Primary percutaneous intervention (PPCI) is an accepted norm in patients with acute ST-elevation myocardial infarction (STEMI). It has been the recommended perfusion procedure when it can be administered by an experienced team within 90–120 min from patient’s first medical contact.
In the 1980s, streptokinase was used successfully as a fibrinolytic agent, followed by the more fibrin-specific recombinant t-PA alteplase. Infusion of t-PAs decreased mortality; r-PA (reteplase) was found to be easier to administer, and TNK-tPA (tenecteplase) has the advantage of being a single bolus that can provide rapid treatment, and is widely still used as a fibrinolytic agent today.
With PPCI, data indicates that coronary flow is re-established in about 90% of STEMI patients as opposed to only 40–60% with fibrinolytic therapy. Additionally, a meta-analysis of 23 trials has shown a reduction in mortality from 7% with fibrinolysis to 5% with PPCI, especially if PPCI was done as early as possible. Delays could be as a result of age of the patient, duration of symptoms, and infarct location. Poor outcomes have been noted in delays of more than 60-120 minutes.
So, what could be the fate of STEMI patients who are unable to receive expert medical attention for PPCI within 2hrs of symptoms?
Results from a meta-analysis of 22 trials indicated that a significant reduction in mortality occurred if fibrinolytic therapy could be established within the two hours of symptoms presentation. Fibrinolytic therapy is easier to administer and can be conducted by trained paramedical professionals even before patient arrives at the hospital. In contrast, PPCI requires hospital-based care.
The main risk with fibrinolytic therapy is bleeding that can be associated with considerable morbidity and mortality. Intracerebral haemorrhage can occur in the elderly who are frail, especially women patients, and in those with a previous history of hypertension or cerebrovascular disease.
What about fibrinolytic therapy followed by PCI?
Ideally, since PCI provides better reperfusion, all STEMI patients should be sent to a PCI-facility based medical center, even if fibrinolytic therapy was administered. It has been reported that early PCI intervention can lead to ischemic complications.
European and North American guidelines recommend that rescue PCI should be considered after failed fibrinolytic therapy and routine angiography, if fibrinolytic theray was successful. A time of 3-24hr window for angiography is recommended.
Halvorsen S, Huber K. Fibrinolytic treatment of ST-elevation myocardial infarction
Update 2014. Hämostaseologie 2014;34:-DOI:10.5482/HAMO-13-07-0040.