Polygon of confluence in IVUS
Polygon of confluence is a term often used in intravascular ultrasound (IVUS) imaging of the coronary arteries. It is the confluence of left main coronary artery (LMCA), left circumflex (LCX) and left anterior descending (LAD) coronary artery. The 5,6,7,8 criteria mentions that the LCX should have an area of 5 sq. mm, LAD 6 sq. mm, polygon of confluence 7sq. mm and LMCA 8 sq. mm. If these areas are achieved after an IVUS guided PCI (percutaneous coronary intervention) of distal LMCA, that is taken as a good result.
The minimum lumen area (MLA) in the polygon of confluence can be taken as a surrogate of overall severity of the left main bifurcation lesion.1 MLA of the polygon of confluence is also predictive of clinical events during follow up after PCI of left main. It has also been considered to give an indication of post PCI minimum lumen area of LCX ostium. A lot of stress has been given to adequate lesion preparation before stenting in LMCA bifurcation stenosis with IVUS guidance.
- Kang SJ et al. Intravascular ultrasound assessment of distal left main bifurcation disease: the importance of the polygon of confluence of the left main, left anterior descending, and left circumflex arteries. Catheter Cardiovasc Interv. 2013;82:737-45.