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Polymeric Biomaterials
Published in Joseph D. Bronzino, Donald R. Peterson, Biomedical Engineering Fundamentals, 2019
Hai Bang Lee, Gilson Khang, and Jin Ho Lee
kinked molecular chains. ey can be highly stretched. Embolus: Any foreign matter, as a blood clot or air bubble, carried in the blood stream. Fibrinogen: A plasma protein of high molecular weight that is converted into brin through the action
How valvular calcification can affect the outcomes of transcatheter aortic valve implantation
Published in Expert Review of Medical Devices, 2020
Stephan Milhorini Pio, Jeroen Bax, Victoria Delgado
Clinical trials comparing TAVI and surgical aortic valve replacement (SAVR) showed a significant higher incidence of stroke at 30 days in high surgical risk TAVI patients (5.5% TAVI vs 2.4% SAVR in PARTNER trial) and low surgical risk SAVR patients (0.6% TAVI vs 2.4% SAVR in PARTNER 3 trial) whereas data are controversial for intermediate-risk patients (5.5% TAVI vs 6.1% SAVR in PARTNER 2 trial – non-significant difference -, and 4.5% TAVI vs 6.5% SAVR in SURTAVI trial – significant difference) [2–4,58]. However, long-term follow-up rates of stroke are not significantly different between patients who underwent TAVI and SAVR, irrespective of surgical risk [20,59–61]. Nonetheless, TAVI patients who received balloon-expandable valves had a significantly higher incidence of stroke compared to the ones who received self-expandable valves [62,63]. The rate of new radiographic cerebral lesions after aortic valve replacement can be higher than 60%, and although only a minority of patients develop a focal neurological deficit, they have been shown to negatively affect cognitive function and increase the risk of future stroke [64–68]. Aiming at reducing the load of emboli reaching cerebral vascular territory, embolic protection devices were developed. Embolic material was observed in 99% of patients from 2 prospective studies and included thrombi, valve tissue, arterial wall/necrotic core, calcification, foreign material, and myocardium [69]. Despite a good rationale for their use and reduction of the burden of cerebral embolism during TAVI, the studies have not clearly demonstrated a decline in hard clinical outcomes, such as mortality and stroke [64,70,71].