Left Ventricular Mechanics Differ in Subtypes of Aortic Stenosis Following Transcatheter Aortic Valve Replacement

BackgroundLeft ventricular (LV) mechanics are impaired in patients with severe aortic stenosis (AS). We hypothesized that there would be differences in myocardial mechanics, measured by global longitudinal strain (GLS) recovery in patients with four subtypes of severe AS after transcatheter aortic valve replacement (TAVR), stratified based upon flow and gradient.MethodsWe retrospectively evaluated 204 patients with severe AS who underwent TAVR and were followed post-TAVR at our institution for clinical outcomes. Speckle-tracking transthoracic echocardiography was performed pre- and post-TAVR. Patients were classified as: (1) normal-flow and high-gradient, (2) normal-flow and high-gradient with reduced LV ejection fraction (LVEF), (3) classical low-flow and low-gradient, or (4) paradoxical low-flow and low-gradient.ResultsBoth GLS (−13.9 ± 4.3 to −14.8 ± 4.3, P < 0.0001) and LVEF (55 ± 15 to 57 ± 14%, P = 0.0001) improved immediately post-TAVR. Patients with low-flow AS had similar improvements in LVEF (+2.6 ± 9%) and aortic valve mean gradient (−23.95 ± 8.34 mmHg) as patients with normal-flow AS. GLS was significantly improved in patients with normal-flow (−0.93 ± 3.10, P = 0.0004) compared to low-flow AS. Across all types of AS, improvement in GLS was associated with a survival benefit, with GLS recovery in alive patients (mean GLS improvement of −1.07 ± 3.10, P < 0.0001).ConclusionsLV mechanics are abnormal in all patients with subtypes of severe AS and improve immediately post-TAVR. Recovery of GLS was associated with a survival benefit. Patients with both types of low-flow AS showed significantly improved, but still impaired, GLS post-TAVR, suggesting underlying myopathy that does not correct post-TAVR.

Left ventricle geometry, atrial strain, ventricle strain and hemodynamics across aortic valve before and after transcatheter aortic valve replacements

Background: Transcatheter Aortic Valve Replacements (TAVR) has become widespread throughout the world. To date there are no echocardiographic study of TAVR patients from Southeast Asia (SEA). We sought to evaluate 1) changes in echocardiographic and strain values pre and post TAVR 2) relationship between aortic stenosis (AS) severity and strain values, 3) left ventricle geometry in severe AS 4) relationship of flow rate to dimensionless index (DVI) and acceleration time (AT) and 5) effect of strains on outcome. Methods: Retrospective study of 112 TAVR patients in our center from 2009 to 2020. The echocardiographic and strain images pre (within 1 months), post (day after) and 6 months post TAVR were analyzed by expert echocardiographer. Results: The ejection fraction (EF) increased at 6 months (53.02 ± 12.12% to 56.35 ± 9.00%) (p=0.044). Interventricular septal thickness in diastole (IVSd) decreased (1.27 ± 0.21cm to 1.21 ± 0.23cm) (p=0.038) and left ventricle internal dimension in diastole (LVIDd) decreased from 4.77 ± 0.64cm to 4.49 ± 0.65cm (p = 0.001). No changes in stroke volume index (SVI pre vs 6 months p =0.187), but the flow rate increases (217.80 ± 57.61mls/s to 251.94 ± 69.59mls/s, p<0.001). Global Longitudinal Strain (GLS) improved from -11.44 ± 4.23% to -13.94 ± 3.72% (p <0.001), Left Atrial Reservoir strain (Lar-S) increased from 17.44 ± 9.16% to 19.60 ± 8.77% (p=0.033). 8 patients (7.5%) had IVSd < 1.0cm, and 4 patients (3.7%) had normal left ventricle (LV) geometry. There was linear relationship between IVSd and mean PG (r=0.208, p=0.031), between GLS to aortic valve area (AVA) and aortic valve area index (AVAi) (r = – 0.305, p=0.001 and r= – 0.316, p = 0.001). There was also relationship between AT (r=-0.20, p=0.04) and DVI (r=0.35, p< 0.001) with flow rate. Patients who died late (after 6 months) had lower GLS at 6 months. (Alive; -13.94 ± 3.72% vs Died; -12.43 ± 4.19%, p= 0.001) Conclusion: At 6 months TAVR cause reverse remodeling of the LV with reduction in IVSd, LVIDd and improvement in GLS and LAr-S. There is linear relationship between GLS and AVA and between IVSd and AVA.

Economic Considerations in Access to Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) has revolutionized the treatment of aortic stenosis, with the number of procedures and sites offering the procedure steadily rising over the past decade in the United States. Despite this, growth into certain markets has been limited as hospitals have to balance high TAVR costs with the ability to offer a complete array of state-of-the-art therapies for aortic stenosis. This trade-off often results in decreased access to TAVR services by patients cared for in hospitals that cannot afford these services or have difficulty meeting procedural requirements, recruiting skilled physicians, and initiating and then maintaining a functioning TAVR program. The lack of access is more common among patients of color or those who are socioeconomically disadvantaged. The purpose of this review is to describe the hospital-level economic considerations of TAVR in the United States and the resulting effects on geographic, racial, ethnic, and socioeconomic access for Americans.

Transcheter aortic valve implantation as a method of treatment of chronic heart failure in elderly and old patients: Literature review (part 1)

Стеноз аортального клапана (АК) - самое частое приобретенное клапанное заболевание с растущей распространенностью из-за старения населения, требующее хирургического или эндоваскулярного вмешательства. Транскатетерная имплантация АК (Transcatheter Aortic Valve Implantation, TAVI) представляет собой настоящую революцию в области интервенционной кардиологии для лечения пациентов старческого возраста или из группы высокого риска с тяжелым симптомным стенозом АК. TAVI позволяет выполнять коррекцию аортального порока наиболее тяжелой группе больных ХСН с выраженной коморбидностью, которым противопоказано выполнение открытой операции по замене АК, для прерывания порочного круга в прогрессировании ХСН, стимуляции обратного ремоделирования миокарда, облегчения симптомов, улучшения качества жизни и прогноза больных, а также в качестве «моста» к трансплантации сердца. Благодаря разработке устройств нового поколения, TAVI превратилась из сложной и опасной процедуры в эффективную и безопасную методику. Наибольший научный интерес в настоящее время представляет изучение долговечности клапана и возможности расширения показаний к выполнению TAVI у категорий пациентов с низким хирургическим риском, а также более молодого возраста. Aortic valve (AV) stenosis is the most common acquired valvular disease with an increasing prevalence due to an aging population, requiring surgical or endovascular intervention. Transcatheter Aortic Valve Implantation (TAVI) represents a real revolution in the field of interventional cardiology for the treatment of elderly or high-risk patients with severe symptomatic AV stenosis. TAVI allows for the correction of aortic defect in the most severe group of patients with chronic heart failure (CHF) with severe comorbidity, who are contraindicated for open surgery to replace AV, in order to interrupt the vicious circle in the progression of CHF, stimulate reverse myocardial remodeling, alleviate symptoms, improve the quality of life, and prognosis of patients, and also as a «bridge» to heart transplantation. With the development of next-generation devices, TAVI has evolved from a complex and dangerous procedure to an effective and safe technique. Currently, the greatest scientific interest is the study of valve durability and the possibility of expanding the indications for performing TAVI in categories of patients with low surgical risk, as well as in younger age groups.

The Transaxillary Approach via Prosthetic Conduit for Transcatheter Aortic Valve Replacement With the New-Generation Balloon-Expandable Valves in Patients With Severe Peripheral Artery Disease

Background: The left subclavian artery (LSA) is an infrequently used alternative access route for patients with severe peripheral artery disease (PAD) in patients who underwent transcatheter aortic valve replacement (TAVR). We report a new endovascular approach for TAVR combining an axillary prosthetic conduit-based access technique with new-generation balloon-expandable TAVR prostheses.Methods and Results: Between January 2020 and December 2020, 251 patients underwent TAVR at the West German Heart and Vascular Center. Of these, 10 patients (3.9%) were deemed to be treated optimally by direct surgical exposure of the left or right axillary artery via a surgically adapted prosthetic conduit. All procedures were performed under general anesthesia. One procedural stroke occurred due to severe calcification of the aortic arch. No specific complications of the subclavian access site (vessel rupture, vertebral, or internal mammary ischemia) were reported. Two minor bleedings from the access site could be treated conservatively. No surgical revision was necessary.Conclusion: The axillary prosthetic conduit-based access technique using new-generation balloon-expandable valves allows safe and successful TAVR in a subgroup of patients with a high risk of procedural complications due to severe peripheral vascular disease. Considering the increasing number of patients referred for TAVR, this approach could represent an alternative for patients with limited access sites.

Characterization of Turbulent Flow Behind a Transcatheter Aortic Valve in Different Implantation Positions

The development of turbulence after transcatheter aortic valve (TAV) implantation may have detrimental effects on the long-term performance and durability of the valves. The characterization of turbulent flow generated after TAV implantation can provide fundamental insights to enhance implantation techniques. A self-expandable TAV was tested in a pulse replicator and the three-dimensional flow field was extracted by means of tomographic particle image velocimetry. The valve was fixed inside a silicone phantom mimicking the aortic root and the flow field was studied for two different supra-annular axial positions at peak systole. Fluctuating velocities and turbulent kinetic energy were compared between the two implantations. Velocity spectra were derived at different spatial positions in the turbulent wakes to characterize the turbulent flow. The valve presented similar overall flow topology but approximately 8% higher turbulent intensity in the lower implantation. In this configuration, axial views of the valve revealed smaller opening area and more corrugated leaflets during systole, as well as more accentuated pinwheeling during diastole. The difference arose from a lower degree of expansion of the TAV's stent inside the aortic lumen. These results suggest that the degree of expansion of the TAV in-situ is related to the onset of turbulence and that a smaller and less regular opening area might introduce flow instabilities that could be detrimental for the long-term performance of the valve. The present study highlights how implantation mismatches may affect the structure and intensity of the turbulent flow in the aortic root.