Stent thrombosis definitions

Most commonly used definitions
There have been different definitions in different studies.

Definition based on timing of stent thrombosis (ST)

 * Acute	    < 24 hrs
 * Subacute   24 hrs – 30 days and
 * Evidence of ST by way of one or more of
 * angiographic vessel occlusion with TIMI 0-1 flow
 * new Q-wave MI in an area supplied by the stented vessel,
 * unexplained death from a cardiac cause

Some studies looked at clinical events from soon after procedure to a few days after the procedure. One of the reasons for this method was that a significant proportion of clinical events in this time period was proceudure related.
 * Late ST    30 d  - 360 days
 * > 30 d following stent implantation and new myocardial infarction (MI) with occlusion of the stented artery on angiography.

Some studies had a definition of “ late” after the 6th month.
 * Very Late ST	> 360 days
 * ( > 4 yrs ) At the moment there is only sparse data beyond four years.

Definition based on certainty of ST
In order to standardize and semi-quantify the certainty of ST, the academic research consortium (ARC) recommended the following classification (ref ) Unexplained death occurring more than 30 days after the index procedure.
 * Definite ST
 * Angiographic confirmation of thrombus, with or without vessel occlusion, associated with
 * clinical or ECG signs of acute ischemia or
 * elevation of serum creatinine kinase (CK) to twice the normal value within 48 hours of angiography.
 * Probable ST
 * Unexplained death occurring within 30 days after the index procedure or
 * if a myocardial infarction, occurring at any time after the index procedure, was documented in an area supplied by the stented vessel in the absence of angiographic confirmation of stent thrombosis or other culprit lesion.
 * Possible ST

NOTE : Events occurring after repeat target lesion revascularization would be included.