Dr.S.Venkatesan MD

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

1. The tighter the stenosis , it is  more likely to be a culprit . (Of course , blind  belief on this rule  can result in huge errors ! )
2. Eccentric lesions
3. Thrombotic lesions
4. Grafts /Post PCI lesions if present carry high chances of becoming culprits.
5. 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.
6. Deep ST depression in V1 to V3 would indicate LCX a definite culprit .(It could even be a STEMI equivalent )
7. 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 .)

Exceptions

• 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.

Final message

The  delicate   exercise of identifying the angina related  artery is  important  for two reasons.

1. 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.
2. Secondly , stenting a wrong lesion   and persistence of angina after a  PCI  will take  away  the  hard earned credentials  of  cardiologists  instantaneously !

Reference

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