Composite models including angiographic and clinical vari- ables have been developed but generally require validation in larger cohorts of patients. 3.3. PCI Complications In an analysis of the NCDR CathPCI database of patients undergoing PCI between 2004 and 2007, the overall inhos- pital mortality rate was 1.27%, ranging from 0.65% in elective PCI to 4.81% in STEMI.236 Factors associated with an increased risk of PCI-related death include advanced age, comorbidities (eg, diabetes, CKD, congestive heart failure), multivessel CAD, high-risk lesions, and the setting of PCI (eg, STEMI, urgent or emergency procedure, cardiogenic Causes of procedural and periprocedural MI include acute artery closure, embolization and no-reflow, side branch oc- clusion, and acute stent thrombosis. The incidence of procedure-related MI depends to a great degree on the definition of MI used, the patient population studied, and whether or not cardiac biomarkers are routinely assessed after PCI. The definition and clinical significance of PCI-related MI have been controversial. Criteria for defining a PCI- related MI have evolved over time.8,239,240 The 2007 universal definition of MI240 states that after PCI, elevations of cardiac biomarkers above the 99th percentile upper reference limit indicate periprocedural myocardial necrosis. Increases of biomarkers 3 times the 99th percentile upper reference limit were designated as defining PCI-related MI.240 According to this definition, 15% of patients undergoing PCI would be defined as having periprocedural MI.241,242 Issues in procedure-related MI are discussed in Section 5.10. 