It is estimated multi-vessel CAD occur in about 70 % of NSTEMI/UA.In high risk NSTEMI early invasive strategy is popular (Though it is not yet an undisputed choice !) .Tackling the culprit artery and restoring the blood flow , providing immediate relief from angina is the primary aim . Myocardial salvage is a lesser aim !
The lesion that is immediately responsible for angina is referred to as culprit lesion and artery .(Ideally may be called as Angina related artery ARA .)
If we have multiple culprit like lesions it is difficult to identify the target lesion. Inexperienced cardiologists may not consider this as an issue !
The following features may be helpful
- The tighter the stenosis , it is more likely to be a culprit . (Of course , blind belief on this rule can result in huge errors ! )
- Eccentric lesions
- Thrombotic lesions
- Grafts /Post PCI lesions if present carry high chances of becoming culprits.
- ECG characteristics may be use full (Global ST depression can not occur with isolated RCA/LCX NSTEMI .It generally indicate LAD lesion to be the culprit.
- Deep ST depression in V1 to V3 would indicate LCX a definite culprit .(It could even be a STEMI equivalent )
- Echo – Angio correlation can provide a useful clue in identifying the culprit. (Example : In a patient with Multi vessel CAD , if there is severe resting wall motion defect in Infero -Lateral segments with relative sparing of septum LCX lesion should be the culprit .)
- It is not always easy to identify the culprit artery .There can be multiple active plaques .
- Diffuse inflammatory vessel are reported in few with NSTEMI
- Occasionally there can be no culprit lesion at all (No active plaques ) , as the rest angina may be related to excess demand like fever or anemia with a stable non critical plaque.
The delicate exercise of identifying the angina related artery is important for two reasons.
- We can not afford to prolong the PCI procedure in the setting of ACS as increased procedure time is clearly related to peri- procedural events.
- Secondly , stenting a wrong lesion and persistence of angina after a PCI will take away the hard earned credentials of cardiologists instantaneously !
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