RESUMEN
Objective To investigate the transient hemodynamic changes during balloon deflation in coronary interventional operation, so as to explore the potential influence of balloon deflation on the occurrence of post-operative no-reflow. Methods An in vitro experimental apparatus was built, in which a high-speed camera was used to take snapshots of balloon deformation and flow field (marked by dyed water) during balloon deflation. Subsequently, image processing techniques were employed to derive the parameters of balloon deformation and estimate the flow velocity downstream from the balloon. A computer model of the experimental apparatus was constructed, with the incorporation of the measured balloon deformation data, to simulate the balloon deflation process under various perfusion pressure and fluid conditions. Results The balloon exhibited a highly nonlinear deformation behavior during deflation. The measured and simulated flow velocities downstream from the balloon were in reasonable agreement, both manifesting a monotonic increase with post-deflation time and perfusion pressure. Numerical simulations further revealed that when the flow velocity downstream from the balloon approached the physiological value of blood flow velocity in the coronary artery, the flow velocity in the balloon-vessel gap and wall shear stress (WSS) reached up to 8-10 times and 60-70 times of their physiological values, respectively. Conclusions Balloon deflation led to a sharp acceleration of flow in balloon-vessel gap and a concomitant abnormal rise in WSS, which might promote the stripping of plaque or thrombus flakes. In view of the fact that the balloon deflation-induced rise in WSS was augmented by the increase in perfusion pressure, taking strategies such as lowering pre-operative blood pressure or implementing balloon deflation during diastole in coronary interventional operation might help to reduce the risk of no-reflow.
RESUMEN
BACKGROUND/AIMS: The ballooning time in endoscopic papillary large balloon dilation (EPLBD) remains controversial. The aim of this study was to evaluate the significance of the ballooning time comparing an immediate balloon deflation method with a conventional ballooning time of > 45 seconds. METHODS: Between January 2010 and December 2010, 126 patients with bile duct stones treated with EPLBD and endoscopic sphincterotomy were divided according to the ballooning time: the immediate deflation group (n=56) and the conventional inflation group (ballooning time 45s to < 60s) (n=70). RESULTS: The overall success rate and the success rate of the first attempt of ERCP (endoscopic retrograde cholangio-pancreatography) were 96.4% (54/56) and 80.4% (45/56) in the immediate group and 97.1% (68/70) and 77.1% (54/70) in the conventional inflation group. There were no statistically significant differences in the overall success and the first attempt of ERCP success rate (p=0.99, p=0.66). The frequency of mechanical lithotripsy was 0% in the immediate deflation group and 7.1% in the conventional inflation group (p=0.065). Complications occurred in 3.6% (2/56) patients in the immediate deflation group and 8.6% (4/70) patients in the conventional inflation group (p=0.298). CONCLUSIONS: The ballooning time in EPLBD does not affect the outcomes of the treatment for bile duct stones. And the feasibility of the immediate deflation method in EPLBD is acceptable.