Leaman Score Calculator – Coronary Atherosclerotic Burden
Coronary angiographic assessment
Select coronary dominance and the most severe luminal diameter reduction in each native coronary segment.
Coronary dominance
Choose the angiographically determined coronary circulation pattern. The original score provides right- and left-dominant weighting.
Right coronary artery (RCA)
Enter the most severe stenosis among RCA segments 1–4. The original method evaluates only the segment with the most severe RCA disease.
Left main coronary artery (LM)
Luminal diameter reduction in the left main coronary artery.
LAD – proximal
Proximal left anterior descending artery.
LAD – mid
Mid left anterior descending artery.
LAD – distal
Distal left anterior descending artery.
First diagonal branch (D1)
First diagonal branch of the LAD.
Second diagonal branch (D2)
Second diagonal branch of the LAD.
Left circumflex (LCx) – proximal
Proximal circumflex artery.
First obtuse marginal branch (OM1)
First obtuse marginal branch.
Atrial circumflex branch
Atrial circumflex branch as represented in the original coronary segment model.
Posterolateral branch
Posterolateral circumflex branch (segment 14).
Posterior descending branch (PDA)
Posterior descending artery. Its segment weight depends on coronary dominance.
No qualifying obstructive lesion selected
The original Leaman score includes lesions with 70% or greater luminal diameter reduction. This score is a weighted angiographic burden measure, not a validated categorical risk class.
Segmental score contribution
| Segment | Location weight | Stenosis factor | Contribution |
|---|---|---|---|
| No qualifying lesion selected. | |||
About the Leaman Score
The original Leaman coronary score was developed to quantify the severity of obstructive coronary artery disease using coronary angiography. It weights coronary segments according to their contribution to left ventricular blood supply and multiplies the segment weight by a stenosis-severity factor.
Calculation method
Segment contribution = anatomical weighting factor × stenosis weighting factor. The total Leaman score is the sum of the segment contributions.
| Luminal diameter reduction | Stenosis factor |
|---|---|
| Below 70% | 0 (not scored) |
| 70–89% | 1 |
| 90–99% | 3 |
| 100% (total occlusion) | 5 |
Important methodological notes
- The RCA is represented by one input for the most severely diseased segment among original segments 1–4; the original publication states that only the most severe RCA segment was analyzed.
- Collateral flow is not incorporated in the original score because its true significance was considered uncertain.
- The original publication describes postoperative handling of patent and occluded bypass grafts. This calculator is intended for native-vessel angiographic scoring and does not implement post-CABG graft adjustment.
- The original model provides right- and left-dominant weighting. Balanced dominance is not added because it was not specified in the original scoring method.
Interpretation
A higher score indicates a greater weighted burden of obstructive coronary disease. The original paper does not establish universal low-, intermediate-, or high-risk cutoffs for clinical decision-making. Do not interpret the numeric score as a standalone prognosis or treatment recommendation.
References
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