心脏和脑循环功能相互影响的动力学模型

心脏和脑血管疾病是医学研究的热点。本文整合心脏、体循环和脑循环,构建了循环系统的整体动力学模型,力图揭示心脏和脑循环功能的相互影响。结论表明,从血液动力学角度,不但心脏特性变化会对脑循环产生影响,脑血管异常也会对心血管功能（如血压）发生作用。     

左心室脱血回注循环辅助法对急性心肌梗死血流动力学的改善作用

目的:实验观察左心室脱血回注循环辅助法对急性心肌梗死血流动力学的改善作用.方法:18只杂种犬分两组制作急性心肌梗死泵衰竭模型,治疗组给予左心室脱血回注循环辅助,对照组不进行治疗.观察比较两组间心律失常、死亡率、外周动脉压、肺动脉毛细血管楔嵌压(PCWP)、左心室舒张末期压(LVEDP)、左心室内径的变化.结果:治疗组室性期外收缩、心室纤颤发生率和死亡率显著低于对照组;对照组的外周动脉收缩压低于80 mmHg以下,治疗组维持在100mmHg以上(P＜0.01);治疗组PCWP和LVEDP值在45 min以后的各时段低于对照组(P＜0.01);治疗组的左室舒张末期内径小于对照组(P＜0.01).结论:左心室脱血回注循环辅助法能够减少急性心肌梗死泵衰竭的心室纤颤发生率和死亡率,有显著改善血流动力学、防止梗死后心肌扩张和有效的左心室辅助作用.     

The effects of high-dose epinephrine combined with isoprenaline on isolated rabbit heart and cardiomyocytes after cardioversion of ventricular fibrillation

The effects of high-dose epinephrine (HDE) combined with isoprenaline (Iso) on myocardial hemodynamics of isolated rabbit heart were studied. The electrophysiology and L-type Ca²⁺ channel of single ventricular myocyte after cardioversion of ventricular fibrillation were determined. The results suggest that parameters of hemodynamics were significantly enhanced by HDE+Iso than that of HDE (p < 0.01). The OS and V_max of HDE+Iso increased 83.7 and 10.15% respectively compared to HDE alone. The APF of HDE+Iso is much more rapid than that of HDE (138.38 ± 9.96 vs. 55.58 ± 8.63 min^-1, p < 0.001). The APD₅₀ and APD₉₀ of HDE+Iso were significantly decreased; HR was increased (134.16 ± 1.48 vs 62.20 ± 6.25 min^-1); and the amplitude current of through L-type Ca²⁺ channel was reduced but was significantly higher than the control. We conclude that HDE+Iso can improve the hemodynamics and improve electrophysiology of cardiomyocytes after cardioversion of ventricular fibrillation which is likely interrelated with ICa. The combined use of epinephine and isoprenaline for cardiopulmonary resuscitation of primary ventricular fibrillation may be beneficial when employed in clinical situations.     

灯盏花素注射液联合依达拉奉注射液对未溶栓急性脑梗死患者神经功能、脑血流动力学和血清炎症细胞因子的影响

摘要 目的：观察灯盏花素注射液联合依达拉奉注射液对未溶栓急性脑梗死（ACI）患者神经功能、脑血流动力学和血清炎症细胞因子的影响。方法：选取2020年4月~2022年1月来我院接受治疗的未溶栓ACI患者82例。采用随机数字表法将患者分为对照组（依达拉奉注射液治疗,41例）和实验组（灯盏花素注射液联合依达拉奉注射液治疗,41例）。观察两组临床疗效,神经功能、脑血流动力学和血清炎症细胞因子的变化,记录两组不良反应情况。结果：实验组的临床总有效率为90.24%,高于对照组的68.29%,差异有统计学意义（P<0.05）。实验组治疗7d后美国国立卫生研究院卒中量表（NIHSS）评分低于对照组,日常生活活动能力（ADL）评分高于对照组P<0.05）。实验组治疗7d后脑血流平均血流速度（Vm）、收缩期峰值血流速度（Vs）、舒张期血流速度（Vd）高于对照组（P<0.05）。实验组治疗7 d后白介素-6（IL-6）、超敏C反应蛋白（hs-CRP）水平低于对照组（P<0.05）。两组均未出现严重的不良反应。结论：依达拉奉注射液联合灯盏花素注射液治疗未溶栓ACI患者,可调节脑血流动力学,减轻神经功能损伤,降低血清炎症细胞因子,且具有较好的安全性。     

通督调神针刺法联合胞磷胆碱对脑梗死后血管性痴呆患者认知功能、血液流变学和脑血流动力学的影响

摘要 目的：观察通督调神针刺法联合胞磷胆碱对脑梗死后血管性痴呆（VD）患者认知功能、血液流变学和脑血流动力学的影响。方法：选择2018年3月～2021年3月期间安徽中医药大学第二附属医院收治的98例脑梗死后VD患者,采用随机数字表法分为对照组（49例,胞磷胆碱联合传统针刺治疗）和观察组（49例,通督调神针刺法联合胞磷胆碱治疗）。对比两组疗效、认知功能、痴呆症状、日常生活能力、血液流变学和脑血流动力学。结果：观察组的临床总有效率高于对照组（P<0.05）。治疗后,观察组日常活动能力量表（ADL）、长谷川痴呆修正量表（HDS-R）、简易智力状态检查量表（MMSE）评分高于对照组（P<0.05）;观察组血细胞比容、血浆黏度、全血高切黏度、全血低切黏度低于对照组（P<0.05）;观察组收缩期峰值速度（Vmax）、搏动指数（PI）高于对照组;舒张期峰值速度（Vmin）、阻力指数（RI）低于对照组（P<0.05）。结论：胞磷胆碱联合通督调神针刺法治疗脑梗死后VD,可促进其痴呆症状、认知功能和日常生活能力改善,可能与调节血液流变学和脑血流动力学有关。     

Monte Carlo modeling of photon migration in realistic human thoracic tissues for noninvasive monitoring of cardiac hemodynamics

Noninvasive monitoring of cardiac hemodynamics remains challenging in cardiovascular medicine. The possibility of noninvasive optical monitoring of cardiac hemodynamics was theoretically investigated in this study. By utilizing the Monte Carlo simulation method for voxelized media (MCVM) and Visible Chinese Human dataset, we quantified and visualized the photon migration in human thoracic region. The light fluence distribution was showed to reach heart tissue (～3 cm depth underbody surface) and 12% of the total fluence was absorbed by the myocardium. The proportion of spatial sensitivity distribution (SSD) in cardiac tissue to the total SSD reached 0.0195%. The portion of SSD increased following with cardiac diastole and diffuse reflectance deceased linearly with increasing cardiac volume. The optimal separation between the light source and detector was provided to be 3.5 to 4.0 cm for future development of noninvasive cardiac hemodynamics monitoring. A pilot experimental study was conducted to measure the diffuse reflectance light and fingertip photoplethysmography. These data suggest that the fluctuation period of near‐infrared (NIR) diffuse reflectance was consistent with the cardiac cycle, while the fluctuation features of the NIR signal was not consistent with that of photoplethysmography. All results indicate the great potential of noninvasive optical monitoring of myocardial hemodynamics.     

MRI-based modeling of spleno-mesenteric confluence flow

Characterization of hepatic blood flow magnitude and distribution can lead to a better understanding of the pathophysiology of liver disease. However, the underlying patterns and dynamics of hepatic flow, such as the helical flow structure that often develops following the spleno-mesenteric confluence (SMC) of the hepatic portal vein, have not yet been comprehensively studied. In this study, we used magnetic resonance image (MRI)-based computational models to study the effects of the helical flow structure and SMC geometry on portal blood flow distribution. Additionally, we examined these flow dynamics with four-dimensional (4D) flow MRI in a group of 12 cirrhotic patients and healthy subjects. A validation model was also created to compare computational data to particle image velocimetry (PIV) data. We found significant correlations between flow structure development, vessel geometry, and blood flow distribution in both virtually modified models and in healthy and cirrhotic subjects. However, the direction of these correlations varied among vessel configuration types. Nonetheless, validation model results displayed good qualitative agreement with computational model data.     

Splenic hemodynamics and decreased endothelial nitric oxide synthase in the spleen of rats with liver cirrhosis

The enlarged spleen in liver cirrhosis is considered to play a role in the pathogenesis of portal hypertension, but the splenic hemodynamics and molecular mechanisms behind the phenomenon have not been elucidated. The present study aimed to examine the splenic hemodynamics associated with splenic microcirculation and congestion, and to determine the status of the endothelial nitric oxide synthase (eNOS) signaling pathway in the spleen of rats with liver cirrhosis. Liver cirrhosis was induced by bile duct ligation. In rats with bile duct ligation (BDL rats) and control rats, splenic blood flow was measured using a laser Doppler flowmeter, and splenic blood volume was measured using a near-infrared spectrophotometer. The expressions of eNOS and its upstream effectors, Akt, TNF-alpha and VEGF, in the spleen were also determined. Specific splenic blood flow was significantly decreased in BDL rats compared with control rats. Specific splenic blood volume was also decreased in BDL rats, while their total splenic blood volume, especially the deoxygenated volume, was significantly increased. The expressions of phosphorylated and total eNOS, and the eNOS phosphorylation ratio, were all significantly decreased in the spleen of BDL rats. The Akt phosphorylation ratio and TNF-alpha concentration were also decreased in the spleen of BDL rats although the expression of VEGF was increased. These findings suggest that the eNOS signaling pathway is suppressed in the spleen of cirrhotic rats, and may contribute to the measured decreases in specific blood flow and volume in the spleen of liver cirrhosis. Determination of the factors influencing the suppression of eNOS in the spleen may shed light on how liver cirrhosis results in hypodynamic intrasplenic circulation.     

Computational investigations on the hemodynamic performance of a new swirl generator in bifurcated arteries

Hemodynamic behaviour of blood in the bifurcated arteries are closely related to the development of cardiovascular disease. The secondary flows generated at the bifurcation zone promotes the deposition of atherogenic particles on the outer walls. The present study aims at suppressing the development of atherosclerosis plaque by inducing helical flow structure in the arterial passage. To realize this objective a novel swirl generator (stent like structure with an internal groove) has been developed to induce helicity in the bifurcated passage. The functional requirement of the swirl generator is to minimize the relative residence time (RRT) of the fluid layer near the endothelial wall without generating any additional pressure drop. Different configurations of the swirl generator have been tested computationally using large eddy simulation (LES) model. It is observed that the induced helical flow redistributes the kinetic energy from the centre to the periphery. A single rib swirl flow generator proximal to the stent treated passage can generate sufficient helicity to bring down the RRT by 36% without generating any additional pressure drop. The swirl flow adds azimuthal instability which increase vortex formations in the passage. The induced helical flow in the domain provokes more linked vortices, which may act as self-cleaning mechanism to the arterial wall.     

脾切除及贲门周围血管离断术对肝硬化门静脉高压患者肝脏血流动力学的影响及其术后门静脉血栓形成的因素分析

目的:探讨脾切除及贲门周围血管离断术对肝硬化门静脉高压患者肝脏血流动力学的影响,并分析患者术后门静脉血栓形成的危险因素。方法:选择2016年1月-2017年12月在我院进行脾切除及贲门周围血管离断术的96例肝硬化门静脉高压患者,于术前、术后1d、3d、7d采用彩色多普勒超声对患者的肝脏血流动力学指标进行动态监测。统计术后7d内患者门静脉血栓的发生率,并将患者分为血栓组(n=28)和无血栓组(n=68),对两组患者的一般资料、手术指标、彩色多普勒超声监测指标等进行单因素分析,并采用Logistic多因素回归分析门静脉血栓形成的危险因素。结果:患者在术前、术后1d、3d、7d时的门静脉内径、最大流速、血流量呈逐渐降低的趋势,肝动脉内径、最大流速、血流量呈逐渐升高的趋势,且各时间点间两两比较差异有统计学意义(P0.05)。术后7d内有28例患者出现门静脉血栓,发生率为29.17%。血栓组和无血栓组患者在性别、年龄、体质量指数、手术时间、术前门静脉流速比较差异无统计学意义(P0.05);血栓组患者Child-Pugh分级为B级比例、术中出血量、脾质量、腹水量、术前门静脉内径均高于无血栓组,术后门静脉内径、术后门静脉流速均低于无血栓组(P0.05)。经Logistic多因素回归分析显示,患者术后门静脉内径、术后门静脉流速是门静脉血栓形成的危险因素(P0.05)。结论:行脾切除及贲门周围血管离断术的肝硬化门静脉高压患者术后进行肝脏血流动力学监测,有助于患者术后的疗效判断,且术后门静脉内径、术后门静脉流速是门静脉血栓形成的危险因素。