Iapicca, Cristina (2023) Before and After Transcatheter Aortic Valve Implantation: The Role of New Echocardiographic Tools. [Tesi di dottorato]

Anteprima

Testo Iapicca_Cristina_36.pdf Download (4MB) | Anteprima

Abstract

Degenerative aortic stenosis (AS) is the most common heart valve disease among people >65 years in developed countries, with an increasing prevalence due to population ageing (1-2). AS leads to compensatory anatomical and physiological changes in the left ventricle (LV) culminating in detrimental effects including left ventricular hypertrophy (LVH), diastolic dysfunction and ultimately LV failure [3]. Transcatheter aortic valve implantation (TAVI) is an established therapy for patients with symptomatic severe aortic stenosis (AS), irrespective of operative risk (4). TAVI has been shown to improve symptoms, reduce progression of LV dysfunction and ultimately reduce mortality [5].Transthoracic echocardiography (TTE) remains the investigation of choice for diagnosing and quantifying the severity of AS with several echocardiographic parameters being used. Historically, left ventricular ejection fraction (LVEF) has been the most commonly used measure to determine LV systolic function. More recently however deformation imaging has become an important method of determining clinical and subclinical assessment of heart chamber function. Deformation imaging encompasses myocardial strain such as shortening, thickening and lengthening of myocardial fibres and includes global longitudinal strain (GLS) and peak atrial longitudinal strain (PALS) [6]. GLS is an important echocardiographic parameter that may be used as a predictor of cardiovascular outcomes and subclinical changes in LV function. Deformation imaging also allows us to assess left atrial function and also can assess the different phases of left ventricular filling dynamics. In the left atrial (LA) reservoir phase, as the LA fills and stretches, there is deformation called peak left atrial longitudinal strain (PALS), which peaks in systole at the end of LA filling, before the opening of the mitral valve, and is reflective of LV systolic function. There is an emerging data showing that LA function evaluated by PALS is more sensitive than LA volume to assess subtle LA reverse remodeling after TAVI (7). In the recent years, myocardial work (MW) has emerged as an alternative tool for myocardial function assessment. This new parameter derives from GLS, with the advantage to incorporate information on afterload, through interpretation of strain in relation to dynamic noninvasive LV pressure. Russel et al. demonstrated that non-invasively pressure-strain loops (PSLs) could estimate LV performance deriving LV pressure curves during a cardiac cycle from non-invasively acquired brachial artery cuff pressure (8-9). Myocardial work is approximatively calculated as the area of PSL. Experimental studies have shown a strong correlation of LV-PSL area with cardiac metabolism, assessed by fluorine 18 fluorodeoxyglucose-positron emission tomography (9). The clinical application of MW measurement has been shown in several pathological conditions, including LV dyssinchrony (10-11), ischemia (12-13), hypertrophic (14), hypertensive and dilated cardiomyopathy (15). Among patients with moderate-to-severe AS, lower MW indices reflect a more advanced cardiac damage and are associated with increased mortality at long-term follow up (16). Considering the increasingly wide availability of these new advanced techniques, which seem to be more sensible than traditional echocardiographic parameters, we have explored the feasibility, efficacy and prognostic role of these new diagnostic tools in the evaluation of TAVI patients, both before and after the procedure. Since the introduction of TAVI, the long-term durability of transcatheter heart valves (THV) has been debated. Most surgical aortic valves (SAV) degenerate within 10–20 years [17], whereas the performance of THVs in the very long term is currently unknown. These concerns remain essential today because of the expansion of TAVI to low-risk and young patients with longer life expectancies [18]. A comprehensive echocardiographic examination should always include information on THV function and should immediately recognize possible prosthesis dysfunction. In this thesis we reported some review on echocardiography role in the assessment of prosthesis function, hemodynamic performance as well as cardiac function changes after TAVI with a special focus on the comparison between transcatheter and surgical aortic valves and between self-expandable and balloonexpandable valves. We also analyzed a recently proposed AS staging classification based on LV structural and functional changes induced by AS (19) to assess the prognostic performance of this classification in a real-word cohort of patients undergoing TAVI and to investigate the impact of the procedure on the extent of extra-aortic valve cardiac damage. Finally, we investigated the impact of coronavirus disease-2019 (COVID-19) pandemic on timing and early clinical outcomes of transcatheter aortic valve implantation.

Downloads

Actions (login required)

Modifica documento