[Numerical study of the effect of geometrical parameters of straight impellers on the flow and hemolysis performance of centrifugal blood pumps].

Red blood cells are destroyed when the shear stress in the blood pump exceeds a threshold, which in turn triggers hemolysis in the patient. The impeller design of centrifugal blood pumps significantly influences the hydraulic characteristics and hemolytic properties of these devices. Based on this premise, the present study employs a multiphase flow approach to numerically simulate centrifugal blood pumps, investigating the performance of pumps with varying numbers of blades and blade deflection angles. This analysis encompassed the examination of flow field characteristics, hydraulic performance, and hemolytic potential. Numerical results indicated that the concentration of red blood cells and elevated shear stresses primarily occurred at the impeller and volute tongue, which drastically increased the risk of hemolysis in these areas. It was found that increasing the number of blades within a certain range enhanced the hydraulic performance of the pump but also raised the potential for hemolysis. Moreover, augmenting the blade deflection angle could improve the hemolytic performance, particularly in pumps with a higher number of blades. The findings from this study can provide valuable insights for the structural improvement and performance enhancement of centrifugal blood pumps.

Long-term discontinuation of warfarin in a patient with HeartMate 3 left ventricular assist device without thromboembolic events.

The gold standard therapy for end-stage heart failure is cardiac transplantation. However, in the face of a donor shortage, a mechanical assist device such as the left ventricular assist device HeartMate 3 (Abbott Laboratories, Abbott Park, IL, USA) serves as bridging therapy to transplantation and/or destination therapy. Current guidelines recommend anticoagulation with a vitamin K antagonist in combination with low-dose aspirin. We herein report a challenging anticoagulation regimen in a patient with a HeartMate 3 in whom systemic anticoagulation with warfarin was not feasible for 4 years because of low compatibility and a rare X-factor deficiency. This is a rare hematological disorder, estimated to affect approximately 1 in every 500,000 to 1,000,000 people in the general population. The patient finally received a modified anticoagulation regimen involving the combination of rivaroxaban and clopidogrel without warfarin. Under this regimen, the patient remained free of thromboembolic complications for 4 years with in situ placement of the left ventricular assist device. This case illustrates that under specific circumstances, long-term absence of warfarin therapy is feasible in patients with a HeartMate 3.

Evaluating the efficacy and safety of temporary mechanical circulatory support devices in acute cardiogenic shock: A subgroup-specific systematic review.

OBJECTIVE: This systematic review aims to assess the comparative effectiveness and safety of temporary mechanical circulatory support (MCS) devices in various subgroups of patients with acute cardiogenic shock, providing insights for personalized clinical decision-making. METHODS: We conducted a comprehensive search across major databases to identify studies that reported on the use of temporary MCS devices like TandemHeart, Impella, and VA-ECMO in acute cardiogenic shock. Special attention was given to subgroup analyses based on etiologies of shock, patient demographics, and comorbid conditions. RESULTS: Our analysis revealed that while devices like TandemHeart and Impella offer significant hemodynamic support, their effectiveness and safety profiles vary across different patient subgroups. VA-ECMO demonstrated the highest flow rates and potential for mortality benefits but requires careful management due to associated risks. The lack of randomized controlled trials in specific patient subgroups highlights a gap in the current literature, underscoring the need for targeted research. CONCLUSION: The review underscores the necessity of a personalized approach in selecting temporary MCS devices for patients with acute cardiogenic shock, guided by specific patient characteristics and clinical scenarios. Future research should focus on addressing the identified evidence gaps through well-designed studies that provide robust subgroup-specific data, enabling clinicians to optimize treatment strategies and improve patient outcomes in this critical care context.

Thromboembolic complications following implantation of durable left-ventricular assist devices.

INTRODUCTION: As the utilization of left-ventricular assist devices (LVADs) continues to rise and patients experience extended survival duration with these devices, the overall incidence of adverse events and complications has shown a notable increase. Among the major adverse events, thromboembolic complications are particularly significant. The aim of this study is to present our experience and assess the risk of thromboembolic complications after implantation of durable continuous-flow left-ventricular assist devices (CF-LVAD) in patients with end-stage heart failure. PATIENTS AND METHODS: From 2007 to 2022, 169 left ventricular continuous-flow durable mechanical assist devices were implanted at our institute. Three types of devices were employed: HeartMate II (n = 54, 32%), HeartMate 3 (n = 70, 41.4%), and Heart Ware (n = 45, 26.6%). The data were extracted from the EUROMACS register. RESULTS: Thromboembolic complication, pump thrombosis was observed in 11/169 patients (6.5%), with 2 patients experiencing stroke after embolism to the central nervous system. Among these cases, 10 patients (90.9%) were equipped with the Heart Ware device while 1 patient (9.1%) had the Heart Mate II device implanted. Nine patients received the durable device as a bridge to transplant therapy and two as a bridge to candidacy. The overall mean age of the patients was 47.6±10.2 years, with 2 women and 10 men. The pump thrombosis was managed through thrombolytic therapy, high-intensity heparin anticoagulation protocol, pump exchange, pump explantation, and early heart transplant. The combined hospital and long-term mortality rate was 4/11 patients (36.4%). CONCLUSION: Based on our experience, thromboembolic complications presenting primarily as pump thromboses, were a relatively common phenomenon experienced in association with the second-generation continuous-flow devices, but rarely seen with the third-generation devices. Thrombolysis followed by early heart transplantation proved to be a safe treatment option (Tab. 1, Ref. 14). Text in PDF www.elis.sk Keywords: durable mechanical assist device, durable left ventricular assist devices, outcomes, thromboembolic complications.

Outcomes and Complications after Left Ventricular Assist Device Implantation.

BACKGROUND: Heart transplantation is the treatment of choice for selected patients with end-stage heart failure. Persistent donor organ shortage causes a growing demand for mechanical circulatory support not only as a bridge to transplantation but mainly as a destination therapy (DT). METHODS: The aim of the study was to analyze the indications, comorbidities, and complications during the follow-up of all patients undergoing left ventricular assist device (LVAD) implantation with at least 12 months of follow-up time in one of the most experienced clinics in Poland between 2015 and 2023. RESULTS: There were 125 individuals with LVAD implantation, from which 90 had full 12 months of follow-up (85 males - 94%, 5 females - 6%), with a median age of 58 (50.25-63.75) years. The median body mass index was 27.12 (25.27-29.68). The etiology of heart failure was ischemic (n = 44, 49%), dilated cardiomyopathy (n = 44, 49%), and others. Preoperative echocardiography revealed a mean LV ejection fraction of 13.8% and a median LV dimension of 7.55 (6.92-8.2) cm. In 61 patients (68%), imaging confirmed pulmonary hypertension. Thirty-four patients (38%) had diabetes and 16 (18%) were active smokers. Median follow-up was 30 (17.25-42) months, with the longest period being about 82 months. 40 (44%) patients had kidney failure before LVAD implantation, and in 43 cases (48%), we observed relevant, transient deterioration of kidney function. Almost all patients (n = 82, 91%) suffered from anemia (Hb <13 g/dL in males and <12 g/dL in females) in different periods after LVAD implantation due to perioperative bleeding, gastrointestinal bleeding or unknown causes. The lowest Hb level was observed in the first week after LVAD implantation in 53 cases (58%). Median red cell concentrate transfusion demand before the discharge after surgery was 6 (2-8, 5) units. CONCLUSIONS: Appropriate selection of candidates and timing of LVAD implantation are critical for improved outcomes of DT. Anemia and kidney failure are the most frequent follow-up complications. Improved results and increased applicability and durability of LVADs have established this treatment option as an excellent alternative for patients with end-stage heart failure.

Driveline Infection in Patients With Left Ventricular Assist Devices Implanted as Destination Therapy.

BACKGROUND: Donor organ shortages cause increasing demand for mechanical circulatory support in patients with end-stage heart failure not only as a bridge to heart transplantation but mainly as a destination therapy. Improved results and increased applicability and durability of left ventricular assist devices (LVADs) have established this treatment option as an alternative to heart transplantation in selected patients. One of the most common complications after LVAD implantation is driveline infections (DLIs). METHODS: This study aimed to expand the understanding of DLI epidemiology and potential changes in implantation techniques regarding optimizing DLI prevention and treatment among all patients undergoing LVAD (Medtronic's Heartware HVAD and HeartMate 3 Abbott LVAD system) implantation with at least 12 months of follow-up time between 2015 and 2022. RESULTS: There were 120 individuals with LVAD implantation, of whom 90 had 12 months of follow-up (85 men [94%], 5 women [6%]) with a median age of 58 years (50.25-63.75). The median body mass index was 27.12 kg/m2 (25.27-29.68). Of the 90 patients, 43 had ischemic heart failure (48%), 43 had dilated cardiomyopathy (48%), and the remaining 3 had other etiologies (3%), such as postinflammatory, and the remaining 1 had congenital heart defect (1%). Preoperative echocardiography revealed a mean left ventricle ejection fraction of 13.8% and a median left ventricle dimension of 7.55 cm (6.92-8.2). Imaging confirmed pulmonary hypertension in 61 patients (68%). Thirty-four of the 90 patients had diabetes (38%), and 16 were active smokers (18%). Median follow-up was 30 months (17.25-42), with the longest period being 82 months. More than half of the patients (n = 52; 57%) experienced a DLI. The median time to the first episode of DLI was 13 months (6-25). The most common pathogen revealed in wound swab culture was methicillin-sensitive Staphylococcus aureus (n = 23; 44%), Pseudomonas aeruginosa (n = 9; 17%), Proteus mirabilis (n = 4; 7%), and others. We observed that deeper driveline implantation below the left rectus muscle and just above the posterior rectus sheath resulted in fewer DLIs and longer free-from-DLI follow-up time. There was no statistically significant difference in DLI frequency between patients with or without diabetes mellitus. CONCLUSIONS: Appropriate selection of candidates and timing of LVAD implantation are critical for improved outcomes of destination therapy. DLI is the most common complication after LVAD implantation. Optimal surgical techniques and early implementation of targeted antibiotics are crucial. Significant challenges remain in optimizing DLI prevention and treatment.

Mechanical circulatory support in patients with congenital heart disease: a European Registry for Patients with Mechanical Circulatory Support (EUROMACS) study.

OBJECTIVES: This study aims to explore characteristics and clinical outcomes of patients with congenital heart disease (CHD) in the European Registry for Patients with Mechanical Circulatory Support (EUROMACS). METHODS: This is a retrospective study of EUROMACS participants receiving MCS as bridge-to-transplant, possible bridge-to-transplant, or rescue therapy/bridge-to-recovery from 2011 to 2023 (n = 5340). Adult and paediatric cohorts were analysed separately. The primary outcome was mortality on MCS; secondary outcomes included recovery, transplant and complications including bleeding, cerebrovascular events, and sepsis. RESULTS: Among adult patients, mortality at 1-year was 33.3% among the CHD cohort vs 22.1% in the non-CHD cohort. Adult CHD patients had higher hazards of mortality within the first year after MCS implantation [hazard ratios 1.98, 95% confidence interval (CI) 1.35-2.91, P < 0.001] and bleeding events (subdistribution hazard ratios 2.10, 95% CI 1.40-3.16, P < 0.001) compared with non-CHD patients. Both associations remained significant after accounting for multiple mediators. Among paediatric patients, mortality at 1 year was 22.1% in the CHD cohort vs 17.3% in the non-CHD cohort (hazard ratios 1.39, 95% CI 0.83-2.32, P = 0.213). CONCLUSIONS: Adult and paediatric patients with CHD on MCS have higher adverse event risk compared with non-CHD MCS patients, though children did not have greater risk of mortality. As the number of CHD patients requiring advanced heart failure management continues to grow, these findings can enhance informed decision-making. CLINICAL TRIAL REGISTRATION NUMBER: Registry name: EUROMACS.

Transvenous Lead Extraction in the Left Ventricular Assist Device Patient.

The population of patients with advanced heart failure continues to increase steadily as does the need for mechanical circulatory support. Combination therapy with left ventricular assist devices (LVADs) and cardiovascular implantable electronic devices (CIEDs) is unavoidable. CIED complications in patients with LVADs are common and often necessitate device system revision and transvenous lead extraction. Despite this, management recommendations are limited, and guidelines are lacking.

Atrial fibrillation increases thrombogenicity of LVAD therapy.

BACKGROUND: This study investigates the hypothesis that presence of atrial fibrillation (AF) in LVAD patients increases thrombogenicity in the left ventricle (LV) and exacerbates stroke risk. METHODS: Using an anatomical LV model implanted with an LVAD inflow cannula, we analyze thrombogenic risk and blood flow patterns in either AF or sinus rhythm (SR) using unsteady computational fluid dynamics (CFD). To analyze platelet activation and thrombogenesis in the LV, hundreds of thousands of platelets are individually tracked to quantify platelet residence time (RT) and shear stress accumulation history (SH). RESULTS: The irregular and chaotic mitral inflow associated with AF results in markedly different intraventricular flow patterns, with profoundly negative impact on blood flow-induced stimuli experienced by platelets as they traverse the LV. Twice as many platelets accumulated very high SH in the LVAD + AF case, resulting in a 36% increase in thrombogenic potential score, relative to the LVAD + SR case. CONCLUSIONS: This supports the hypothesis that AF results in unfavorable blood flow patterns in the LV adding to an increased stroke risk for LVAD + AF patients. Quantification of thrombogenic risk associated with AF for LVAD patients may help guide clinical decision-making on interventions to mitigate the increased risk of thromboembolic events.

Microaxial Flow Pump or Standard Care in Infarct-Related Cardiogenic Shock.

BACKGROUND: The effects of temporary mechanical circulatory support with a microaxial flow pump on mortality among patients with ST-segment elevation myocardial infarction (STEMI) complicated by cardiogenic shock remains unclear. METHODS: In an international, multicenter, randomized trial, we assigned patients with STEMI and cardiogenic shock to receive a microaxial flow pump (Impella CP) plus standard care or standard care alone. The primary end point was death from any cause at 180 days. A composite safety end point was severe bleeding, limb ischemia, hemolysis, device failure, or worsening aortic regurgitation. RESULTS: A total of 360 patients underwent randomization, of whom 355 were included in the final analysis (179 in the microaxial-flow-pump group and 176 in the standard-care group). The median age of the patients was 67 years, and 79.2% were men. Death from any cause occurred in 82 of 179 patients (45.8%) in the microaxial-flow-pump group and in 103 of 176 patients (58.5%) in the standard-care group (hazard ratio, 0.74; 95% confidence interval [CI], 0.55 to 0.99; P = 0.04). A composite safety end-point event occurred in 43 patients (24.0%) in the microaxial-flow-pump group and in 11 (6.2%) in the standard-care group (relative risk, 4.74; 95% CI, 2.36 to 9.55). Renal-replacement therapy was administered to 75 patients (41.9%) in the microaxial-flow-pump group and to 47 patients (26.7%) in the standard-care group (relative risk, 1.98; 95% CI, 1.27 to 3.09). CONCLUSIONS: The routine use of a microaxial flow pump with standard care in the treatment of patients with STEMI-related cardiogenic shock led to a lower risk of death from any cause at 180 days than standard care alone. The incidence of a composite of adverse events was higher with the use of the microaxial flow pump. (Funded by the Danish Heart Foundation and Abiomed; DanGer Shock ClinicalTrials.gov number, NCT01633502.).

Management of incessant ventricular arrhythmias in a patient with left ventricular assist device: a case report.

BACKGROUND: The implantation of left ventricular assist devices (LVADs) as a bridge to transplantation or as destination therapy in end-stage heart failure patients is frequently complicated by the emergence of ventricular arrhythmias (VAs). These arrhythmias have been implicated in precipitating deleterious clinical outcomes, increased mortality rates and augmented healthcare expenditures. CASE PRESENTATION: We present a challenging case of a 49-year-old male with a history of dilated cardiomyopathy who received an LVAD. Post-implantation, the patient suffered from intractable VAs, leading to multiple rehospitalizations and hemodynamic deterioration. Despite exhaustive medical management and electrical cardioversion attempts, the patient's VAs persisted, ultimately necessitating prioritization for cardiac transplantation. DISCUSSION: This case highlights the challenges in managing VAs in LVAD patients and the importance of multidisciplinary collaboration. While pharmacological intervention is the initial strategy, catheter ablation may be considered in selected cases when medication is insufficient. In instances of intractable VAs, expeditious listing for heart transplantation as a high-priority candidate is advisable when feasible.

Outcomes of outflow graft stenting in HeartMate 3 left ventricular assist devices: A systematic review and individual patient data meta-analysis.

PURPOSE: LVAD outflow graft stenosis continues to remain prevalent with a high complication rate. We sought to pool the existing evidence on indications, utilization patterns, and outcomes of transcatheter interventions for outflow graft stenosis in the HeartMate 3 LVAD. METHODS: An electronic search was performed to identify all studies in the English literature reporting on HeartMate 3 LVAD outflow graft stenting. Patient-level data were extracted for analysis. RESULTS: Thirteen published reports and one unpublished case comprising a total of 28 patients were included. Median patient age was 68.5 years [Interquartile range: 58, 71] and 25.9% (7/27) were female. Dyspnea [60.7% (17/28)] was the most common presenting symptom. Low flow alarms were present in 60% (15/25) of patients. Findings included external compression [35.7% (10/28)], graft twist [21.4% (6/28)], graft twist and external compression [14.3% (4.28)], intraluminal thrombus [10.7% (3/28)], graft twist and intraluminal thrombus [3.6% (1/28)], and pseudoaneurysm of outflow graft [3.6% (1/28)]. Median time from LVAD implantation to stenting was 2.1 years [1.4, 3]. Immediate flow normalization after stenting was observed in 85.7% (24/28). The 30-day mortality was 12% (3/25). Overall mortality was 12% (3/25) at a median follow-up of 3.9 months [1, 17]. CONCLUSION: Outflow graft stenting in the HeartMate 3 LVAD appears to be a reasonable treatment option for outflow graft stenosis, with low overall rates of complications and mortality. Further refinement of indications and approaches may improve outcomes.

Evaluation of cardiac arrhythmia in pediatric patients with Left Ventricular Assist Device (L-VAD).

OBJECTIVE: Pediatric heart failure is an important cause of morbidity and mortality in childhood. Left ventricular assist devices (L-VAD) are used for bridging to transplantation in patients with indications for heart transplantation. PATIENTS AND METHODS: The children included in the study were patients who underwent implantation of an L-VAD due to advanced heart failure at Ege University Faculty of Medicine Hospital between January 2009 and January 2023. RESULTS: Of the 33 patients who underwent L-VAD implantation, 16 (48.5%) were female and 17 (51.5%) were male. The median age at surgery was 13 years (IQR, 9.5-15). The median weight was 44 kg (IQR, 25.65-52), the median height was 158 cm (IQR, 134.5-168.5), and the median body surface area was 1.37 m2 (IQR, 0.95-1.51). All patients who underwent L-VAD implantation had an echocardiographic diagnosis of dilated cardiomyopathy. The patients underwent a median of 16 (IQR, 9-21) ECGs, and the median number of 24-hour Holter ECGs obtained was 3 (IQR, 2-5). Arrhythmias that occurred after L-VAD implantation were classified as atrial and ventricular. Ventricular arrhythmia included ventricular tachycardia (VT) lasting for more than 30 seconds (sustained VT), VT lasting for less than 30 seconds (nonsustained VT), and ventricular fibrillation. Atrial arrhythmias included atrial flutter, atrial fibrillation, supraventricular tachycardia, and atrial ectopic tachycardia. During the follow-up, atrial or ventricular arrhythmias were observed in 11 (33%) patients. The most common rhythm disturbances before L-VAD implantation were ventricular arrhythmias, while after the surgery, atrial arrhythmias were found to be the most frequent. A total of 5 patients underwent cardioversion (n=2) or defibrillation (n=3) due to arrhythmia. CONCLUSIONS: In patients undergoing L-VAD implantation, rhythm disorders that could normally lead to hemodynamic instability are frequently encountered. In these rhythm disorders, medical therapy should be attempted before resorting to cardioversion or defibrillation, and subsequently, more aggressive treatment methods should be considered.

Plastic Surgery Involvement With Surgical Management of Infected Ventricular Assist Devices Decreased Lifetime Return to Operating Room and 90-Day Infectious Complications.

BACKGROUND: The use of left ventricular assist devices (LVADs) for patients with end-stage cardiac failure awaiting heart transplantation has become increasingly common. However, ventricular assist device-related infections remain a major problem complicating their long-term use. Retrospective review has previously shown a decrease in lifetime return to operating room (RTOR) with no change in 90-day complications when a muscle or omental flap is used for coverage after washout for infection. We wished to determine if early plastic surgery intervention led to a decreased length of stay for these patients. METHODS: Patients with LVAD readmitted for LVAD infection at a single institution from 2008 to 2021 were identified using a preexisting database. Patients were followed retrospectively for an average of 3.2 years. Patient demographics, preoperative diagnosis/disease state, type of ventricular assist device inserted, postoperative day of ventricular assist device infection onset, definitive device coverage, timing of coverage procedure after the initial washout for infection, type of flap used for coverage, 90-day complications after definitive coverage, and lifetime return to operating room for infection were reviewed. Comparison analysis with χ2 and analysis of variance testing was used to analyze outcomes. RESULTS: Of 568 patients admitted with an LVAD infection, 104 underwent operative debridement and closure by plastic and reconstructive surgery (PRS) or cardiothoracic surgery (CTS). Fifty-three underwent PRS closure, and 51 underwent CTS closure. There was an increased incidence of diabetes among the PRS group (P < 0.001); otherwise, there was no difference in baseline characteristics. There was increased RTOR over a lifetime with CTS closure compared with PRS (P = 0.03) and increased 90-day risk of infection (P = 0.007). Patients with PRS closure had an increased risk of postoperative hematoma (P = 046). Plastic and reconstructive surgery was typically consulted on hospital day 10. Both PRS and CTS closure patients were discharged on postoperative day 7, on average (P = 0.542). CONCLUSIONS: Plastic surgery involvement with surgical decision making and closure of infected LVAD devices has a decrease in lifetime RTOR and decreased 90-day complications related to infections. There may be a benefit to earlier PRS consultation for coverage assessment.

Durable left ventricular assist device explantation following recovery in paediatric patients: Determinants and outcome after explantation.

OBJECTIVES: Myocardial recovery in children supported by a durable left ventricular assist device is a rare, but highly desirable outcome because it could potentially eliminate the need for a cardiac transplant and the lifelong need for immunosuppressant therapy and the risk of complications. However, experience with this specific outcome is extremely limited. METHODS: All patients < 19 years old supported by a durable left ventricular assist device from the European Registry for Patients with Mechanical Circulatory Support database were included. Participating centres were approached for additional follow-up data after explantation. Associated factors for explantation due to myocardial recovery were explored using Cox proportional hazard models. RESULTS: The incidence of recovery in children supported by a durable left ventricular assist device was 11.7% (52/445; median duration of support, 122.0 days). Multivariable analyses showed body surface area (hazard ratio 0.229; confidence interval 0.093-0.565; P = 0.001) and a primary diagnosis of myocarditis (hazard ratio 4.597; confidence interval 2.545-8.303; P < 0.001) to be associated with recovery. Left ventricular end-diastolic diameter in children with myocarditis was not associated with recovery. Follow-up after recovery was obtained for 46 patients (88.5%). Sustained myocardial recovery was reported in 33/46 (71.7%) at the end of the follow-up period (28/33; >2 year). Transplants were performed in 6/46 (11.4%) (in 5 after a ventricular assist device was reimplanted). Death occurred in 7/46 (15.2%). CONCLUSIONS: Myocardial recovery occurs in a substantial portion of paediatric patients supported with durable left ventricular assist devices, and sustainable recovery is seen in around three-quarters of them. Even children with severely dilated ventricles due to myocarditis can show recovery. Clinicians should be attentive to (developing) myocardial recovery. These results can be used to develop internationally approved paediatric weaning guidelines.

Echocardiography in the Recognition and Management of Mechanical Complications of Acute Myocardial Infarction.

PURPOSE OF REVIEW: Although rare, the development of mechanical complications following an acute myocardial infarction is associated with a high morbidity and mortality. Here, we review the clinical features, diagnostic strategy, and treatment options for each of the mechanical complications, with a focus on the role of echocardiography. RECENT FINDINGS: The growth of percutaneous structural interventions worldwide has given rise to new non-surgical options for management of mechanical complications. As such, select patients may benefit from a novel use of these established treatment methods. A thorough understanding of the two-dimensional, three-dimensional, color Doppler, and spectral Doppler findings for each mechanical complication is essential in recognizing major causes of hemodynamic decompensation after an acute myocardial infarction. Thereafter, echocardiography can aid in the selection and maintenance of mechanical circulatory support and potentially facilitate the use of a percutaneous intervention.

A multi-constituent model for assessing the effect of impeller shroud on the thrombosis potential of a centrifugal blood pump.

Centrifugal blood pumps can be used for treating heart failure patients. However, pump thrombosis has remained one of the complications that trouble clinical treatment. This study analyzed the effect of impeller shroud on the thrombosis risk of the blood pump, and predicted areas prone to thrombosis. Multi-constituent transport equations were presented, considering mechanical activation and biochemical activation. It was found that activated platelets concentration can increase with shear stress and adenosine diphosphate(ADP) concentration increasing, and the highest risk of thrombosis inside the blood pump was under extracorporeal membrane oxygenation (ECMO) mode. Under the same condition, ADP concentration and thrombosis index of semi-shroud impeller can increase by 7.3% and 7.2% compared to the closed-shroud impeller. The main reason for the increase in thrombosis risk was owing to elevated scalar shear stress and more coagulation promoting factor-ADP released. The regions with higher thrombosis potential were in the center hole, top and bottom clearance. As a novelty, the findings revealed that impeller shroud can influence mechanical and biochemical activation factors. It is useful for identifying potential risk regions of thrombus formation based on relative comparisons.