Clinical Importance of Left Atrial Infiltration in Cardiac Transthyretin Amyloidosis

ObjectivesThe aim of this study was to characterize left atrial (LA) pathology in explanted hearts with transthyretin amyloid cardiomyopathy (ATTR-CM); LA mechanics using echocardiographic speckle-tracking in a large cohort of patients with ATTR-CM; and to study the association with mortality.BackgroundThe clinical significance of LA involvement in ATTR-CM is of great clinical interest.MethodsCongo red staining and immunohistochemistry was performed to assess the presence, type, and extent of amyloid and associated changes in 5 explanted ATTR-CM atria. Echo speckle tracking was used to assess LA reservoir, conduit, contractile function, and stiffness in 906 patients with ATTR-CM (551 wild-type (wt)-ATTR-CM; 93 T60A-ATTR-CM; 241 V122I-ATTR-CM; 21 other).ResultsThere was extensive ATTR amyloid infiltration in the 5 atria, with loss of normal architecture, vessels remodeling, capillary disruption, and subendocardial fibrosis. Echo speckle tracking in 906 patients with ATTR-CM demonstrated increased atrial stiffness (median [25th-75th quartile] 1.83 [1.15-2.92]) that remained independently associated with prognosis after adjusting for known predictors (lnLA stiff: HR: 1.23; 95% CI: 1.03-1.49; P = 0.029). There was substantial impairment of the 3 phasic functional atrial components (reservoir 8.86% [5.94%-12.97%]; conduit 6.5% [4.53%-9.28%]; contraction function 4.0% [2.29%-6.56%]). Atrial contraction was absent in 22.1% of patients whose electrocardiograms showed sinus rhythm (SR) “atrial electromechanical dissociation” (AEMD). AEMD was associated with poorer prognosis compared with patients with SR and effective mechanical contraction (P = 0.0018). AEMD conferred a similar prognosis to patients in atrial fibrillation.ConclusionsThe phenotype of ATTR-CM includes significant infiltration of the atrial walls, with progressive loss of atrial function and increased stiffness, which is a strong independent predictor of mortality. AEMD emerged as a distinctive phenotype identifying patients in SR with poor prognosis.     

Surface engineering of artificial heart valve disks using nanostructured thin films deposited by chemical vapour deposition and sol-gel methods

Pyrolytic carbon (PyC) is widely used in manufacturing commercial artificial heart valve disks (HVD). Although PyC is commonly used in HVD, it is not the best material for this application since its blood compatibility is not ideal for prolonged clinical use. As a result thrombosis often occurs and the patients are required to take anti-coagulation drugs on a regular basis in order to minimize the formation of thrombosis. However, anti-coagulation therapy gives rise to some detrimental side effects in patients. Therefore, it is extremely urgent that newer and more technically advanced materials with better surface and bulk properties are developed. In this paper, we report the mechanical properties of PyC-HVD, i.e. strength, wear resistance and coefficient of friction. The strength of the material was assessed using Brinell indentation tests. Furthermore, wear resistance and coefficient of friction values were obtained from pin-on-disk testing. The micro-structural properties of PyC were characterized using XRD, Raman spectroscopy and SEM analysis. Also in this paper we report the preparation of freestanding nanocrystalline diamond films (FSND) using the time-modulated chemical vapour deposition (TMCVD) process. Furthermore, the sol-gel technique was used to uniformly coat PyC-HVD with dense, nanocrystalline-titanium oxide (nc-TiO₂) coatings. The as-grown nc-TiO₂ coatings were characterized for microstructure using SEM and XRD analysis.     

Effect of oscillation on elevating shear stresses

The effect of oscillation on elevating turbulent shear stresses through the Jellyfish and St. Vincent valves has been investigated. Laser Doppler anemometry was employed to determine the velocity and shear stress distributions at various locations downstream of the valves. Comparison between two valves revealed that at 0.5D downstream of the valves the magnitude of shear stresses in the Jellyfish valve were much higher than those of the St. Vincent valve at cardiac outputs of 4, 5.5 and 7 l min^?1. The cause of high shear stresses in close proximity to the Jellyfish valve could be attributed to the oscillation of the membrane which in turn generated a wake downstream of the valve (in the core of valve chamber) and produced a wide region of disturbance further downstream. This resulted in further pressure drag, and consequently higher pressure drops across the valve and higher shear stresses downstream of the valve.     

实时三维超声心动图在三尖瓣反流中的应用

超声心动图对诊断病理性三尖瓣反流发挥着重要作用。实时三维超声心动图可完整显示三尖瓣及其周围结构,其彩色多普勒技术衍生出缩流颈面积这一新指标,可准确测量收缩期中各个时刻的瞬时反流流量,在诊断重度三尖瓣反流及确定其截断值方面更有价值。尤其是在经导管的三尖瓣手术中,实时三维超声心动图占据重要地位。本文总结实时三维超声心动图在三尖瓣反流中的应用和不足,为优化其临床评估提供参考。     

Potential deleterious role of anti‐Neu5Gc antibodies in xenotransplantation

Human beings do not synthesize the glycolyl form of the sialic acid (Neu5Gc) and only express the acetylated form of the sugar, whereas a diet‐based intake of Neu5Gc provokes a natural immunization and production of anti‐Neu5Gc antibodies in human serum. However, Neu5Gc is expressed on mammal glycoproteins and glycolipids in most organs and cells. We review here the relevance of Neu5Gc and anti‐Neu5Gc antibodies in the context of xenotransplantation and the use of animal‐derived molecules and products, as well as the possible consequences of a long‐term exposure to anti‐Neu5Gc antibodies in recipients of xenografts. In addition, the importance of an accurate estimation of the anti‐Neu5Gc response following xenotransplantation and the future contribution of knockout animals mimicking the human situation are also assessed.     

The PARTNER 3 Bicuspid Registry for Transcatheter Aortic Valve Replacement in Low-Surgical-Risk Patients

ObjectivesThe study compared 1-year outcomes between transcatheter aortic valve replacement (TAVR) patients with bicuspid aortic valve (BAV) morphology and clinically similar patients having tricuspid aortic valve (TAV) morphology.BackgroundThere are limited prospective data on TAVR using the SAPIEN 3 device in low-surgical-risk patients with severe, symptomatic aortic stenosis and bicuspid anatomy.MethodsLow-risk, severe aortic stenosis patients with BAV were candidates for the PARTNER 3 (Placement of Aortic Transcatheter Valves 3) (P3) bicuspid registry or the P3 bicuspid continued access protocol. Patients treated in these registries were pooled and propensity score matched to TAV patients from the P3 randomized TAVR trial. Outcomes were compared between groups. The primary endpoint was the 1-year composite rate of death, stroke, and cardiovascular rehospitalization.ResultsOf 320 total submitted BAV patients, 169 (53%) were treated, and most were Sievers type 1. The remaining 151 patients were excluded caused by anatomic or clinical criteria. Propensity score matching with the P3 TAVR cohort (496 patients) yielded 148 pairs. There were no differences in baseline clinical characteristics; however, BAV patients had larger annuli and they experienced longer procedure duration. There was no difference in the primary endpoint between BAV and TAV (10.9% vs 10.2%; P = 0.80) or in the rates of the individual components (death: 0.7% vs 1.4%; P = 0.58; stroke: 2.1% vs 2.0%; P = 0.99; cardiovascular rehospitalization: 9.6% vs 9.5%; P = 0.96).ConclusionsAmong highly select bicuspid aortic stenosis low-surgical-risk patients without extensive raphe or subannular calcification, TAVR with the SAPIEN 3 valve demonstrated similar outcomes to a matched cohort of patients with tricuspid aortic stenosis.     

Prognostic Implications of Progressive Systemic Ventricular Dysfunction in Congenitally Corrected Transposition of Great Arteries

ObjectivesThe purpose of this study was to determine the risk factors for and prognostic implications of progressive right ventricular systolic dysfunction (RVD) in adults with congenitally corrected transposition of great arteries.BackgroundThere are no effective therapies for RVD; hence the need to identify and modify risk factors for progressive RVD.MethodsRV systolic function was assessed by using RV longitudinal strain (RV-LS). The first echocardiogram (baseline echocardiogram) and all subsequent annual echocardiograms performed within 5 years from the baseline echocardiogram were analyzed. Progressive RVD (temporal decline in RV-LS) was assessed as the average annual change in RV-LS within 5 years of imaging follow-up.ResultsOf 186 patients (mean age 40 ± 12 years), the RV-LS at baseline was –17% ± 4%, and the annual decline in RV-LS was –4% (95% CI: –6 to –2). The risk factors for progressive RVD were left ventricular (LV) systolic dysfunction, LV pacing, and systemic hypertension. Cardiovascular events (heart failure hospitalization, heart transplant, and death) occurred in 57 (27%) patients. Progressive RVD was associated with cardiovascular events, independent of RV systolic function at baseline. In subgroup analyses assessing impact of therapies (medical therapy, cardiac resynchronization therapy, and tricuspid valve replacement), only tricuspid valve replacement was associated with improvement in RV systolic function when performed before onset of RVD.ConclusionsPatients with congenitally corrected transposition of great arteries were at risk for progressive RVD, and the risk factors for progressive RVD were LV pacing, systemic hypertension, and concomitant LV dysfunction. Further studies are required to determine whether strict blood pressure control and early tricuspid valve replacement will prevent progressive RVD.     

Overriding atrioventricular valves. An angiographic-anatomical correlate

An analysis of 6 patients with overriding atrioventricular valve was performed in order to correlate the anatomic and angiographic features of this malformation. The atrial arrangement was usual (situs solitus) in each patient. The ventricular chambers were normally related in 4 and the mirror image of normal in 2. The atrioventricular connexion was concordant in parallel fashion in 4, discordant in 1 and double inlet left ventricle in 1 heart. In 2 of 4 hearts with concordant atrioventricular connexion, the right atrioventricular valve (tricuspid) overrode the septum and connected partially to the left ventricle. In 2, the left atrioventricular valve (mitral) overrode the septum and partially connected with the right ventricle. One heart with discordant atrioventricular connexion had its right atrioventricular valve (mitral) overriding the septum. The remaining heart with double inlet left ventricle had an overriding left atrioventricular valve. Each overriding atrioventricular valve had its "septal" leaflet (the one committed to the contralateral ventricle) divided into 2 segments by a large cleft. Ventricular septal defects at different locations were present in all cases. The ventriculoarterial connexion was double outlet right ventricle in 5 patients and was discordant in 1. Malalignment of the atrial and ventricular septa was present to some degree in all cases. This was well depicted on ventriculograms in four chamber view in those with an overriding tricuspid valve. It was not detected in those with an overriding mitral valve. The displaced leaflets of the overriding and/or stradding valve had a vertical motion on cineangiograms similar to those observed in atrioventricular septal defects. Abnormal morphology and motion of the septal leaflet of the overriding atrioventricular valve and malalignment of the atrial and ventricular septal structures were the most important angiographic findings in this series.