The investigators want to assess the use of the residual SYNTAX score and the SYNTAX Revascularization Index as predictors for in-hospital outcomes and mid-term (6 months to 1 year) outcomes in patients with multi-vessel disease (MVD) who undergo PCI in the setting of STEMI or NSTEACS. Both values will be calculated in a number of patients over one year, and the relationship between both values and patient outcomes will be evaluated.

Significant non-culprit coronary stenosis is noted in 40-70% of patients with ST-elevation Myocardial Infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). Presence of multivessel disease (MVD) has been associated with poorer clinical outcomes. MVD in STEMI may confer an increased risk of recurrent ischemia and mortality. However, the impact of MVD on prognosis in STEMI may vary depending on the characteristics of coronary artery disease (CAD) present.

Current guidelines recommend that only the infarct-related artery should be treated. However, RCTs have suggested that a strategy of multivessel PCI, either at the time of primary PCI or as a planned, staged procedure, may be beneficial and safe in selected patients with STEMI. On the basis of these findings, the prior Class III (Harm) recommendation with regard to multivessel primary PCI in hemodynamically stable patients with STEMI has been upgraded and modified to a Class IIb recommendation to include consideration of multivessel PCI, either at the time of primary PCI or as a planned, staged procedure.

Early invasive treatment in high-risk patients with non-ST-elevation acute coronary syndrome (NSTEACS) has been shown to improve their prognosis in terms of cardiovascular death and reinfarction. The prevalence of multivessel disease in these patients stands at about 50% and experts agree that performing complete revascularization is beneficial in such patients.

Accordingly, the SYNergy between PCI with TAXus and cardiac surgery (SYNTAX) score has been developed in 2005 in Erasmus Medical Center in the Netherlands to evaluate the severity of coronary artery disease in the settings of left main or MVD.

The investigators have observed a growing interest in residual disease burden after PCI. The residual SYNTAX score (rSS), described by Genereux and colleagues is a strong prognostic factor of coronary events and all-cause death in patients who have undergone PCI. This score has subsequently been validated by other groups and been shown to have good prognostic accuracy for adverse ischemic outcomes after PCI.

The SYNTAX Revascularisation Index (SRI), which takes into account the severity and extent of baseline CAD (as assessed by the baseline SYNTAX score [bSS]) and the residual CAD after PCI (as assessed by the rSS) has been used in determining the proportion of CAD that has been treated, and has been shown to have prognostic utility in PCI for MVD.

Here, the investigators want to assess the use of the residual SYNTAX score and the SYNTAX Revascularization Index as predictors for in-hospital outcomes and mid-term (up to two year) outcomes in patients with multi-vessel disease (MVD) who undergo PCI in the setting of STEMI or NSTEACS.

Inclusion Criteria:

• All ACS (STEMI and NSTEACS) patients undergoing PCI in the setting of MVD.

Exclusion Criteria:

• Patients receiving fibrinolytic therapy.
• Patients with cardiogenic shock
• Post-CABG patients
• Patients with severe renal impairment

All consecutive patients admitted to the Assiut University Hospitals Department of Cardiology will be collected over one year starting 1st of July 2017 till 30th of June 2018.

Considering the primary end-point of the study (MACE rate 28%) (Khan et al, 2016), the estimated sample size of the population, based on power of 85%, and alpha= 5%, is calculated to be = 108 patients.

IPD will not be shared with other researchers.