TIMI Risk Score for NSTEMI Calculator

How does this TIMI risk score for NSTEMI calculator work?

This is a heart disease risk stratification tool allowing medical professionals to assess the adverse outcome and mortality risk in patients suffering from a non ST elevation myocardial infarction or other acute coronary syndrome conditions such as unstable angina. It is a tool that differentiates nonSTEMI from STEMI ischemic events.

It comprises of 7 factors that are evaluated through a simple questionnaire, each of the answers being given a certain amount of points. In order to provide the result, this TIMI risk score for NSTEMI calculator sums the points and delivers a mortality risk percentage. The factors taken into account are presented below.

■ Age ≥ 65 – the higher the age, the higher cardiovascular risk is, above 65 for both genders in similar proportion

■ ≥ 3 Coronary Artery Disease Risk Factors – family history of CAD, hypertension, hypercholesterolemia, diabetes mellitus or smoking

■ Known CAD (Stenosis ≥ 50%) – increases risk of ischemic accidents

■ ASA Use in Past 7 days – frequent aspirin usage in the preceding days to the episode

■ Severe angina (≥ 2 episodes in 24 hrs) – more than 2 episodes of severe angina symptomatology in the last 24 hours

■ EKG ST changes ≥ 0.5mm – relevant ST changes in electrocardiogram test

■ Positive Cardiac Marker – positive biomarker results, used to evaluate heart function and in the early detection of ACS ischemic events. In this case, troponin and CK-MB in blood.

The TIMI risk score can also stratify risk in patients with angina and is widely used in chest pain management in clinical stages. It is the predecessor of troponin testing models such as GRACE or HEART with more up to date risk stratification.

It is still used because of the good determination in chest pain symptomatology but in results of 0 or 1 points where the risk is considered 5% low, other risk models like the ones above should be used to discriminate further and assess whether at this stage is there really necessary to adopt a more aggressive or invasive management of the heart condition.

TIMI result interpretation

Non ST elevation MI

Non STEMI is the less severe type of MI, evidenced in the electrocardiogram test without a ST elevation, in this case ST depression. This informs the medical specialists of the severity of the coronary artery occlusion, in most cases, with non ST, only partial, involving less than full thickness of the cardiovascular tissue, therefore the heart muscle is partially infracted.

Amongst the main risk factors there are hypertension, high cholesterol, family and personal history, diabetes mellitus and smoking.

The most common symptoms are chest pain which is usually located in the middle of the chest and may radiate towards the arm, shoulder, neck or jaw, difficulty breathing, palpitation due to the nervous system activation and even cardiogenic shock if the AMI is of increased severity. First hand diagnosis can be put after ECG, blood cardiac markers, full blood count with elevated WBC, chest X rays and/or echocardiography.

Some of the most common complications include heart arrhythmias, acute heart failure, cardiogenic shock or mitral regurgitation due to papillary muscle damage.

References

1) Wiviott SD, Morrow DA, Frederick PD, Antman EM, Braunwald E; National Registry of Myocardial Infarction. (2006) Application of the Thrombolysis in Myocardial Infarction risk index in non-ST-segment elevation myocardial infarction: evaluation of patients in the National Registry of Myocardial Infarction. J Am Coll Cardiol; 47(8):1553-8

2) Antman EM, Cohen M, Bernink PJ, McCabe CH, Horacek T, Papuchis G, Mautner B, Corbalan R, Radley D, Braunwald E. (2000) The TIMI risk score for unstable angina/non-ST elevation MI: A method for prognostication and therapeutic decision making. JAMA; 284(7):835-42.