Tesla blood pumps demonstrate a reduced propensity for hemolysis and thrombosis compared with vane blood pumps. Considering the restricted driving force within the secondary flow channel of vane blood pumps, along with the low hydraulic efficiency of conventional Tesla blood pumps and their internal flow characteristics that significantly contribute to hemolysis and thrombosis, this study introduces a set of vanes atop the rotor of the Tesla blood pump. This forms a dual-fluid domain rotor, and an axial dual-outlet volute shell structure is adopted to realize the separation of the fluid domains. Through numerical simulations of the new structure, a comparative analysis was conducted in this study on the internal flow characteristics of double-outlet and single-outlet volute shells, and symmetric and asymmetric cross-sections of the same rotor. The results indicate that the flow field distribution is more uniform under the double-outlet volute shell structure, and overall energy dissipation is decreased. After implementing the double-outlet design, in the asymmetric cross-section, compared with the symmetric cross-section, the fluid velocity gradient and turbulent kinetic energy at the tongue of the septum are reduced, and the fluid velocity gradient at the convergence of the diffuser tube outlets are also decreased. The maximum scalar stress is lower, and the decline in head and efficiency is mitigated. Moreover, compared with the single-outlet volute shell, the hemolysis index in the asymmetric cross-section is reduced. In summary, this paper proposes a novel dual-outlet centrifugal disk blood pumps, which can provide a reference for the structural design and performance optimization of magnetically levitated centrifugal blood pumps.
Objective To evaluate the therapeutic efficacy of percutaneous transhepatic portal vein catheterization and thrombolysis on acute superior mesenteric vein thrombosis. Methods The treatment and therapeutic efficacy of 7 cases of acute superior mesenteric vein thrombosis underwent percutaneous transhepatic portal vein catheterization and thrombolysis under ultrasound guidance from August 2005 to April 2009 were analyzed. Results All the patients succeeded in portal vein catheterization and no bile leakage or abdominal bleeding occurred during the procedure. The clinical symptoms such as abdominal pain, abdominal distension， and passing bloody stool relieved were relieved and liquid diet began at postoperative of day 2-5. Emergency operation was done in one case and there was no intestinal fistula. The angiography after the operation showed that the majority of thrombosis were cleared and the blood of portal vein and superior mesenteric vein flowed smoothly. During the follow-up of 3 months to 3 years, all the patients’ status maintained well and no recurrence occurred. Conclusion Treatment of acute superior mesenteric vein thrombosis by percutaneous transhepatic portal vein thrombolysis is safe and effective.
ObjectiveTo evaluate the CT findings and causes of thrombosis formation after transjugular intrahepatic portosystemic shunt (TIPS). MethodsOne hundred forty-two patients with cirrhosis after TIPS were included. The imaging features of thrombus in the stent after TIPS were recorded and causes of thrombosis formation were analyzed. The presence, location and amount of thrombus, the location of ends of TIPS stent were analyzed. ResultsThe incidence of thrombosis formation after TIPS was 19.0% (27/142). The thrombus could locate around the upper end (7.4%), lower end (18.6%) of the stent and inside the stent (74.0%), there was significant differences in the incidence of stent thrombosis in different locations (P < 0.05). The thrombus might presented as little mural thrombus (12/27, 44.4%), marked thrombus (3/27, 11.1%) and thrombotic occlusion (12/27, 44.4%), there was a significant difference in the incidence of stent thrombosis with different thrombus volume (P < 0.05). There were stent outlet vascular stenosis in most patients with stent thrombosis (88.9%). ConclusionsStent thrombosis after TIPS is common. Dual source computed tomography angiography could evaluate the thrombotic features. Stent outlet vascular stenosis might be associated with thrombosis formation after TIPS.
ObjectiveTo explore the value of portable ultrasound in assessing peripheral vein thrombosis of the injured in Lushan earthquake on April 20, 2013. MethodsFrom April 20th to May 5th in 2013, 321 earthquake victims were admitted into our hospital, and 203 fractured patients of them accepted peripheral venous two-dimensional and color doppler ultrasound examination beside the bed every three days. ResultsSixty-three patients (82 locations) suffered from venous thrombosis in the 203 earthquake victims, and the rate was 31.03% (63/203). Among them, one suffered from iliac vein thrombosis; 53 patients (71 limbs) were attacked by lower limb venous thrombosis; 9 patients (10 limbs) suffered from upper limb venous thrombosis. The time was from 2 to 15 days after trauma when the victims were diagnosed to have thrombus at the first time, averaging (6.1±3.8) days. On admission day, 45 victims were diagnosed with peripheral vein thrombosis. Among them, 19 patients increased the scope of thrombus after admission in hospital, while 26 victims reduced the scope. Eighteen victims suffered from newly developed peripheral venous thrombus after admission in hospital. None of the hospitalized patients died of pulmonary embolism. ConclusionsThe victims injured in the earthquake have a high incidence of peripheral vein thrombosis, and the calf is the main site of the disease. After trauma, peripheral venous thrombosis occurs within a short time. Bedside portable ultrasound is the first choice for peripheral vein thrombosis in the earthquake victims.
Objective To optimize the hemodynamics of a disk blood pump in children. Method We used the computational fluid dynamics technology to simulate the flow in a pediatric blood pump numerically, and finally analyzed the results for deep study about the thrombosis and hemolysis produced in it, to improve the design according to the results of the flow field analysis. Results We calculated results between the flow rate and the pressure elevation at different rotational speed: 2 500 rpm, 3 000 rpm, and 4 000 rpm, respectively. Under each rotational speed, it was selected five different discharge outlet boundary conditions. The simulation results conformed to the experimental data. The increased pressure of the blood pump was effective. But the phenomenon of flow separation was increased the at blade surface in the low speed region. The maximum wall shear stress was maintained within 100 Pa. Conclusion The design of disc blood pump has a good fluid dynamic performance. And the flow line is fluent, the probability of thrombosis and hemolysis occurred is in the range of control. But the phenomenon of flow separation is appeared. There is a room to improve.
To investigate the significance of activated platelet levels before and after surgical operation in patients with severed finger by severe injury, the P-selectin (CD62p) positive platelet percent in peripheral blood was studied in 32 patients before and after operation by flow cytometric immunology. At the second and third day after operation, seventeen patients, which in a high positive platelet percent, were measured again after anticoagulation treatment with a large dose of urokinase etc. The results were that the levels of CD62p positive platelet in peripheral blood before and after operation were significantly higher than that of the normal group (P lt; 0.01). The CD62p positive platelet percent was increased not much more in the anti-coagulation patients than in the normal ones (P gt; 0.05). There were a few vascular crisis observed. This study suggested that severed fingers by a crushing or wringing injury enhance the platelet activity and resulted in hypercoagulation, thus anti-coagulation measures should be taken to avoid possible thrombosis and improve the survival rate of replantation. CD62p was one of the sensitive indices of activated platelet, which could be used in calculating hypercoagulation accurately.
Objective To evaluate the effect of Fogarty balloon catheter embolectomy on arteriovenous graft thrombosis in hemodialysis patients. Methods We retrospectively analyzed the clinical data of 11 patients who underwent maintaining hemodialysis and arteriovenous graft thrombosis through Fogarty balloon catheter embolectomy between March 2010 and November 2014. The thrombosed graft was incised, and a 4 or 6 French catheter was placed in the venous and arterial limbs of the graft respectively. The Fogarty balloon was passed beyond the thrombus and pulled out after saline was infused into the balloon, and the thrombus was taken out. The procedure was considered unsuccessful if the blood flow was not re-established or if the graft re-thrombosed within hours. Results The treatment was successfully performed in all the patients. Of the 11 patients, 3 received balloon dilation due to stenosis of venous anastomosis, and 2 received angioplasty due to underlying arterial anastomosis lesion. After corresponding measures were taken, the thrombus of all the 11 patients were taken out, and blood flow was recovered. Two to seven days after surgery, low molecular weight heparin was used for anti-coagulation. The blood flow of all arteriovenous grafts reached over 250 mL/min. All the patients were followed up for 4 to 30 months. During the follow-up, the arteriovenous graft remained functional in 5 patients; 4 patients had re-thrombosis on day 2, 3, 25, and 71 after surgery respectively; one changed to undergo peritoneal dialysis due to rupture and infection of the graft, and one patient was transferred to another hospital in another area and was not followed up any longer. The therapy was successful in 81.8% of this group of patients. Conclusion Fogarty balloon catheter embolectomy is effective in restoring patency of thrombosed arteriovenous graft in hemodialysis patients, and more studies are needed.
ObjectiveTo analyze the reason and prevention of late bioprosthetic heart valve thrombosis (LBVT). MethodsBioprosthetic heart valves were implanted in 580 patients between January 2001 and July 2013 in Changhai Hospital, and only found one case of LBVT (0.2%). Reoperation was performed for a 67-year-old male patient 3 years after bioprosthetic aortic valve replacement due to severe aortic valve stenosis. Retrospectively analyzed the clinical data and reviewed the literature between January 1989 and December 2013 in Pubmed. ResultsNo risk factor for thrombosis was revealed in this patient. Pathology revealed valve thrombosis and collagen and elastic fibers fragmentation and disruption in valve leaflets. In literature review, 20 articles and 47 cases were brought in. The morbidity of LBVT was 0.2%-1.0%. At least 18 patients had high risk factors, and 15 of the 18 patients discontinued anticoagulation after 3 months. However, at least 10 patients had no high risk factors. Forty-four of the 47 patients received stented porcine valve replacement, only one patient received stented bovine pericardial valve replacement. ConclusionsLBVT is a rare but serious complication after bioprosthetic valve replacement, the causes of which include the feature of the patients and the bioprosthetic valves. Bovine pericardial valves could be superior to porcine valves in preventing LBVT. Postoperative long-time aspirin therapy is recommended for patients without high risk factors. Patients with any high risk factors should prolong anticoagulation.
The International Society on Thrombosis and Hemostasis (ISTH) recently released the first ISTH guideline for antithrombotic treatment of COVID-19, which provides recommendations on anticoagulant and antiplatelet agents for patients with COVID-19 in different clinical settings. The target audience includes clinicians in internal medicine, intensive care, infectious diseases, hematology, vascular medicine, residents, family physicians, and other health care providers providing inpatient or outpatient care to COVID-19 patients. This article interprets the important parts of ISTH guideline.
ObjectiveTo analyze the clinical and immunological characteristics of 26 patients with antiphospholipid syndrome (APS). MethodsThe clinical and immunological features of APS in 26 patients treated between January 2009 and January 2012 were analyzed retrospectively. ResultsThe study consisted of 8 male and 18 female patients with a mean age of 38 years at diagnosis. Seven patients had primary APS. Nineteen patients had APS associated with autoimmune diseases, including 11 cases of systemic lupus erythematosus. Seventy-five percent of the patients had thrombosis, 16 had venous thrombosis, 7 had arterial thrombosis, and 2 had both arterial and venous thrombosis. The deep veins of the lower limbs and the cerebral arterial circulation were the most common sites of venous and arterial thrombosis. Fetal morbidity rate of 16 married women in our study was 43.8%. Thrombocytopenia and anemia were present in 57.7% and 69.2% of the patients respectively. ConclusionAPS is characterized by recurrent thrombosis, pregnancy morbidity and positive antiphospholipid antibodies tests. Early diagnosis and management is essential for APS.