The study examined 39 patients who underwent various cardiac surgeries. A prospective analysis was performed. The course of the postoperative period was studied when using a fiber-optic system for counterpulsation on the basis of central hemodynamic parameters and echocardiography data. A protocol has been developed for the use of intra-aortic balloon counterpulsation with a fiber-optic system in patients undergoing cardiac surgery, and indications for counterpulsation with a fiber-optic sensor have also been determined. According to the results of the dissertation work, it was noted that the indications for the use of the fiber-optic system of intra-aortic balloon counterpulsation are the impossibility of stopping artificial blood circulation for two hours, or the increase in signs of left ventricular failure after the cessation of artificial blood circulation or in the early postoperative period

Leonid Rumiantsev, defended the degree of Candidate of Medical Sciences in 2021. He works as a cardiovascular surgeon at the Republican Hospital No. 1 of the Sakha Republic. The number of works is 11, the Hirsch index is 2.