There are a variety of classification schemes that are designed to characterize the severity of<unk> .  Some are used in clinical practice, others are used to quantitate<unk>  in clinical trials.
Quantitating the incidence of<unk>  is critical to characterize the side effects of new drugs, surgical procedures and devices. The incidence of<unk>  complications varies from 1% to 10% during treatment of acute coronary syndromes (ACS) and PCI (Percutaneous coronary intervention). This is in part due to use of combination of multiple drugs like aspirin, heparin, warfarin, platelet P2Y12 inhibitors, glycoprotein IIb/IIIa inhibitors, direct thrombin inhibitor and also the invasive procedures (percutaneous coronary intervention, Coronary artery bypass graft) during this period. Also, the<unk>  complications have been found to be associated with increase in incidence of short and long term adverse outcomes like death, non-fatal MI (myocardial infarction), stroke and stent thrombosis. The exact mechanism underlying this is not clearly defined but may be due to the cessation of evidence based therapies (like antiplatelet, Beta blockers, statin), effect ofblood transfusion, co morbidities and anemia that are seen more in patients with<unk>  complications. Therefore,<unk>  presents as an important safety endpoint in many of the cardiovascular trials. 
However, there is a lack of uniformity in the definitions of<unk>  that could be used in the cardiovascular trials that in turn make it difficult to conduct and compare the results of different trials. Several<unk>  definitions have been used in different clinical trials such as the TIMI, GUSTO, ACUITY, HORIZONS,and PLATO<unk>  scales.  To reduce the heterogeneity and to adopt standardized<unk>  end-point definitions for patients receiving antithrombotic therapy, the<unk>  Academic Research Consortium (BARC) was convened comprising representatives from different fields of medicine. These standardized definitions will help researchers determine the relative safety of different antithrombotic therapies. These definitions are recommended for both clinical trials and registries
Bleeding classification
Lower gastrointestinal bleeding classification
Nausea and vomiting classification
Goiter classification
Asplenia classification
Hematuria classification
Lymphadenopathy classification
Boil classification