Aortic valve replacement with the MedInzh-ST full-flow mechanical implant and modern bicuspid model: comparison of short-term results

Introduction: Mechanical heart valves prostheses have certain disadvantages related to impeding blood flow due to their shape and the design principle of the locking elements. The design of the new model of mechanical prostheses is based on the principle of full flow, which enables to increase the effective area of the valve opening and retain the identical dimensions of the implant. The results of using this type of prosthesis have not been sufficiently studied. Objective: The study aimed to compare the short-term results of aortic valve replacement with the mechanical full-flow prosthesis and with the standard mechanical prosthesis. Methods: The retrospective study included 246 patients who underwent aortic valve replacement with mechanical prosthesis over the period from 2015 to 2021. The MedInzh-2 classical bicuspid valve was implanted in 134 patients, and the new full-flow prosthesis was used in 112 patients. A pseudorandomization procedure (Propensity score matching) was performed to equalize the groups. The level of the transprosthetic gradient was used as the primary endpoint. Results: Propensity score matching resulted into forming two groups of 90 patients each. Hospital mortality in the MedInzh-ST group and the MedInzh-2 group amounted to 2.2% and 6.7%, respectively (Р = 0.178). In the early postoperative period, no differences in the processes of left ventricular cavity remodeling were found between the groups. In the MedInzh-ST full-flow prosthesis group, significantly lower values of transprosthetic gradients were revealed (mean gradients 12.6 versus 16.1 mm Hg, P < 0.001). The effective prosthetic orifice area was statistically higher in the full-flow implant group (2.04 versus 1.89 cm2, P < 0.001). Conclusion: Application of the MedInzh-ST mechanical valve proved to be safe at surgical correction of aortic valve diseases. The prosthesis was hemodynamically effective that was confirmed by a significantly lower level of transprosthetic gradient and a larger effective valve orifice area in comparison to the standard bicuspid mechanical prosthesis.