Introduction: Percutaneous coronary interventions (PCI) are one of the most effective methods of treatment acute myocardial infarction (AMI). However, re-stenosis/thrombosis inside the stent remains one of the main limiting factors of this procedure. The spread of atherosclerosis in other arteries can also provoke the development of recurrent AMI.

Purpose: to compare specifities of clinical course of recurrent AMI in patients with re-stenosis/thrombosis inside old coronary stent and/or with new coronary stenoses outside it.

Materials and methods: Totally 212 patients treated in CCU of our hospital about recurrent AMI in 2018-2021 were examined. All of them were treated according last version of ESC guidelines. All patients were urgently undergone coronary angiography with subsequent percutaneous coronary intervention currently as well as during previous hospitalization. In 22,8% bare metal stent, in 77,2 %  drug eluting stent were used. Tests typical for AMI protocol were performed. Patients were divided into 2 cohorts: the 1-st  -  110 persons (males 80%, females 20%) with in-stent re-stenosis/ thrombosis, their average age was  64,3 ± 1,1 years. 72 of them were diagnosed AMI with ST segment elevation, 38– without it. Patients in 2-nd cohort had new coronary arteries stenoses outside old stents - 102 persons: 62,7% males, 37,3% females, average age – 66,4 ± 1,2 years. AMI with ST elevation -  66 pts,  36  – without ST elevation. Data were statistically assessed.

Results: In patients of Group I recurrent ?MI occurred in average after 3,9 years, in 2-nd one – 5,5 years (p= 0,04). Medical history: 1-st  cohort: chronic heart failure  II-III by NYHA - 68%, 2-nd  -  50% patients (p=0,73); diabetes mellitus 2 type :  I - 32,7%  versus 7,7%  in II (p=0,04);   chronic renal disease: in I  - 38,2%, in II – 14,7%, (p=0,03).     During index hospitalization: rates of AMI with/without ST-elevation were not statistically differed:  I - 57,9%  and 42,1%, versus II - 60,2% and 39,8% respectively (? >0,05). Anterior/inferior AMI rates were in 1-st group 44,3/35,8% versus 43,4/35,9 in 2-nd (? > 0,05). In 1-st cohort alterations of  large arterial coronary branches were more common: 79,1% versus 51,0 % in 2-nd . Patients in cohort I had significantly lower left ventricular (LV) ejection fraction in comparison with II: 42,9±1,0 versus 51,4±1,4. Acute heart failure Killip II- III in I-st - 26,4%, in II  – 14,7 % (? < 0,05). Significant supraventricular arrythmias had I  - 68,8%,  II- 17,7%  (? < 0,05). Significant ventricular arrythmias had I – 8,2% versus II-  2,9%  (? < 0,05).  In-hospital mortality: I - 11,8% versus II - 3,9% (? < 0,05).