Search

In recent years, transcatheter aortic valve replacement (TAVR) has become the leading method for treating aortic stenosis. While the procedure has improved dramatically in the past decade, there are still uncertainties about the impact of TAVR on coronary blood flow. Recent research has indicated that negative coronary events after TAVR may be partially driven by impaired coronary blood flow dynamics. Furthermore, the current technologies to rapidly obtain non-invasive coronary blood flow data are relatively limited. Herein, we present a lumped parameter computational model to simulate coronary blood flow in the main arteries as well as a series of cardiovascular hemodynamic metrics. The model was designed to only use a few inputs parameters from echocardiography, computed tomography and a sphygmomanometer. The novel computational model was then validated and applied to 19 patients undergoing TAVR to examine the impact of the procedure on coronary blood flow in the left anterior descending (LAD) artery, left circumflex (LCX) artery and right coronary artery (RCA) and various global hemodynamics metrics. Based on our findings, the changes in coronary blood flow after TAVR varied and were subject specific (37% had increased flow in all three coronary arteries, 32% had decreased flow in all coronary arteries, and 31% had both increased and decreased flow in different coronary arteries). Additionally, valvular pressure gradient, left ventricle (LV) workload and maximum LV pressure decreased by 61.5%, 4.5% and 13.0% respectively, while mean arterial pressure and cardiac output increased by 6.9% and 9.9% after TAVR. By applying this proof-of-concept computational model, a series of hemodynamic metrics were generated non-invasively which can help to better understand the individual relationships between TAVR and mean and peak coronary flow rates. In the future, tools such as these may play a vital role by providing clinicians with rapid insight into various cardiac and coronary metrics, rendering the planning for TAVR and other cardiovascular procedures more personalized. [ABSTRACT FROM AUTHOR]

Introduction: Most studies to date confirm that any increase in the needle insertion force increases the damage to the tissue. When it comes to brain tissue, even minor damage can cause a long-lasting traumatic brain injury. Thus there is a great demand for innovative minimally invasive needles among the medical community. In our previous studies a novel bioinspired needle design with specially designed barbs was used to perform insertion tests into Polyvinyl chloride (PVC) tissue-mimicking gels, in which it decreased the insertion force by as much as 25%. Material and methods: In this work, bioinspired needles were designed using a CAD software, and were then manufactured using a 3 D printer. The insertion tests into bovine brain and liver were then performed to further investigate the performance of our bioinspired needles in real tissues. Results: Our results show that there was a 10-25% decrease in the insertion force for insertions into bovine brain, and a 35-45% reduction in the insertion force for insertions into bovine liver using the proposed bioinspired needles. Conclusion: The reduction in the insertion force is due to the decrease in the friction force of the bioinspired needle with the bovine tissues, and its results are consistent with our previous results. [ABSTRACT FROM AUTHOR]