Variations in the bifurcation level of the abdominal aorta, formation level of the inferior vena cava, and insertion level of the left renal vein into the inferior vena cava and their clinical importance in laparoscopic surgery

Objective: It is important to minimize the risk of major vascular injury during pneumoperitoneumestablishment in laparoscopic surgeries for patients with unusual variations in the levels of theabdominal aorta, the inferior vena cava (IVC), and the left renal vein, which will decrease the morbidityand mortality. The study aims to assess the variations regarding the bifurcation level of the abdominalaorta, formation level of the IVC, and insertion level of the left renal vein into the IVC.Methods: This retrospective study was conducted on 100 patients (50 males and 50 females) referred tothe Department of Radiology, Jordan University Hospital for abdomino-pelvic CT with intra-venouscontrast from January 2018 to December 2019. The three vessels were determined on the axial plane,the coronal plane, and the midsagittal plane. The central vertebral body height as well as the distance ofthe level of the point of interest to the upper end plate of the vertebrae were measured. Afterwards, theresults were classified into the following categories, upper end plate, lower end plate, intervertebral disc,upper half, and lower half of the vertebra.Results: The aortic bifurcation was mainly found at the level of the L4 vertebral body (65, 65%). In theremaining cases, the bifurcation was found to be variably located spanning from L3 in 11 (11%) cases to3 (3%) cases at L5. As for the iliocaval junction, the most common site was also at the level of L4 with41 (41%) cases followed by 39 (39%) cases at the level of L5, and 20 (20%) cases at the intervertebral discof L4/L5. The left renal vein most commonly joined the IVC at the level of L1 with 62 (62%) cases followedby 20 (20%) cases at the intervertebral disc T12/L1. There was wide variation in its entry to the IVCspanning from 4 (4%) cases at T12/L1 to 1 (1%) case at L4.Conclusion: The anatomical variation of the major vessels can be found in the normal population.Therefore, sufficient investigation of the anatomical position of these vessels is essential for patientsbefore laparoscopic surgery.

An Experimental Set-Up for the in Vitro Simulation of a Physiological Pulsatile Flow in the Abdominal Aorta

In vitro experimental set-up is an important tool for investigating abdominal aortic aneurysm (AAA). Accurate reproduction of the physiological pulsatile flow waveform in the abdominal aorta at various anatomic locations is an important component of these experimental methods. The objective of this study is to establish an experimental set-up to generate a physiological pulsatile flow for in vitro simulations of the abdominal aorta. The physiological flow was established by a computer-controlled peristaltic pump and the flow field in a circular straight pipe is measured under pulsatile flow conditions by a 2-dimensional particle image velocimetry system (2D-PIV). Experimental results show that the in vitro experimental set-up provides a flow with a period of 2 s, a reasonable cross-sectional velocity distribution and an approximate inlet velocity profile that is close to the human abdominal aorta.

Angiograms of the Abdominal Aorta in a Patient of Middle Aortic Syndrome

A 42-year old woman of middle aortic syndrome presented with severe hypertension for 20 years, whose abdominal aorta angiography revealed long segment and nearly complete occlusion in the mid portion of abdominal aorta, and extensively enlarged collateral vascular supply to the lower portion of abdominal aorta. The pressures proximal and distal to stenosis were 185/110 and 95/70 mmHg, and the pressure gradient across the stenosis was 90/40 mmHg. After the operation of thoraco-abdominal bypass graft, the pressure difference between the upper and lower extremities eventually disappeared.

Detection of atherosclerotic plaque progression in the abdominal aorta of rabbits with 3T magnetic resonance imaging

Background With features of high tissue contrast, MRI can be used for the qualitative and quantitative evaluation of atherosclerosis plaques. In this study we investigated the development of atherosclerosis plaque with high resolution 3T MRI in a rabbit model and compared the findings with the histopathological results. Method Twenty male New Zealand white rabbits were randomly allocated into an experimental group （n=16） and a control group （n=4）. Atherosclerotic lesions were induced in the abdominal aorta by balloon injury and cholesterol feeding. Multiple sequences MRI examination （ToF, TIWI, T2WI, and CE T1WI） were performed at the 2nd, 3rd, and 4th months after aortic denudation. Vessel wall thickness, total vessel area, lumen area, and vessel wall area were recorded. Plaque components were analyzed using histological results as a standard reference. Results Seventeen rabbits （14 in the experimental group and 3 in the control group） received all three MR examinations. Gradually, from 2 months to 4 months, vessel wall thickness and area in the experimental group increased significantly compared with the control group （P 〈0.01）. In the lumen area progressive stenosis was not found, even a slight dilation had developed in the experimental group. Lipid, fibrotic and calcified plaques can be differentiated by MR image. According to histological results, MRI had good performance in detection of lipid plaque. Conclusion MRI can be used to monitor progression of atherosclerosis and differentiate plaque components.

AN EXPERIMENTAL STUDY OF INTRAVASCULAR STENT IN ABDOMINAL AORTA OF ATHEROSCLEROTIC MINIATURE PIGS

To study the effects of nitinol alloy stent in the treatment of atherosclerotic arterial stenosis, eight miniature pigs were subject to abdominal aortic balloon denudation and high-fatty food. Then 8 nitinol alloy stents were implanted into each abdominal aortas of pigs. The pigs were equally divided into two groups. One group was given captopril (3 mg / kg / d). All animals were sacrified) for pathological examination 6 to 10 months after stent implantation. The degree of arterial intima proliferation in the areas of stent implantation not significantly different from that of areas of balloon denudation alone; the atherosclerotic lesions were found at the arterial surface of stent implantation sites. The intima layer was rich in smooth muscle cells, with atherosclerotic plaque formed around the stent wire. On the other hand, significant decrease in arterial intima proliferation was found in group Ⅱ with no atherosclerotic plaque. The arterial stenosis resulting from atherosclerotic lesion could not be prevented by implantation of intravascular stent, and on the contrary, the mechanical stress of stent wire might worsen the atherosclerosis. Captopril might impede the development of atherosclerotic stenosis after stent implantation.

Multiple recurrent cystic echinococcosis with abdominal aortic involvement: A case report

BACKGROUND Recurrent cystic echinococcosis(CE)with vital organ involvement is a challenge for clinicians.Herein,we report a case of aortic involvement in recurrent retroperitoneal CE lesions following primary splenic CE resection.CASE SUMMARY A 60-year-old male was admitted due to progressive abdominal pain and poor appetite.He was diagnosed with multiple recurrent CE with abdominal aortic involvement according to preoperative evaluation.During surgical resection,major aortic bleeding accidentally occurred while dissecting the cyst,which was firmly attached to the abdominal aortic wall.Hemostasis attempts were conducted to deal with this emergency situation and maintain circulation.Postinterventional recovery was uneventful,and 2-year follow-up showed no sign of recurrence or any other complications.CONCLUSION Radical resection of recurrent complicated CE with aortic involvement should be carefully planned and performed to prevent possible severe adverse complications,thereby improving the postoperative outcome.

Monitoring somatosensory evoked potentials in spinal cord ischemia-reperfusion injury

It remains unclear whether spinal cord ischemia-reperfusion injury caused by ischemia and other non-mechanical factors can be monitored by somatosensory evoked potentials. Therefore, we monitored spinal cord ischemia-reperfusion injury in rabbits using somatosensory evoked potential detection technology. The results showed that the somatosensory evoked potential latency was significantly prolonged and the amplitude significantly reduced until it disappeared during the period of spinal cord ischemia. After reperfusion for 30-180 minutes, the amplitude and latency began to gradually recover; at 360 minutes of reperfusion, the latency showed no significant difference compared with the pre-ischemic value, while the somatosensory evoked potential amplitude in- creased, and severe hindlimb motor dysfunctions were detected. Experimental findings suggest that changes in somatosensory evoked potentia~ ~atency can reflect the degree of spinat cord ischemic injury, while the amplitude variations are indicators of the late spinal cord reperfusion injury, which provide evidence for the assessment of limb motor function and avoid iatrogenic spinal cord injury.

Comparison of invasive dynamic blood pressure between superior mesenteric artery and common carotid artery in rats

The purpose of this study was to identify the consistency of invasive dynamic blood pressure (BP) monitoring between the superior mesenteric artery (SMA) and the common carotid artery (CCA). METHODS: Eight male Sprague-Dawley rats were cannulated in SMA and CCA simultaneously for BP monitoring, respectively. The abdominal aorta was prepared for the induction of BP change through clamping/de-clamping by a microvascular clip. The dynamic BP monitoring was performed by a polygraph system. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) values would be recorded during different time periods: the baseline (T1), the increasing period after clamping (T2), the platform period during clamping (T3), the decreasing period after de-clamping (T4), and the final platform period (T5). Three trials were performed on each rat with 15-minute intervals between consecutive monitoring. RESULTS: Systolic BP showed no significant differences between SMA and CCA. However, significant difference was found in diastolic blood pressure except at T5 (P=0.534). Mean arterial pressure of two arteries were signi cantly different only at T1 (P=0.015). The strength of association was significantly high between BP measurements through SMA and CCA (P<0.001). The Bland- Altman analyses showed that mean bias of MAP changed no more than 5 mmHg and standard deviation less than 8 mmHg during T2 and T4, respectively. CONCLUSION: The study indicates SMA might be an alternative site for invasive BP monitoring during abdominal aorta occlusion and release, especially in cerebrovascular-related research.

Endovascular aneurysm repair as a mean of treatment for ruptured abdominal aortic aneurysms

The metamorphosis of abdominal aortic aneurysm （AAA） repair from open surgical to endovascular means has evolved substantially over the past 2 decades. Today, endovascular abdominal aneurysm repair （EVAR） is considered as the first choice of therapy for treatment of infrarenal AAA in patients with favorable morphology.

Effect of cholesterol lowering on stiffness of aortic and femoral arterial walls in rabbits on a high fat diet

Background Researches in arterial elasticity have increased over the past few years. We investigated the effects of simvastatin on vascular stiffness in fat fed rabbits by ultrasonography. Methods Thirty rabbits were assigned randomly to 3 groups： normal control group （A）, the cholesterol group （B）, simvastatin group （C： high fat diet for 4 weeks and high fat diet ＋ simvastatin for further 4 weeks）. Stiffness coefficient, pressure strain elastic modulus and velocity of pulse waves in abdominal aorta and femoral artery were measured by ultrasonographic echo tracking at the end of the 4th and the 8th weeks. Results At the end of the 4th week, stiffness coefficient, pressure strain elastic modulus and pulse wave velocity of femoral artery were significantly increased in group B compared with those in group A. Similarly, at the end of the 8th week, the same parameters of abdominal aorta were significantly increased in group B compared with those in group A. In contrast, stiffness coefficient, pressure strain elastic modulus and pulse wave velocity of femoral artery were significantly decreased in group C compared with those in group B, however, there was no significant difference in parameters of abdominal aorta between groups B and C. Conclusion Short term administration of simvastatin can improve the elasticity of femoral artery but not abdominal aorta.

Protective effect of tanshinone Ⅱ A on signal transduction system protein kinase B in rats with myocardial hypertrophy

The effects of tanshinone II A on cell signal transduction system protein kinase B in rats with myocardial hypertrophy induced by the abdominal aorta partial coarctation were investigated.Rat models of myocardial hypertrophy were established by using abdom-inal aorta partial coarctation method.Forty-eight rats were randomly divided into sham group(S group),model group(M group),valsartan treatment group(X group),low-dose tanshinone treatment group(LD group),medium-dose tanshinone treatment group(MD group),and high-dose tanshinone treatment group(HD group)(n=8 in each group).Left ventricular mass index(LVMI),left ventri-cular posterior wall(LVPW),and septal thickness(IVS)were detected by high frequency ultrasonography.Myocardialfiber diameter(MFD)was examined by Hematoxylin-Eosin(HE)staining,and the contents of phosphorylated protein kinase B(p-Akt)and p-Gsk3βin myocardium were assayed by Western blot.The results showed that compared with S group,the values of LVMI,LVPW,IVS and MFD were increased in other groups(P<0.05),and the contents of p-Akt,and p-Gsk3βwere also increased in other groups.As compared with MD group,the values of LVMI,LVPW,IVS and MFD were decreased in all treatment groups(P<0.05),and the contents of p-Akt,and p-Gsk3βwere also decreased in all treatment groups.However,there were no significant differences among LD,MD,and HD groups(P>0.05),and there were no significant differences between X group and tanshinone treatment groups(P>0.05).It was suggested that tanshinone II A could prevent myocardial hypertrophy by its action on the Akt signaling pathway.

Application of occluders in endovascular repair of aortic aneurysms

Since Parodi et all reported the first successful case of endovascular treatment for abdominal aortic aneurysm （AAA） in 1991, the endovascular repair has become an important option for the surgical treatment of aortic aneurysms.2-4 The occluder is a newly-developed device introduced intraluminally to block the blood flow in certain arteries. It was mainly adopted by cardiologists in occluding the ventricular septal defect （VSD） and atrial septal defect （ASD）.5-6 Afterwards, vascular surgeons found it could also be used in endovascular repair of aortic aneurysms, especially when the aorto-uni-iliac （AUI） stent-grafts were implanted.7 Herein we present 6 patients with AAA, who were treated with endovascular deployment of AUI stent-grafts combined with a newly- designed occluder.