Comparison of biomechanical and structural properties between human aortic and pulmonary valve

Funding Information: This study was supported by a grant from the Latvian Council of Science.Objective: Pulmonary valve autografts have been reported as clinically effective for replacement of diseased aortic valve (Ross procedure). Published data about pulmonary valve mechanical and structural suitability as a long-term substitute for aortic valve are limited. The aim of this study was to compare aortic and pulmonary valve properties. Methods: Experimental studies of biomechanical properties and structure of aortic and pulmonary valves were carried out on pathologically unchanged human heart valves, collected from 11 cadaveric hearts. Biomechanical properties of 84 specimens (all valve elements: cusps, fibrous ring, commissures, sinotubular junction, sinuses) were investigated using uniaxial tensile tests. Ultrastructure was studied using transmission and scanning electron microscopy. Results: Ultimate stress in circumferential direction for pulmonary valve cusps is higher than for aortic valve (2.78±1.05 and 1.74±0.29 MPa, respectively). Ultimate stress in radial direction for pulmonary and aortic cusps is practically the same (0.29±0.06 and 0.32±0.04 MPa, respectively). In ultrastructural study, different layout and density in each construction element are determined. The aortic and pulmonary valves have common ultrastructural properties. Conclusions: Mechanical differences between aortic and pulmonary valve are minimal. Ultrastructural studies show that the aortic and pulmonary valves have similar structural elements and architecture. This investigation suggests that the pulmonary valve can be considered mechanically and structurally suitable for use as an aortic valve replacement.Peer reviewe

Polymorphisms on PAI-1 and ACE genes in association with fibrinolytic bleeding after on-pump cardiac surgery

Publisher Copyright: © 2015 Ozolina et al.Background: Carriers of plasminogen activator inhibitor -1 (PAI-1) -675 genotype 5G/5G may be associated with lower preoperative PAI-1 plasma levels and higher blood loss after heart surgery using cardiopulmonary bypass (CPB). We speculate if polymorphisms of PAI-1 -844 A/G and angiotensin converting enzyme (ACE) intron 16 I/D also might promote fibrinolysis and increase postoperative bleeding. Methods: We assessed PAI-1 -844 A/G, and ACE intron 16 I/D polymorphisms by polymerase chain reaction technique and direct sequencing of genomic DNA from 83 open heart surgery patients that we have presented earlier. As primary outcome, accumulated chest tube drainage (CTD) at 4 and 24 h were analyzed for association with genetic polymorphisms. As secondary outcome, differences in plasma levels of PAI-1, t-PA/PAI-1 complex and D-dimer were determined for each polymorphism. SPSS® was used for statistical evaluation. Results: The lowest preoperative PAI-1 plasma levels were associated with PAI-1 -844 genotype G/G, and higher CTD, as compared with genotype A/A at 4 and 24 h after surgery. Correspondingly, 4 h after the surgery CTD was higher in carriers of ACE intron 16 genotype I/I, as compared with genotype D/D. PAI-1 plasma levels and t-PA/PAI-1 complex reached nadir in carriers of ACE intron 16 genotype I/I, in whom we also noticed the highest D-dimer levels immediately after surgery. Notably, carriers of PAI-1 -844 genotype G/G displayed higher D-dimer levels at 24 h after surgery as compared with those of genotype A/G. Conclusions: Increased postoperative blood loss secondary to enhanced fibrinolysis was associated with carriers of PAI-1 -844 G/G and ACE Intron 16 I/I, suggesting that these genotypes might predict increased postoperative blood loss after cardiac surgery using CPB.publishersversionPeer reviewe

Inflammatory cytokines and antimicrobial peptides in acquired heart diseases

Introduction. One of the risk factors for cardiovascular disease is inflammation. The role that it plays in the pathogenesis of cardiovascular disease remains a topic of ongoing research. The aim of this study was to identify the appearance and distribution of inflammatory markers, interleukins 1α (Il-1α) and 10 (Il-10) and β defensins 2 (βD2), 3 (βD3), and 4 (βD4), in the right atrial tissue from different acquired heart diseases. Methods. During cardiac surgery, right atrial tissue fragments were taken from 23 patients with acquired heart diseases. Tissue fragments were stained for immunohistochemical detection of Il-1α, Il-10, βD2, βD3 and βD4. Results. Few to a moderate number of Il-1α-positive cells and a moderate to great number of Il-10-, βD2- and βD3-positive cells were detected in right atrial tissue. There was a positive correlation between the level of CRP and the number of βD3-positive cardiomyocytes (rs 0.463; p 0.026). We found a negative correlation between the left ventricular ejection fraction and the number of βD2-positive cells in connective tissue (rs -0.524; p 0.012). Conclusions. The rich expression of antimicrobial peptides and its association with CRP support the idea that an inflammatory process is involved in the pathogenesis of acquired heart diseases. The worst preoperative condition is associated with increased antimicrobial peptide expression in the right atrial cells

St. Jude Epic Heart Valve Bioprostheses Versus Native Human and Porcine Aortic Valves - Comparison 0f Mechanical Properties

St. Jude Epic heart valve bioprostheses versus native human and porcine aortic valves - comparison of mechanical propertie

Comparison of radial deformability of stent posts of different aortic bioprostheses.

Little is known about the stent deformability required for optimal stented heart valve bioprosthesis design. Therefore, two bioprosthetic valves with known good long-term clinical results were tested. The strain in the radial direction of the stent posts of these valves was compared with contemporary bioprosthetic valves and a native porcine aortic root. Medtronic Intact and Carpentier-Edwards Standard (CES), and four contemporary bioprostheses, including one self-expanding prosthesis, were tested with three sonomicrometry probes per valve fixed at commissure attachment points. The mean values from 2400 data points from three measurements of the interprobe distances were used to calculate the radius of the circle circumscribed around the three probes. Changes in the radius of the aortic root at pressures 70-90 and 120-140 mmHg (pressure during diastole and systole) and that of the stent posts at 70-90 and 0-10 mmHg (transvalvular pressure gradient during diastole and systole) were compared. An increase in radius by 7.3 ± 2.6, 8.7 ± 0.0 and 3.9 ± 0.0% for the porcine aortic root, CES and Intact valves, respectively, was observed during transition from diastolic to systolic pressure and less for contemporary bioprostheses-mean 2.5 ± 0.9%, lowest 1.2 ± 0.0. The results indicate that the radial deformability of bioprosthetic valve stent posts can be as low as 1.2% for xenoaortic and 3.0% for xenopericardial prostheses with no compromise of valve durability. Although these results suggest that valve stent post-deformability might not be of critical importance, a concrete answer to the question of the significance of stent deformability for valve durability can be obtained only by acquiring long-term follow-up results for valve prostheses with rigid stents