SYNTAX Score Calculation
SYNTAX Score Calculation
🔢 What is the SYNTAX Score?
The SYNTAX score is an anatomical grading tool to determine the complexity of coronary artery disease (CAD) in patients with multivessel or left main CAD. It helps guide treatment decisions between PCI and CABG.
📌 Components Assessed
- Number of lesions (>50% diameter stenosis, ≥1.5 mm vessels)
- Location of lesions (proximal LAD, bifurcations, etc.)
- Lesion complexity (total occlusions, tortuosity, calcification)
- Presence of thrombus or diffuse disease
🧮 How It’s Calculated
Each coronary lesion is assigned a score based on its characteristics using a standardized algorithm available online.
👉 Use the official SYNTAX calculator: www.syntaxscore.org
📊 Score Ranges and Interpretation
| SYNTAX Score | CAD Severity | Recommended Strategy |
|---|---|---|
| 0–22 | Low complexity | PCI preferred |
| 23–32 | Intermediate complexity | Individualized decision |
| ≥33 | High complexity | CABG preferred |
Note: SYNTAX II Score includes clinical factors (age, EF, creatinine, etc.) for better risk prediction.
SYNTAX I Score
SYNTAX II Score
1. The SYNTAX score primarily quantifies which of the following?
SYNTAX is an angiographic (anatomic) score measuring lesion complexity (bifurcations, total occlusions, calcification, etc.).
2. The original SYNTAX score was developed from data of patients enrolled in which treatment comparison?
The SYNTAX score arose from analysis of patients in trials comparing PCI (drug-eluting stents) with CABG for complex CAD.
3. Which lesion feature is scored in the SYNTAX calculation?
SYNTAX scores lesion-level anatomical features — bifurcation involvement increases the complexity score.
4. A commonly used SYNTAX score threshold that defines “high” anatomical complexity is:
SYNTAX categories: low (≤22), intermediate (23–32), and high (≥33) — high scores indicate complex disease favoring CABG.
5. Which of these increases the SYNTAX score for an individual lesion?
Chronic total occlusion is explicitly scored and increases SYNTAX complexity.
6. In clinical decision-making, a high SYNTAX score generally favors which revascularization strategy?
High SYNTAX (≥33) was associated with better outcomes after CABG than PCI in trials, so CABG is usually preferred.
7. Which of the following is NOT directly part of the anatomical SYNTAX score calculation?
Patient age is a clinical variable (used in SYNTAX II), but not in the original anatomical SYNTAX calculation.
8. SYNTAX II score differs from SYNTAX I by adding:
SYNTAX II integrates clinical factors (age, gender, LVEF, creatinine, COPD, peripheral vascular disease) with anatomy to guide decision-making.
9. Which coronary segment involvement often contributes disproportionately to the SYNTAX score due to myocardial territory at risk?
Proximal left main or proximal LAD lesions are weighted heavily because they jeopardize large myocardial territories.
10. Which procedural or lesion characteristic reduces the ease of percutaneous treatment and increases SYNTAX score?
Severe calcification complicates PCI (stent expansion) and therefore raises the anatomical complexity score.
11. How is the SYNTAX score typically calculated in practice?
Operators map each lesion on angiography and use the SYNTAX algorithm or validated calculator to compute the score.
12. Which statement about SYNTAX score is TRUE?
SYNTAX is an angiographic tool to quantify complexity and assist choice between PCI and CABG when combined with clinical judgment.
13. In a patient with 3-vessel disease and SYNTAX score of 18, what is the usual interpretation?
A score ≤22 is considered low; for multivessel disease with low SYNTAX, PCI outcomes may be comparable to CABG in selected patients.
14. Which of the following is a limitation of the SYNTAX score?
SYNTAX I is purely anatomical; important clinical factors (age, LVEF, creatinine) are not included unless using SYNTAX II.
15. Which anatomical finding commonly scored in SYNTAX indicates increased technical difficulty during PCI?
Severe tortuosity complicates guidewire/catheter passage and is assigned points in SYNTAX.
16. For which patient group is SYNTAX scoring most commonly applied clinically?
SYNTAX is particularly useful when choosing between CABG and PCI for multivessel or left main disease.
17. Which of the following changes would LOWER a patient’s SYNTAX score?
SYNTAX reflects the angiographic anatomy — if anatomy is reassessed and complexity reduced (fewer scored lesions), the score falls.
18. A SYNTAX score can help predict which long-term outcome difference between PCI and CABG?
Higher SYNTAX correlates with higher repeat revascularization rates after PCI compared with CABG in complex disease.
19. Which clinical variable is specifically included in the SYNTAX II algorithm but NOT SYNTAX I?
SYNTAX II adds clinical predictors such as LVEF, age, creatinine clearance, etc., to the anatomical score.
20. Which practical step is recommended when a heart team evaluates a patient with multivessel disease?
Best practice: combine anatomical scoring (SYNTAX) with clinical variables (SYNTAX II) and multidisciplinary heart-team discussion to individualize revascularization.
SYNTAX score, a tool used in cardiology to quantify the severity of coronary artery disease based on its anatomical complexity.
Here’s a breakdown of the notation:
- SYNTAX: This signifies the SYNTAX score itself.
- >50% diameter stenosis: This refers to the degree of narrowing or blockage in a coronary artery. Specifically, it means the lesion causes a reduction of more than 50% in the vessel’s diameter.
- vessel size >1.5 mm: This refers to the diameter of the coronary artery itself. Only lesions in vessels larger than 1.5mm are considered for the SYNTAX score calculation.
Therefore, “Syntax >50% diameter vessel size >” indicates that the report is describing a coronary lesion that is significant (causing more than 50% narrowing) and located in a major vessel (larger than 1.5 mm in diameter) that will be included in the calculation of the overall SYNTAX score.
Additional details about the SYNTAX score
- The SYNTAX score is lesion-based, meaning each lesion is scored separately, and the total score is the sum of these individual scores.
- The score also considers other characteristics of the lesion, such as its location within the coronary tree, the presence of total occlusions, bifurcations, trifurcations, and other factors that reflect the complexity of the disease.
- The SYNTAX score helps guide treatment decisions for patients with multivessel coronary artery disease, with higher scores suggesting that coronary artery bypass graft (CABG) surgery might be more beneficial than percutaneous coronary intervention (PCI).
- While a 50% narrowing is the threshold for including lesions in the SYNTAX score, the ESC/EACTS guidelines on myocardial revascularization and other studies define moderate stenosis as 50-69% and severe stenosis as 70-99% for most coronary arteries. The left main coronary artery has a lower threshold, with >50% stenosis considered significant.
In essence, “Syntax >50% diameter vessel size >” in a medical report would be interpreted as a significant finding, indicating a significant blockage in a major coronary artery that contributes to the patient’s overall SYNTAX score and risk assessment.
