Functional condition of the left ventricle after myocardial revascularization in patients with non-ST-segment elevation myocardial infarction at different times from the onset of symptoms

Abstract

The aim – to conducted in order to determine the effect of myocardial revascularization performed at different times from the onset of symptoms in patients with non-ST-segment elevation myocardial infarction (NSTEMI) on the function of left ventricular (LV) contractility during long-term follow-up (within 1 year) according to echocardiography. In addition, the study evaluated the functional state of the LV in patients with NSTEMI who did not undergo revascularization of the myocardium.Materials and methods. Patients with NSTEMI included in the study (n=128) were divided into 5 groups according to the time of revascularization (emergent or selective revascularization), as well as by the method of revascularization (stenting or bypass grafting), including a group of patients who did not undergo revascularization. Group 1 consisted of patients (n=28) who underwent emergent coronary angiography and ad hoc stenting in the first 72 hours from the onset of symptoms. Group 2 included patients (n=61) who underwent coronary angiography and coronary stenting in a planned manner after 72 hours or more from the onset of symptoms. Group 3 included patients (n=12) who underwent a scheduled bypass operation selectively. Group 4 consisted of patients with NSTEMI (n=27) who, after emergent coronary angiography, did not undergo revascularization control group. And group 5 is a general revascularization group, which consists of patients from all of the above groups (n=101) who underwent revascularization in any way. Patients of all groups underwent initial coronary angiography, determined the initial level of cardiac troponins, performed an ultrasound examination of the left ventricle using a standard technique to evaluate the initial indicators of regional and general myocardial contractility. In the absence of contraindications (patients of groups 2 and 3), tests with dosed physical activity were performed (to identify the class of angina pectoris). During the short-term (upon discharge from the hospital, after 1 month and after 3 months), as well as long-term (after 6 months and after 1 year), the parameters of the left ventricular contractile function – the ejection fraction (LVEF) were repeatedly measured and the functional class of angina was determined.Results and discussion. An analysis of the results of testing with dosed physical activity revealed the following: if class 0–I angina before stenting in patients with NSTEMI stenting was 0 % of cases, then after 6 months of observation this figure was 70.6 %, and 12 months after stenting – 73.8 %. The number of cases of severe angina pectoris decreased from 44.1 % during the initial examination to 7.7 % after 12 months of follow-up. An analysis of the results of indicators of regional and general LV contractility revealed a significantly significant improvement in these parameters in patients with NSTEMI after 12 months in both the urgent group and the planned stenting group. The number of normokinetic segments increased by 10 % (from 84.2 to 94.2 %), and the number of hypokinetic segments decreased by more than 2 times (from 16.5 to 6.8 %). LVEF indicators for 12 months of observation both in the urgent group and in the planned stenting group significantly increased. In the control group, as well as in the coronary bypass group, no significant changes in LV contractile function were observed for 12 months after NSTEMI.Conclusions. Coronary stenting, both urgent and planned, in patients with NSTEMI, according to a year of observation, significantly improves the functional and volume indicators of LV. The improvement of these indicators significantly reduced the class of angina in NSTEMI patients after stenting, which improved the quality of life of these patients.