SamenvattingCalcific aortic valve disease (CAVD) is one of the most important heart valve diseases in the western world. Aortic valve (AV) calcification is an important predictor of adverse outcome in CAVD and is associated with an increased disease progression. The amount and localization of calcification is important when grading AV stenosis (AS) severity or when planning an intervention. The accurate quantification of AV calcifications is therefore mandatory, but can currently only be assessed by computed tomography (CT) scan, which is an ionizing technique not suited for serial follow-up of patients. Echocardiography is the preferred technique to determine AS severity, but it provides only a subjective visual calcium scoring.
In this thesis we investigated the use of echocardiography as a non-ionizing technique to quantify AV calcifications. We first demonstrated that calibrated integrated backscatter (cIB) of ultrasound can be used to differentiate between AV calcifications and AV thickening in rats. Secondly, we showed that it enables follow-up of progression and regression of AV calcifications in rats. Thirdly, we showed in rats that renal failure induces AV calcifications which are not further increased by dyslipidaemia, and that cIB can be used to quantify those calcifications, no matter where the calcifications are localized. Furthermore, we developed a phantom with calcifications, and showed that the exact amount of calcium can be measured with ultrasound. Finally, we performed a clinical study in patients with CAVD, showing that an echocardiographic global calcium score can be calculated that correlates well with the CT Agatston score for AV calcification quantification.
|26 jun 2017
|Bernard Cosyns (Promotor), Steven Droogmans (Co-promotor), Johan De Mey (Jury), Carlo De Asmundis (Jury), Caroline Weytjens (Jury), Ivo Van derbilt (Jury), Luc Pierard (Jury), Nico Van de Veire (Promotor) & Bram Roosens (Co-promotor)