors for coronary artery disease:

Five risk factors are included. These are:

  • Hypertension (high blood pressure)
  • Hypercholesterolemia (high blood cholesterol level)
  • Family   history of coronary artery disease
  • Diabetes
  • Smoking
Number of risk factors for coronary artery disease Score
Presence of less than three 0
Presence of three or more 1

 

3. Prior coronary artery stenosis:

Coronary angiography is done to see the stenosis.

Prior coronary artery stenosis Score
Less than 50% 0
50% or more 1

 

4. ST-segment deviation on ECG:

It includes horizontal ST-segment depression or transient ST-segment elevation more than 1 mm.

Positive ECG findings for TIMI score

ST-segment deviation on ECG Score
Absent 0
Present 1

 

5. Prior aspirin intake:

Prior aspirin intake Score
No aspirin intake in the last 7 days 0
Aspirin intake in the last 7 days 1

 

6. Severe anginal chest pain:

Severe anginal chest pain Score
No or one episode in last 24 hours 0
Two or more episodes in last 24 hours 1

 

7. Elevated cardiac markers (CK–MB or troponin):

Elevated cardiac markers Score
Absent 0
Present 1

 

Risk stratification by TIMI score in patients with NSTEMI or unstable angina:

Risk stratification Score
Low risk patients 0 – 2
Medium risk patients 3 – 4
High risk patients 5 – 7

 

Plan of treatment according to TIMI score:

In low risk patients with nstemi or unstable angina, drug therapy is appropriate and surgical intervention is reserved for those who fail to settle with drug therapy. By contrast, medium to high risk patients with nstemi or unstable angina should be treated with multiple drugs and considered for early coronary angiography and revascularization.

Interpretation of TIMI score in NSTEMI or unstable angina:

 

Total score Rate of death, or new or recurrent myocardial infarction, or severe recurrent anginal chest pain requiring urgent revascularization in 14 days
0 – 1 4.7%
2 8.3%
3 13.2%
4 19.9%
5 26.2%
6 – 7 40.9%

 

Example for a patient with NSTEMI:

A male patient with NSTEMI is 72 years of age, has four risk factors for coronary artery disease, prior coronary artery stenosis 65%, horizontal ST-segment depression in ECG, who has no history of aspirin intake in the last 7 days, no anginal chest pain in last 24 hours but did have elevated serum cardiac marker. His TIMI score would be: 1 + 1 + 1 + 1 + 0 + 0 + 1 = 5. He is a high risk patient and has a 26.2% risk of death or recurrent myocardial infarction or severe recurrent anginal chest pain requiring urgent revascularization in 14 days.

Example for a patient with unstable angina:

A male patient with unstable is 68 years of age, has three risk factors for coronary artery disease, prior coronary artery stenosis 45%, his ECG shows T-wave inversion but no horizontal ST-segment depression or transient ST-segment elevation, who has no history of aspirin intake in the last 7 days, no anginal chest pain in last 24 hours and his serum cardiac marker level is normal. His TIMI score would be: 1 + 1 + 0 + 0 + 0 + 0 + 0 = 2. He is a low risk patient and has an 8.3% risk of death or myocardial infarction or severe recurrent anginal chest pain requiring urgent revascularization in 14 days.

TIMI risk score for patients with STEMI:

Eleven variables are used to assess risk in STEMI that are age of patient, history of anginal chest pain, history of hypertension, history of diabetes, systolic blood pressure, heart rate, Killip class, weight of patient, anterior myocardial infarction in ECG, left bundle branch block (LBBB) in ECG and delay to treatment after an attack.

1. Age of patient:

Age of patient Score
Less than 65 years 0
65 – 74 years 2
75 years or more 3

 

2. History of anginal chest pain:

History of anginal chest pain Score
Absent 0
Present 1

 

3. History of hypertension (high blood pressure):

History of hypertension Score
Absent 0
Present 1

 

4. History of diabetes:

History of diabetes Score
Absent 0
Present 1

 

5. Systolic blood pressure:

Systolic blood pressure Score
100 mg Hg or more 0
Less than 100 mg Hg 3

 

6. Heart rate:

Heart rate Score
Less than 100 beats/minute 0
100 beats/minute or more 2

 

7. Killip class:

Killip class Score  
I – No heart failure. 0
II – Crackles audible in lower half of lung field. 0
III – Crackles audible in whole lung field. 2
IV – Cardiogenic shock 2

 

8. Weight of patient:

Weight of patient Score
Less than 67 kg 0
67 kg or more 1

 

9. Anterior myocardial infarction:

It can be detected in ECG that shows ST segment elevation and pathological Q wave formation in leads V1-V6.

Anterior myocardial infarction Score
No 0
Yes 1

 

10. Left bundle branch block (LBBB):

LBBB is diagnosed by ECG. ECG shows M pattern in lead V5 and V6, and wide QRS complex (more than 0.12 second).

Left bundle branch block Score
Absent 0
Present 1

 

11. Delay to treatment after attack:

Delay to treatment Score
Less than 4 hours 0
4 hours or more 1

 

Interpretation of TIMI score in STEMI:

Total score Risk of death at 30 days
0 0.8%
1 1.6%
2 2.2%
3 4.4%
4 7.3%
5 12.4%
6 16.1%
7 23.4%
8 26.8%
9 – 16 35.9%

 

Example for patient with STEMI:

A male patient with STEMI is 70 years of age, who has no history of anginal chest pain, hypertension and diabetes, his systolic blood pressure is 110 mg Hg and heart rate is 95 beats/minute, has a Killip class ll, weight 70 kg, has no anterior myocardial infarction or left bundle branch block in ECG and he treated within 4 hours of attack. His TIMI score would be: 2 + 0 + 0 + 0 + 0 + 0 + 0 + 1 + 0 + 0 + 0 = 3. He has about a 4.4% risk of death at 30 days.