Pharmaco Invasive approach (PIA) is the new mantra in the management of ACS.It simply means the intention to do PCI should always be the driving force in every STEMI patient , whether the Initial lysis is successful or failed .
This concept is exclusively created for centers where there is no cath lab (This would include hospitals with inactive labs , cardiologist team who lack required expertise !)
What to do after lysis ?
- If the initial lysis has failed “Rush” them for an emergency PCI.
- If Initial lysis is successful “Send” them for PCI in a less emergent manner.
Generally the time window for PIA is 3-24 hours. In failed lysis technically it could be as early as 1 hour as that is the time to assess the efficacy of initial lysis. (Of-course the theoretical transfer time to be added )
Why the 3 hour period for PIA ?
We know routine facilitated-PCI(f-PCI) with various combinations of fibrinolytics and 2b -3a antagonists is a failed concept. (FINNESS )
One of the primary reason for f-PCI to fail is , the very narrow time window between drug and balloon which somehow end up in more hazard (Needle -Balloon window) .
If they are very close the harm is likely to be more ,still they have to be closer if lysis has failed .(This is the reason many old studies had depressing results with even with the concept of rescue PCI !)
Lytic agents and PCI even though we assume to compliment each other real world evidence indicate they share a love hate relationship .
Beware, PIA is one form of facilitated PCI.
If we agree routine f-PCI is a failed concept we are in for real trouble. PIA indeed may masquerade as f-PCI if you combine lytic and PCI in sequential fashion in a hurry !
My point of view is is a successfully lysed STEMI should not be rushed to cath lab .If he some how reach the cath lab ultra fast manner , it behaves like a f-PCI and he is going to harmed more ! by the current evidence base isn’t ?
If the inital lysis was successful , with a less complex anatomy, it is possible your PCI that is going make the lesion more vulnerable.
(The other issue is tied with flawed human instinct. One can’t stop with CAG in a PIA* .Interventional cardiologists rarely have the courage to leave a well recannalised IRA without PCI.)
**Still , you need to facilitate the PCI in complex intervention in true rescue situation.That’s were we require the collective wisdom.
Assumptions galore in ACS
We have difficulty in identifying true success and failure of lysis .Vagueness with which we make decisions in CCUs and cath labs , is exemplified by the following facts. Post thrombolysis , 40% patients with persistent ST elevation are asymptomatic and 30 % of all those with complete ST regression , still have occluded IRA.
We are also uncertain when do the muscle truly die after a STEMI ! It is 6 hours in some, 12 in many, 24h in few , 36 h in a lucky ones .The role of collaterals, intermittent patency , individual variation resistance to myocardial hypoxia injury cannot be be quantified .
Final message
- The importance of Needle to Balloon time (NBT) time in PIA is to be strongly emphasized.
- This time can vary between 1-24 hours .But practically it will start from 3 hours .
- The irony is , we have conflicting engagement with time in PIA. We have to strive for both narrowing as well as intentionally prolonging this time window .
- It has to be narrowed in true rescue situations and optimally prolonged (Or is it indefinitely ! ) in non rescue situations !
After thought
Can we do pharmaco-Invasive approach(PIA) in PCI capable center ?
- Even in PCI capable centre one may get struck in proceeding with anticipated primary PCI for various reasons . If delay is anticipated we have to fall back on thrombolysis .This we call as unscheduled or bail out phamaco Invasive strategy .
- Intentional PIA in a PCI capable hospital for all low risk MI is also a viable and option .Never think primary lysis for STEMI even if we have lab ready is serious medial crime . After all , pPCI has a very marginal benefits in if any in all low risk STEMI!
Dr.S.Venkatesan MD 