SYNTAX Score

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SYNTAX Score: A Tool for Revascularization Strategy in Complex Coronary Artery Disease

The SYNTAX Score is a semi-quantitative scoring system designed to assess the complexity of coronary artery disease (CAD) and guide the choice between percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). Developed through expert consensus and validated in the SYNTAX trial, this tool evaluates angiographic characteristics to predict clinical outcomes and aid in personalized treatment decisions.

The SYNTAX Score was created to address the need for a standardized method to evaluate the anatomical complexity of CAD, particularly in patients with multivessel disease or left main coronary artery disease. It integrates multiple variables, including the number of lesions, their location, and specific characteristics such as bifurcations, chronic total occlusions (CTOs), calcification, and thrombus presence. These factors are weighted and summed to produce a total score, which stratifies patients into low, intermediate, and high-risk categories.

Clinical applications

The SYNTAX Score is primarily used to:

  1. Guide Revascularization Strategy: Patients with low scores (≤22) are often recommended for PCI, while those with high scores (≥33) are typically advised to undergo CABG due to better long-term outcomes. Intermediate scores (23–32) require careful consideration by a heart team.
  2. Predict Outcomes: The score has been validated to predict major adverse cardiac events (MACE), including mortality, myocardial infarction, and repeat revascularization. For example, in the SYNTAX trial, patients with high scores had significantly higher mortality and MACE rates compared to those with low scores.
  3. Monitor Quality of Care: By providing an objective measure of CAD complexity, the SYNTAX Score helps standardize treatment protocols and improve clinical decision-making.

Strengths and limitations

The SYNTAX Score’s strength lies in its ability to comprehensively evaluate angiographic complexity, making it a valuable tool for risk stratification. However, it has several limitations:

  1. Reproducibility: The score’s calculation can be cumbersome and time-consuming, with reported inter-observer variability (κ values ranging from 0.45 to 0.76).
  2. Lack of Clinical Variables: The original SYNTAX Score focuses solely on anatomical factors, ignoring clinical variables such as age, diabetes, and renal function, which significantly impact outcomes.
  3. Inconsistent Predictive Value: While effective in PCI-treated patients, its predictive ability is less robust in CABG-treated patients, as surgery can bypass complex lesions irrespective of their angiographic complexity.

Evolution: SYNTAX Score II

To address these limitations, the SYNTAX Score II was developed, incorporating both anatomical and clinical variables. This updated version improves predictive accuracy for 10-year mortality and 5-year MACE, offering a more personalized approach to revascularization strategy. For instance, SYNTAX Score II includes factors like age, creatinine clearance, and left ventricular ejection fraction, enhancing its utility in clinical practice.

Future Directions

Ongoing research aims to refine the SYNTAX Score further. For example, the CatLet Score has been proposed as an alternative, addressing some of the SYNTAX Score’s shortcomings, such as its inability to account for coronary dominance variability and its reliance on subjective lesion weighting. Additionally, integrating functional assessments like fractional flow reserve (FFR) could enhance the score’s predictive accuracy.

The SYNTAX Score remains a cornerstone in the management of complex CAD, providing a structured approach to revascularization strategy. While it has limitations, its evolution into SYNTAX Score II and potential future refinements underscore its enduring relevance in cardiology. By combining anatomical and clinical data, it continues to support heart teams in delivering personalized, evidence-based care.

References

  1. SYNTAX Score Official Website. https://syntaxscore.org/ .
  2. ESC/EACTS Guidelines on Myocardial Revascularization. https://syntaxscore.org/index.php/references .
  3. CatLet Score: A Potential Alternative to SYNTAX Score. https://www.sohu.com/a/443524114_186367 .
  4. SYNTAX Score II Validation Study. https://syntaxscore.org/ .
  5. SYNTAX II 2020: Personalized Decision-Making Tool. https://paper.sciencenet.cn/htmlpaper/2020/10/2020101216555179158941.shtm .
  6. Example Cases and Tutorials. https://syntaxscore.org/index.php/tutorial/example-cases .
Updated on 2025-01-18