Paravalvular Leakage(PVL)has been recognized as one of the most dangerous complications in relation to Transcathether Aortic Valve Implantation(TAVI)activities.However,data available in the literature about Fluid Str...Paravalvular Leakage(PVL)has been recognized as one of the most dangerous complications in relation to Transcathether Aortic Valve Implantation(TAVI)activities.However,data available in the literature about Fluid Structure Interaction(FSI)for this specific problem are relatively limited.In the present study,the fluid and structure responses of the hemodynamics along the patient aorta model and the aortic wall deformation are studied with the aid of numerical simulation taking into account PVL and 100%TAVI valve opening.In particular,the aorta without valve(AWoV)is assumed as the normal condition,whereas an aorta with TAVI 26 mm for 100%Geometrical Orifice Area(GOA)is considered as the patient aorta with PVL complication.A 3D patient-specific aorta model is elaborated using the MIMICS software.Implantation of the identical TAVI valve of Edward SAPIEN XT 26(Edwards Lifes ciences,Irvine,California)is considered.An undersized 26 mm TAVI valve with 100%valve opening is selected to mimic the presence of PVL at the aortic annulus.The present research indicates that the existence of PVL can increase the blood velocity,pressure drop and WSS in comparison to normal conditions,thereby paving the way to the development of recirculation flow,thrombus formation,aorta wall collapse,aortic rupture and damage of endothelium.展开更多
Background: Long standing aortic stenosis leads to elevated left ventricular (LV) pressure and as a result LV hypertrophy and myocardial fibrosis shall increase. The left ventricular ejection fraction (EF) usually rem...Background: Long standing aortic stenosis leads to elevated left ventricular (LV) pressure and as a result LV hypertrophy and myocardial fibrosis shall increase. The left ventricular ejection fraction (EF) usually remains adequately-preserved until advanced and late stages of aortic stenosis. But the preserved muscle of the LV is only limited to a portion of the entire myocardium. Speckle tracking echocardiography has proved its superiority to the standard two-dimensional echocardiography method in the detection of Left Ventricular (LV) function. Global Longitudinal strain (GLS) is considered as the most robust myocardial strain component.?Objective: The aim of the study is to assess the early course of left ventricular reverse remodelling after Transcutaneous Aortic Valve Implantation (TAVI) in patients with symptomatic severe aortic valve stenosis.?Methods: 50 patients with severe symptomatic valvular aortic stenosis undergoing TAVI as decided by the heart team after comprehensive discussion.?Standard transthoracic echocardiography including Doppler analysis was performed. 2D speckle-tracking strain assessment of Global radial, circumferential and longitudinal strain at parasternal mid-ventricular short-axis view (at the level of papillary muscle) and from the apical long-axis, two-chamber and four-chamber views with a frame rate between 40 and 80 frames per second. Tracing of endocardial borders was done. Patients with significant coronary artery disease were fully revascularized by percutaneous coronary intervention prior to the study and the procedure. Results: 23 (46%) patients were males, while 27 (54%) were females. The patients’ stratification according to comorbidities/associated risk factors revealed that 54% of the patients had DM, 86% were hypertensive, 38% had chronic kidney disease (CKD), and 32% had a previous percutaneous coronary intervention (PCI).?The mean age for our study participants ranged?from 60 to 92 years (Mean ± SD = 76.60 ± 5.96). Left ventricular diastolic diameter (LVDd) was 44.24?±?2.8?mm before TAVI that became 45.5?±?2.6?mm after TAVI, and ejection fraction (EF) increased from 52.82?±?6.3?before TAVI to 56.70?±?5.4?after TAVI, both with highly significant difference (P P value less than 0.001. Global circumferential strain (GCS) also improved significantly from -20.14?±?1.8 before TAVI to -21.72?±?1.7 after TAVI with a P value less than 0.001. Global radial strain (GRS) also increased significantly from 37.38?±?8 before TAVI to 41.68?± 6.3 after TAVI with a P value less than 0.001. Conclusion: TAVI is effective in improving left ventricular function presented not only by ejection fraction (EF%), but also in global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS).展开更多
Transcatheter aortic valve replacement (TAVR), which is also referred to as transcatheter aortic valve implantation (TAVI), is a minimally invasive procedure to treat aortic stenosis. An estimated 12% of individuals o...Transcatheter aortic valve replacement (TAVR), which is also referred to as transcatheter aortic valve implantation (TAVI), is a minimally invasive procedure to treat aortic stenosis. An estimated 12% of individuals over the age of 75 have aortic stenosis, and it is currently the most common reason for valve replacement in elderly Americans. TAVR was introduced as an alternative treatment to surgical aortic valve replacement (SAVR), which involves an open-heart surgery. In the U.S., the first transcatheter valve was approved by the U.S. Food and Drug Administration (FDA) in November 2011. Since then, FDA has expanded its approval to intermediate- and low-risk patients. The purpose of this manuscript is to expand nurses’ knowledge about the TAVR procedure as TAVR is one of the most rapidly growing medical procedures in the U.S. This manuscript provides a background of the TAVR procedure, reviews relevant research, and highlights common complications. Compared to SAVR, TAVR has established its safety, efficacy, and cost-effectiveness as a treatment option for patients with severe aortic stenosis.展开更多
Bioprosthetic heart valves(BHVs)are important for transcatheter valve replacement.Current commercial BHVs on the market are basically porcine or bovine pericardium(BP)crosslinked with glutaraldehyde(GA).Simply applyin...Bioprosthetic heart valves(BHVs)are important for transcatheter valve replacement.Current commercial BHVs on the market are basically porcine or bovine pericardium(BP)crosslinked with glutaraldehyde(GA).Simply applying GA to BHVs can enhance mechanical stability,but cannot alleviate in vivo calcification.In this work,we developed a two-step decellularization(TSD)strategy to modify this biomacromolecular network,in which BP was post-treated,as the second step of decellularization,with a mild biosurfactant n-dodecyl-β-D-maltoside in a mixture of isopropanol and phosphate-buffered saline after the first step of traditional decellularization and GA cross-linking.The TSD-treated BP exhibited not only low cytotoxicity and excellent mechanical properties in vitro,but also low immune responses and significant anticalcification in vivo.After 60 days of subcutaneous implantation in the back of Wistar rats,the calcium content was,as quantified with an inductively coupled plasma optical emission spectrometer,only 1.1µg/mg compared to 138.6µg/mg in the control group without the post-treatment.In addition,collagen fibrils were observed with field emitting scanning electron microscopy(SEM),and the morphology and composition of the calcified sites resulting from in vivo biomineralization were studied with SEM with energy dispersive spectroscopy and also X-ray diffraction.This study proposes a facile yet effective anticalcification strategy for the modification of the bovine pericardial bioprosthetic heart valve,a natural biomacromolecular network.展开更多
Aortic Stenosis (AS) has become the most frequent valvular heart disease in the western countries with increased prevalence in the elderly. It is associated with very poor prognosis in the absence of surgical treatmen...Aortic Stenosis (AS) has become the most frequent valvular heart disease in the western countries with increased prevalence in the elderly. It is associated with very poor prognosis in the absence of surgical treatment and worse quality of life. Patients aged between 80 - 85 years with no major comorbidities and left ventricular ejection fraction between 30% - 50% are still not referred to valve surgery, even if these subjects would likely benefit from surgery in terms of duration and quality of life as compared with the expected outcome of the disease. The decision making process in octogenarian population are not only related to the decision of whether to operate or not, but also to the timing of surgery. The identification of symptoms related to AS is difficult in the elderly and this also delay surgery. Balloon Aortic Valvuloplasty (BAV) and, in the recent years, Transcatheter Aortic Valve Implantation (TAVI) seem to offer an additional chance of valve correction, in patients at high surgical risk or inoperable. For ethical reasons, the first TAVI cases were performed exclusively on patients who had contraindications to surgery because of end stage heart disease and/or severe comorbidities. This accounted for high mid-term mortality rates;however, these findings demonstrated the feasibility of this alternative approach. An overall patient evaluation based on a team approach (involving cardiologists, surgeons and geriatricians) is essential. Results from randomized clinical trials on elderly patients who underwent TAVI are encour-aging and result from one and two years follow-up are now available.展开更多
基金Universiti Putra Malaysia,for providing funds for this project through Grant UPM GP-IPM/2019/9675000.
文摘Paravalvular Leakage(PVL)has been recognized as one of the most dangerous complications in relation to Transcathether Aortic Valve Implantation(TAVI)activities.However,data available in the literature about Fluid Structure Interaction(FSI)for this specific problem are relatively limited.In the present study,the fluid and structure responses of the hemodynamics along the patient aorta model and the aortic wall deformation are studied with the aid of numerical simulation taking into account PVL and 100%TAVI valve opening.In particular,the aorta without valve(AWoV)is assumed as the normal condition,whereas an aorta with TAVI 26 mm for 100%Geometrical Orifice Area(GOA)is considered as the patient aorta with PVL complication.A 3D patient-specific aorta model is elaborated using the MIMICS software.Implantation of the identical TAVI valve of Edward SAPIEN XT 26(Edwards Lifes ciences,Irvine,California)is considered.An undersized 26 mm TAVI valve with 100%valve opening is selected to mimic the presence of PVL at the aortic annulus.The present research indicates that the existence of PVL can increase the blood velocity,pressure drop and WSS in comparison to normal conditions,thereby paving the way to the development of recirculation flow,thrombus formation,aorta wall collapse,aortic rupture and damage of endothelium.
文摘Background: Long standing aortic stenosis leads to elevated left ventricular (LV) pressure and as a result LV hypertrophy and myocardial fibrosis shall increase. The left ventricular ejection fraction (EF) usually remains adequately-preserved until advanced and late stages of aortic stenosis. But the preserved muscle of the LV is only limited to a portion of the entire myocardium. Speckle tracking echocardiography has proved its superiority to the standard two-dimensional echocardiography method in the detection of Left Ventricular (LV) function. Global Longitudinal strain (GLS) is considered as the most robust myocardial strain component.?Objective: The aim of the study is to assess the early course of left ventricular reverse remodelling after Transcutaneous Aortic Valve Implantation (TAVI) in patients with symptomatic severe aortic valve stenosis.?Methods: 50 patients with severe symptomatic valvular aortic stenosis undergoing TAVI as decided by the heart team after comprehensive discussion.?Standard transthoracic echocardiography including Doppler analysis was performed. 2D speckle-tracking strain assessment of Global radial, circumferential and longitudinal strain at parasternal mid-ventricular short-axis view (at the level of papillary muscle) and from the apical long-axis, two-chamber and four-chamber views with a frame rate between 40 and 80 frames per second. Tracing of endocardial borders was done. Patients with significant coronary artery disease were fully revascularized by percutaneous coronary intervention prior to the study and the procedure. Results: 23 (46%) patients were males, while 27 (54%) were females. The patients’ stratification according to comorbidities/associated risk factors revealed that 54% of the patients had DM, 86% were hypertensive, 38% had chronic kidney disease (CKD), and 32% had a previous percutaneous coronary intervention (PCI).?The mean age for our study participants ranged?from 60 to 92 years (Mean ± SD = 76.60 ± 5.96). Left ventricular diastolic diameter (LVDd) was 44.24?±?2.8?mm before TAVI that became 45.5?±?2.6?mm after TAVI, and ejection fraction (EF) increased from 52.82?±?6.3?before TAVI to 56.70?±?5.4?after TAVI, both with highly significant difference (P P value less than 0.001. Global circumferential strain (GCS) also improved significantly from -20.14?±?1.8 before TAVI to -21.72?±?1.7 after TAVI with a P value less than 0.001. Global radial strain (GRS) also increased significantly from 37.38?±?8 before TAVI to 41.68?± 6.3 after TAVI with a P value less than 0.001. Conclusion: TAVI is effective in improving left ventricular function presented not only by ejection fraction (EF%), but also in global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS).
文摘Transcatheter aortic valve replacement (TAVR), which is also referred to as transcatheter aortic valve implantation (TAVI), is a minimally invasive procedure to treat aortic stenosis. An estimated 12% of individuals over the age of 75 have aortic stenosis, and it is currently the most common reason for valve replacement in elderly Americans. TAVR was introduced as an alternative treatment to surgical aortic valve replacement (SAVR), which involves an open-heart surgery. In the U.S., the first transcatheter valve was approved by the U.S. Food and Drug Administration (FDA) in November 2011. Since then, FDA has expanded its approval to intermediate- and low-risk patients. The purpose of this manuscript is to expand nurses’ knowledge about the TAVR procedure as TAVR is one of the most rapidly growing medical procedures in the U.S. This manuscript provides a background of the TAVR procedure, reviews relevant research, and highlights common complications. Compared to SAVR, TAVR has established its safety, efficacy, and cost-effectiveness as a treatment option for patients with severe aortic stenosis.
基金the National Natural Science Foundation of China(No.52130302).
文摘Bioprosthetic heart valves(BHVs)are important for transcatheter valve replacement.Current commercial BHVs on the market are basically porcine or bovine pericardium(BP)crosslinked with glutaraldehyde(GA).Simply applying GA to BHVs can enhance mechanical stability,but cannot alleviate in vivo calcification.In this work,we developed a two-step decellularization(TSD)strategy to modify this biomacromolecular network,in which BP was post-treated,as the second step of decellularization,with a mild biosurfactant n-dodecyl-β-D-maltoside in a mixture of isopropanol and phosphate-buffered saline after the first step of traditional decellularization and GA cross-linking.The TSD-treated BP exhibited not only low cytotoxicity and excellent mechanical properties in vitro,but also low immune responses and significant anticalcification in vivo.After 60 days of subcutaneous implantation in the back of Wistar rats,the calcium content was,as quantified with an inductively coupled plasma optical emission spectrometer,only 1.1µg/mg compared to 138.6µg/mg in the control group without the post-treatment.In addition,collagen fibrils were observed with field emitting scanning electron microscopy(SEM),and the morphology and composition of the calcified sites resulting from in vivo biomineralization were studied with SEM with energy dispersive spectroscopy and also X-ray diffraction.This study proposes a facile yet effective anticalcification strategy for the modification of the bovine pericardial bioprosthetic heart valve,a natural biomacromolecular network.
文摘Aortic Stenosis (AS) has become the most frequent valvular heart disease in the western countries with increased prevalence in the elderly. It is associated with very poor prognosis in the absence of surgical treatment and worse quality of life. Patients aged between 80 - 85 years with no major comorbidities and left ventricular ejection fraction between 30% - 50% are still not referred to valve surgery, even if these subjects would likely benefit from surgery in terms of duration and quality of life as compared with the expected outcome of the disease. The decision making process in octogenarian population are not only related to the decision of whether to operate or not, but also to the timing of surgery. The identification of symptoms related to AS is difficult in the elderly and this also delay surgery. Balloon Aortic Valvuloplasty (BAV) and, in the recent years, Transcatheter Aortic Valve Implantation (TAVI) seem to offer an additional chance of valve correction, in patients at high surgical risk or inoperable. For ethical reasons, the first TAVI cases were performed exclusively on patients who had contraindications to surgery because of end stage heart disease and/or severe comorbidities. This accounted for high mid-term mortality rates;however, these findings demonstrated the feasibility of this alternative approach. An overall patient evaluation based on a team approach (involving cardiologists, surgeons and geriatricians) is essential. Results from randomized clinical trials on elderly patients who underwent TAVI are encour-aging and result from one and two years follow-up are now available.
