Aortic root prosthesis with pericardial cusps "Russian conduit": A hydrodynamic experiment

<p><strong>Aim.</strong> The study aimed to compare the hydrodynamic characteristics and durability of the aortic root prosthesis with pericardial cusps with various options for the formation of commissures.</p><p><strong>Methods.</strong> Nine conduits with pericardial valves were formed according to the technique described by Ozaki. The prostheses were divided into 3 groups of 3 specimens each: group 1 — without additional reinforcing seams on the top of the commissure; group 2 — with an additional U-shaped seam without gasket; and group 3 — with an additional suture with an opposite pericardial gasket. The prostheses were fixed on a stand for hydrodynamic testing of artificial heart valves. The hydrodynamic characteristics of the prostheses were evaluated. The hydrodynamics of the frame biological prosthesis was used for comparison. After assessing the hydrodynamic parameters of the aortic root prostheses, their work durability was tested. Defects of the pericardial cusps were studied macroscopically.</p><p><strong>Results. </strong>Two samples from group 2 were withdrawn from testing ahead of schedule at around 11 × 10⁶ cycles, which is approximately 3.5 months of normal heart function. The other prostheses remained competent and were removed for an examination at 32 × 10⁶ cycles, which is approximately 9.6 months of normal heart function.</p><p><strong>Conclusion. </strong>The hydrodynamics of the aortic root prosthesis with pericardial valves was comparable to the hydrodynamics of the frame biological prosthesis. Additional U-shaped sutures in the commissure area of the pericardial cusps did not increase the functional durability of the aortic root prosthesis with pericardial leaflets and served as additional risk factors for leaflet perforation. Implantation of pericardial leaflets into a vascular graft resulted in a different distribution of dynamic stress compared to the original aortic valve neocuspidisation, which preserved the aortic root.</p><p>Received 8 July 2021. Revised 30 August 2021. Accepted 7 September 2021.</p><p><strong>Funding:</strong> The study did not have sponsorship.</p><p><strong>Conflict of interest:</strong> Authors declare no conflict of interest.</p><p><strong>Contribution of the authors<br /> </strong>Conception and study design: V.V. Bazylev, P.A. Batrakov<br /> Data collection and analysis: P.A. Batrakov, D.M. Khadiev, A.A. Egorov, N.A. Eremin<br /> Drafting the article: P.A. Batrakov<br /> Critical revision of the article: V.V. Bazylev, P.A. Batrakov<br /> Final approval of the version to be published: V.V. Bazylev, P.A. Batrakov, D.M. Khadiev, A.A. Egorov, N.A. Eremin<strong> </strong></p>

The Use of Polymeric Materials in Modern Dentistry

The achievements and discoveries of chemical science have firmly established themselves in all branches of humanity. One of the most significant chemistry possibilities is the polymerization and polycondensation of compounds, which, in turn, are methods for producing polymers. Polymers are high molecular weight compounds consisting of many units (monomers) linked by chemical bonds. Unique polymer compounds are the basis of plastics, chemical fibers, rubber, paints, and varnishes, adhesives [8]. Polymers are used for the manufacture of removable prostheses, materials for fillings and inlays, orthodontic appliances, artificial teeth, dental implants, as well as in the creation of artificial heart valves, artificial kidney devices, artificial circulation, artificial heart [6].

Standardization of in vitro testing for cardiovascular implants in the era of European Medical Device Regulation

In case of cardiovascular implants classified as class III medical products there is a specific responsibility for manufacturers as well as regulatory authorities to follow international standards to guarantee for safety and efficacy. Fast developments of science and technology as well as novel clinical findings create permanent needs to match the standardization. Therefore, a set of international standards is analyzed with respect to their use for particular coronary drug-eluting stents and artificial heart valves. It was found that standards (ISO, ASTM) exist for general requirements on passive implants, but also specifically relate to arterial stents, stent grafts, bioresorbable and drug-eluting stents, as well as artificial heart valves. New work items address new methods for characterization of coating integrity, particulate matter and simulated use testing. European Medical Device Regulation (MDR) requires technical expertise and capacity at Notified Bodies supported by independent test laboratories. Generally, the interest in standardization from industry, test laboratories and authorities is high, but more input from medical experts would further improve the value of standardization and its relevance for safe and even more effective implants.

Standardization of in vitro testing for cardiovascular implants in the era of European Medical Device Regulation

In case of cardiovascular implants classified as class III medical products there is a specific responsibility for manufacturers as well as regulatory authorities to follow international standards to guarantee for safety and efficacy. Fast developments of science and technology as well as novel clinical findings create permanent needs to match the standardization. Therefore, a set of international standards is analyzed with respect to their use for particular coronary drug-eluting stents and artificial heart valves. It was found that standards (ISO, ASTM) exist for general requirements on passive implants, but also specifically relate to arterial stents, stent grafts, bioresorbable and drug-eluting stents, as well as artificial heart valves. New work items address new methods for characterization of coating integrity, particulate matter and simulated use testing. European Medical Device Regulation (MDR) requires technical expertise and capacity at Notified Bodies supported by independent test laboratories. Generally, the interest in standardization from industry, test laboratories and authorities is high, but more input from medical experts would further improve the value of standardization and its relevance for safe and even more effective implants.