**2. The evolution of treatment strategies and guidelines for revascularization in patients with STEMI and MVCAD. The current evidence base. What do we know?**

Earlier results of trials comparing MPS and CO approaches were controversial [12–19], prob‐ ably due to the heterogeneity of patient samples, variable endpoints, distinct inclusion criteria and different study protocols. European and American Cardiology Societies for 2010–2013 [1–3] recommended limiting PPCI to the vessel with a culprit stenosis with the exception of cardiogenic shock and persistent ischemia after PCI. Moreover, performance of PPCI in a noninfarct artery was considered harmful [2].

However, randomized controlled trial (RCT) results [20–23] demonstrated usefulness and safety of multivessel stenting in patients with STEMI and MVCAD, both with MPS and MSS approaches. The current guidelines were updated by this data [4–6].

MPS approach was tested in two randomized controlled trials: PRAMI (Preventive Angio‐ plasty in Acute Myocardial Infarction) [20] and CvLPRIT (Complete Versus Culprit‐Lesion Only Primary PCI) [21]. In PRAMI trial, combined endpoint defined as cardiac death, nonfatal recurrent myocardial infarction (MI), or refractory angina at mean follow‐up of 23 months occurred in 21 (9%) patients treated with MPS approach compared to 53 (22%) patients treated with CO approach (hazard ratio (HR): 0.35; 95% confidence interval (CI): 0.21–0.58) [20]. Authors concluded that MPS approach significantly reduces the risk of adverse car‐ diovascular events, as compared to PCI limited to IRA [20]. In the CvLPRIT trial, authors showed that major adverse cardiac events (MACE) including all‐cause mortality, recurrent MI, heart failure, and ischemic‐driven revascularization at 12 months follow‐up occurred in 15 (10%) patients treated with MPS approach compared to 31 (21%) patients treated with CO approach (HR: 0.45; 95% CI: 0.24–0.84) [21]. In concordance with the PRAMI trial, researchers concluded that complete revascularization is beneficial for patients with STEMI and MVCAD in comparison with CO approach [21].

The MSS approach was also tested in two randomized controlled trials: DANAMI 3 PRIMULTI (Third Danish Study of Optimal Acute Treatment of Patients With ST‐segment Elevation Myocardial Infarction) [22] and PRAGUE‐13 (Primary Angioplasty in Patients Transferred From General Community Hospital to Specialized PTCA Units With or Without Emergency Thrombolysis) [23]. In the DANAMI 3 PRIMULTI trial, the MSS approach was based on the fractional flow reserve (FFR) value ≤ 0.80. Combined endpoint, defined as recurrent MI, all‐cause mortality, and ischemia‐ driven revascularization at 27 months follow‐up occurred in 40 (13%) patients treated with MSS approach and in 68 (22%) patients treated with CO approach (HR: 0.56; 95% CI: 0.38–0.83) [22]. Therefore, the MSS approach in patients with STEMI and MVCAD reduced the risk of adverse out‐ comes [22]. However, PRAGUE‐13 trial did not find significant differences between MSS and CO approaches (frequencies of primary composite endpoint including all‐cause mortality, recurrent MI, or stroke at 38 months follow‐up were 13.9% vs. 16.0%, respectively) [23].

All these findings provided the possibility for endorsement (class IIb) of MPS and MSS strat‐ egies to patients with STEMI and MVCAD by European and American Cardiology Societies since 2014 [4] and 2015 [5], respectively. Moreover, in 2016, the American Cardiology Society accepted appropriate use criteria for coronary revascularization in patients with acute coronary syndrome considering revascularization of arteries with nonculprit stenosis at initial procedure or during the initial hospitalization [6]. According to these criteria, (1) stable patients immediately following PCI of culprit artery and one or more additional severe/intermediate (50–70%) stenoses may be defined as appropriate for MPS approach; (2) asymptomatic patients after successful treatment of culprit artery by PPCI and one or more additional severe/intermediate (50–70%) stenoses are appropriate for MSS approach if having ischemia on noninvasive testing/FFR ≤ 0.80; (3) asymptomatic patients after suc‐ cessful treatment of culprit artery by PPCI and one or more additional severe stenoses may be appropriate for MSS approach [6].

Hence, both MPS and MSS approaches have sufficient evidence base for being applied to patients with STEMI and MVCAD and are included in recent clinical guidelines. However, there is a number of unresolved issues such as stent choice, effect of residual SYNTAX score, timing of staged PCI, and the choice between two multivessel stenting approaches. Addressing these issues is crucially important for personalized treatment of STEMI and MVCAD.
