Search Results (2)

During an angioscopy operation, a transparent liquid called dextran is sprayed out from a catheter to flush the blood away from the space between the camera and target. Medical doctors usually inject dextran at a constant flow rate. However, they often cannot obtain clear angioscopy visibility because the flushing out of the blood is insufficient. Good flushing conditions producing clear angioscopy visibility will increase the rate of success of angioscopy operations. This study aimed to determine a way to improve the clarity for angioscopy under different values for the parameters of the injection waveform, endoscope position, and catheter angle. We also determined the effect of a stepwise waveform for injecting the dextran only during systole while synchronizing the waveform to the cardiac cycle. To evaluate the visibility of the blood-vessel walls, we performed a computational fluid dynamics (CFD) simulation and calculated the visible area ratio (VAR), representing the ratio of the visible wall area to the total area of the wall at each point in time. Additionally, the normalized integration of the VAR called the area ratio (AR_VAR) represents the ratio of the visible wall area as a function of the dextran injection period. The results demonstrate that the AR_VAR with a stepped waveform, bottom endoscope, and three-degree-angle catheter results in the highest visibility, around 25 times larger than that under the control conditions: a constant waveform, a center endoscope, and 0 degrees. This set of conditions can improve angioscopy visibility. Full article

Background: Despite significant interest in intracoronary thrombi in patients with vasospastic angina (VSA), the phenomenon remains unclarified. Therefore, we investigated a possible relationship using coronary angioscopy (CAS) in VSA patients. Methods: Sixty patients with VSA, for whom we could assess the spastic segment using CAS, were retrospectively studied. An intracoronary thrombus on CAS was a white thrombus and an erosion-like red thrombus. We verified the clinical characteristics and lesional characteristics as they determined the risk of intracoronary thrombus formation. Results: There were 18 (30%) patients with intracoronary thrombi. More of the patients with intracoronary thrombi were male, current smokers and had severe concomitant symptoms; however, no statistically significant difference was observed upon logistic regression analysis. There were 18 (26%) coronary arteries with intracoronary thrombi out of 70 coronary arteries recognised in the spastic segments. Furthermore, atherosclerotic changes and segmental spasms were significant factors responsible for such lesions. Conclusion: Intracoronary thrombi occurred in 30% of VSA patients and much attention should be paid to the intracoronary thrombogenicity of VSA patients. Full article