Less than a century ago an easy chair was enough to manage this most important medical emergency of mankind. Of course, at that time mortality of STEMI was estimated to be around 30%.We have since pushed the in-hospital death rate down to less than 10 % and its around 5-8% currently.(*The lifeless chairs were able to save 70 lives is a different story!)
Heparin , thrombolytic agents, critical coronary care has helped us to achieve this , of course It must be admitted primary PCI also played a small role (at best 1 % ) in our fight against this number one killer.
Now, why not combine both lysis and PCI ?
The concept of PIA (Pharmaco Invasive approach) came into vogue primarily for two reasons.
1.If thrombolysis and pPCI are powerful strategies by individual merits why not combine both and achieve double the benefit ?
2. Since pPCI is going to be a logistical nightmare in most points of care and we can’t afford to lose time . So, let us lyse first and consider PCI later !
Unfortunately medical science is not math .One plus one in medicine is rarely two !
Though , it looks attractive , Pharmaco invasive approach has its own troubles.Fortunately , most of them are man-made, few are beyond our knowledge though.
Following general rules may help us
- STEMI should ideally managed by early thrombolysis (or PCI) in all deserving patients.
- Don’t wait for PCI if you think , there will be delay or reduced expertise and poor track record of the center in this modality.
- Pharmaco invasive therapy is not a default in all STEMI .Do good quality , monitored lysis , (Not necessarily new generation thrombolytic .(I prefer one hour sustained thrombolytic regimen , not the hit or miss bolus) .As a learned cardiologist we need to assess individual patients according to the type and risk of MI.Its not wise to blindly follow the guidelines ,because these guidelines , though based on evidence never answers a query in a single patient perspective !
The key “branch points” in decision making after lysis
- Invasive strategy should begin within one hour if the patient has failed thrombolysis and has developed any mechanical issues.( Mind you, LVF requires good medical stabilization .Rushing such patients to cath lab without application of mind can be disastrous )
- If the Initial lysis is excellent and the patient is asymptomatic one need not proceed with invasive limb at all.(A significant chunk of apparently failed lysis by ECG are asymptomatic and comfortable , these are patients require delicate assessment regarding further intervention. )
- If the MI is large and the clinical stability is “not confirmed” one may proceed urgently within 24 h.
- In any case there is no role for invasive approach after 24 hours* Unless fresh ischemia suspected to come from IRA or non IRA.
- Having said that, there are many centers that do a diagnostic angiogram alone just prior to discharge (48-72h) for risk stratification and then take a genuine call for a possible PCI or CABG. In my opinion it appears a sensible strategy , though a non invasive stress test pre/post discharge can even avoid that coronary angiogram !
One issue with Rescue PIA
Though by current definition PIA is to be done 3-24 hours , don’t wait for the 4th hour if you have recognized a failed thrombolysis earlier than three hours.( Ofcourse , as the gap between P and I gets too narrowed it may carry some adverse effects witnessed in routine facilitated PCI -Refer FINESSE study ) Similarly,there need not be a blanket ban on PCI beyond 24 hours if residual ischemia is active.
Final message
PIA is a dynamic coronary re -perfusion strategy . Nothing is fixed in science. . The optimal gap between Pharmaco and invasive strategy can be anywhere between 1 hour to “Infinitely deferred” depending upon individual risk perception and wisdom of the treating cardiologist.
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Dr.S.Venkatesan MD 